# TECHNOLOGIES TO MEET NUMERIC

NUTRIENT CRITERIA AT FLORIDA’S DOMESTIC WATER RECLAM A TION

FACILITIES
November 1 8 , 2009Carollo Engineers 1 

### Table of Contents Execut ive Summary.

................................................................................................ ........................ 2 Exist ing and Proposed Nutrient Standards

...................................................................................... 4 Curr ent Nutrient Removal Techno lo gy ........................ ........................................ ........................... 5 Addit io nal Techno lo gi es to Meet Proposed Numeric Nutrient Cri teri a . .............................. ...........5 Challenges Associated with Reverse Osmosis Systems

................................................................ .. 7 Costs to Meet the Numeric Nutrient Criteria A Specific Case Study

......................................................................................................... 8 The Big P icture

.............................................................. ...................................................... 9 Sam ple of Utilit ies

............................................................................... ..............................10 Concl usi on s ........................................................ ............................................................................ 1 1Carollo Engineers 2



## TECHNOLOGIES TO MEET NUMERIC NUTRIENT CRITERIA AT FLORIDA’S DOMESTIC WATER

RECLAMTION FACILITIES EXECUTIVE SUMMARY The consent decree between the US Environmental Protection Agency (EPA) and a coalit io n of environmental groups over the need to set numeric nutrient criteria (NNC) for surface waters in th e State of Florida will have severe consequences for Florida’s wastewater utilit ies and the customers they

serve. If the expect ed NNC to be proposed by EPA are implemented in the state’s water qualit y regulat io ns, all Florida wastewater facilit ies that discharge reclaimed water to rivers, streams, lakes and estuaries will likely be required to meet new, very low limits on the di sc harge of total nitrogen (TN) and total phosphorus (TP). These new limits are ant ic ipated to requi re a reducti on in the current discharge of TN by 40 to 80% and TP by 90 to 95%

. Should the proposed numeric nutri ent cri teri a become incorporated in the disc harge permit s f or th ese treatment plants, Florida ut ilit ies will spend an est imated $24.4 to $50.7 billio n in capi tal costs for addit io nal treatment facilit ies, and will incur an estimated $0.4 to $1.3 billio n dollars per year more in increased operating c osts. This corresponds to tens of billio ns o f dollars in costs passed down to approximately three quarters of the individual cit izens and businesses in the State of Fl ori da. In addi

ti on, the treatment technologies needed to achieve these limit s will potent ia lly use almo st 5 percent of the total electric power generating capacit y in the State of Florida and contribute over 17.4 millio n tons of carbon dio xide (CO 2 ) emissio ns per year. According to the Florida Department of Environmental Protection (FDEP), the re are approximately

2,100 permi

tted domesti c wastewater facilit ies in the State with a total treatment capacit y of

about 2.4 billio n gallo ns per day , approximately half of which discharge effluent to surface waters. FDEP reported in 2005 that approximately 64% of Fl ori da’s popul at io n is served by central sewer systems that feed these treatment facilit ies. Florida’s total population is in excess o f 18 millio n residents according to the US Census Bureau. Based on these figures, approximately

12 milli on

ci ti z ens of Flori da are served by permitted wastewater treatment facilit ies that will be impacted by the proposed NNC. Requi red facilit y upgrades to treat the 2.4 billio n gallo ns o f wastewater per day to the new standards would result in a cost of approximately $1.6 to $3.3 billio n dollars per year over the next 30 years in addi

ti on to current treatment costs. Considering the interest paid on bonds requi red to fund these improvements, the State’s wastewater utilit ies are facing a $47.6 to $98.7 billio n dollar p ri ce tag to meet the proposed nutrient criteria over the next 30 years. These figures do not account for the corresponding increase in operating costs. We est imate that annual user fees for customers served by the impacted facilit ies will increase by an av erage of $673 to $726Carollo Engineers 3

per year in total. Table 1 summarizes the potential cost to Florida and the average individual househo ld. This paper addresses the anticipated costs for Florida utilit ies to be in co mp liance with EPA

prom ulgated numeric nutri ent cri te ri a; the treatment technologies available to achieve the proposed criteria ; and l astly , the addi ti onal $673 to $726 in yearly costs to customers should th ese regulat io ns be adopted. Table 1 Summary of Estimated Project Costs and the Estimated Average In crease in

