Onsite Sewage Treatment and Disposal Systems 

Evaluation for Nutrient Removal 

Interim Report

Submitted to Florida Department of Environmental Protection

Submitted by

Dr. Ni-Bin Chang, Dr. Marty Wanielista, Dr. Ammarin Daranpob 

Fahim Hossain, Zhemin Xuan, Junna Miao, Sha Liu, 

Zachary Marimon, Shalimar Debusk 

Stormwater Management Academy

University of Central Florida

January 7, 2010 

This project was funded by an Urban Nonpoint Source Research Grant from the Bureau of 

Watershed Restoration, Florida Department of Environmental Protection. 
ii

Table of Contents

Executive Summary..................................................................................................................................................... 1

Chapter 1: Introduction.............................................................................................................................................. 5

1.1 Objectives..................................................................................................................................................... 5

1.2 Nutrient Impact Resulting from Conventional On-site Wastewater Treatment ........................................... 7

1.3 Passive On-site Wastewater Treatment......................................................................................................10

1.4 Current Regulation of Water Quality and OSTDS Standards....................................................................10

1.5 NSF 245 Standard ......................................................................................................................................11

Chapter 2 Alternatives to Conventional OSTDS ....................................................................................................13

2.1 UCF OSTDS Testing Center......................................................................................................................13

2.1.1 Introduction to UCF Field-scale Test Center..............................................................................................13

2.1.2 Influent conditions......................................................................................................................................15

2.2 Nutrient removal mechanism and sorption media......................................................................................15

2.2.1Nutrient removal mechanism.......................................................................................................................15

2.2.2 Sorption media............................................................................................................................................17

2.3 Bold & GoldTM (B&G) drain field with sorption media.............................................................................19

2.4 Upflow wetlands with sorption media and plant species ...........................................................................21

2.4.1 Upflow wetlands design with sorption media............................................................................................21

2.4.2 Wetland plant species................................................................................................................................. 22

2.5 Conventional septic system with recirculation tank..................................................................................25

Chapter 3 Conventional Passive On-Site Wastewater Treatment System with Ground Water Impacts..........28

3.1 Conventional drain field.............................................................................................................................28

3.2 Conventional drain field with a recirculation tank .....................................................................................28

3.2 Ground water quality impact below the conventional OSTDS ................................................................. 28

Chapter 4 Passive On-Site Wastewater Treatment System with Bold & GoldTM Drain Field ...........................33

4.1 System design of Bold & GoldTM drain field .............................................................................................33

4.2 B&G drain field removal efficiency...........................................................................................................35

4.3 B&G drain field effluent concentrations...................................................................................................35

Chapter 5 Passive On-Site Wastewater Treatment System with Subsurface Upflow Wetland (SUW) and 

Sorption Media ..........................................................................................................................................................38

5.1 System design of subsurface upflow wetland (SUW) with sorption media ...............................................38

5.2 SUW removal efficiency............................................................................................................................41

5.3 SUW effluent concentrations.....................................................................................................................41
Onsite Sewage Treatment and Disposal Systems 

Evaluation for Nutrient Removal 

Interim Report

Submitted to Florida Department of Environmental Protection

Submitted by

Dr. Ni-Bin Chang, Dr. Marty Wanielista, Dr. Ammarin Daranpob 

Fahim Hossain, Zhemin Xuan, Junna Miao, Sha Liu, 

Zachary Marimon, Shalimar Debusk 

Stormwater Management Academy

University of Central Florida

January 7, 2010 

This project was funded by an Urban Nonpoint Source Research Grant from the Bureau of 

Watershed Restoration, Florida Department of Environmental Protection. 
ii

Table of Contents

Executive Summary..................................................................................................................................................... 1

Chapter 1: Introduction.............................................................................................................................................. 5

1.1 Objectives..................................................................................................................................................... 5

1.2 Nutrient Impact Resulting from Conventional On-site Wastewater Treatment ........................................... 7

1.3 Passive On-site Wastewater Treatment......................................................................................................10

1.4 Current Regulation of Water Quality and OSTDS Standards....................................................................10

1.5 NSF 245 Standard ......................................................................................................................................11

Chapter 2 Alternatives to Conventional OSTDS ....................................................................................................13

2.1 UCF OSTDS Testing Center......................................................................................................................13

2.1.1 Introduction to UCF Field-scale Test Center..............................................................................................13

2.1.2 Influent conditions......................................................................................................................................15

2.2 Nutrient removal mechanism and sorption media......................................................................................15

2.2.1Nutrient removal mechanism.......................................................................................................................15

2.2.2 Sorption media............................................................................................................................................17

2.3 Bold & GoldTM (B&G) drain field with sorption media.............................................................................19

2.4 Upflow wetlands with sorption media and plant species ...........................................................................21

2.4.1 Upflow wetlands design with sorption media............................................................................................21

2.4.2 Wetland plant species................................................................................................................................. 22

2.5 Conventional septic system with recirculation tank..................................................................................25

Chapter 3 Conventional Passive On-Site Wastewater Treatment System with Ground Water Impacts..........28

3.1 Conventional drain field.............................................................................................................................28

3.2 Conventional drain field with a recirculation tank .....................................................................................28

3.2 Ground water quality impact below the conventional OSTDS ................................................................. 28

Chapter 4 Passive On-Site Wastewater Treatment System with Bold & GoldTM Drain Field ...........................33

4.1 System design of Bold & GoldTM drain field .............................................................................................33

4.2 B&G drain field removal efficiency...........................................................................................................35

4.3 B&G drain field effluent concentrations...................................................................................................35

Chapter 5 Passive On-Site Wastewater Treatment System with Subsurface Upflow Wetland (SUW) and 

Sorption Media ..........................................................................................................................................................38

5.1 System design of subsurface upflow wetland (SUW) with sorption media ...............................................38

5.2 SUW removal efficiency............................................................................................................................41

5.3 SUW effluent concentrations.....................................................................................................................41
iii

Chapter 6 Passive On-Site Wastewater Treatment System with Sorption Media-Based Recirculation Tank..45

6.1 System design of recirculation tank with sorption media...........................................................................45

6.2 Performance of conventional OSTDS and recirculation tank with Citrus sand (Recirculation I).............46

6.3 Performance of Conventional OSTDS and recirculation tank with coarse sand (Recirculation II) ...........49

6.4 Performance of conventional OSTDS and recirculation tank with coarse sand (Recirculation III)...........51

Chapter 7 Performance-based Evaluation of Three Conventional OSTDS with B&G and SUW Designs.......55

7.1 Comparison of removal efficiencies..........................................................................................................55

7.2 Removing rate per unit area of drain field ................................................................................................. 57

7.3 Comparison of effluent concentrations ......................................................................................................58

Chapter 8 Conclusions ..............................................................................................................................................63

8.1 Summary and remarks...............................................................................................................................63

8.2 Ground water impacts from conventional drain field.................................................................................64

8.3 Cost analyses..............................................................................................................................................64

8.4 Certification and commercialization .........................................................................................................66

8.5 Future work...............................................................................................................................................66

References ..................................................................................................................................................................68
73

Servizi, J. A. and G ordon, R . W. (2005). Acute l ethal t oxicity o f am monia an d s uspended 

sediment m ixtures t o c hinook s almon ( Oncorhynchus tshawytscha). B ulletin of 

Environmental Contamination and Toxicology 44(4), 650-656. 

Shin, H. S., Yoo, K. S., and Park, J. K. (1999). Removal of polychlorinated phenols in sequential 

anaerobic-aerobic bi ofilm r eactors pa cked with t ire c hips, Water Environment Research, 

71(3), 363-367. 

Smith, D . P ., O tis, R ., and F lint, M . ( 2008). F lorida pa ssive ni trogen removal s tudy ( Final 

report), Florida Department of Health, Tallahassee, Florida. 

Steer, D., Fraser, L., Boddy, J., and Seibert, B., (2002). Efficiency of small constructed wetlands 

for subsurface treatment of single-family domestic effluent. Ecological Engineering 18, 429–

440. 

Tanaka, N., Jinadasa, K. B. S. N., Werellagama, D. R. I. B., Mowjood, M. I. M., and Ng, W. J. 

(2006). C onstructed t ropical w etlands w ith i ntegrated s ubmergent-emergent p lant f or 

sustainable water quality management. Journal of Environmental Science and Health Part A, 

41, 2221–2236. 

Tarazona, J . V ., M unoz, M . J., O rtiz, J. A ., N unez, M . O ., a nd C amargo, J . A . ( 2008). Fish 

mortality due to acute ammonia exposure. Aquaculture Research, 18(2), 167-172. 

Tee, H .C., S eng, C .E., N oor, A . M d., a nd Lim, P . E . ( 2009). P erformance c omparison of 

constructed w etlands w ith g ravel- and r ice h usk-based m edia f or ph enol a nd ni trogen 

removal. Science of the Total Environment 407 (11), 3563-3571. 

Turner Building C ost I ndex. ( 2009). ( An i ndex ba sed on l abor a nd m aterial c osts). 

http://www.turnerconstruction.com/Uploads/Documents/4thQtr2009.pdf 

U.S. Environmental Protection Agency (USEPA) (2002). USEPA Onsite Wastewater Treatment 

Systems Manual, EPA/625/R-00/008, O ffice of Research and D evelopment, W ashing t on 

DC, USA. 

United S tates E nvironmental P rotection A gency ( USEPA) ( 1988). Design manual-constructed 

wetlands and aquatic plant systems for municipal wastewater treatment, EPA/525/1-88/022, 

US E nvironmental P rotection A gency, C enter for E nvironmental R esearch Information, 

Cincinnati, OH. 
74

United S tates E nvironmental Protection A gency ( USEPA) ( 2005). Handbook for Managing 

Onsite and Clustered (Decentralized) Wastewater Treatment Systems. E PA 832 -B-05-001, 

Washington DC, USA. 

Urynowicz, M . A., B oyle, W . C ., B edessem, M. E . a nd J in, S . ( 2007). N itrogen r emoval i n 

recirculation s and filter s ystems w ith up flow a naerobic c omponents, Journal of 

Environmental Engineering, ASCE 133(5), 464-470. 

Venhuizen, D ( 1998). S and f ilter/Drip i rrigation s ystems s olve w ater r esources p roblems, i n 

proceedings of the Eighth National Symposium on Individual and Small Community Sewage 

systems, American Society of Agricultural Engineers, St. Joseph, USA. 

Vohla, C ., A las, R ., N urk, K ., B aatz, S . a nd Mander, U . (2007). Dynamics of phos phorus, 

nitrogen and carbon removal in a horizontal subsurface flow constructed wetland. Science of 

The Total Environment 380(1-3), 66-74. 

Vymazal, J. (2009). The use constructed wetlands with horizontal sub-surface flow for various 

types of wastewater. Ecological Engineering 35,1-17. 

Wanielista, M ., C hang, N . B ., a nd M akkeasorn, A . ( 2008). P rovisional P atent: “ Passive 

Underground D rainfield f or S eptic T ank N utrient R emoval U sing S pecial F unctionalized 

Green Filtration Media. Atty. Docket No: UCF-663. US Patent filed for review. 

Wanielista, M., Baldassari, T, Ryan, P., Rivera, B., Shah, T., and Stuart, E. (2008). Feasibility 

Study of Waste Tire Use in Pollution Control for Stormwater Management, Drainfields and 

Water Conservation in Florida. Seminole County Florida and State DEP. 

Water Environment Federation (WEF) and American Society of Civil Engineers (ASCE) (2005). 

Biological nut rient r emoval ( BNR) ope ration i n w astewater t reatment pl ants, M anual of 

practice no. 30, WEF press and McGraw Hill Publishing, USA

World Health Organization (WHO) (2003). Guidelines for d rinking water quality, 3 rd edition, 

Geneva, Switzerland.

Xuan, Z., C hang, N . B., D aranpob, A ., a nd W anielista, M . 2009. Initial test o f a subsurface 

constructed wetland w ith green sorption media f or nutrient removal i n on-site wastewater 

treatment systems. Water Quality, Exposure and Health, Doi: 10.1007/s12403-009-0015-6. 

Zhang, T. C. (2002). Nitrate removal in sulfur: limestone pond reactor, Journal of Environmental 

Engineering, ASCE, 128(1), 73-84. 
iii

Chapter 6 Passive On-Site Wastewater Treatment System with Sorption Media-Based Recirculation Tank..45

6.1 System design of recirculation tank with sorption media...........................................................................45

6.2 Performance of conventional OSTDS and recirculation tank with Citrus sand (Recirculation I).............46

6.3 Performance of Conventional OSTDS and recirculation tank with coarse sand (Recirculation II) ...........49

6.4 Performance of conventional OSTDS and recirculation tank with coarse sand (Recirculation III)...........51

Chapter 7 Performance-based Evaluation of Three Conventional OSTDS with B&G and SUW Designs.......55

7.1 Comparison of removal efficiencies..........................................................................................................55

7.2 Removing rate per unit area of drain field ................................................................................................. 57

7.3 Comparison of effluent concentrations ......................................................................................................58

Chapter 8 Conclusions ..............................................................................................................................................63

8.1 Summary and remarks...............................................................................................................................63

8.2 Ground water impacts from conventional drain field.................................................................................64

8.3 Cost analyses..............................................................................................................................................64

8.4 Certification and commercialization .........................................................................................................66

8.5 Future work...............................................................................................................................................66

References ..................................................................................................................................................................68
iv

List of Figures

Figure 1 A simple layout of OSTDS at UCF test center..............................................................................................14

Figure 2 Schematic of the B&G Drain Field (Wanielista et al., 2008). Numbers refer to sampling points in the 

treatment train. ..............................................................................................................................................20

Figure 3 Configuration of septic tank followed by a 4-cell wetland system including a shut-off valve, a cleanout, and 

a flow meter...................................................................................................................................................25

Figure 4 Schematic flow and sampling diagrams of the UCF conventional OSTDS with RSF..................................27

Figure 5 Ground water monitoring wells are located around experimental site at UCF..............................................30

Figure 6 Ammonia concentrations in the ground water under UCF test site...............................................................31

Figure 7 Nitrate-N concentrations in the ground water under UCF test site................................................................31

Figure 8 Soluble Reactive Phosphorus (SRP) concentrations in the ground water under UCF test site......................32

Figure 9 Tracking of nitrogen species in the B&G OSTDS system shows nitrification process in aerobic layer, and 

denitrification process in the anaerobic layer. ...............................................................................................34

Figure 10 Relationship between influent DO and effluent nitrate-N...........................................................................34

Figure 11 Overall septic and B&G drain field removal efficiency..............................................................................35

Figure 12 Effluent TSS and CBOD5 of B&G drain field. ...........................................................................................36

Figure 13 Effluent nitrogen of B&G drain field. ........................................................................................................36

Figure 14 Effluent phosphorus of B&G drain field. ....................................................................................................36

Figure 15 Effluent bacteria of B&G drain field...........................................................................................................37

Figure 16 Plant species selected in the study: (a) Canna; (b) Blue flag; (c) Bulrush..................................................40

Figure 17 SUW with green sorption media design.....................................................................................................40

Figure 18 A summary of overall removal efficiencies of septic tank and SUW..........................................................41

Figure 19 Effluent TSS of SUW.................................................................................................................................42

Figure 20 Effluent CBOD5 of SUW............................................................................................................................42

Figure 21 Effluent nitrogen concentration in SUW....................................................................................................43

Figure 22 Effluent phosphorus concentration in SUW...............................................................................................43

Figure 23 Bacteria counts in SUW effluent.................................................................................................................43

Figure 24 Schematic and design of green sorption media inside the recirculation filter tank. ....................................46
v

Figure 25 A summary of removal efficiency of the conventional OSTDS Recirculation I with Astatula sand in the 

recirculation tank shows comparisons of two drain field systems. The hatched bars represent the OSTDS 

with Astatula sand drain field. The solid bars represent the OSTDS with Wash Builder’s sand drain field.

