NOAA Technical Memorandum

NMFS-SEFC-200

WASTE CHARACTERIZATION STUDY FOR

THE KEMP'S RIDLEY SEA TURTLE

5

FEBRUARY 1988

u. s. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric

Administration

National Marine Fisheries Service

Souteast Fisheries Center

Galveston Laboratory

Galveston, Tx 77551-5997
NOAA Technical Memorandum

SEFC-NMFS- 200

WASTE CHARACTERIZATION STUDY FOR

THE KEIVIP'S RIDLEY SEA TURTLE

By

Ronald F. Malone and Mark Guarisco

U. S. DEPARTMENT OF COMMERCE

National Oceanic and Atmospheric Administration

National Marine Fisheries Service

William E. Evans, Assistant Administrator for Fisheries

FEBRUARY 1988

This Technical Memorandum series is used for documentation and timely

communication of preliminary results, interim r ports, or similar specialpurpose information. Although the memoranda are not subject to complete

formal r view, editorial control, or detailed editing, they are expected to

reflect sound prof ssional work.

0

INT 0*
TABLE OF CONTENTS

Page

LIST OF FIGURES . . . . . . . . . . . . . . . . . . . . . . . . iii

LIST OF TABLES . . . . . . . . . . . . . . . . . . . . . . . . iv

INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 1

OBJECTIVES . . . . . . . . . . . . . . . . . . . . . . . . . . 3

METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Description of Prototype Holding System . . . . . . . . . 3

Excretion Study . . . . . . . . . . . . . . . . . . . . . 8

Partitioning Study . .. . . . . . . . . . . . . . . . . . . 10

System Monitoring . . . . . . . . . . . . . . . . . . . . 11

Chemical Methods . . . . . . . . . . . . . . . . . . . . . 11

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Behavior . . . . . . . . . . . . . . . . . . . . . . . . . 13

Excretion Study . . . . . . . . . . . . . . . . . . . . . 14

Partitioning Study . . . . . . . . . . . . . . . . . . . . 14

System Monitoring . . . . . . . . . . . . . . . . . . . . 14

Summary . . . . . . . . . . . . . . . . . . . . . . . . . 19

INTERIM DESIGN RECOMMENDATIONS . . . . . . . . . . . . . . . . 21

Operation and Maintenance Guidelines . . . . . . . . . . . 31

CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . 34

RECOMMENDATIONS . . . . . . . . . . . . . . . . . . . . . . . . 35

ACKNOWLEDGEMENTS . . . . . . . . . . . . . . . . . . . . . . . 36

LITERATURE CITED . . . . . . . . . . . . . . . . . . . . . . . 37

ii
Figure

LIST OF FIGURES

Page

Prototype holding system used

at Louisiana State University ............... 4

2

3

Rock filter underdrain system

used in conjunction with the

holding system •••••••••••••••••••••••

Foam fractionation unit situated

in the submerged rock filter ••

6

7

4 Testing apparatus used with the

waste characterization study •• ........... 9

5 Total Kjeldahl nitrogen loading curves

projected for 105 Kemp's ridley sea turtles

based upon average growth patterns for the

1985 year class (Caillouet and Koi, 1985) and

mean weight normalized, nitrogen excretion rates

derived from the yearling turtles •••••••••••••• 20

6 Projected biochemical oxygen demand loading

curves for 105 Kemp's ridley sea turtles based

upon average growth patterns for the 1985 year

class (Caillouet and Koi, 1985) and mean, weight

normalized, nitrogen excretion rates derived

from the yearling turtles •••••••••••••••••• 20

7 Conceptual design of a partitioned

turtle raceway system •••••••••••••••••••• 24

8 Typical turtle compartment within

the partitioned raceway system ••••••••••••••• 25

9 Outlet detail in the partitioned

raceway sys tern ••••••••••••••••••••••• 26

10 System layout for the proposed

raceway •••....••.•••.••.•••••..... 28

11 Details for the filter design,

underdrain system, and piping

required for the proposed raceway

system ••••••••••••••••••••••••••• 29

Hi
LIST OF TABLES

Table Page

Water quality parameters included in

the waste characterization study . . . . . . . . . . . . . 12

2 Water quality tests performed and

instruments used (Standard Methods,

15th edition) . . . . . . . 6 . . . . . . . . . . . . . 12

3 Results of the waste characterization

study (mg/day) . . . . . . . . . . . . . . . 15

4 Normalized results of the waste

characterization study (mg/g-day) . . . . . . . . . . . . . 16

5 Test conditions encountered during

the excretion study . . . . . . . . . . . . . . . . . . . . 17

6 Comparison of non-filtered vs.

filtered samples . . . . . . . . . . . . . . . . . . . . . . 17

7 Water quality tests on prototype

holding system . . . . . . . . . . . . . . . . . . . . . . . 18

8 Treatment components considered for

inclusion in the Ridley turtle

treatment system . . . . . . . . . . . . . . . . . . . . . . 22

iv
WASTE CHARACTERIZATION STUDY FOR THE

KEMP'S RIDLEY SEA TURTLE

INTRODUCTION

The Kemp's Ridley sea turtle, Lepidochelys kempi is an endangered

species. The National Marine Fisheries Service's Head Start program is

part of an international operation to save the turtles from extinction.