Annual Sewer Rates for the State of Florida to Implement Numeric Nutrient Criteria. Project Cost 1 Annual Debt Service 2 Increase in

Annual Operating Costs 3 Yearly Sewer

Rate Increase per Customer4 Fl ori da Facili

ti es wi th NPDES Permi ts 5 $24,400 ,000,000 $1,600,000,000 $433,000,000 $673 All Fl ori da Facilit ies 5 $50,700,000,000 $3,300,000,000 $1,330,000,000 $726
Notes: 1. Project costs include estimated construction costs plus contingencies, administrative, legal, engineering and financing costs. Est imates also assume all private facilities must be upgraded to provide advanced wastewater treatment, microfiltration, and reverse osmosis with concentrate drying with landfill disposal. Assumes public facilities with deep wells will construct new deep well s for concentrate disposal. All other public fa cilities assumed to construct facilities for concentrate drying. 2. Annual debt service based on 30

- year amortization schedule and 5% interest. 3. Assumes current flow is 50% of design flow, and that this is repres entative of "actual" usage of the plant. Capital upgrades will be required for the entire design flow, while operating costs are based on actual usage. 4. Average cost for public and private systems. Customer size estimated at 2.1 persons per household based on US Census information. 5. The range of project costs was based on two scenarios. The lower project cost assumes that only surface water dischargers (e.g. assumed to be plants with NPDES permits) would be required to comply with the proposed nutrient criter ia. The higher project cost assumes that all Florida plants will be required to comply with the proposed nutrient criteria.Carollo Engineers 4



### EXISTING AND PROPOSE D NUTRIENT ST ANDARDS Fl ori da’s water reclamation plants already operate wi

thin a co mp lex system o f water qual it y regul at io ns that are among the most stringent in the world. Current ly, the highest level o f treatment provi ded by Fl ori da wastewater treatment plants is Advanced Wastewater Treatment (AWT). In Florida, the term “AWT” is often used to refer to wastewat er treatment that produces a recl aimed water achieving standards set out in section 403.086(4), Florida Statutes, i.e. recl aimed water containing no more than 5 mg/ L of carbonaceous five

- day bi ochemical oxy gen demand (cBOD 5 ), 5 m

g/L total suspended so lids (TSS), 3 m g/L TN, and 1 m

g/L TP. According to the proposed consent decree between EPA and a coalit io n of environmental groups, EPA i s to propose NNC for fresh waters in Florida in January 2010 and marine waters by January 2011. NNC proposed by FDEP in Ju ne 2008 would drop the TN limit fro m 3.0 m g/L to 0.82

– 1.73 mg/L and TP limit s f rom 1.0 m g/L down to 0.069

–

0.415 mg/L. Based on review comments from EPA on the FDEP NNC, the actual values for EPA's NNC are expected to be lo wer than the NNC proposed by t he FDEP. While these proposed changes might seem small, th e new NNC are at (for TP) or below (for TN) the concentrations achievable wit h proven nutrient removal technologies now in full

- scale use at municipal wastewater plants. Table 2 allows a comparison of

the current standards for secondary and AWT standards wit h the proposed NNC standards. The very low concentration cri teri a on TN and TP being proposed can be met, although at si gnificant cost, by

adding addi

ti onal treatment processes at the end of a Flo ri da advanced wastewater treatment (AWT) plant. AWT as current ly pract iced will not provide consistent com pliance wi

th the proposed NNC, and addit io nal techno lo gies must be emplo yed. Table 2 Comparison of Maximum Pollutant Concentrations Allowed by Wate r

Reclamation Standards Pollutant Secondary Limits 1 AWT Limits 2 Proposed Numeric Nutrient Limits 3 cBOD 5 , m

g/L 20

- 30 5

- TSS, m g/L 20

- 30 5

- TN, m g/L No limit 3 0.82

– 1.73 TP, m g/L No limit 1 0.069

– 0.415 Notes: 1. Nationwide technology based standards required by the Clean Water Act for all wastewater treatment plants. 2. Florida standards required by state law for discharge to specific nutrient sensitive water bodies. 3. Proposed in