.....................................................................................................................................................................47

Figure 26 Conventional OSTDS effluent concentration of Recirculation I at S7 in Astatula sand drain field and S10 

in Washed Builder’s sand drain field shows low TSS, CBOD5, and bacteria levels. ..................................48

Figure 27 Conventional OSTDS effluent concentration of Recirculation I at S7 in Astatula sand drain field and S10 

in Washed Builder’s sand drain field of Recirculation I shows moderate levels of nitrogen and 

phosphorus...................................................................................................................................................48

Figure 28 A summary of overall removal efficiency of the conventional OSTDS Recirculation II with very coarse 

sand in the recirculation tank shows comparisons of two drain field systems. The hatched bars represent 

the OSTDS with Astatula sand drain field. The solid bars represent the OSTDS with Wash Builder’s sand 

drain field. ...................................................................................................................................................49

Figure 29 Conventional OSTDS effluent concentration of Recirculation II shows very low TSS, CBOD5, and 

bacteria levels. .............................................................................................................................................50

Figure 30 Conventional OSTDS effluent concentration of Recirculation II shows moderate levels of nitrogen and 

phosphorus...................................................................................................................................................50

Figure 31 A summary of overall removal efficiencies of the conventional OSTDS Recirculation III with sorption 

media in the recirculation tank associated with the wash builder’s sand drain field. ..................................52

Figure 32 Conventional OSTDS effluent concentration of Recirculation III at S10 shows low TSS, CBOD5, and 

bacteria levels. .............................................................................................................................................52

Figure 33 Conventional OSTDS effluent concentration of Recirculation III at S10 shows high level of nitrogen, but 

low level of phosphorus...............................................................................................................................53

Figure 34 Tracking of nitrogen species in the conventional OSTDS with sorption media-based recirculation tank. 54

Figure 35 Comparative evaluation of removal efficiencies between conventional OSTDS, B&G system, and SUW 

with Canna in terms of TSS, CBOD5, and bacteria. ....................................................................................56

Figure 36 Nutrient removal efficiencies of the conventional OSTDS using the washed builder’s sand drain field, 

B&G drain field and SUW with Canna plants.............................................................................................56

Figure 37 Nitrogen Species removal rate per unit area for five treatment trains........................................................57

Figure 38 Phosphorus Species removal rate per unit area for five treatment trains.....................................................58

Figure 39 TSS and CBOD5 removal rate per unit area for five treatment trains .........................................................58

Figure 40 Effluent concentrations of nitrogen species in all OSTDS are compared. SUW with Canna plants and 

B&G performed the best..............................................................................................................................59

Figure 41 Phosphorus level in effluents where SUW with Canna plants and B&G performed the best. ...................60

Figure 42 Summary of 1-year average effluent bacteria concentration in all systems. ..............................................60

Figure 43 Effluent concentrations of TSS and CBOD5 of all systems are compared. ................................................61
vi

List of Tables

Table 1 Influent concentration - average and standard deviation ................................................................................15

Table 2 Sorption media used to treat wastewater ........................................................................................................17

Table 3 UCF developed green sorption media ............................................................................................................18

Table 4 Wetland performance throughout the world by different kinds of vegetation................................................24

Table 5 A summary of the experimental settings of conventional passive OSTDS ....................................................28

Table 6 Summary of mean, minimum and maximum values of water quality parameters in the effluent of the B&G 

drain field ......................................................................................................................................................37

Table 7 Summary of wetland plant species .................................................................................................................40

Table 8 A summary of the mean, maximum, and minimum values of all water quality parameters...........................44

Table 9 A summary of sampling locations used to calculate overall removal efficiencies .........................................47

Table 10 A summary of standard deviation of effluents at UCF Test Center.............................................................61

Table 11. A summary of effluent conditions at UCF Test Center. ..............................................................................62

Table 12 A summary of concentration changes for OSTDS at UCF Test Center........................................................63

Table 13. Highest measured concentrations from two sampling wells beneath the conventional OSTDS compared to 

the lowest background levels.......................................................................................................................64

Table 14 Cost comparison between a conventional OSTDS and advanced new passive OSTDS for nutrient removal 

including B&G and SUW designed at 500 gpd (mid-year 2009 basis). ......................................................66
1 

Executive Summary

There are increasing nutrients in many of the ground and surface waters of the State. Higher 

levels of nutrients have resulted in impaired waters. Loss of resource utilization has resulted, 

especially in spring areas. Elevated nutrient levels in ground water and surface water may cause 

public health problems, such as blue baby syndrome, and may impair or destroy environmentally

sensitive ecosystem habitat through algal blooms and eutrophication. Impaired waters and loss 

of resource utilization has resulted in increased cost and loss of recreational opportunities. 

The major causes of these problems are widely acknowledged to be from nonpoint sources 

of pollution, especially those from both urban and rural areas and include conventional septic 

tanks, or onsite sewage treatment and disposal systems (OSTDS). Approximately one-third of 

Florida’s population is served by OSTDS representing about 2.5 million systems (Briggs, Roeder 

et al. 2007). OSTDS systems are currently regulated by the Florida Department of Health 

(FDOH) and in specific nutrient terms, a limiting nitrate level of 10 mg/L is set. However, this 

level is about one order of magnitude too high to protect springs and other water bodies from 

nutrient degradation. Nitrogen compounds cannot be significantly reduced in the conventional 

OSTDS and thus nitrogen levels within ground waters may increase. 

In many Florida aquifers and springs, nitrate concentrations have been increasing with time. 

For 56 Upper Floridian aquifer wells in Marion County, Phelps (2004) measured nitrate 

concentrations of up to 12 mg/L, with a median of 1.2 mg/L, during 2000-2001. For Wakulla 

Springs, Katz (2009) reported that there has been a steady increase in nitrate levels to about 0.9 

mg/L over the past 30 years. The median nitrate levels beneath a Wakulla area conventional 

OSTDS drain field was measured at 19 mg/L. 

Because of the concern for nitrate levels from OSTDS, scientists, engineers, regulators and 

manufacturers in the wastewater treatment industry have developed a wide range of alternative 

technologies designed to address removal of specific nutrients and pathogens from OSTDS. 

Another concern is the use of energy for some of the more advanced performance based systems. 

FDOH has been promoting performance based OSTDS in the Florida Keys and other areas, but 

they are expensive to install and operate and may not always produce a consistent nutrient 
2

reduction. Among OSTDS treatment trains, passive systems are of interest because of their 

consistent nutrient reduction capabilities and relatively low initial and operating cost. 

Within this report are the results of a Florida Department of Environmental Protection 

sponsored research program using three passive OSTDS treatment trains operating at the 

University of Central Florida (UCF) Onsite Wastewater Test Center. The first OSTDS treatment 

train is a conventional design to include a septic tank with and without a media recirculation tank 

and two drain fields in parallel. The drain fields have a different type of sand media. The 

second OSTDS treatment train is a Bold & GoldTM (B&G) drain field with green sorption media. 

The third is a subsurface upflow wetland (SUW) with innovative subsurface hydraulic flow 

patterns, green sorption media and various plant species. 

To obtain the best possible nutrient reduction from the conventional septic tank and drain 

field, a recirculation tank was added to the conventional treatment train at the Test Center. Thus, 

effluent water quality comparisons can be made for the B&G and SUW to the conventional 

system with the best effluent water quality from a conventional system. During a year of 

operation and testing, two alternative passive OSTDSs, namely B&G and SUW with new 

sorption media and flow patterns, have proven to 1) be effective in nutrient reduction, 2) 

maintain operating reliability, and 3) have no energy requirements. All three factors are major 

concerns of any OSTDS application. The newly developed passive technologies, B&G and 

SUW systems, installed at the UCF Test Center underwent an intensive sampling for system 

performance, modeling of the pollutant transport and fate, and an assessment for integration of 

the planning, design, installation, maintenance, and management functions for future 

implementation. Average effluent concentrations of the sorption media B&G and the sorption

media with plants, called SUW, are compared in Table ES-1. The comparison illustrates that the 

nutrient removal effectiveness of the B&G and SUW systems are more effective compared to the 

conventional OSTDS with and without recirculation. Nitrates in particular are less than 10 

mg/L with the B&G and SUW sorption systems. 

Also from ground water measurements below the drain field of the conventional OSTDS, 

elevated nutrient levels were noted. Nitrate nitrogen was as high as 29.9 mg/L. These elevated 

levels beneath the drain field of a conventional OSTDS were also noted beneath the drain fields 

of a conventional OSTDS in the Wakulla basin (Katz, 2009). 
3

Table ES-1 Comparison of average effluent concentrations for two conventional OSTDS and two 

sorption OSTDS namely B&G and SUW 

Conventional DF 

with recirculation

Conventional DF no 

recirculation

B&G 

Sorption 

Drain Field

SUW –

Sorption with 

Canna Plants

CBOD5 (mg/L) 7 1 8 4 

Nitrate-N (mg/L) 29.8 38.9 3.15 0.006

TN (mg/L) 31.1 55.7 12.9 1.96

SRP (mg/L) 6.44 4.73 1.00 0.018

TP (mg/L) 6.78 5.52 1.39 0.096

Fecal (cfu/100mL) 1 1 11 657

E.Coli. 

(cfu/100mL) 1 1 9 7 

Using construction, operating, and unit cost data, B&G and SUW are the least costly for 

nutrient removal as shown in Table ES-2. The cost for conventional OSTDS cannot be 

compared when additional nutrient removal is needed. The cost data are based on a design flow 

rate of 500 gpd. The cost of the conventional, B&G, and SUW are from actual installation 

records while the cost of the performance ones (last two rows in Table ES-2) were estimated 

from previous reports (Mayer and Sherman, 1998). All costs were verified with local OSTDS

installers. The annual operating cost for the conventional and the B&G are based on inspection

and hydraulic repair cost only, which in many situations is zero but assumed equal to $200 for 

this analyses. It should be noted that these costs are highly variable from region to region in our 

State, but the relative cost of each should not change. 

Table ES-2 Cost Comparison (mid-year 2009 basis) of a conventional OSTDS with systems that 

have a higher level of nutrient removal including B&G and SUW and based on a 500 gpd flow 

Construction Cost 

with 20% 

contingency ($)

Annualized 

Construction Cost at 

6% interest rate and 

20 years ($)

Annual 

Operating 

cost ($) 

Unit Cost 

$/1000 gallons

Conventional OSTDS $ 6,920 $ 600 $ 200 $ 4.38

B&G with sorption 

media $ 9,320 $ 810 $ 200 $ 5.53

SUW with sorption 

media and plants $ 10,200 $ 890 $ 400 $ 7.07

Continuous Feed 

Cyclic Reactor & 

Drip Irrigation

$ 18,200 $ 1,590 $ 1,800 $ 18.58

Recirculation Tank & 

Drip Irrigation $ 27,800 $ 2,420 $ 1,850 $ 23.40
4

Based on full scale operation and measurement at the UCF OSTDS Test Center, it is 

recommended that the State of Florida require the implementation of the passive options of a 

green sorption media drain field (B&G) and a subsurface upflow wetland with green sorption 

media and plants (SUW). They both are effective alternatives for reduction of nutrients in 

OSTDS, produce reliable operation, and consume no energy. Furthermore, they have the least 

construction and operation costs relative to others that remove more nutrients than the 

conventional systems. 
5

Chapter 1: Introduction

1.1 Objectives

Aquifer and springs are vulnerable to impacts from anthropogenic activities, especially in 

areas where the aquifer is not confined or only thinly confined, such as throughout much of 

central and north Florida. Nitrate concentrations have increased in the Floridian aquifer and in 

springs since the 1950s, exceeding 1 mg/L in recent years at some springs. As an example, 

Phelps (2004) measured nitrate concentrations of up to 12 mg/L, with a median of 1.2 mg/L, for 

56 Upper Floridian aquifer wells sampled in Marion County during 2000-2001. Elevated 

nutrient levels in ground water may even cause public health problems, such as blue baby 

syndrome, and may impair or destroy environmentally sensitive surface water ecosystems 

through algal blooms and eutrophication. 

Nonpoint sources of pollution are the primary cause of water quality impairment in Florida. 

In addition to agricultural and urban stormwater, some of the impacts on the aquifers, surface 

waters, and springs are coming from septic tanks and their associated drain fields. There are 

more than 2 million septic tanks and drain fields in the State of Florida. When urban regions 

gradually expand due to regional development, centralized sewage collection, treatment, and 

disposal is often unavailable for economic reasons. Thus, decentralized or on-site sewage

treatment and disposal systems (OSTDS) (i.e., septic tank systems) are necessary to protect 

public health. In rural communities, nitrates are contributed from fertilized landscaped areas and 

failed septic tank effluents from residential areas. The most common type of OSTDS is a septic

tank followed by a drain field system, A.K.A. “septic system”. The most significant benefit of 

OSTDS is their cost effectiveness and ease of operation and maintenance. To reduce the impacts 

of OSTDS on ground water, the Florida Department of Health (FDOH) has required 

performance-based OSTDS in the Florida Keys and certain springsheds. However, recent 

experience has shown that these systems are expensive to install, operate, and maintain. 

Additionally, their ability to consistently reduce nutrients is highly variable. Passive nutrient 

removing OSTDS provide the promise of higher levels of nutrient reduction in a cost effective 

and relatively maintenance free manner.
6

Given the need to reduce nitrates and total nitrogen in the springs, surface water, and 

aquifers of Florida, the objectives of this study are to: 

1) Evaluate the removal efficiency of nutrients (nitrogen and phosphorous) associated with 

new passive OSTDS treatment trains and compare to conventional designs. 

2) Document the operation and cost of these systems, and 

3) Document the fate and transport of nutrients in vadose zone and ground water aquifer 

from a conventional drain field. 

In short, the focus of this work is on the development and evaluation of performance-based, 

passive nutrient removing on-site wastewater treatment technologies. Based on previous research 

by the Principal Investigators and an extensive literature review of the myriad of alternative 

technologies available (passive and non passive), three of them are selected for testing. Existing 

and alternative treatment media (natural sand and amendment mixtures) in on-site wastewater 

treatment process are studied, focusing on the use of a filtering device, a subsurface wetland, and 

an innovative passive drain field with soil substitution systems. To verify the cost-effectiveness

and nutrient removal performance, a septic tank with a conventional drain field is used as a 

control for comparative basis. 

Ground water wells are used for monitoring the water quality within the vadose zone and the 

surrounding aquifers. Treatment trains for comparison testing are constructed at University of 

Central Florida (UCF) where the soil and water table conditions are representative of 

environmental settings in much of Florida where OSTDS are used widely. Accordingly, the 

general findings gained in this study are transferable to many communities statewide. 

This research aims at addressing the following critical questions that have not been fully 

answered in the literature:

1) What are effective treatment media for removing nutrients from septic tank effluent? 

2) What are the underlying processes of such treatment media and their associated function, 

effectiveness, and longevity? 

3) What insights are available on how such systems have been designed, installed, 

maintained, controlled, and replaced that may be applicable to on-site sewage treatment?
7

4) What comparative basis can be used when different sorption media are used in passive 

treatment processes and are compared against other treatment trains, such as the use of a 

conventional drain field? 

The research team provided a thorough literature review of possible passive nutrient 

removal treatment media, such as sawdust, zeolites, tire crumb, decayed vegetation, and 

spodosols etc, and developed recommendations for on-site applications. The project thus focuses 

on clarifying these four questions through full scale testing. The following chapters of this report 

explain the facilities operational scenarios, sampling scheme, modeling analysis, monitoring 

results, and cost assessment separately and in great detail.

OSTDS have been constructed, operated, and monitored at the UCF Test Center since spring 

2008. There are three treatment technologies. The first treatment technology consists of a septic 

tank, a recirculation tank, and two types of conventional drain fields in parallel to allow testing 

of two differing types of sand to be arranged with the same influent. The first drain field uses 

washed builder’s sand as its filtrating media while the second drain field design uses Astatula 

(citrus grove sand). The second treatment technology has a septic tank followed by a lined drain 

field filled with Bold and Gold TM sorption media (called “Bold & GoldTM” or B&G drain field in 

our study). The third treatment technology consists of four wetland cells in parallel. Three 

wetland cells each contain a different plant species, and the last wetland cell does not have any 

plants serving as a control cell. All the four wetland cells are filled with sorption media with a 

unique recipe. All of these OSTDS treatment technologies at UCF Test Center received typical 

Florida residential wastewater from a student scholarship house which includes a kitchen, a 

clothes washer, and bathrooms. When students are not in the scholarship house, additional 

wastewater comes from the UCF presidential reception house. 

1.2 Nutrient Impact Resulting from Conventional On-site Wastewater Treatment

On-site sewage contains organic matter (biochemical oxygen demand), suspended solids, 

nutrients, and some pathogens, which can cause a number of diseases through ingestion or 

physical contact. Since the nitrate (NO3

-

) ion is not easily bound to the soil, OSTDS can 

represent a large fraction of nutrient loads to ground water aquifers and surface waters. Nutrients 
8

such as ammonia, nitrite, nitrate, and phosphorus are common contaminants in water bodies all 

over the world. All these nutrients have direct and indirect acute and chronic harmful outcome 

for human beings and ecosystems. Ammonia is an important compound in freshwater 

ecosystems. It can stimulate phytoplankton growth, exhibit toxicity to aquatic biota, and exert an 

oxygen demand in surface waters (Beutel, 2006). Hence, primarily due to the limited nitrogenremoval treatment capabilities of conventional septic systems, their density of use in a watershed 

can produce adverse and undesired aquatic resource impact through accelerated eutrophication. 

Besides, unionized ammonia is very toxic for salmonid and non-salmonid fish species (Tarazona 

et al., 2008). Fish mortality, health and reproduction can be hampered by the presence of minute 

amount of ammonia-N (Servizi and Gordon 2005). Nitrate can cause human health problems 

such as liver damage and even cancers (Gabel et al, 1982; Huang et al., 1998). Nitrate can also 

bind with hemoglobin and create a situation of oxygen deficiency in an infant’s body called 

methemoglobinemia, or Blue-baby syndrome (Kim-Shapiro et al., 2005). Additionally, nitrite 

can react with amines chemically or enzymatically to form nitrosamines that are very strong 

carcinogens (Sawyer et al., 2003). 