Under the Head Start program, eggs from the Ridley's only known wild

nesting beach at Rancho Nuevo in Mexico are transported to Padre Island

on the Texas coast to be hatched. The hatchlings are then reared in the

National Marine Fisheries Service (NMFS), Southeast Fisheries Center,

Galveston Laboratory, until the age of about one year before their

reintroduction into the wild (Fontaine et al. 1985). This "head start"

enables the turtles to develop a survival advantage.

The Galveston facility consists of 15 raceways, 20 ft. by 6 ft. by

2 ft., housed in two aluminum-framed green houses (Fontaine et al.

1985). One hundred and eight turtles are suspended in individual

buckets in each raceway. The turtles are fed floating pellets individually by hand through the open top of the buckets. Uneaten food and

excretions from the turtles fall through holes in the bottom of the

bucket, ultimately coming to rest on the tank bottom. A batch, flowthrough circulation system is currently used to maintain water quality.

At intervals of approximately 48 hours, each rearing tank is manually

drained, scrubbed, and refilled with fresh seawater which is maintained

in heated storage tanks adjacent to the green houses. During these

48 hour cycles, the water in the turtle system can vary from very clean

to, under the worst conditions, a black septic wastewater similar to a

domestic sewage.
2

This system of rearing the young turtles can be highly effective;

survival rates in excess of 90 percent have been reported in recent

years (Fontaine and Caillouet, 1985). Intermittent replacement of

water, however, has a number of drawbacks. The principal concern is the

suspected relationship between the poor water quality in the system and

the disease incidence in the animals. A number of the animals are under

treatment for minor skin diseases at any given time. The nature of

these infections suggest that they may result from high ammonia levels

which can occur in the system at the end of the 48 hour cycle~

Occasionally these diseases are fatal and lead to the loss of turtles.

This system of operation is extremely labor intensive. In

addition, heating costs for replenishing water during the winter months

are reportedly very high. Thus, it can be concluded that the cost

effectiveness of the system can be improved. Finally, the current water

treatment practice can result in water quality conditions which are not

compatible with the high level of public exposure that this facility

receives.

The limitations of the current water handling practices were

recognized by the officials responsible for maintaining the turtles in

the Galveston Laboratory. Mr. Clark T. Fontaine, Research Biologist at

the Galveston Laboratory, initiated the efforts which led to the

principal investigator's involvement in this project. In March of 1986,

Dr. Malone and Dr. Mike Liffmann, Assistant Director of the Louisiana

Sea Grant Program, visited the Galveston lab to observe the facility.

At this time, the principal investigator had the opportunity to discuss

the nature of the problem and research directions with Dr. Charles W.

Caillouet, Chief of the Life Science Division of the NMFS Galveston
Laboratory Program. Arrangements were made for the research team to

obtain permits for handling the endangered Ridley turtles, and for

Mr. Fontaine to transport five turtles to Louisiana State University for

study.

In April of 1986, five turtles were transported to an LSU laboratory equipped with closed, recirculating aquaculture systems for the

purpose of conducting waste characterization research. The turtles were

held in fiberglass tanks during the five months of study. Upon completion of the study, the turtles were returned to the Galveston facility

and were subsequently released to the Gulf of Mexico in the early fall

of 1986.

OBJECTIVES

The principal objective was to develop baseline waste characterization data required to design a wastewater treatment scheme for the

Galveston Head Start facility. As a secondary objective, preliminary

testing of some filtration components was undertaken to determine which

units were most appropriate for inclusion in a wastewater treatment

scheme. Finally, interim treatment recommendations were developed.

METHODOLOGY

Description of Prototype Holding Syste

Diagrams of the two fiberglass tanks and the biofilter system used

to hold the five turtles during their stay in the LSU Civil Engineering

Aquaculture Laboratory are shown in Fig. 1. Salinity ranged from 15 to

20 ppt throughout the study and was adjusted with Rila Marine Mix, an

artificial sea salt. The system water was not changed during the five

month period of study. Fresh tap water was added to compensate for
4

2"x 4" WOOD BEAM ~ HOLDING TANKS

/' + 3'x 6

1

(I' DEEP)

s"x 16"

CINDER-BLOCK

~-~/

'\ I V211 PVC

WOOD ~

PARTITI0N'\

~ SPRAYHEAD

RETURN

CINDER-BLOCK

PARTITI~

t

n.~ ""3- r

n

.,._- .•....-:..•..' :- n······.-i •.-.. -_ .