- stream water quality standards that would become end

- of

- pipe limits unless a facility obtains a mixing zone or site

specific alternative criteria.Carollo Engineers 5 

### CURRENT NUTRIENT REM OV AL TECHNOLOGY Today more than 65 Florida plants with a total treatment capacit y of over 500 millio n gallo ns per day (m gd) use vari ous AWT technol ogi es to produce high qualit y reclaimed water. However, th ese pl ants represent only a relatively

small fraction of the plants in Florida. In order to achieve current AWT water qualit y limits, a pl ant generally m ust remove about 96% to 98% of TN and 85 to 88% of TP from raw sewage. At nearly all AWT pl ants in Florida, reclaimed water meet ing AWT limits is achieved using a combinat io n of a bio lo gical n utri ent removal (BNR) treatment techno lo gy

plus some f

orm of f iltration. BNR processes grow naturally occurring bacteria to remove the oxy

gen demanding organic pollutants, nitrogen, and phosphorus from raw sewage. Most of the nitrogen is released to the atmosphere as nitrogen gas while the phosphorus is removed wi

th bi osolids wasted from

the pl ant. The TN in reclaimed water co nsists of inorganic nitrogen (ammo nia and nitrates) and organic nit rogen. The ammo nia and nitrates can be removed down to low levels by convent io nal BNR processes
–

ni tri ficat io n and denitrificat io n wi th suppl emental

carbon (e.g. methanol) if necessary . Th e presence in reclaimed water of so lu ble nitrogen and phosphorus compounds that are not bi odegradable (also known as refractory compounds) ul

timately sets the lowest concentrations possible at treatment plants that rely on bio lo gical treatment methods. Res earchers call the refractory dissolved organi c ni

trogen (RDON). RDON is present in many raw water supplies and thus is present in the influent to water reclamat io n facilit ies. RDON i s also a by product of bio lo gical

treatment and will be found in reclaimed water even if not found in raw sewage. The effluent TN and TP concentrations reported by Florida AWT plants are generally consistent wi th the l owest effluent concentrations o f TN and TP ty pically reported by

researchers as achievable with current BNR technol ogi es. In other words, Florida AWT plants are already removing nutri ents as well or better than most BNR plants. 

### ADDITIONAL TECHNOLOG IES TO MEET PROPOSED NUMERIC NUTRIENT CRITERIA Water treatment techno lo gi es do exi st to produce reclaimed water with any desired water qualit y such as the ultra pure water required for electronics manufacturing and high

- pressure bo iler feed water. Since most technologies that can achieve these limits are ty pically used for applicat io ns other than removing nutrients fro m recl aimed water, little data exists on their performance in removing nitrogen and phosphorus to meet NNC. The addit io nal treatment techno lo gi es that mi ght be used to meet numeric nutri ent criteria include high

- pressure membranes (reverse osmosis and nano filtrati on), adsorpti on (activatedCarollo Engineers 6

carbon and reactive filtrat io n), oxidation (ozone, UV, peroxide), chemical coagulat io n and preci pi tati on, and i on exchange. Of the aforementioned addit io nal treatment technologies, reverse osmosis (RO) is a leading candidate t echno lo gy

when considering very

l ow nutri ent limits because of its abilit y remov e nearly al l consti tuents in the water to very l ow concentrati ons. In simple terms, RO is a select ively permeable barrier that rejects nearly all contaminants larger than a sp ecific size, while letting water mo lecules through. A number of large water reclamat io n plants currently use RO to produce very

high qualit y reclaimed water. These include the West Basin plant in El Segundo, California (22.5 mgd), the Scottsdale, Arizona W ater Cam pus (14 m