In addition, wastewater also carries bacteria microorganisms such Escherichia coli and 

Salmonella typhi, protozoa like Cryptosporidium parvum and Giardia lamblia, helminthes and 

viruses like hepatitis A. These microorganisms are responsible for different kinds of diseases like 

diarrhea, jaundice, food poisoning, dysentery and nausea (Metcalf and Eddy, 2003; WEF and 

ASCE, 2005). On the other hand, those OSTDS-related diseases may include but are not limited 

to shigellosis, salmonellosis, typhoid fever, and infectious hepatitis (Katzenelson et al., 1976). 

As a consequence, nutrient and pathogen removal is very important for the sustainability of 

the aquatic ecosystem and human health. There are alternative OSTDS typically referred to as 

“Performance-based OSTDS” that are available instead of conventional septic tanks for 

homeowners. However, performance-based OSTDS are energy intensive and they are very 

expensive to install, operate, and maintain. In addition, they are designed to achieve an effluent 

with 10 mg/L nitrate which may be fine to prevent Blue-baby syndrome but is much too high to 

protect springs and other water bodies. Accordingly, there is a need for promoting enhanced 

nitrogen and pathogen removal in a passive OSTDS that is more cost effective. Additionally, a 

better understanding is needed of nutrient removal behavior as the effluent plume passes through

the OSTDS and the soil to the ground water and possibly a receiving water body. 
9

A septic system consists of three (3) main components. The first component is a home’s 

indoor plumbing, which is a system of drains and pipes located inside a home used for 

transporting wastewater outside to the next major component, the septic tank. The septic tank is 

normally an underground, watertight container, made of concrete, fiberglass, or other durable 

material, which provides primary wastewater treatment (settling of solids). The third component 

is the standard drain field that is constructed by a series of parallel, underground, perforated 

pipes that allow septic tank effluent to percolate into the surrounding soil in the vadose 

(unsaturated) zone where it is assumed that most of the residual nutrients may be assimilated.

Several types of effluent distribution are applicable in standard drain field systems. These 

include gravity systems, low pressure dosed systems, drip irrigation systems, etc. and some of 

them require having an additional pump. Through various physical, chemical, and biological 

processes, most bacteria, viruses and nutrients in wastewater are expected to be consumed or 

filtered as the wastewater passes through the soil. After treatment, the effluent enters the vadose 

zone and ultimately a ground water aquifer acts as a receiving water body. When properly 

constructed and maintained, the septic system can provide years of safe, reliable, cost-effective 

service, which have been viewed as important information for decision making (Etnier et al., 

2000). 

Due to widespread concerns about the impacts of OSTDS on ground and surface waters,

scientists, engineers, and manufacturers in the wastewater treatment industry have developed a 

wide range of alternative passive technologies designed to address increasing hydraulic loads, 

energy saving requirements, and improved removal of nutrients and pathogens from on-site 

wastewater treatment. These alternative systems require increased testing to verify system 

performance, pollutant transport and fate, resultant environmental impacts, and an integration of 

the planning, design, siting, installation, maintenance, and management functions. Cost 

effectiveness, system reliability, and proper management become the major concerns in their use. 

In general, passive technologies (those without more than one pump) might be advantageous due 

to their cost effectiveness, system reliability, and low maintenance requirement. This triggers an 

acute need to perform a thorough technology assessment, screening, and prioritization. 
10

1.3 Passive On-site Wastewater Treatment

Passive on-site wastewater treatment is defined by the Florida Department of Health as a type 

of OSTDS that excludes the use of aerator pumps, includes no more than one effluent dosing 

pump with mechanical and moving parts, and uses a reactive media to assist in nitrogen removal. 

Reactive media are materials that effluent from a septic tank or pretreatment device passes 

through prior to reaching the ground water. This may include but are not limited to soil,

sawdust, zeolites, tire crumb, vegetative removal, sulfur, spodosols, or other media. Hence, a 

new generation of passive performance-based, as opposed to conventional, on-site wastewater 

treatment technologies to effectively remove nutrients and better protect public health and our 

ground and surface waters in a cost-effective manner are needed. It is the aim of this project to 

develop and evaluate passive OSTDS for use in Florida. The project evaluates two innovative 

designs, a newly developed cost-effective underground drain field with soil amendments 

(sorption media), and an upflow wetlands with soil amendments all constructed at the UCF Test 

Center. 

1.4 Current Regulation of Water Quality and OSTDS Standards 

The Florida Department of Environmental Protection is charged with implementing the 

requirements of the Federal Clean Water Act and the Florida Water Pollution Control Act set 

forth in Chapter 403, Florida Statutes. DEP has established by rule a water body classification 

system and the supporting surface water quality standards which are designed to protect the 

beneficial uses set forth in the water body classes. With respect to nutrients, DEP has adopted a 

narrative nutrient criterion which states that nutrient levels shall not create an imbalance of flora 

and fauna. DEP currently is working on numeric nutrient criteria and has established water body 

specific ones with the adoption of Total Maximum Daily Loads (TMDLs) for those water bodies 

impaired by nutrients. For example, the TMDL for Wekiwa springs is a monthly average of 286 

ug/L nitrate. In addition, DEP has adopted the Safe Drinking Water Act standards which 

establish nitrate and nitrite maximum contamination levels (MCL) in ground water aquifers and 

potable water. These should not be above 10.0 mg/L nitrate-nitrogen (N03

—N) and 1.0 mg/L 

nitrite-nitrogen (NO2-N), respectively The Florida Department of Health is charged with 

regulating OSTDS through their authority in Chapter 381, F.S., and their implementing 
11

regulations in Chapter 10D-6, F.A.C. DOH’s mission is the protection of public health, not 

water quality, and they use the drinking water standard of 10 mg/L nitrate as their goal. 

1.5 NSF 245 Standard 

National Sanitation Foundation and the American National Standards Institute (NSF/ANSI) 

Standard 245 were developed for residential wastewater treatment systems designed to provide 

for nitrogen reduction in 2007. The evaluation involves six months of performance testing, 

incorporating stress tests to simulate wash day, working parent, power outage, and vacation 

conditions. The standard is set up to evaluate systems having rated capacities between 400 

gallons and 1500 gallons per day. Technologies testing against Standard 245 must either be 

Standard 40 certified (ANSI-40) or be evaluated against Standard 40 at the same time (NSF, 

2009). The NSF 245/ANSI-40 influent concentration standards for testing are: 

• BOD5 : 100 to 300 mg/L 

• TSS : 100 to 350 mg/L 

• TKN : 35 to 70 mg/L as N 

• Alkalinity : greater than 175 mg/L as CaCO3 (alkalinity may be adjusted if 

inadequate)

• Temperature : 10 to 30 oC 

• pH : 6.5 to 9 SU 

Environmental Technology Verification (ETV) protocols are developed for specific 

technology areas and serve as templates for developing test plans for the evaluation of individual 

technologies at specific locations. The ETV protocols for suggested average influent 

requirements are (NSF, 2009): 

• Only suggested ranges:

• CBOD5 : 100 – 450 mg/L 

• TSS : 100 – 500 mg/L 

• TKN : 25 – 70 mg/L 

• Total P : 3 – 20 mg/L 

• Alkalinity : greater than 60 mg/L 

• Temperature : 10o C – 30o C 
12

The NSF Standards 245 would allow chemical addition to adjust influent’s alkalinity using – 

sodium bicarbonate. Throughout the testing, samples are collected during design loading periods 

and evaluated against the pass/fail requirements. 

NSF states that an OSWT system must meet the following effluent concentrations 

averaged over the course of the testing period in order to meet Standard 245 (NSF, 2009): 

• CBOD5 : 25 mg/L 

• TSS : 30 mg/L 

• TKN : less than 50% of average of all influent TKN samples

• pH : 6.0 – 9.0 S.U. 
13

Chapter 2 Alternatives to Conventional OSTDS 

2.1 UCF OSTDS Testing Center 

2.1.1 Introduction to UCF Field-scale Test Center

To achieve the project’s objectives, an OSTDS Test Center was constructed on the UCF 

campus that currently has three OSTDS treatment technologies. The first OSTDS treatment 

technology consists of a septic tank, an optional sand-filter circulation tank, and two drain fields 

in parallel (see Figure 1). There are a total of nine (9) sampling points, including S1, and S3-S10 

(assuming that the conditions of S2 and S3 are not different). S1 is the raw sewage from the 

source before it is mixed with the treated wastewater from the sand-filter tank (S4). S2 and S3 

are the wastewater after the septic tank (1.5 days retention time). The sand-filter tank has approx. 

1-2 hours retention time. S4 is a sampling port at the outlet of the sand-filtered tank. The 

distribution tank has an approximate 0.5 day retention time. Three (3) lysimeters were installed 

at 8”, 16”, and 24” below the infiltrate surface of each drain field. These lysimeters (S5-S10) 

may collect wastewater infiltrate in the vadose zone as the effluent travels through the sand. 

The wastewater source for the Test Center is the 15-person BPW Scholarship House (a 

female dormitory at UCF campus), which contains a kitchen, washing machine, and living 

quarters. The wastewater is pumped to 3.78 m3 (1,000 gallon) and 5.10 m3 (1,350 gallon) septic 

tanks from where the effluents are divided into different final disposal alternatives. While the 

former septic tank handles both the B&G drain field (Figure 1) and the wetland system (Figure 

1), the latter one handles both standard drain fields (Figure 1). A dosing tank is connected to one 

septic tank for handling the collected effluent from B&G and wetland treatment processes. On 

average, the pump and pipe arrangement delivers an average of 0.75 m3/day (200 gpd) to each of 

the four drain fields, including two convention ones with different sands, the B&G drain field, 

and the wetland system with four cells. Each conventional drain field and the B&G drain field 

received about 200 gallons of wastewater daily, whereas each wetland cell received 50 gallons of 

wastewater daily. There are four (4) cells of wetlands (Figure 1). Three different plant species of 

plants were planted into three separate wetland cells for testing. One wetland cell is set up as the 

control case, which has no plants. Each cell of the wetland has 5 sampling ports. The sampling 
14

ports are located at 2’, 4’, 6’, 8’, and 10’ from the inlet of each cell. The estimated hydraulic 

retention time is 1 day.

There are two sets of monitoring wells at UCF Test Center, eight (8) drain field monitoring 

wells and eight (8) background monitoring wells (Figure 1). The eight (8) drain field monitoring 

wells are located near the two standard drain fields to monitor the water quality of the ground 

water up gradient, immediate, and down gradient of each standard drain field. The eight (8) 

background wells are located along the perimeter of the test site to monitor the flow regime and 

the water quality underground. The background monitoring wells (MW1-MW8) were sampled 

once in a month. The drain field monitoring wells were sampled on a biweekly basis for 

monitoring their water quality.

Figure 1 A simple layout of OSTDS at UCF test center. 
15

2.1.2 Influent conditions 

Formal sampling campaign was launched on Oct. 13 2008 in the conventional drain field 

and B&G drain field. The influent concentrations of sewerage are shown in Table 1. 

Table 1 Influent concentration - average and standard deviation 

(a)basic parameters (mg/L)

Parameter ALK TSS BOD5 CBOD5

Influent (S1) (Oct ’08 – Sep ’09) 296 ± 62 208 ± 162 230 ± 225 130 ± 100

NSF/ANSI 40 > 175 100 - 350 - 100 – 300

*ALK: alkalinity, TSS: total suspended solid, BOD5: 5 day biochemical oxygen demand, CBOD5: 5 day 

carbonaceous biochemical oxygen demand 

(b) Influent average and standard deviation concentrations – nitrogen parameters (mg/L)

Parameter Ammonia-N Nitrate-N Nitrite-N TKN Organic N TN

Influent

(S1) (Oct ’08 – Sep ’09) 39.0 ± 16.1 0.335 ± 1.123 0.183 ± 0.518 51.7 ± 15.9 12.7 ± 12.8 50.7 ± 16.2

NSF/ANSI 40 - - - 35 – 70

*TKN: Total Kjeldahl Nitrogen, Organic N: Organic nitrogen, TN: Total nitrogen

(c) Influent average and standard deviation concentrations – phosphorus parameters (mg/L)

Parameter SRP Organic P TP

Avg. Influent (S1) Phase I 4.59 ± 1.5 2.15 ± 1.8 7.12 ± 2.6

* SRP: Solvable reactive phosphorus, Organic P: organic phosphorus, TP: Total phosphorus

2.2 Nutrient removal mechanism and sorption media 

2.2.1Nutrient removal mechanism

The adsorption, absorption, ion exchange, and precipitation processes are actually 

intertwined with the overall physicochemical process in the UCF Test Center nutrient removal 

drain fields no matter if they are conventional or innovative (newly developed). Some nutrients, 

such as phosphorus removed by inorganic media, are likely a sorption/precipitation complex. 

The distinction between adsorption and precipitation is the nature of the chemical bond forming 

between the pollutant and sorption media. Yet the attraction of sorption surface between the 

pollutant and the sorption media causes the pollutants to leave the aqueous solution and simply

adhere to the sorption media. This approach to wastewater treatment has “green” implications 

because of the inclusion of recycled material as part of the material mixture promoting treatment 

efficiency and effectiveness. 
16

In the context of using various green sorption media for nutrient removal, it might appear 

that sorption is followed by precipitation or occurs at the same time in the same physicochemical 

process. The nitrogen cycle in either engineered systems or the built environments are well 

understood. Within the microbiological process, if there are organic sources in the wastewater 

streams, hydrolysis converts particulate organic nitrogen (N) to soluble organic N, and 

ammonification in turn releases ammonia into the water bodies. In addition to ammonification, 

important biochemical transformation processes include nitrification and denitrification. They 

result in the transformation of nitrogen between ammonia, nitrite, and nitrate forms via oxidation

and reduction reactions in microbiological processes. In the presence of ammonia-oxidizing 

bacteria (AOB) and oxygen in the aerobic environment, ammonium is converted to nitrite (NO2

-

) 

and nitrite-oxidizing bacteria (NOB) convert nitrite to nitrate (NO3

-

) continuously. Collectively 

these two reactions are called nitrification. Conversely, denitrification is an anaerobic respiration 

process using nitrate as a final electron acceptor with the presence of appropriate electron 

donors, resulting in the stepwise reduction of NO3

-

 to NO2

-

, nitric oxide (NO), nitrous oxide 

(N2O), and nitrogen gas (N2). Denitrification also requires the presence of an electron donor, 

which may commonly include organic carbon, iron, manganese, or sulfur, to make the reduction 

happen. As long as the hydraulic retention time (HRT) is sufficiently long to promote removal, 

microbe-mineral or sorption media interface can be initiated for either or both nitrification and 

denitrification process. In our case, sawdust is used as electron donors. The relationships 

between the various nitrogen species are well defined and are shown in drawings and by 

equations. Detailed literature review of the effects of nitrification and denitrification within the 

nitrogen cycle can be seen in US EPA (2005), Chang et al 2008b, and FDOH, 2009. 

The two steps of ammonia oxidation can be summarized as below in equations 1 and 2 

(Metcalf and Eddy, 2003): 

2NH4

+

+3O2→2NO2

-

+4H++2H2O (1) 

2NO2

-

+O2→2NO3

-

 (2)

and the denitrification of wastewater is shown in equation 3 (Metcalf and Eddy, 2003), 

C10H19O3N+10NO3

-

→5N2+10CO2+3H2O+NH3+10OH- (3)

All of these three types of reactions are expected to occur in our B&G drain field. 
17

2.2.2 Sorption media

As already described, passive OSTDS use a reactive media to assist in nitrogen removal. 

Reactive media used in OSTDS have included soil, sawdust, zeolites, tire crumb, sulfur, 

spodosols, or other media. Some passive OSTDS technologies use a reactive media to assist in 

nitrogen removal including sawdust and other wood products, zeolites, tire crumb, vegetation, 

sulfur, spodosols, etc. (Chang et al., 2008a). 

Soil augmentation with sorption media mixes result in improvements in nutrient removal of 

current treatment technologies used for stormwater management, wastewater treatment, landfill 

leachate treatment, ground water remediation, and treatment of drinking water (Chang et al., 

2008b). The use of these sorption media in the engineered and natural processes may remove not 

only the nutrients, but also some other pollutants, such heavy metals, pathogens, pesticides, and 

toxins (TCE, PAH, etc.). 

In this project, we have evaluated four types of green sorption media including Bold & Gold 

media, Pollution Control media, Growth media, and Recirculation media. Table 2 summarizes a

list of sorption media previously used for wastewater treatment and their corresponding 

references. Table 3 summarizes the media and their recipes being applied at UCF pilot study. 

Table 2 Sorption media used to treat wastewater

No. Sorption media Additional 

environmental benefits Physical/Chemical Properties References

1 Sand filter Bell et al., 1995

2 Tire crumb/Tire 

chips

2,4-dichlorophenol 

(DCP), 4-chlorophenol 

(CP)

D= 20.00 to 40.00 mm Shin et al., 1999

3 Zeolite + 

Expanded Clay D= 2.50-5.00 mm Gisvold et al., 2000

4 Polyurethane 

porous media

Porous structure, Average diameter 3.00-5.00 mm, 

External pore diameter 300 micron. Han et al., 2001

5 Limestone D= 2.38 to 4.76 mm Zhang, 2002 Sulfur D= 2.38 to 4.76 mm

6 Sand granules Espino-valdés et 

al., 2003

7 Clay Gálvez et al., 

2003

8 High density 

module

Rodgers and 

Zhan, 2004

9 

Sandy clay loam 

(SCL) Sand (53.28%), Silt (24.00%), Clay (22.72%)

Güngör and Ünlü 

2005 Loamy sand (LS) Sand (78.28%), Silt (10.64%), Clay (11.08%)

Sandy loam (SL) Sand (70.28%), Silt (14.64%), Clay (15.08%)
18

No. Sorption media Additional 

environmental benefits Physical/Chemical Properties References

10

Masonry sand Bulk density of masonry sand is 1670 kg/m3

; 

Porosity of masonry sand is 0.30.

Forbes et al., 

2005

Expanded shale

Expanded shale (SiO2 62.06%, Al2O3 15.86%, Fe2O3

5.80%, CaO 1.44%, MgO 1.68%); Bulk density of 

expanded shale is 728.00 kg/m3

; Porosity of 

expanded shale is 0.59.

11 Oyster shell 

powder

Powder form, 28.00% Calcium, Average particle size 

200 micron, Surface area 237.00 m2

/g

Namasivayam et 

al., 2005

12

Limestone D =2.38 to 4.76 mm

Sengupta and 

Ergas, 2006 Oyster shell

Marble chips Mg(OH)2 and CaCO3

13 Soy meal hull Direct and acid dye D<0.125 mm Arami et al., 2006

14

Clinoptilolite Hedström et al., 

2006 Blast furnace 

slag Composed of melilite, merwinite, anorthite, gehlenite

15 Perlite Rebco II, 2007

16

Clinoptilolite D = 0.30 -4.76 mm

Smith et al., 2008

Expanded clay D = 0.40-5.0 mm

Tire crumb D = 0.30-5.00mm

Sulfur D = 2.00-5.00 mm

Crushed oyster 

shell D = 3.00-15.00 mm

Utelite 

(expanded shale) D = 0.40-4.50 mm

Note: D is the diameter of the media

Table 3 UCF developed green sorption media 

Sorption Media Recipe Note

Bold & Gold (B&G)

68% Astatula sand

25% Tire crumb

7% Sawdust

This sorption media is used at the bottom layer in the 

B&G drain field.

Pollution Control Media

50% Astatula sand

20% Limestone

20% Tire crumb

10% Sawdust

This sorption media is used in the middle layer of 

wetlands.

Growth Media

75% Expanded clay

15% Florida moss

10% Vermiculite

This sorption media is used in the top layer of 

wetlands.

Recirculation Media

50% Citrus grove sand

20% Limestone

15% Tire crumb

10% Sawdust

5% Expanded clay

This sorption media is used in the top layer of 

recirculation tank in one of the three testing stage
19

2.3 Bold & GoldTM (B&G) drain field with sorption media 

Engineered, functionalized, and natural sorption media can be used to treat stormwater 

runoff, wastewater effluents, ground water flows, landfill leachate and sources of drinking water 

for nutrient removal via physicochemical and microbiological processes (Chang et al., 2008b).

The media may include but are not limited to sawdust, peat, compost, zeolite, wheat straw, 

newspaper, sand, limestone, expanded clay, wood chips, wood fibers, mulch, glass, ash, pumice, 

bentonite, tire crumb, expanded shale, oyster shell, and soy meal hull (Chang et al., 2008b). This 

approach has “green” implications because of the inclusion of recycled material as part of the 

media mixture (Chang et al., 2008b). The choice of media mixes depend on the desired length of 

service, residence time during an operating cycle, and pollutants in the wastewater. 

With the aid of green sorption media, one of the main objectives of this study is to evaluate 

the basic functionality and effectiveness of the B&G drain field with its unique recipe to remove 

both nutrients and pathogens. This innovative passive underground drain field is highly 

sustainable, will fit in any landscape now used for a conventional drain field, and is highly 

applicable to a wide variety of septic tank designs (Wanielista et al., 2008). The sorption media 

soil amendments in the B&G drain field are used in a manner to foster both a saturated anaerobic 

or anoxic environment. The appropriate arrangement of the piping system for correct dosing, 

along with the optimal sizing of the anoxic environment with adequate partition, eventually 

sustain the functionality of these green sorption media in passive drain fields (Wanielista et al., 

2008). A lab-scaled study was carried out in which sorption isotherm and microcosm tests were 

used to prove the concept (Chang et al., 2008a, 2008b). However, comparative full scale testing 

studies are required to prove the advantageous features of passive treatment technologies within 

the treatment trains at the UCF Test Center.

Figure 2 shows the schematic of the B&G drain field with a green sorption material mixture 

filling the horizontal underground cells beneath a sand layer. It is expected that the influent side 

of the B&G layer (left side in Figure 2) can be designed as an aerobic zone followed by an 

anoxic zone before the effluent is discharged. The drain field is filled with green sorption 

material mixture to provide an alternating cycle of aerobic and anoxic environments to transform 

and remove nutrients and pathogens in wastewater. In the drain field, the hydraulic pattern is 

used in combination with an alternating cycle of aerobic and anoxic environments, which repeats 
20

the reaction mechanism of nitrification and denitrification sequentially, to remove nutrient 

content from the influent. Some vertical pipes (i.e., oxygenators) for venting in the beginning of 

the drain field close to the header pipe may induce air into the initial portion of cell so that the 

aerobic environment can be promoted periodically when needed. In all circumstances, the B&G 

drain field has an impervious liner at the bottom to keep all nitrification and denitrification 

processes in an isolated environment. 

When the system is operational, household sewerage may be directed into the underground 

B&G drain field with sorption media being placed in an open channel within the box partitioned 

by baffles. The total number of baffles required depends on the influent pipe arrangement and the 

need to prevent short circuiting. Dosing the sewerage in the front cell of the manifold (inflow 

pipe) may happen periodically. Perforated pipes at the front cell may be controlled to maintain 

the aerobic condition at the left part of channel (see Figure 2). Then the baffles guide the flow 

through the drain field. While the first part of the channel consumes air and alkalinity for 

nitrification, the dissolved oxygen would gradually decrease making the subsequent process 

anoxic before the riser where denitrification may occur. All cells before the riser baffle in the 

open channel must be filled with sorption media to promote the targeted reactions. After having 

3-5 days retention time, flow eventually passes through a perforated outlet pipe to the disposal 

chamber. However, the retention time necessary for such a treatment should be verified in our 

study later on. The disposal chamber is for sampling purposes and to allow pumping back to a 

central sewer which was required by the FDOH for this experimental site. Infiltrate may

percolate down into the vadose zone gradually in the end. 

Figure 2 Schematic of the B&G Drain Field (Wanielista et al., 2008). Numbers refer to sampling 

points in the treatment train.
21

2.4 Upflow wetlands with sorption media and plant species 

2.4.1 Upflow wetlands design with sorption media

Wetlands play an important role in water conservation, climate regulation, soil erosion 

control, flood storage, and environment purification. Both natural and constructed wetlands have 

been shown to be effective in treating wastewaters and stormwater. The wetland system removes 

nitrogen in the water through a variety of mechanisms including biological, physical and 

chemical reactions. Biological functions such as ammonification, nitrification-denitrification and 

plant uptake under appropriate conditions are regarded as the mechanisms for nitrogen 

transformation and removal. Precipitation of particular form of phosphorus is the main path for 

phosphorus removal. Besides, microbial absorption and accumulation also are important.

Constructed wetlands can be divided into two main types: surface flow (SF) wetland and 

subsurface flow (SSF) wetland. Surface flow wetlands (SF) include emergent vegetation, some 

sort of subsurface barrier to prevent seepage, soil or medium to support the emergent vegetation, 

and a water surface above the substrate. This kind of constructed wetland is particularly efficient 

in pathogens removal, due to the high exposure of the wastewater to the UV component of the 

sunlight. However, these systems may provide habitat to breed mosquito and the denitrification 

may be reduced due to the exposure of the wastewater to the air. In the subsurface flow wetland 

systems (SSF), the wastewater is routed below the surface and passes through the filter media 

until it reaches the outlet zone. Given sufficient retention time of the wastewater in the filter, 

nitrogen reduction is significant with horizontal flow systems, but full nitrification is limited due 

to a lack of oxygen that is characteristic for this kind of systems. There are various designs used 

for constructing a SF or SSF wetland depending upon the objectives. How to optimally assemble 

the physical, chemical and biological mechanisms to optimize nutrient removal through choosing 

and co-locating the different kinds of sorption media and vegetation always captures the design 

imagination of individuals throughout the world. 

The potential of a constructed wetland for treating onsite and varying types of wastewater 

has been explored continuously as evidenced by a large body of literature. Johnson et. al. (1995) 

conducted a pilot project in Santa Rosa County where a conventional OSTDS was replaced with 

a constructed wetland system. They demonstrated that the three cell wetland system removed 
22

88% of the orthophosphate, 60% of the ammonia-N, and 77% of the TKN. Steer (2002)

evaluated the effectiveness of improving water quality for a single-family septic tank/constructed 

wetland system in Ohio. They concluded that domestic treatment wetlands can reduce output of 

fecal coliform 88 ± 27%, total suspended solids 56 ± 53%, biochemical oxygen demand 70 ± 

48%, ammonia 56 ± 31% and phosphorus 80 ± 20%. Mbuligwe (2005) presented the 

performance of a coupled septic tank/engineered wetland (ST/EW) system for treating and 

recycling from a small community. The coupled ST/EW system was able to remove ammonia by 

an average of 60%, nitrate by 71%, sulfate by 55%, chemical oxygen demand (COD) by 91%, 

and fecal coliform as well as total coliform by almost 100%. Tanaka et al (2006) tried an

integrated system of emergent plants and submerged plants to polish the effluent from a septic 

tank treating domestic sewage from a student dormitory. The overall pollutant removal 

efficiencies were 65.7% BOD, 40.8% COD, 74.8% ammonium nitrogen (NH4

+

-N), 38.8% nitrate 

nitrogen (NO3

−

-N), 61.2% phosphate (PO4

3−

), 65.8% total suspended solids (TSS), and 94.8% 

fecal coliform. A thorough review of the use of constructed wetlands with horizontal sub-surface

flow for various types of wastewater covering municipal, industrial and agricultural sectors can 

be seen in the literature (Vymazal, 2009). Various media have been studied and suggested. It 

was shown that green sorption medium consisting of recycled and natural materials provide a 

favorable environment for nutrient removal (Xuan et al., 2009). One of the main objectives of 

this study is to prove the cost-effectiveness of a newly developed subsurface upflow wetland 

(SUW) system with sorption media and selected plant species.

2.4.2 Wetland plant species 

Plants are an extremely important component of a wetland system both in terms of nutrient 

uptake and by serving as a habitat for microorganisms. In the subsurface wetland system, the 

plant rhizosphere provides a potential attachment site for denitrifying bacteria in an anaerobic 

environment. Based on the characteristics of oxygen transmission, the rhizosphere shows an 

aerobic-anaerobic-anoxic state, thereby creating the equivalent of series or parallel anaerobic–

anoxic–oxic (A2O) processing unit. Aerobic areas near the root zone are conducive to 

nitrification and anaerobic areas away from the roots work for denitrification, both of which may 

perform the final clean-up of residual nitrogen from the septic tank effluent. It is expected that 

nitrate may thus be effectively removed by denitrification in rhizospheric zones. TN and TP can 
23

be removed if the plants are harvested routinely. Seidel’s work (1955) is known as the first trial 

to use the wetland vegetation to remove various pollutants from wastewater. Since then, 

researchers have studied different vegetation species to optimize pollutants removal efficiency. 

In Table 4, a literature review using different kinds of vegetation with natural soil as substrate for 

wastewater treatment throughout the world is shown. From 

Table 4, only Phragmites Australis (in case 1b and 1f in SF) showed a good result with 

respect to the nutrients removal (about 90% TN removal). However, Phragmites Australis is a 

kind of typical emergent vegetation, which is unsuitable to be planted in subsurface wetland. 

The importance to developing specific wetland media instead of conventional soil, sand and 

gravel to gain better pollutants removal capacity is widely recognized. Mann’s (1993) 

represented the pioneer trial in the early period from which the comparison of laboratory-scale 

phosphorus adsorption was conducted between regional gravels and alternative adsorptive media 

including industrial slag and ash by-products. The results showed the maximum adsorption 

capacity of regional gravels 25.8 to 47.5 μg P/g, blast furnace slag 160 to 420 μg P/g and fly ash 

260 μg P/g, which warranted the further research via the inclusion of industrial waste media. 

Coombes and Collett (1995) used crushed basalt and limestone chippings in their horizontal 

flow Phragmites australis wetland. Ammonia nitrogen in the effluent averaged less than 2 mg/l. 

Three types of root bed media (Lockport dolomite, Queenston shale and Fonthill sand) were used 

by Pant et al (2001) with Fonthill sand having better performance in removing P from 

wastewater. Vohla et al (2007) tried a designed oil-shale ash derived from oil-shale combustion 

for P retention. The life cycle time was not 8 years as calculated from laboratory batch 

experiments, but several months due to the possible saturation or clogging in terms of quick 

biofilm development on the ash particles. Korkusuz et al (2007) carried out an investigation of 

blast furnace granulated slag (BFGS) and showed that BFGS has high phosphorus (P) sorption 

capacity removing TP concentrations from 6.61 ± 1.78 mg L-1 to 3.18 ± 1.82 mg L-1 due to its 

higher Ca content and porous structure. Park and Polprasert (2008) investigated the ability for P 

removal using an integrated constructed wetland system packed with oyster shells (OS) as 

adsorption and filtration media. The removal efficiency of the integrated system was found to be 

85.7% of N and 98.3% of P. Tee et al (2009) reported a better performance of planted 

constructed wetlands with graveland raw rice husk-based media for phenol and nitrogen removal 

compared with unplanted ones. 
24

Table 4 Wetland performance throughout the world by different kinds of vegetation 

SF Plant Removal Efficiency Reference

1a Typha Latifolia, Phragmites 

Australis, Sparganium Erectum

80% COD, 83% BOD, 45% TN, 47% 

TP

Cadelli (1998)

1b Phragmites Australis, 98% SS, 87% COD, 96% BOD, 91% 

TN, 60% OrthoP

Cadelli (1998)

1c Phragmites Australis, Scirpus 

Lacustris

68% COD, 83% BOD, 26% TN, 2% 

Ortho P

Cadelli (1998)

1d Lemna Sp. 96% SS, 75% COD, 90% BOD, 43% 

TN, 47% TP

Cadelli (1998)

1e Lemna Sp. 98% SS, 96% COD, 94% BOD, 49% 

TN, 49% TP

Cadelli (1998)

1f Phragmites Australis, 87% COD, 97% BOD, 89% TN, 46% 

TP

Cadelli (1998)

1 Phragmites 90% COD, 96% BOD, 92% SS, 63% 

TP, 36% TN

Haberl (1998)

2 Scirpus Cyperinus, Typha Latifolia 73.4% NH4

+

-N, 67.5% TKN Huang (2000)

3a Typha Latifolia, T. Angustofolia, 

Scirpus Taebormontanii

92% BOD, 87% TSS, 99.6% Fecal, 

41% TN, 50% TP

Henneck (2001)

3b Typha Sp. 82% BOD, 86% TSS, 92.4% Fecal, 

51% TN, 59% TP

Henneck (2001)

3c Typha Latifolia 83% BOD, 81% TSS, 99.9% Fecal, 

54% TN, 97% TP

Henneck (2001)

4a Phragmites Mau

Ritianus

25.2% NH4

+

-N, 56.3% COD, 57% TC, 

68% FC

Kaseva (2004)

4b Typha Latifolia 23% NO2-N, 23% NH4

+

-N, 60.7% 

COD, 60% TC, 72% FC

Kaseva (2004)

5a Cyperus Papyrus 75.3% NH4

+

-N, 83.2% TRP Kyambadde 

(2004)

5b Miscanthidium Violaceum 61.5% NH4

+

-N, 48.4% TRP Kyambadde

(2004)

6 Phragmites Australis 30% of TP , 50% Denitrification Brix (2005)

7 Phragmites & Typha 27% TKN, 19% NH4

+

-N, 4% Nitrite Keffala (2005)

8a Juncus effusus L. 54% NH4

+

-N, 55% TN, 95% TP Xuan (2009)

8b Panicum Hemitomon 88% NH4

+

-N, 85% TN, 94% TP Xuan (2009)

8c Zizaniopsis Miliacea 78% NH4

+

-N, 79% TN, 95% TP Xuan (2009)

Note: Surface flow wetland (SF); Subsurface wetland (SSF); Ammonium-nitrogen (NH4

+

-N); Ammonium (NH4

+

); 

Nitrite (NO2

-

); Total Reactive Phosphorus (TRP); Total Kjeldahl Nitrogen (TKN); Nitrite-nitrogen (NO2-N); Fecal 

Coliform (FC); total carbon (TC) total suspended solid (TSS); Biochemical Oxygen Demand (BOD); Chemical 

Oxygen Demand (COD), Total Phosphorus (TP); Total Nitrogen (TN) 

There are four parallel 1.52 m wide × 3.05 m long × 0.91 m deep (each 5 ft wide × 10 ft long 

× 3 ft deep) cells in this test bed. Each of four cells contains an impermeable liner, a gravel 

substrate, green sorption media and selected plants; a gravel-filled gravity distribution system 

including header pipe, distribution pipe, collection pipe, flow meter, various lysimeters, and a 

planted bed of special green sorption media with an underdrain collection system. These 

wetlands operated as a subsurface upflow wetland (SUW). With the aid of a suite of selected 
25

plant species, this SUW is configured to handle 189 liters per day (50 GPD) influent. The 

hydraulic retention time (HRT) is about 6-7 days, based on a porosity of 30%. In addition, an 

innovative upflow (i.e. outlet of SUW is higher than inlet) design was introduced to avoid 

clogging, which is the main disadvantage of the conventional subsurface flow wetlands. Three 

sets of plant species were tested against the control which had no plant species. Figure 3 shows 

a plan-view of the SUW system test configuration.