gd), the GWRS (70 mgd) pl ant in Orange Count y California, and four NEWater plants in Singapore (Bedok, 8.4 mgd; Kranji, 10.6 mgd; Seletar, 5.0 mgd; and Ulu Pandan, 39.1 mgd) among others. All of these facilit ies have successfully used mem brane techno logies to produce exceptionally high qualit y water for other purposes than to remove nutrients. Specifically, the West Basin plant in El Segundo and the GWRS plant use MF/RO treated reclaimed water to create saltwater intrusion barriers and forindirect potable reuse. The Scottsdale plant treats to drinking water standards and th en injects MF/RO treated water into an aquifer to supplement drinking water supplies, and the fo ur NEWater pl ants in Singapore use MF/RO or UF/RO to create high qualit y industrial water supplies for electronics manufacturing and to provide supplemental water to a reservoir used as a drinking water supply

. Figure 1 provides a schemat ic representation of the sequence of treatment zones in the typical Fl ori da water reclamati on plant desi gned to meet AWT limits using BNR alo ng with the selected addi ti onal technol ogy

of reverse osmosis membranes and associated concentrate disposal.Carollo Engineers 7 Crystallizer Product Water

Brine Concentrator Microfiltration (MF) Reverse

Osmosis (RO)

Solids to Disposal To AOP/ Stabilization Disinfection

Anoxic Anoxic Clarifier

Aeration Aeration Anaerobic

Filters Advanced Wastewater Treatment (AWT)

MF/RO Concentrate Treatment

Figure 1. Schematic illustration of the type of processes likely required for Florida waste water plants to comply with the proposed numeric nutrient criteria.


### CHALLENGES ASSOCIA TE D WITH REVERSE OSMOS IS SYSTEMS RO systems create several significant challenges. First, since membranes simply separate vari ous constituents fro m water, RO creates a “ concentrate” stream, ty pically 15 to 20% of the feed water, that contains concentrated levels of the rejected constituents. For example, if the mineral cal cium was in the untreated water at 100 mg/L, it would be treated to nearly 0 mg/L in the treated stre am

wi th a concentrati on of

about 500 mg/L in the concentrate stream that then needs to be di sposed of. Finding econo mical methods that will co mp ly wi th regulatory

and public percepti on requi

rements for reuse or dispose of concentrate can be a challenge. In areas wit h sui table geology , deep well disposal is an option. Concentrate cannot be recycled upstream of an RO system

as the salt concentration very quickly builds to intol erable l evels. Concentrate can also be evaporated, dried, and landfilled; however , both the capi tal and operating costs of drying concentrate are on the order of $3.00 per 1000 gallons treated more expensive than other disposal methods. Another si gnificant drawback to RO treatment is the high power cost required to operate an RO syste m. Adding RO to the ty pical water recl amat io n plant will increase power consumpt io n fo r an already

energy- int ensive system by at least 90%. Power requirements for RO systems treating recl aimed water range from about 1,400 to 2,400 kWh per mgal treated, com pared wi th theCarollo Engineers 8

average power consumpt io n fo r exi st ing water reclamat io n fa cilit ies of about 1,500 kWh/mgal. RO membranes also tend to foul quickly in reclaimed water applicat io ns, requiring pretreatment of f eed water and regul ar chemical cleaning of the me mbranes, both of which increase the cost and co mp lexit y of

building and operating an RO system. At present most reclaimed water RO systems use microfiltrat io n (MF) for pretreatment. Finally , RO treatment still needs to be preceded by a BNR process. RO alon e will not remove ammo nia and nitrate to the degree required due to their similar size and mo le cular characterist ic s to water. A ty

pical RO membrane will reject about 90% of the nitrate and 95% of the ammo nia in the feedwater. While phosphates are better r emo ved by RO membranes (reject io n ≥99.8%), too m uch phosphorus going to an RO system will also foul

membranes as a result of the preci pi tati on of inso lu ble phosphate compounds. 