Figure 3 Configuration of septic tank followed by a 4-cell wetland system including a shut-off 

valve, a cleanout, and a flow meter. 

2.5 Conventional septic system with recirculation tank 

The Florida Keys On-site Wastewater Nutrient Reduction Systems (OWNRS) 

Demonstration Project was initiated in 1995 to demonstrate the use of a OWNRS to reduce the 

concentrations of nutrients discharged to the coastal region of the Keys (Anderson et al., 1998). 

One of the five treatment trains in the OWNRS was a septic tank followed by a recirculation 

sand filter (RSF). The overall treatment effectiveness of this passive OSTDS was shown to be 

about 96.5% TSS, 95.5% TKN, 47.6% TN and 92.8% TP (Anderson et al. 1998). Healy et al. 

(2004) found the removal efficiencies of 83.2% TN, 100% NH4-N, 43.3% P and 100% SS from 

dairy parlor washing with 6.6 days hydraulic retention time (HRT) and recirculation ratio of 3.0. 

If properly operated, an RSF can remove 87% of NH3-N, 96% of BOD, 96%of TSS, and 50% of 
26

TP (IDNR, 2007). Urynowicz et al. (2007) tried to evaluate the performance of RSF in terms of 

nitrogen removal from septic tank wastewater and found 72.0% nitrogen removal with 

recirculation ratio of 5.0 and 63.0% nitrogen removal with recirculation ratio of 3.7 (Urynowicz 

et al., 2007). 

Figure 4(a) shows a conventional passive septic system diagram in which the nitrification 

can be promoted in the RSF while denitrification mainly occurs in septic tank and drain field.

Shown in Figure 4(b) are the sampling locations at the UCF Test Center for this treatment train, 

The nitrification and denitrification mechanisms (i.e. equations 4-7) can be expressed as 

below: 

• Nitrification:

2NH4

+ + 3O2 → 2NO2- + 4H+ + 2H2O (4)

2NO2

- + O2 → 2NO3- 

 (5) 

NH4

+ + 2O2 → NO3- +2H+ +H2O (6) 

• Denitrification: 

C10H19O3N+10NO3

- → 5N2 +10CO2 +3H2O +NH3 +10OH- 

 (7) 

One of the problems associated with RSF is their potential clogging due to physical (i.e. 

solid accumulation), chemical (i.e. precipitation reaction) and biological (i.e. biofilm growth or 

slow decomposition of organic matters) activities going on in the filter (Venhuizen, 1998; Hurst, 

2006). A RSF may be a chamber for simultaneous nitrification and denitrification if properly 

designed. However, until now, little has been known about the performance of nitrification and 

denitrification in a RSF and how the performance could be improved by using different sorption 

media. Accordingly, the replacement of sand in the recirculation tank may have value in nutrient 

reduction and an RSF with sorption media is also part of the UCF Test Center operation.. 
27

(a). Flow diagram of the UCF conventional OSTDS with RSF

(b): Sampling locations at UCF conventional OSTDS

Figure 4 Schematic flow and sampling diagrams of the UCF conventional OSTDS with RSF 

Standard drain field 

with Builder’s 

washed sand

Standard drain field 

with Astatula sand

Distribution 

tank

Septic tank Recirculation 

sand filter 

tank

Dosing 

tank

S5 S6 S7 S8 S9 S10

Lysimeter

S3

S1

S4

S2

4A

4B
28

Chapter 3 Conventional Passive On-Site Wastewater Treatment System with 

Ground Water Impacts

3.1 Conventional drain field 

The conventional passive OSTDS at UCF consists of a RSF and two drain fields The first 

uses washed builder’s sand as the filtrating media of the drain field, while the second uses 

Astatula sand (A.K.A. Citrus Grove sand). The performance of these two systems with respect 

to water quality improvement was measured for a one year period. Also the impact on the 

ground water was measured.

3.2 Conventional drain field with a recirculation tank 

To explore the feasibility of using sorption media to replace the tradition fine or coarse sand 

in the RSF, three different designs were used in this study. The first design using fine sand as 

media in the RSF was conducted between Oct – Nov 2008. The second design using coarse sand 

as media in RSF was conducted between Mar – Apr 2009. Finally the third design using green 

sorption media was conducted on Sep – Oct 2009. The experimental settings of these three 

designs are summarized in Table 5. 

Table 5 A summary of the experimental settings of conventional passive OSTDS 

ID Date Number of Dataset Experimental Settings

Recirculation I Oct – Nov 

2008 3 

• Septic tank – Recirculation – Drain Field

• Astatula sand used as the filtrating media in the 

recirculation tank

Recirculation II Mar – Apr 

2009 4 • Approx. 3:1 Return-To-Forward ratio

• Very coarse sand media in the recirculation tank

Recirculation III Sep – Oct 

2009 3 • Precisely 3:1 RTF ratio

• Green Sorption Media

3.2 Ground water quality impact below the conventional OSTDS 

There are 16 monitoring wells at the UCF OSTDS site. Eight of them monitor the ground 

water around the perimeter of the test site, whereas the other eight wells concentrate on 

monitoring the ground water at and around the two conventional drain fields. There is no need to 

monitor the ground water around the B&G drain field and the SUWs because they are lined with 

impermeable material. Figure 5 shows the overall flow direction of the ground water at the test 
29

site. It flows from northeast to southwest. The SUWs are located upstream, the B&G are in the 

middle, and the two conventional drain fields are downstream (Astatula or citrus grove sand is 

furthest downstream). Figures 6 - 8 present the ground water conditions, in which the ground 

water nutrient maps were generated based on the average values of three datasets measured 

between March and April, 2009. 

Figure 6 shows the ammonia-N concentration in the ground water with the highest 

ammonia-N concentration located downstream from the conventional drain fields (slightly higher 

downstream of the washed builders sand). The SUW and B&G drain field should not release any 

nutrients into the ground water due to the use of impermeable material to prevent any leakage. It 

is believed that the peak on the upstream end (right-hand side) was from historic fertilizer use. 

Figure 7 shows the nitrate-N concentrations in the ground water. It was observed that peak 

values appeared downstream of the Astatula sand drain field and correlated with the high level 

trends of ammonia-N (see Figure 6). There are two possibilities of having a high level of nitrate 

at this location. First, the nitrate was introduced by the Astatula sand drain field (most 

downstream rectangular in Figure 7). Second, the ammonia released from the washed builder’s 

sand drain field was converted to nitrate and travel downstream. The gradient of ammonia 

concentration in Figure 6 confirms that such transport of ammonia is highly likely. 

Considering the levels of ammonia-N and nitrate-N at the downstream location of the washed 

builder’s sand drain field, it was highly likely that the washed builder’s sand drain field released 

nitrogen into the ground water. The nitrate-N concentration gradient shown in Figure 7 indicates 

the source of nitrate-N is from the washed builder’s sand drain field. Figure 8 shows the soluble 

reactive phosphorus (SRP) in the ground water downstream from the Astatula sand drain field. It 

is unknown which conventional drain field contributes most of the SRP to the ground water. 

Nevertheless, there is a higher concentration of SRP in the ground water downstream of the 

conventional drain fields. In parallel with this project, a detailed study conducted by the United 

State Geological Survey (USGS) and Florida State University (FSU) has been geared toward 

investigate the fate and transport of pollutants in the vadose zone of drain field and ground water 

(FDEP, 2009). 
30

Flow direction

BPW House

Astatula Sand Washed Builders’

Figure 5 Ground water monitoring wells are located around experimental site at UCF. 

Additional monitoring wells are also located inside the conventional drain fields. Ground 

water flows in the southwest direction as indicated with the arrow. The location of the house 

generating the sewage flow is also shown and noted as the BPW House. 
31

Figure 6 Average Ammonia concentrations in the ground water under UCF test site. 

Figure 7 Average Nitrate-N concentrations in the ground water under UCF test site. 
32

Figure 8 Average Soluble Reactive Phosphorus (SRP) concentrations in the ground water under 

UCF test site.
33

Chapter 4 Passive On-Site Wastewater Treatment System with Bold & 

GoldTM Drain Field

4.1 System design of Bold & GoldTM drain field

The B&G drain field is designed to treat 400 gallons per day of pre-treated residential septic 

tank wastewater effluent. The drain field is designed to provide an aerobic zone for nitrification 

and an anaerobic zone for denitrification in series to remove nitrogen through nitrification and 

denitrification processes. The nitrification process is able to convert the organic nitrogen to 

ammonia and further convert the ammonia to nitrite while the denitrification process is the 

biological reduction process of nitrite and nitrate to nitrogen gas. In principle, over half of the 

oxygen consumed in the nitrification reaction can be recovered by denitrification and the 

alkalinity destroyed in the nitrification reaction is also recovered. Consequently, denitrification 

can play an important role in reducing the process energy requirements and maintaining the 

process pH values within the optimal range for nitrification. Figure 9 presents a representative 

result from one sampling date for nitrogen species, dissolved oxygen, and alkalinity in the septic 

tank and B&G drain field system. Figure 9 supports expected relationships among the nitrogen 

species for nitrification and denitrification conditions. 

It was observed that both nitrification and denitrification processes occurred in the B&G 

drain field. The transition from septic effluents to B&G aerobic zone shows significant 

reductions of ammonia and alkalinity while nitrate concentrations were increased due to the 

nitrification process (see Figure 9). The dataset shown in Figure 9 was collected on April 1st

, 

2009, which was the latest dataset of the experiment on B&G drain field. There was a trend of 

high organic nitrogen concentrations in the B&G system in the aerobic zone as well; thus, 

ammonia concentration increased when the wastewater traveled through the B&G (see Figure 9). 

This observational evidence confirms that a nitrification process did happen at that right location

of the system. Yet some ammonia remained in the B&G aerobic zone indicating an incomplete 

nitrification process. This is partially due to the insufficient alkalinity available to sustain the 

noticeable nitrification process all the way to the end. 

Denitrification process was observed in the anaerobic zone where nitrate concentrations were 

reduced considerably (see Figure 9). The fact that nitrate almost completely disappeared in the 
34

anoxic zone, but then reappeared at the B&G effluent reveals that a secondary nitrification 

occurred again between the anoxic zone and the B&G effluent point. This secondary nitrification 

process was the consequence of the presence of organic nitrogen, ammonia, and dissolved 

oxygen simultaneously. This implies that a complete nitrification process at the early stage must 

be obtained in order to better remove total nitrogen from the wastewater, effectively. A 

relationship between influent dissolved oxygen and effluent nitrate concentration was found. 

Obviously, the higher the DO in B&G aerobic zone, the lower the nitrate-N concentration in the 

effluent (see Figure 10).

Figure 9 Tracking of nitrogen species in the B&G OSTDS system shows nitrification process in 

aerobic layer, and denitrification process in the anaerobic layer. 

Figure 10 Relationship between influent DO and effluent nitrate-N 
35

4.2 B&G drain field removal efficiency

The B&G drain field shows promising results in treating typical Florida household 

wastewater streams. Sampling was carried out from Oct. 2008 to April 2009 to collect 5 data 

sets. Figure 11 summarizes the removal efficiencies between the inlet of septic tank and the 

outlet of B&G drain field for all pollutants considered. Approximately 70% of total nitrogen and 

more than 99.99% of bacteria were removed. TSS and CBOD5 were also substantially removed. 

The nitrification process may be improved by introducing more alkalinity using limestone as an 

integral part of the sorption media. 

Figure 11 Overall septic and B&G drain field removal efficiency.

4.3 B&G drain field effluent concentrations 

It is also important to examine effluent concentrations leaving the drain field and entering 

the ground water. Average TSS and CBOD5 concentrations were below 11 mg/L and 8 mg/L, 

respectively or below the NSF standard of 30 mg/L for TSS and 25 mg/L for CBOD5. Total 

nitrogen concentration in the effluent was about 13 mg/L on average. Nitrate and nitrite 

concentrations were 3 mg/L and 1 mg/L, respectively, which are below the USEPA MCL for 

drinking water. Phosphorus concentration in effluent was very low. The bacteria concentration in 

the B&G was about 10 cfu /100 mL on average. Figures 12-15 collectively present the whole 
36

results. Table 6 summarizes mean, minimal, and maximal values of water quality parameters in 

the effluent of the B&G drain field. 

Figure 12 Effluent TSS and CBOD5 of B&G drain field.

Figure 13 Effluent nitrogen of B&G drain field.

Figure 14 Effluent phosphorus of B&G drain field. 
37

Figure 15 Effluent bacteria of B&G drain field.

Table 6 Summary of mean, minimum and maximum values of water quality parameters in the 

effluent of the B&G drain field 

B&G Effluent (Oct 08 - Apr 09)

 Average Min Max Median

Alkalinity (mg/L) 220.5 190.0 256.0 220.5

TSS (mg/L) 10.7 1.2 23.3 10.7

BOD5 (mg/L) 11.2 4.4 29.7 9.0

CBOD5 (mg/L) 7.7 2.0 21.0 5.2

Ammonia-N (μg/L) 6101.5 2617.0 8533.0 6439.5

NOX-N* (μg/L) 3198.0 2.0 6851.0 3065

Nitrite-N (μg/L) 52.3 3.0 141.0 35.5

Nitrate-N (μg/L) 3145.7 -1.0 6820.0 2998.0

Org. N (μg/L) 3361.3 499.0 16401.0 760.5

TKN (μg/L) 9462.8 6513.0 19018.0 7607.5

TN (μg/L) 12902.3 6520.0 19020.0 13581.5

SRP (μg/L) 1003.8 3.0 2203.0 824.0

Org. P (μg/L) 258.3 0.0 669.0 153.5

TP (μg/L) 1386.8 33.0 2909.0 1384.0

Fecal (cfu/100mL) 242.0 1.0 1400.0 5.0

E.Coli. (cfu/100mL) 240.7 1.0 1400.0 4.5

 *[NOX-N] = [Nitrite-N]+[ Nitrate-N]
38

Chapter 5 Passive On-Site Wastewater Treatment System with Subsurface 

Upflow Wetland (SUW) and Sorption Media

5.1 System design of subsurface upflow wetland (SUW) with sorption media 

A subsurface upflow wetland (SUW) system receives septic tank effluent and is treating up 

to 454 m3 (120 gallon) per day with each of the four SUW cells treating 50 gallons per day. The 

septic tank before the SUWs has a size of 1000 gallon per day providing 2-3 days hydraulic 

retention time (HRT). The septic tank effluent enters a gravel-filled gravity distribution system 

including header pipe, equalization distribution box, distribution pipe, and flow meter. The four 

SUW cells are packed with special green sorption media. Within the full scale field study, a new 

set of green sorption media is used for both nutrient and pathogen removal in the SUW. An 

innovative upflow operation is used. The operation includes a high porosity gravel as the 

substrate at the bottom, vertical piping to introduce oxygen to the bottom, and an outlet that is 

higher than inlet. The design fosters an upflow hydraulic pattern and an amenable nitrificationdenitrification environment as well as minimizing clogging and flooding, which overcomes the 

main disadvantage of the conventional subsurface flow wetlands. Such a design reduces the 

effect of rainwater since most rainwater drains from the higher outlet directly instead of mixing 

with the wastewater, which provides more accurate evaluation of the performance of the SUW. 

Through various physical, chemical, and biological processes, most bacteria and viruses in 

wastewater, as well as nutrients, are consumed and intercepted as the wastewater effluent travels 

up through the pollution control layer (i.e., aerobic layer at the bottom) and growth media layer 

(i.e., anaerobic layer in the middle) before reaching the root zone. Combined with the gravel 

layer and the sand layer beneath the pollution control layer and the plant species on the top of the 

growth media, the SUW may promote pathogen, nitrogen and phosphorus removal via 

nitrification, denitrification adsorption, absorption, ion exchange, filtration, and precipitation 

collectively. 

Three kinds of plant species are tested against the control case with no plant species. Using 

the criteria for screening plant species as described in previous study (Xuan et al, 2009), we 

selected three kinds of native vegetation with similar volumes and costs, Canna (Canna 
39

Flaccida), Blue flag (Iris versicolor L.), and Bulrush (Juncus effusus L.) (Figure 16). These were 

evenly planted in SUW cells 1, 2 and 3, respectively as listed in Table 6. Wetland cell 4 is the 

control without any plant species but it does include the placement of the same layered green 

sorption media. 

There are four parallel 1.52 m wide × 3.05 m long × 0.91 m deep (5 ft wide × 10 ft long × 3 

ft deep) cells in each test bed. Each of four cells contains an impermeable liner at the bottom, a 

gravel substrate, fabric interlayer, sand, pollution control media (called PC media hereafter), 

growth media (called G media hereafter) and selected plants. An overall section is shown in 

Figure 17. G medium layer (75% Expanded Clay, 10% Vermiculite, and 15% Peat Moss) is used 

to support the root zone and PC medium layer (50% Citrus grove sand, 15% tire crumb, 15% 

sawdust and 20% lime stone) is used to help nutrient removal. Both are 30.48-cm (12-inch) deep. 

The gravel substrate at the bottom creates additional pore space allowing water to spread across 

the bottom of a SUW more freely while maintaining a desired flow rate. The purpose of the 

separation fabric liner on the top of the gravel layer is to keep the sand above the gravel layer. A 

15.24-cm (6-in) sand layer is added beneath the PC medium to improve the removal of pathogen 

and total suspended solid (TSS). The 30.48-cm (12-inch) layer PC media was used to remove 

nutrients, TSS, and BOD. The main function of the G media layer is to support the root zone and 

to aid in further nitrogen removal. The HRT is about 6-7 days. Once the gravel layer is fully 

saturated, the water level would rise up gradually, passing through the sand and PC medium 

layer up to the outlet. In each SUW, two customized oxygenators were inserted on both sides of 

inlet into the gravel layer to enhance the nitrification at the bottom of the SUW cells so as to 

fulfill the design ideas configured for the SUW. The samplers were installed at the interface 

between different layers with three depths. Horizontally, the samplers in the four SUW cells are 

33%, 67% and 100% along the length of the SUW and well as the control wetland (See Figure 

17). 
40

Figure 16 Plant species selected in the study: (a) Canna; (b) Blue flag; (c) Bulrush

Figure 17 SUW with green sorption media design. 

Table 7 Summary of wetland plant species

SUW ID Plant Species

SUWcell 1 Canna

SUW cell 2 Blue Flag

SUW cell 3 Bullrush

Control Wetland None

(a) (b) (c)
41

5.2 SUW removal efficiency

Figure 18 shows the overall removal efficiencies between the inlet of the septic tank and the 

outlet of the four SUW cells. The plant species in the SUW cells demonstrated higher nitrogen 

and phosphorus removal relative to the control without plants. Yet the TSS removal efficiency 

was less than expected. It must be noted that the sampling point at the effluent was not the most 

suitable one for the TSS measurements due to the fact that the sampling ports were buried in the 

media and fine particles collected in the sample. 

Figure 18 A summary of overall removal efficiencies of septic tank and SUW.

5.3 SUW effluent concentrations 

In Figure 19 and 20, TSS and CBOD5 concentrations of the SUWs’ effluents are shown. The 

TSS concentrations were near 30 mg/L with an average below 30 mg/L, which is the NSF 245 

requirement for effluent TSS. TSS removal is expected to be lower with a simple modification 

at the SUW sampling outlet. CBOD5 concentrations average below 5 mg/L (the NSF 245 

requirement is 25mg/L). Figures 21 and 22 show a set of effluent concentrations for nitrogenand phosphorus-species. The effluent TKN and TN of the four SUW cells were different, 

depending on the plant species. Overall, SUW cells 1 and 2 performed best in removing nitrogen 
42

with the nitrate, nitrite, and total nitrogen concentrations below the measured values in cell 3 and 

the control cell. In fact, nitrogen concentrations in the effluent of SUW cells 1 and 2 were below 

the USEPA MCL of nitrate (10 mg/L) and nitrite (1 mg/L) for drinking water. Bacteria counts in 

all SUW effluents were high, even though the removal efficiencies were more than 99.9%. 

However, it must be taken into account that once the effluent was released into the underground 

vadose zone, most bacteria would be consumed or filtered out by the soil. Table 8 summarizes 

the mean, maximal, and minimal values of all water quality parameters.

Figure 19 Effluent TSS of SUW.

Figure 20 Effluent CBOD5 of SUW.
43

Figure 21 Effluent nitrogen concentration in SUW. 

Figure 22 Effluent phosphorus concentration in SUW. 

Figure 23 Bacteria counts in SUW effluent.
44

Table 8 A summary of the mean, maximum, and minimum values of all water quality parameters 

(a) From wetlands (1) and (2)

 Wetland 1 Effluent (Aug-Sep 2009) Wetland 2 Effluent (Aug-Sep 2009) 

Average Min Max Median Average Min Max Median

Alkalinity (mg/L) 378.8 277.0 465.0 38.01 312.6 112.0 423.0 369.0 

TSS (mg/L) 34.6 29.0 42.0 34.0 17.6 12.5 32.0 14.0 

BOD5 (mg/L) 5.22 2.9 8.7 3.7 7.8 2.3 21.9 3.6 

CBOD5 (mg/L) 3.6 2.3 5.5 3.1 3.5 2.2 5.5 3.2 

Ammonia-N (μg/L) 859.6 304.0 1437.0 972.0 6461.2 987.0 27566.0 1313.0 

NOX-N* (μg/L) 7.8 4.0 16.0 5.0 9.0 5.0 20.0 5.0 

Nitrite-N (μg/L) 1.6 1.0 3.0 1.0 4.8 1.0 15.0 3.0 

Nitrate-N (μg/L) 6.2 2.0 14.0 4.0 4.2 2.0 7.0 4.0 

Org. N (μg/L) 1097.4 337.0 2030.0 1139.0 3037.6 760.0 9689.0 1888.0 

TKN (μg/L) 1957.0 1536.0 2576.0 1711.0 9498.8 2227.0 28326.0 2924.0 

TN (μg/L) 1964.2 1540.0 2578.0 1727.0 9507.2 2232.0 28336.0 2929.0 

SRP (μg/L) 18.0 11.0 27.0 17.0 174.6 12.0 717.0 28.0 

Org. P (μg/L) 78.0 38.0 101.0 79.0 313.0 95.0 753.0 122.0 

TP (μg/L) 96.0 51.0 125.0 96.0 487.6 123.0 1470.0 134.0 

Fecal (cfu/100mL) 657.0 1.0 3000.0 20.0 11590.6 120.0 51000.0 3000.0 

E.Coli. (cfu/100mL) 6.8 1.0 30.0 1.0 4933.8 1.0 24600.0 1.0

 *[NOX-N] = [Nitrite-N]+[ Nitrate-N] 

(b) From wetlands (3) and (4) 

Wetland 3 Effluent (Aug-Sep 2009) Wetland 4 Effluent (Aug-Sep 2009)

 Average Min Max Median Average Min Max Median

Alkalinity (mg/L) 364.8 141.0 486.0 459.0 217.8 82.0 375.0 217.0

TSS (mg/L) 32.0 18.5 50.5 30.0 23.5 16.0 36.8 22.0

BOD5 (mg/L) 7.2 3.2 13.2 6.1 11.5 5.8 19.2 8.5

CBOD5 (mg/L) 4.3 2.5 5.7 4.7 5.0 3.9 6.0 4.9

Ammonia-N (μg/L) 17327.6 805.0 46645.0 14441.0 42376.4 4582.0 71220.0 56233.0

NOX-N* (μg/L) 6.0 5.0 10.0 5.0 4.4 1.0 6.0 5.0

Nitrite-N (μg/L) 2.2 1.0 3.0 2.0 1.6 1.0 3.0 1.0

Nitrate-N (μg/L) 3.8 2.0 8.0 3.0 2.8 0.0 5.0 3.0

Org. N (μg/L) 3458.8 333.0 7835.0 3129.0 8847.2 476.0 25355.0 3169.0

TKN (μg/L) 20786.4 1138.0 49774.0 19498.0 51223.6 5058.0 83966.0 59402.0

TN (μg/L) 20790.6 1148.0 49779.0 19500.0 51227.4 5059.0 83971.0 59407.0

SRP (μg/L) 15.2 9.0 23.0 16.0 24.2 9.0 74.0 12.0

Org. P (μg/L) 87.6 50.0 137.0 79.0 628.4 53.0 1392.0 571.0

TP (μg/L) 102.8 64.0 147.0 102.0 652.6 65.0 1401.0 594.0

Fecal (cfu/100mL) 13422.2 1.0 66800.0 20.0 12544.6 1.0 62400.0 8.0

E.Coli. (cfu/100mL) 9890.6 1.0 49200.0 16.0 8242.0 1.0 4120.00 4.0

 *[NOX-N] = [Nitrite-N]+[ Nitrate-N]
45

Chapter 6 Passive On-Site Wastewater Treatment System with Sorption 

Media-Based Recirculation Tank

6.1 System design of recirculation tank with sorption media

Design improvements have been made to the recirculation tank based on our evaluation of 

the three different media used inside the recirculation tank and their resulting differences in 

performance. Replacement of sand with green sorption media together with a unique hydraulic 

design in the recirculation tank eventually improves the overall system performance. The basic 

design (Recirculation I) started out with a recirculation tank filled with Astatula sand. However, 

the major goal in Recirculation I is to discern the removal efficiency of two types of sand, 

including Astatula sand and wash builder’s sand, associated with these two conventional drain 

field to examine whether or not they have significantly different performance for final 

wastewater disposal. Once the better choice may be determined, we started altering the sand 

materials within the recirculation tank. The initial run caused clogging in the Astatula sand, 

increasing the hydraulic retention time in the recirculation tank and sometimes overflows. With 

this experience, the design (Recirculation II) in the second set of tests stage used very course 

sand (washed builder’s sand) instead of Astatula sand. The coarse sand did not get clogged, but 

made marginal if any improvement on treating wastewater. 

The last and most up-to-date design (Recirculation III) incorporated two layers of media. 

The top layer was 27.94 cm (11-inch) coarse sand. The bottom layer was 27.94 cm (11-inch) 

green sorption media. There was an overflow weir at the outlet of the recirculation tank to 

maintain the standing water level inside the tank at the transition between the sand and the 

media. This standing water inside the tank would cause a saturation condition in the sorption 

media layer and maintain an anaerobic condition promoting denitrification whereas the coarse 

sand layer may perform the nitrification process as usual. Figure 24 shows the novel design of 

this recirculation tank with green sorption media and coarse sand. In principle, the coarse sand 

would allow more dissolved oxygen to dissolve in the wastewater streams, which should 

improve the nitrification process. After the nitrification process, the denitrification process is 

expected to occur in the submerged media layer and drain field as shown in Figure 24. 
46

Figure 24 Schematic and design of green sorption media inside the recirculation filter tank. 

6.2 Performance of conventional OSTDS and recirculation tank with Citrus sand 

(Recirculation I)

In this recirculation option, the recirculation tank was filled with Astatula sand. The 

conventional OSTDS showed average nitrogen and phosphorus removal at about 50 percent. 

TKN conversion was high. The evidence of low TN and high TKN conversion indicates that 

nitrification process probably occurred effectively, but the denitrification process was not 

significant. TSS, CBOD5, and bacteria removals were excellent. Figure 25 presents the overall 

removal efficiencies of the Recirculation I conventional OSTDS while the sampling locations are 

identified in Table 9. Figures 26 and 27 summarize the differences in effluent concentrations of 

Recirculation I (Astatula sand drain field) and Recirculation II (Washed Builder’s sand drain 

field). Note these removals are with respect to influent conditions and as such the nitrate 

concentrations increased as expected in the effluent and were near zero in the influent. A large 

negative number would have to be presented in the comparison tables and thus was not added. 

Influent

Effluent
47

Table 9 A summary of sampling locations used to calculate overall removal efficiencies

for each OSTDS.

ID Influent Point Effluent Point

Conventional DF with Astatula Sand Inlet of septic tank (S1) At 24 inches below filtrating sand 

(S7)

Conventional DF with Wash 

Builder’s sand Inlet of septic tank (S1) At 24 inches below filtrating sand (S10)

Septic tank with B&G DF Inlet of septic tank (S1) At the outlet of the B&G drain field

Septic tank with SUW 1 Inlet of septic tank (S1) At the outlet of the SUW

Septic tank with SUW 2 Inlet of septic tank (S1) At the outlet of the SUW

Septic tank with SUW 3 Inlet of septic tank (S1) At the outlet of the SUW

Septic tank with Control Wetland Inlet of septic tank (S1) At the outlet of the control wetland

Figure 25 A summary of removal efficiency of the conventional OSTDS Recirculation I with 

Astatula sand in the recirculation tank shows comparisons of two drain field systems. The 

hatched bars represent the OSTDS with Astatula sand drain field. The solid bars represent the 

OSTDS with Wash Builder’s sand drain field. 
48

Figure 26 Conventional OSTDS effluent concentration of Recirculation I at S7 in Astatula sand 

drain field and S10 in Washed Builder’s sand drain field shows low TSS, CBOD5, and bacteria 

levels.

Figure 27 Conventional OSTDS effluent concentration of Recirculation I at S7 in Astatula sand 

drain field and S10 in Washed Builder’s sand drain field of Recirculation I shows moderate 

levels of nitrogen and phosphorus. 
49

6.3 Performance of Conventional OSTDS and recirculation tank with coarse sand 

(Recirculation II)

In Recirculation II the media in the recirculation tank was replaced with very coarse sand 

(Washed Builders Sand) to improve the clogging situation in Recirculation I. Removal 

efficiency of total nitrogen in Recirculation II was similar to that in Recirculation I. Both are 

close to about 50%. There was an improvement of TKN conversion efficiency (75% to 85%). 

TSS, CBOD5, and bacteria removal efficiencies were also similar in Recirculation I and 

Recirculation II. Phosphorus removal was not promising in both cases. In fact, Recirculation II 

was even worse than the Recirculation I. Figure 28 shows the overall removal efficiencies of the 

conventional OSTDS and recirculation tank with coarse sand. This system achieved moderate 

TN removal, and poor phosphorus removal. Bacteria removal was excellent. Figures 29 and 30 

collectively present the effluent concentrations for TSS, CBOD5, and bacteria and for nutrients 

(nitrogen and phosphorus), respectively. Again they were measured at S7 in the Astatula sand 

drain field and at S10 in the Washed Builder’s sand drain field. 

Figure 28 A summary of overall removal efficiency of the conventional OSTDS Recirculation II 

with very coarse sand in the recirculation tank shows comparisons of two drain field systems. 

The hatched bars represent the OSTDS with Astatula sand drain field. The solid bars represent 

the OSTDS with Wash Builder’s sand drain field. 
50

Figure 29 Conventional OSTDS effluent concentration of Recirculation II shows very low TSS, 

CBOD5, and bacteria levels.

Figure 30 Conventional OSTDS effluent concentration of Recirculation II shows moderate 

levels of nitrogen and phosphorus.
51

6.4 Performance of conventional OSTDS and recirculation tank with coarse sand 

(Recirculation III)

Recirculation III with the recirculation tank uses an innovative modification by 

incorporating unsaturated and saturated zones. The tank is constructed mainly into two layers. 

The top layer is 11-inch of coarse sand, which is designed to be the unsaturated zone to increase 

dissolved oxygen, accommodating better nitrification process. The bottom layer is made of a 

mixture of sorption media, specifically design to improve denitrification process. Figure 24

indicates the media layers in the recirculation tank of Recirculation option III.

Figure 31 presents the overall removal efficiencies of the Recirculation III conventional 

OSTDS. TSS and CBOD5 removal efficiencies were better than the earlier designs. Figures 32 

and 33 show the effluent concentrations at S10 for conventional and nutrient pollutants 

respectively. TKN conversion was about equal to the other design recirculation options. It can 

be seen that phosphorus removal efficiency in Recirculation III was similar to that in 

Recirculation II. However, the nitrogen removal efficiency in Recirculation III was not as good 

as in the two earlier designs. Further observational evidence may be gained in Figure 34. It 

shows only nitrification process was observed in the conventional OSTDS, but the denitrification 

process was missing. This is why good TKN removal efficiency was observed while TN removal 

efficiency was poor. There was relatively low retention time (less than one hour) in the 

recirculation tank. The finding herein confirms that without sufficient hydraulic retention time, 

green sorption media may not be able to perform well as expected. 
52

Figure 31 A summary of overall removal efficiencies of the conventional OSTDS Recirculation

III with sorption media in the recirculation tank associated with the wash builder’s sand drain 

field.

Figure 32 Conventional OSTDS effluent concentration of Recirculation III at S10 shows low 

TSS, CBOD5, and bacteria levels.
53

Figure 33 Conventional OSTDS effluent concentration of Recirculation III at S10 shows high 

level of nitrogen, but low level of phosphorus. 