### COSTS TO M EET THE NUMERIC NUTR IENT CRITERIA A Specific Case Study To illustrate the costs to implement addit io nal treatment to meet the proposed numerical nutrient cri teria , consi der an exist ing 10 mgd Florida water reclamat io n plant that meets advanced secondary water quali

ty standards for public access reuse. To meet the numeric nutrient criteria, th e bio lo gi cal

porti on of

thi s plant m

ust be upgraded to meet AWT limits, and then addit io nal terti ary physical

- chemical

treatment processes must be added. For this example, assume that convent io nal BNR and MF/RO processes will be used. Based on a study

of 50 BNR upgrad e proj ects, the expected cost to upgrade a 10 mgd plant from secondary to AWT standards is on average about $82 millio n. Based on bid

- data available from el even wastewater treatment plants using MF

- RO, adding MF

- RO treatment to an exist ing water recl amat io n plant i s est imated to cost between $54 millio n to $81 millio n depending on the concentrate disposal method. These costs could be significant ly higher at exist ing sites because of si te constraints. The total capital cost to upgrade a 10

- mgd water reclamati on f acili ty n ot al ready meet ing AWT limits could be in the range of $140

– $160 millio n, and operating costs would increase by

at l east $1.00 per thousand gallo ns treated (about $3.6 millio n per year), not including concentrate disposal costs which can r ange fro m an addi ti onal $1.10 per thousand gallo ns fo r a deep well up to $3.00 per thousand gallo ns fo r a brine concentrator system (these numbers have been normalized to reflect design flow and not concentrate flow). These addit io nal operating costs are in addit io n to the estimated $1.00 to $1.50 per thousand gallo ns being treated al ready being spent for ty

pical Florida treatment facilit ies producing water for reuse. Table 3 summarizes the incremental capital costs required to meet the proposed NNC.Carollo Engineers 9

Furth er, meet ing lo w yearly average nutri ent limits requires highly consistent performance by the treatment process, which will likely resul t in significant conservat ism in the sizing of treatment facilit ies, provisio n of redundant systems, and other provisio ns to increase reliabilit y that ul timately add addit io nal costs. These addit io nal costs are not accounted for in the estimates provi ded here. Table 3 Summary of Incremental Capital Costs ($M) for BNR and MF/RO

Treatment to Upgrade a 10 - mgd Water Reclama tion Facility for Three Different Concentrate Disposal Options.

Deep Well (10,000 ft) 3 Deep Well

(2,500 ft) 3 Zero Liquid

Discharge 4 BNR Upgrade 80 80 80 MF

- RO Systems 1 50 50 50 Concentrate Disposal 2 11 4 31 Total 141 134 161 Notes : 1. Assumed rec overies: MF = 95%; RO = 85%. 2. Concentrate disposal costs are estimated from a combination of bid

- data, vendor quotes, and a report published by the AWWA Membrane Residuals Management Subcommittee. 3. Excluding any pretreatment and standby disposal system

. 4. With a brine concentrator and brine crystallizer; excluding cost for solids disposal; brine concentrator recovery assumed = 95%. 

### The Big Picture In order to further quantify the effect of the proposed NNC on the State, the case study v ariables descr ibed above were applied to all publicly owned wastewater treatment plants documented by FDEP. The plants were broken down into plants that already have AWT and ones that do not. AWT technology

upgrades were assumed and projected to cost $8.20 per design ga llo n to upgrade. Subsequently, all plants would be required to be upgraded by the addit io n of an advanced tertiary

technol ogy

f ol lo wing AWT. Reverse osmosis was assumed at an average cost of $5.00 per gallon per day

of design treatment capaci

ty . An addi

ti o nal cost of $1.10 per gallo n of design treatment capaci

ty was applied for concentrate disposal for facilit ies that have an exist ing deep inject io n well, as they were assumed to be able to construct an additional deep inject io n well for RO concentrate dispo sal . All other facilit ies included a $3.10 per gallo n capital cost for a brine concentrator, as these facilit ies were assumed to not have access to a deep inject io n well. Lastly, the estimated increase in annual operating costs was calculated as fo llo ws: $ 1.00 per 1,000