To further view the systematic trend, Figure 34 shows traces of nitrogen species and 

alkalinity at various sampling locations from the beginning to the end of the Recirculation I 

conventional OSTDS process, where S1 is the starting point (raw wastewater) and S12 is the 

ending point (8-foot below the washed builder’s sand drain field). It strongly suggests that most 

of the nitrification happened between S4 (outlet of the recirculation tank) and S8 (inlet of the 

drain field), as evidenced by the disappearance of organic nitrogen and ammonia in parallel with 

the spike of nitrate at S8 whereas alkalinity dropped dramatically. It was observed at S12 (8-foot 

below the drain field) that most of the total nitrogen was in nitrate form. This condition support 

that the nitrification process was obvious while the denitrification process was almost 

nonexistent in the recirculation tank. This evidence agrees with the spike of nitrate in the ground 

water as shown in Figure 7. Overall, Recirculation option I had the best removal efficiencies in 

terms of nitrogen and phosphorus removal when compared against option II and option III. But 

the fine sand was clogged easily making the maintenance become an issue. As a consequence, 

Recirculation option II performs relatively better than Recirculation option III in terms of TN 

and TP removal. 
54

Figure 34 Tracking of nitrogen species in the conventional OSTDS with sorption media-based 

recirculation tank.
55

Chapter 7 Performance-based Evaluation of Three Conventional OSTDS with 

B&G and SUW Designs 

7.1 Comparison of removal efficiencies 

In this chapter, the average removal efficiencies for the conventional septic tank and drain 

field system with two recirculation designs, one without recirculation, the B&G drain field 

system, and the SUW (with Canna) are compared against each other. When recirculation is 

added, there is a high probability that additional conversion to nitrate can be accomplished and 

possibly denitrification. If this is the case, additional removal of nitrogen is possible. As shown 

in Figure 35 there is negligible differences in the measures of TSS, CBOD5, and bacteria among 

the five systems. It should again be noted that TSS as measured in the SUW had additional 

solids added because of the sampling method. CBOD5 removal efficiencies of all systems 

exhibit slightly different results but meet current standards. Bacteria removal efficiencies of all 

systems were over 99.9%. Figure 36 shows that the SUW with Canna and B&G had higher 

removal effectiveness of total nitrogen and phosphorus. All five systems converted the influent 

raw waste ammonia nitrogen (see TKN values) to nitrates. There were near zero nitrates in the 

raw wastewater. The conventional septic tank drain field designs, even with recirculation, did 

not perform well in removing total nitrogen. In two conventional system designs, the soluble 

phosphorus increased relative to the influent. 
56

Figure 35 Comparative evaluation of removal efficiencies between conventional OSTDS, B&G 

system, and SUW with Canna in terms of TSS, CBOD5, and bacteria.

Figure 36 Nutrient removal efficiencies of the conventional OSTDS using the washed builder’s 

sand drain field, B&G drain field and SUW with Canna plants. 
57

7.2 Removing rate per unit area of drain field

To evaluate the relative importance of the surface area of the drain field with respect to 

pollutant removal we calculated the removal rates per unit area of drain field. The use of surface 

area reflects the relative importance in land and is an important cost consideration of each 

system. The SUW with Canna plants and B&G showed the best total nitrogen unit area removal 

efficiency as shown in Figure 37. Since there is minimal nitrate in the raw waste, a removal 

should not be significant if no nitrate appears in the effluent, however if nitrate appears in the 

effluent (as it does in conventional designs) then a negative removal or addition and be expected. 

In regard to the phosphorus removal per unit area, the SUW with Canna plants and the B&G 

present the best performance (see Figure 38). For TSS unit area removal, the B&G drain field 

was the best, while for BOD5, the conventional system with recirculation and the B&G drain 

field were the best (see Figure 39).

Figure 37 Nitrogen Species removal rate per unit area for five treatment trains
58

Figure 38 Phosphorus Species removal rate per unit area for five treatment trains

Figure 39 TSS and CBOD5 removal rate per unit area for five treatment trains

7.3 Comparison of effluent concentrations 

In the effluent measurements, the SUW had the lowest nitrogen concentration with the B&G 

drain field having the second lowest total nitrogen concentration and the conventional drain field 

systems having the highest nitrogen levels (see Figure 40). Similarly, the phosphorus level in the 

SUW with Canna cell (#1) was the lowest. B&G drain field had the second lowest level of 
59

phosphorus. The conventional drain field systems had the highest level of phosphorus in the 

effluent (see Figure 41). The bacteria level in the SUW effluent was the highest (see Figure 42). 

There were single measures where the fecal coliform counts exceeded the wastewater standard of 

800 cfu/100mL. Average counts of fecal and E. Coli were less than the wastewater standard of 

200 cfu/100mL. The effluent concentration of CBOD5 in all systems was low as shown in Figure 

43. The conventional OWST designs of this work are expected to have the greatest removal of 

nutrients, organics, and bacteria among all conventional systems because of the recirculation 

tank. Without recirculation tank, the removals are expected to be lower. In summary, the effluent 

data are reorganized in Tables 10 and 11 to ease the understanding of the variations versus 

averages with Table 10 reporting the standard deviation and Table 11 listing the overall average 

effluent concentrations.

Figure 40 Effluent concentrations of nitrogen species in all OSTDS are compared. SUW with 

Canna plants and B&G performed the best. 
60

Figure 41 Phosphorus level in effluents where SUW with Canna plants and B&G performed the 

best. 

Figure 42 Summary of 1-year average effluent bacteria concentration in all systems.
61

Figure 43 Effluent concentrations of TSS and CBOD5 of all systems are compared.

Table 10 A summary of standard deviation of effluents at UCF Test Center. 

Standard Deviation of Effluent

Conventional 

DF 

Recirculation I

Conventional DF 

Recirculation II

Conventional 

DF 

Recirculation III

B&G Drain 

Field

SUW - Canna 

Plants

Alk. (mg/L) 54.4 2.1 18.9 22.2 70.1

TSS (mg/L) 1.5 1.9 0.4 8.0 4.7

BOD5 (mg/L) 0.8 8.4 0.9 9.4 2.7

CBOD5 (mg/L) 0.0 7.5 1.0 7.1 1.3

Ammonia-N 

(μg/L) 29 24 5,578 1,928 499 

NOX-N (μg/L) 23,490 5,149 4,495 3,454 5 

Nitrite-N (μg/L) 2.3 3.9 1,137 55 0.9

Nitrate-N (μg/L) 23,488 5,146 3,657 3,417 4.9

Org. N (μg/L) 26,229 1,074 16,940 7,647 632

TKN (μg/L) 26,205 1,093 14,857 7,769 500

TN (μg/L) 23,881 15,394 10,698 4,431 499

SRP (μg/L) 1,647 1,013 1,445 1,111 6.6

Org. P (μg/L) 285 229 224 304 25.2

TP (μg/L) 1,289 1,077 1,439 1,405 30.5

Fecal (cfu/100mL) 1.2 0.1 0.1 15.0 1315 

E.Coli. 

(cfu/100mL) 0.1 0.1 0.1 12.3 13.0
62

Table 11. A summary of effluent conditions at UCF Test Center. 

Average Effluent Concentration

Conventional 

DF 

Recirculation I 

Conventional DF 

Recirculation II

Conventional DF 

Recirculation III

B&G Drain 

Field

SUW - Canna 

Plants

Alk. (mg/L) 203 96 30 221 379

TSS (mg/L) 4 2 0 11 35

BOD5 (mg/L) 3 13 1 11 5 

CBOD5 (mg/L) 2 7 1 8 4 

Ammonia-N 

(μg/L) 47 44 3,829 6,102 860

Nitrite-N (μg/L) 6 7 1,062 52 2 

Nitrate-N (μg/L) 14,860 29,749 38,923 3,146 6 

Org. N (μg/L) 15,143 1,283 11,898 3,361 1,097

TKN (μg/L) 15,191 1,327 15,727 9,463 1,957

TN (μg/L) 40,057 31,103 55,711 12,902 1,964

SRP (μg/L) 3,071 6,436 4,729 1,004 18

Org. P (μg/L) 4,815 208 795 258 78

TP (μg/L) 3,883 6,780 5,524 1,387 96

Fecal (cfu/100mL) 2 1 1 11 657

E.Coli. 

(cfu/100mL) 1 1 1 9 7 
63

Chapter 8 Conclusions 

8.1 Summary and remarks 

Passive nutrient removal OSTDS technologies, including the B&G and the subsurface 

upflow wetland (SUW), were evaluated in a full scale operational mode. The B&G and SUW 

systems have an advantage over conventional and performance-based OSTDS due to their higher

nutrient removal efficiency, system reliability, no energy needed, and low maintenance 

requirement. Three tables present data to summarize and compare water quality results. Table 12 

shows a summary of concentration changes of the three conventional OSTDS designs, the B&G 

drain field, and from the SUW with Cana as the plant species. For non-nutrient pollutants, the 

performance for the B&G drain field and the SUW is similar to the conventional septic tank 

systems. For nutrients, the B&G and the SUW perform much better. This table is developed 

based on the average raw water (inflow) and outflow conditions in a year. 

Table 12 A summary of concentration changes for OSTDS at UCF Test Center.

Concentration Changes (- indicates an increase)# 

Conventional DF 

Recirculation I

Conventional DF 

Recirculation II

Conventional DF 

Recirculation III

B&G Drain 

Field

SUW - Canna 

Plants

Alk. (mg/L) 32.63% 67.88% 88.02% 26.33% -46.76%

TSS (mg/L) 98.13% 99.17% 99.53% 94.73% 44.56% * 

BOD5 (mg/L) 90.14% 95.91% 98.51% 85.15% 94.79%

CBOD5 (mg/L) 91.86% 96.01% 98.45% 88.35% 95.74%

Ammonia-N (μg/L) 99.84% 99.89% 91.33% 81.78% 98.13%

Org. N (μg/L) 52.01% 85.30% 45.42% 85.83% 94.55%

TKN (μg/L) 74.91% 97.21% 76.16% 82.71% 97.04%

TN (μg/L) 49.07% 52.29% 16.21% 70.21% 96.69%

SRP (μg/L) 38.66% -33.98% -28.44% 79.11% 99.51%

Org. P (μg/L) 3.21% 86.73% 66.91% 83.56% 96.68%

TP (μg/L) 48.70% 11.01% 9.21% 81.79% 98.41%

Fecal (cfu/100mL) >99.9% >99.9% >99.9% >99.9% >99.9%

E.Coli. (cfu/100mL) >99.9% >99.9% >99.9% >99.9% >99.9%

* Includes additional particulate matter or measurement error. The resulting % removal (change) should be higher. 

# Change or removal is based on influent or raw sewage concentration values and the effluent from the drain fields. 

Nitrate is not included because in raw sewage the nitrogen form typically is not nitrates or near zero. 
64

8.2 Ground water impacts from conventional drain field 

For the soil conditions at the UCF OSTDS Test Center, which are primarily well drained 

sand with low water table (greater than 10 feet below the surface), nitrogen and phosphorus 

concentrations in the ground water were measured based on full scale operation of the 

conventional septic tank and drain field designs. The average measured data from 16 

groundwater sampling wells (2 beneath the conventional OSTDS drain field) as shown in 

Figures 6,7, and 8 indicate that the nutrient levels are greater under the conventional drain field 

relative to the background average nutrient values. Maximum levels of nutrients under the drain 

field are also noted and compared to the lowest background levels in 5 up-gradient wells as 

shown in Table 13. In particular, the highest level of nitrate nitrogen measured under the 

conventional OSTDS was 29.9 mg/L and the background levels were frequently below detection. 

The measured data under the conventional drain field are similar to those data reported in the 

Wakulla springs drain field study (Katz, 2009). These water quality data show the potential 

impact of increasing nutrients on ground water if nutrients are not controlled. 

Table 13. Highest measured concentrations from two sampling wells beneath the conventional 

OSTDS compared to the lowest background levels. 

Parameter/Location Background 

concentration

Highest beneath the 

conventional drain fields

TN (mg/L) .426 46.4 

Nitrate-N (mg/L) BDL* 29.9 

Ammonia-N (mg/L) .034 42.6 

TP (mg/L) .032 6.53 

SRP (mg/L) .004 2.89 

* BDL – below detection level

8.3 Cost analyses 

Cost data are developed using both operation and construction data. The cost of operating 

the B&G and the SUW is no more than the cost of operating a conventional system without 

recirculation, except for the replacement of plants. Plant replacement cost was estimated on a 

yearly basis and assumes that 25% of the plants will be replaced. The B&G and SUW require no 

energy. If a recirculation tank is added to a conventional system, an energy cost must be 

assigned because of the pump operation. A one-half horse power pump is assumed for recycle. 
65

Construction cost estimates are based on the designs and materials used for the B&G and 

SUW as built at the UCF OSTDS Test Center. The B&G and SUW cost estimates are based on a 

flow rate of 500 gpd. Additional flow rates and cost estimates with details are provided by 

Wanielista (2008). It is recognized that other systems may be designed to incorporate the 

concepts and will have a different construction cost. The construction cost increase for the 

B&G is approximately $2,400 more than the conventional system and the construction cost 

increase for the SUW is about $3,300 more than the conventional system. Cost data are from 

actual purchased prices for materials and labor for installation and includes a 20% contingency 

margin. 

Cost comparison data are provided for construction, annual operating and cost per thousand 

gallons of sewage treated. The flow rate base for design is 500 gallons per day. The cost for the 

conventional, B&G, and SUW systems were calculated based on the actual cost at the time of 

installation and are considered to be on a 2009 cost basis. The cost data for the other nutrient 

reduction OSTDS are based on published data from construction and operation in Florida (Mayer 

and Sherman, 1998). The cost data for these systems were calculated in 1998 dollars, thus 

construction and operating costs were inflated to mid-year 2009 using a 60% increase in 

construction cost and a 40% increase in operating cost to adjust the 1998 numbers to a mid-year 

2009 estimate. The increases are based on a building construction cost index and the estimate 

does take into account a construction cost decrease of 8.4% from mid-year 2008 through 2009 

(Turner, 2009). For nutrient reduction, the B&G and the SUW are the more cost effective 

options as seen in Table 14. The conventional system is the least costly but does not meet 

nutrient reduction standards. 

From a report for the Wekiva area and an interest rate of 7%, Anderson (2006) concluded 

that for a performance based technology, the life cycle cost per year would be about $2232.71. 

The passive sorption options within this report range from $1010 to $1230 per year. A Savings 

to each home owner of over $1000 per year relative to the Wekiva site performance based 

technology. The most expensive performance based technology from Table 14 is $4270 per 

year. It should be noted that the cost in Table 14 are highly variable from region to region in our 

State, but the relative cost of each should not change. 
66

Table 14 Cost comparison between a conventional OSTDS and advanced new passive OSTDS 

for nutrient removal including B&G and SUW designed at 500 gpd (mid-year 2009 basis). 

Construction Cost 

with 20% 

contingency ($)

Annualized 

Construction Cost at 

6% interest rate and 

20 years ($)

Annual 

Operating 

cost ($) 

Unit Cost 

$/1000 gallons

Conventional OSTDS 6,920 600 200 4.38

B&G with sorption 

media 9,320 810 200 5.53

SUW with sorption 

media and plants 10,200 890 400 7.07

Conventional OSTDS 

with Drip Irrigation 12,600 1,100 1,460 8.00

Continuous Feed 

Cyclic Reactor & 

Drip Irrigation*

18,200 1,590 1,800 18.58

Rotating Biological 

Contactor & Drip 

Irrigation*

18,800 1,640 1,740 18.58

Fixed Activated 

Sludge & Drip 

Irrigation*

18,800 1,640 2,110 20.55

Recirculation Tank & 

Drip Irrigation* 27,800 2,420 1,850 23.40

* from Mayer and Sherman, 1998. 

8.4 Certification and commercialization

Two US patents had been filed in 2008 and 2009 associated with the B&G drain field and 

the subsurface upflow wetland system, respectively. UCF is now seeking the industrial 

partnership to promote the outreach relationships and implement the technology transfer. During 

the pathway, we are eager to pursue any certification should our future industrial partners are 

interested in this route for final commercialization.

8.5 Future work 

 Continuing efforts will be directed toward more system reliability testing such as the stress 

test reflecting the situation that the B&G drain field and the subsurface upflow wetland system

could be overloaded during abnormal conditions. Tracer test is required to track down if the flow 

pathway has any shortcut in the innovative passive OSTDS so as to provide ideas in regard to 

how to improve the hydraulic design as part of the final design criteria. Operational manuals 

have to be prepared based on long-term operational experience in addition to the design manuals. 

During the commercialization, some additional tests to customize these passive technologies in 
67

order to fit in a variety of needs in real world systems are inevitable. We are also preparing 

several modeling packages to characterize these three types of drain fields. For example, the 

computer code, HYDROGEOCHEM, has been developed by Dr. George Yeh (i.e., a faculty with 

UCF) to characterize the conventional drain field, the Subwet 2.0 developed by the United 

Nations Environment Program (UNEP) will be applied to characterize the B&G drain field and 

the wetland system to compare against the system dynamics model that had already been applied

to characterize the SUW system. 

 
68

References

Anderson, D.L., Tyl, M.B., Otis, R.J., Mayer, T.G., and Sherman, K.M. (1998). On-site 

wastewater nutrient reduction system for nutrient sensitive environment. In Proceedings of 

the Eighth National Symposium on individual and small community sewage systems, Hyatt 

Orlando, Orlando, Florida, March 8-10, 1998, pp. 436-445. 

Anderson, D. (2006). A Review of Nitrogen Loading and Treatment Performance 

Recommendations for Onsite Wastewater Treatment Systems (OWTS) in the Wekiva Study 

Area. Hazen and Sawyer.

Arami, M, Limaee, N. Y., Mohmoodi, N. M., and Tabrizi, N. S. (2006). Equilibrium and kinetics 

studies for the adsorption of direct and acid dyes from aqueous solution by soy meal hull, 

Journal of Hazardous Materials, B135, 171-179. 

Bell, W., Stokes, L., Gavan, L. J., and Nguyen, T. N. (1995). Assessment of the pollutant 

removal efficiency of Delaware Sand filter BMPs, City of Alexandria, Department of 

Transportation and Environmental Services, Alexandria, VA. 

Beutel, M. W. (2006). Inhibition of ammonia release from anoxic profundal sediments in lakes 

using hypolimnetic oxygenation. Ecological Engineering 28(3), 271-279. 

Briggs, G. Roeder, E, et al. (2007). Nitrogen Impact of Onsite Sewage Treatment and Disposal 

Systems in the Wekiva Study Area, Florida Department of Health, Bureau of Onsite Sewage 

Programs, Division of Environmental Health. Tallahassee. 

Brix, H. and Arias, C.A. (2005). The use of vertical flow constructed wetlands for on-site 

treatment of domestic wastewater: new Danish guidelines, Ecological Engineering 25, 491-

500. 

Cadelli, D., Radoux, M., and Nemcova, M., (1998). in Vymazal, H. Brix, P.F. Cooper, M.B. 

Green and R. Haberl (eds), Constructed wetland for wastewater treatment in Europe – 

Backhuys publishers, Leiden, The Netherlands: 77-93. 

Chang, N. B., Wanielista, M., and Hossain, F. (2008b). The use of filter media for nutrient 

removal in natural and built environments: problems, perspectives, and challenges. 

Environmental Engineering Science, in review. 
69

Chang, N. B., Wanielista, M., and Xuan Z. (2008a). Characterizing green sorption media in 

vadose zone to improve nutrient removal of septic tank drain fields. Environmental 

Engineering Science, in review. 

Coombes, C. and Collett, P. J. (1995). Use of constructed wetland to protect bathing water 

quality. Water Science and Technology 32 (3), 149-158. 

Espino-valdés, M. S, Manzanares-papayanópoulos, L. I., Nevárez-moorillón, G. V.; Keerrendón, A., and Bautista-margulis, R. (2003). Biological removal of nitrogen to improve 

quality of reclaimed wastewater for ground water recharge, Acta Biotechnol., 23, 131-140. 

Etnier, C., Nelson, V., and Pinkham, R. (2000). Economics of decentralized Wastewater 

Treatment Systems: Direct and Indirect Costs and Benefits. Department of Agricultural 

Engineering, Agricultural University of Norway, Norway.

Florida Administrative Code (FAC) (2006). Chapter 403.087 Florida Department of 

Environmental Protection, Tallahassee, FL. 

Florida Administrative Code (FAC) (2009). Chapter 64E-6, Florida Department of Health, 

Tallahassee, FL.

Florida Department of Health (FDOH) (2007). Standards for on-site sewage treatment and 

disposal systems, Chapter 64E-6, Florida administrative code, Tallassee, Florida. 

Florida Department of Health (FDOH) (2009). Florida Onsite Sewage Nitrogen Reduction

Strategies Study-Task A2 Literature Review of Nitrogen Reduction Technologies for Onsite 

Sewage Treatment Systems. Research Report.

Florida Department of Environmental Protection (FDEP) (2009). Fate of Effluent-Borne 

Contaminants Beneath Septic Tank Drainfields Overlying a Karst Aquifer. Research Report 

WM926 submitted by Katz. B, et al., Wakulla USGS Final Report, USGS. Tallahassee. 

Forbes, M. G., Dickson, K. L., Saleh, F., Doyle, R. D., Hudak, P., and Waller, W. T. (2005). 

Recovery and fractionation of phosphate retained by lightweight expanded shale and 

masonry sand used as media in subsurface flow treatment wetlands, Environmental Science 

& Technology, 39(12), 4621-4627. 

Gabel, B., Kozicki, R., Lahl, U., Podbielski, A., Stachel, B., and Struss, S. (1982). Pollution of 

drinking water with nitrate. Chemosphere 11, 1147-1154. 
70

Gálvez, J. M., Gómez, M. A., Hontoria, E., and López, J. G. (2003). Influence of hydraulic 

loading and air flow rate on urban wastewater nitrogen removal with a submerged fixed-file 

reactor, Journal of Hazardous Materials, B101, 219-229. 

Gibert, O., Pomierny, S., Rowe, I, and Kalin, RM (2008). Selection of organic substances as 

potential reactive materials for use in a denitrification permeable reactive barrier (PRB), 

Bioresource Technology 99, 7587-7596. 

Gisvold, B., Ødegaard, H., and Føllesdal, M. (2000). Enhanced removal of ammonium by 

combined nitrification/ adsorption in expanded clay aggregate filters, Water Science and 

Technology, 41(4-5), 409-416. 

Güngör, K. and Ünlü, K. (2005). Nitrite and nitrate removal efficiencies of soil aquifer treatment 

columns, Turkish J. Eng. Env. Sci., 29, 159-170. 

Haberl, R., Perfler, R., Laber, J., and Grabher D., ‘Austria’, 1998, in Vymazal, H. Brix, P.F. 

Cooper, M.B. Green and R. Haberl (eds), Constructed wetland for wastewater treatment in 

Europe, Backhuys publishers, Leiden, The Netherlands: 67-76. 

Han, D. W., Yun, H. J., and Kim D. J. (2001). Autotrophic nitrification and denitrification 

characteristics of an up flow biological aerated filter, Journal of Chemical Technology and 

Biotechnology, 76, 1112-1116. 

Healy, M. G., Rodgers, M., and Mulqueen, J. (2004). Recirculating sand filters for treatment of 

synthetic dairy parlor washings, Journal of Environmental Quality 33, 713-718. 

Hedström, A. (2006). Reactive filter materials for ammonium and phosphorus sorption in small 

scale wastewater treatment, Doctoral Dissertation, Luleå University of Technology, IAAN: 

1402-1544. 

Henneck, J., Axler, R., McCarthy, B., Geerts, S.M., Christophenson, S.H., Anderson, J., and 

Crosby, J., 2001. On-site treatment of septic tank effluent in Minnesota using SSF 

constructed wetland: performance, costs and maintenance, on-site wastewater treatment Proc.

of the 9th National Symposium on Individual and Small Community Sewage Systems, 

ASAE, St. Joseph, MI. 

Huang, C. P., Wang, H. W., and Chiu, P. C. (1998). Nitrate reduction by metallic iron, Water 

Research 32(8), 2257-2264. 

Huang, J., Reneau, R. B., and Hagedorn, C. (2000). Nitrogen removal in constructed wetlands 

employed to treat domestic wastewater, Water Recourses 34(9), 2582-2588. 
71

Hurst, J. (2006). The Use and Management of Alternative Systems in Utah, M.Sc thesis, 

Department of Civil and Environmental Engineering, Utah State University, Logan, USA. 

Johnson, K. D., Martin, C.D, and Harper, J. P. (1995). Reducing Nonpoint Source Pollution in 

Nearshore Coastal Environments, Final report submitted to U.S. EPA Gulf of Mexico 

Program.

Kaseva, M. E. (2004). Performance of a sub-surface flow constructed wetland in polishing pretreated wastewater- a tropical case study, Water Research 38, 681-687. 

Katz. B, et al. (2009). Fate of Effluent-Borne Contaminants Beneath Septic Tank Drainfields 

Overlying a Karst Aquifer, Wakulla USGS Final Report, USGS. Tallahassee. 

Katzenelson, E., Buium, I., and Shuval, H. I. (1976). Risk of communicable disease infection 

associated with wastewater irrigation in agricultural settlements. Science 26, 194. 

Keffala, C. and Ghrabi, A., 2005. Nitrogen and bacterial removal in constructed wetlands 

treating domestic waste water, Desalination 185, 383-389. 

Kim-Shapiro, D. B., Gladwin, M. T., Patel, R. P., and Hogg, N. (2005). The reaction between 

nitrite and hemoglobin: the role of nitrite in hemoglobin-mediated hypoxic vasodilation. 

Journal of Inorganic Biochemistry 99(1), 237-246. 

Korkusuz, A., Beklioğlu, M., and Demirer, G. N. (2007). Use of blast furnace granulated slag as 

a substrate in vertical flow reed beds: field application. Bioresource Technology 98, 2089-

2101. 

Kyambadde, J., Kansiime, F., Gumaelius, L., and Dalhammar, G. (2004). A comparative study 

of Cyperus Papyrus and Miscanthidium Violaceum based constructed wetlands for 

wastewater treatment in a tropical climate, Water Research 38, 475-485. 

Mayer, T. and Sherman, K. (1998). Florida Keys Onsite Wastewater Nutrient Reduction 

Systems Demonstration Project. Ayers and Associates. March.

Mann, R. A. and Bavor, H. J. (1993). Phosphorus removal in constructed wetlands using gravel 

and industrial waste substrata. Wat. Sci. Tech. 27(1), 107-113. 

Mbuligwe, S. E. (2005). Applicability of a septic tank/engineered wetland coupled system in the 

treatment and recycling of wastewater from a small community. Environmental Management

35(1), 99–108. 

Metcalf and Eddy (2003). Wastewater engineering: treatment and reuse, 4th edition, McGraw 

Hill Publishing, New York, USA.
72

Namasivayam, C., Sakoda, A., and Suzuki, M. (2005). Removal of phosphate by adsorption onto 

oyster shell powder-kinetic studies, Journal of Chemical Technology and Biotechnology, 80, 

356-358. 

NSF International (2009). Relevant Standards and Protocols. NSF/ANSI Standards 245: 

Wastewater Treatment Systems - Nitrogen 

Reduction. http://www.nsf.org/business/wastewater_certification/standards.asp?program=W

astewaterCer#245

Pant, H. K., Reddy, K. R., and Lemon, E. (2001). Phosphorus retention capacity of root bed 

media of sub-surface flow constructed wetlands. Ecological Engineering 17(4), 345-355. 

Park, W. H. and Polprasert, C. (2008). Roles of oyster shells in an integrated constructed wetland 

system designed for P removal. Ecological Engineering 34, 50-56. 

Phelps, G. G., 2004. Chemistry of ground water in the Silver Springs basin, Florida, with 

emphasis on nitrate: U.S. Geological Survey Scientific Investigations Report 2006-1107. 

Rebco II (2007). www.perlite.net, accessed in June, 2007. 

Rocca, C. D., Belgiorno, V., and Meric, S. (2005). Cotton-supported heterotrophic denitrification 

of nitrate-rich drinking water with a sand filtration post-treatment, Water South Africa, 31(2), 

229-236. 

Rodgers, M. and Zhan, X. M. (2004). Biological nitrogen removal using a vertically moving 

biofilm system, Bioresource Technology, 93, 131-319. 

Ryan, P., Wanielista, M., and Chang, N. B., (2009). Reducing nutrient concentrations from a 

stormwater wet pond using a chamber upflow filter and skimmer (CUFS) with green sorption 

media. Water, Air and Soil Pollution, doi:10.1007/s11270-009-0174-x.

Sawyer, C. N., McCarty, P. L., and Parkin, G. F. (2003). Chemistry for Environmental 

Engineering Science, McGraw-Hill, New York, USA, Fifth Edition. 

Seidel, K., (1955). Die Flechtbinse, Scirpus lacustris L. Oekologie, Morphologie und 

Entwicklung, ihre Stellung bei den Völkern und ihre wirtschaftliche Bedeutung. 

Sweizerbart'sche Verlagsbuchhandlung, Stuttgart, Germany: 37–52. 

Sengupta, S. and Ergas, S. J. (2006). Autotrophic biological denitrification with elemental sulfur 

or hydrogen for complete removal of nitrate-nitrogen from a septic system wastewater, a 

report submitted to The NOAA/UNH cooperative institute for costal and estuarine 

environmental technology (CICEET). 
73

Servizi, J. A. and Gordon, R. W. (2005). Acute lethal toxicity of ammonia and suspended 

sediment mixtures to chinook salmon (Oncorhynchus tshawytscha). Bulletin of 

Environmental Contamination and Toxicology 44(4), 650-656. 

Shin, H. S., Yoo, K. S., and Park, J. K. (1999). Removal of polychlorinated phenols in sequential 

anaerobic-aerobic biofilm reactors packed with tire chips, Water Environment Research, 

71(3), 363-367. 

Smith, D. P., Otis, R., and Flint, M. (2008). Florida passive nitrogen removal study (Final 

report), Florida Department of Health, Tallahassee, Florida. 

Steer, D., Fraser, L., Boddy, J., and Seibert, B., (2002). Efficiency of small constructed wetlands 

for subsurface treatment of single-family domestic effluent. Ecological Engineering 18, 429–

440. 

Tanaka, N., Jinadasa, K. B. S. N., Werellagama, D. R. I. B., Mowjood, M. I. M., and Ng, W. J. 

(2006). Constructed tropical wetlands with integrated submergent-emergent plant for 

sustainable water quality management. Journal of Environmental Science and Health Part A, 

41, 2221–2236. 

Tarazona, J. V., Munoz, M. J., Ortiz, J. A., Nunez, M. O., and Camargo, J. A. (2008). Fish 

mortality due to acute ammonia exposure. Aquaculture Research, 18(2), 167-172. 

Tee, H.C., Seng, C.E., Noor, A. Md., and Lim, P. E. (2009). Performance comparison of 

constructed wetlands with gravel- and rice husk-based media for phenol and nitrogen 

removal. Science of the Total Environment 407 (11), 3563-3571. 

Turner Building Cost Index. (2009). (An index based on labor and material costs). 

http://www.turnerconstruction.com/Uploads/Documents/4thQtr2009.pdf 

U.S. Environmental Protection Agency (USEPA) (2002). USEPA Onsite Wastewater Treatment 

Systems Manual, EPA/625/R-00/008, Office of Research and Development, Washing ton 

DC, USA. 

United States Environmental Protection Agency (USEPA) (1988). Design manual-constructed 

wetlands and aquatic plant systems for municipal wastewater treatment, EPA/525/1-88/022, 

US Environmental Protection Agency, Center for Environmental Research Information, 

Cincinnati, OH. 
74

United States Environmental Protection Agency (USEPA) (2005). Handbook for Managing 

Onsite and Clustered (Decentralized) Wastewater Treatment Systems. EPA 832-B-05-001, 

Washington DC, USA. 

Urynowicz, M. A., Boyle, W. C., Bedessem, M. E. and Jin, S. (2007). Nitrogen removal in 

recirculation sand filter systems with up flow anaerobic components, Journal of 

Environmental Engineering, ASCE 133(5), 464-470. 

Venhuizen, D (1998). Sand filter/Drip irrigation systems solve water resources problems, in 

proceedings of the Eighth National Symposium on Individual and Small Community Sewage 

systems, American Society of Agricultural Engineers, St. Joseph, USA. 

Vohla, C., Alas, R., Nurk, K., Baatz, S. and Mander, U. (2007). Dynamics of phosphorus, 

nitrogen and carbon removal in a horizontal subsurface flow constructed wetland. Science of 

The Total Environment 380(1-3), 66-74. 

Vymazal, J. (2009). The use constructed wetlands with horizontal sub-surface flow for various 

types of wastewater. Ecological Engineering 35,1-17. 

Wanielista, M., Chang, N. B., and Makkeasorn, A. (2008). Provisional Patent: “Passive 

Underground Drainfield for Septic Tank Nutrient Removal Using Special Functionalized 

Green Filtration Media. Atty. Docket No: UCF-663. US Patent filed for review. 

Wanielista, M., Baldassari, T, Ryan, P., Rivera, B., Shah, T., and Stuart, E. (2008). Feasibility 

Study of Waste Tire Use in Pollution Control for Stormwater Management, Drainfields and 

Water Conservation in Florida. Seminole County Florida and State DEP. 

Water Environment Federation (WEF) and American Society of Civil Engineers (ASCE) (2005). 

Biological nutrient removal (BNR) operation in wastewater treatment plants, Manual of 

practice no. 30, WEF press and McGraw Hill Publishing, USA

World Health Organization (WHO) (2003). Guidelines for drinking water quality, 3rd edition, 

Geneva, Switzerland.

Xuan, Z., Chang, N. B., Daranpob, A., and Wanielista, M. 2009. Initial test of a subsurface 

constructed wetland with green sorption media for nutrient removal in on-site wastewater 

treatment systems. Water Quality, Exposure and Health, Doi: 10.1007/s12403-009-0015-6. 

Zhang, T. C. (2002). Nitrate removal in sulfur: limestone pond reactor, Journal of Environmental 

Engineering, ASCE, 128(1), 73-84.