- gallons treated for AWT and MF/RO treatment, and $3.00 per 1,000 gallo ns fo r facilit ies that must treat RO concentrate with a brine concentrator. Applying the “dollar” per gallo n unit capital costs to the FDEP database provided a lump sum ca pi tal expendi ture f or the state of $24.4 to $50.7 billio n do llars. This cost was converted to an annual debt payment over anCarollo Engineers 10

assumed 30 years wi

th 5% interest, whi ch amounts $1.6 to $3.3 billio n do llars plus an addit io nal $0.4 to $1.3 billio n dollars per year in increased operating costs. Much of the increase in operating costs can be attributed to power consumpt io n. We anticipate th at the addit io n of these facilit ies will increase overall power demand by almost 26 millio n megawatt
- hours/year. The est imate d increase in connected electrical load requires about 5 percent of the total power generation capacit y in Flori da. Moreover, based on data published by th e Department of Energy on CO 2 emissio ns by power plants, the addit io nal power consumpt io n will increa se CO 2 emissio ns in Fl ori da by over 17.4 millio n tons per year. These costs would be passed along to customers through increased wastewater rates. To estimate th e increase in rates, facilit y upgrade costs and populat io n information were used to calculate th e average mo nt hly

cost per househol d. On average, rates would increase by an average of $673 to $726 per year per househo ld. 

### Sample of Utilities A sampling of utilit ies was conducted to support the general effort of analyzing the cost impacts to all of th e Fl ori da utilit ies described in the “Big Picture” approach. These utilit ies have based th ei r est imated capital costs on various technical alternatives to meet the NNC rule that range fro m th e addi

ti on of RO, to im

plement ing 100% reuse via infrastructureimprovements, to deep well inject io n of effluent for aquifer recharge. The utilit ies sampled have wastewater treatment facilit ies that range in size from 6 to 42 mgd, and are located in various areas of the state. Each utilit y reported thei

r present avera ge monthly resident ia l customer wastewater charge and a preliminary est imate of the anticipated increase in rates to meet the proposed NNC. These percentages were translated to approximate rate increases. Table 4 summarizes the results of this analysis. Th e average rate i ncrease reported across these 8 utilit ies ($618/y r) com pares well wit h th e independent conceptual statewide est imate prepared by the independent engineer ($673/month to $726/month).Carollo Engineers 11

Table 4 Summary of Estimated Capital Costs and I ncreases in Sewer Rates for

Eight Florida Utilities to Construct Facilities to Meet Proposed Numeric Nutrient Criteria . Capital Cost Yearly Sewer Rate Increase per Household STATE OF FLORIDA 1 $24,400,000,000

- $50,700,000,000 2 $673

- $726 Bay Count y $42,0 00,000 $684.44 Broward County $425,000,000 $793.32 Dest in Water $34,000,000 $581.16 Escambia Count y $275,000,000 $590.88 Hollywood $370,000,000 $995.88 Jacksonville $2,000,000,000 $815.04 Cross Ci ty 3 $5,800,000 $336.48 South Walton 3 $16,000,000 $147 .00 Notes : 1. Estimated average costs for the State of Florida including annual O&M expenses and are shown for comparative purposes. 2. The low end of the range provides the probable opinion of cost assuming only plants with surface water discharges will be required to meet numeric nutrient criteriawhile the high end of the range assume that all plants will need to meet numeric nutrient criteria

. 3. Assumes 2.5 persons per connection and 150 gpcd. 

### CONCLUSIONS Im plementati on of

the proposed numeric nutrient cri ter ia will ini ti ate wi despread and dramat ic changes in the way

Fl ori da wastewater utilit ies treat and reuse reclaimed water. The necessary changes will likely

requi re decades to fully

implement. The maj or impacts expected for Fl ori da consumers include the fo l lo wing: 1. Wastewater utilit y rates can be expected to at least double for those utilit ies required to meet th e proposed NNC criteria

. 2. The total municipal wastewater treatment cost to the pe opl e of the State of Florida will range fro m $47.6 to $98.7 billio n dollars over the next 30 years. The actual cost with in this ant ic ipated range will depend upon how many utiliti es would be requi

red

-- besides those di scharging directlyto surface water st reams -- to meet these cri teri a . 3. Energy

requi rements for treatment could increase by almo st 26 millio n megawatt
- hours/year. 4. Emissio n of CO 2 and other greenhouse gases could increase by over 17.4 millio n tons per year of CO 2 .