--

, FILTER # 2 SUMP

" ~,A.FOAM FRACTIONATIONUNIT ---,

A

L

Fig. 1. Prototype holding system used at

Louisiana State University.
5

losses due to evaporation and spillage. Water temperature was allowed

to fluctuate with the room temperature of the lab, which ranged from 22

to 25 degrees Celsius.

Water treatment was performed by flowing the system water through

two sequentially connected downflow submerged rock filters (Fig. 2).

The filters were constructed from 32 gallon plastic trash cans. Underdrains consisted of 1.5 inch PVC piping which was perforated with

3/8 inch holes. Each underdrain was connected to a vertical stand pipe

which allowed for discharge to the top of the next sequential filter or

sump. The stand pipe was open at the top to permit by-pass of water

when flow down through the filter media was restricted. The first

filter was filled with oyster shells which functioned primarily as a

sediment trap. The loosely packed oyster shell bed had a high porosity

and was highly resistant to clogging. The second filter was filled with

a #67 grade (1/2 by 3/4 inch diameter) dolomitic limestone. The media

in this filter contained sufficient surface area to provide for

nitrification and biochemical oxygen demand (BOD) reduction (Manthe et

al. 1983, 1984). The third component of the treatment system is a sump.

A sump pump (Little Giant, Model 5-MSP, 0.1 hp) returned filtered water

to the tanks, and provided a recirculation flow to a foam fractionator

submerged in the first rock filter (Fig. 3). The foam fractionator

effectively removed oils and greases that accumulated in the system.

The turtles were allowed to swim freely, but were separated from

each other in the tanks. One of the six foot long tanks was partitioned

into two 3 ft. long sections with cinder blocks, while the other was

divided into three 2 ft. long sections by a wooden partition. The

turtles were fed floating pellets, Purina Trout Chow, twice a day, at
~2011 ~I IPLASTIC CAN I

FILTER # I FILTER#2

OYSTER SHELL DOLOMITIC LIMESTONE

*Note: Foam Fractionator Not Shown for Clarity

SECTION A-A

UNDERDRAIN ROCK FILTER SYSTEM

6

TO

SPRAYHEADS

--

<.0

I

N

SUMP

OYSTER SHELL OR

DOLOMITE MEDIUM

(SEE SECTION A-A)

SECTION B-B

Fig. 2. Rock filter underdrain system used in

conjunction with the holding system.
FROM SUMP

9-LITER FOAM

COLLECTION BUCKET

4 1 nnr-1ALJr-LJ rr-IVIALr- ^,UW-Lr5/^'PLASTIC WASHER WITH '/8 HOLE

N'THREADED MALE COUPLE

IR

%" AIR HOLE

I"x4"ADAPTER COUPLE

3/4 / 1'/2" REDUCER

Fig. 3. Foam fractionation unit situated in the submerged rock filter. -i

GARDEN HOSE

3

PVC NOZZLE

A

'12 PVC

19 r.A1 I KI P1 AqTir rAN

OYSTER SHELLS
8

9:00 a.m. and 5:00 p.m. They were allowed approximately thirty minutes

to eat, after which time uneaten food was removed from the water.

Intermittently, perhaps once or twice a week, the turtles were fed one

to two live crayfish. The turtles received only indirect lighting from

the overhead fluorescent lights in the lab. The photoperiod was limited

to 10 to 12 hours per day. The lights were turned on manually, typically at 8 a.m., and turned off between 5 and 8 p.m.

Excretion Study

The waste characterization studies were undertaken to provide an

estimate of the amount and character of waste excreted by the turtles in

a 24 hour period. This was accomplished by placing the turtles in an

isolated container of clean water. Chemical analyses of the water after

the 24 hour period were used to quantify the amount of excretion.

A schematic showing details of the testing apparatus used to hold

the turtles is illustrated in Fig. 4. The testing apparatus consisted

of a plastic 32 gallon trash can filled with tap water. This reservoir

served as a constant temperature water bath for the testing container,

water temperature being maintained at 25 degrees Celsius by two aquarium

type water heaters submerged in the can. The testing container was a

circular plastic tub, 18 inches in diameter and 9 inches deep. The

container was clamped to the sides of the garbage can to prevent

tipping. Twelve liters of ammonia-free distilled water were placed in

the tub, adjusted to a salinity of 20 ppt, and allowed to stabilize at

25 degrees Celsius.

During early testing attempts, several turtles moved from the main

tanks to the testing tank appeared ill-adapted to the new environment.

These turtles refused to eat, rendering experimental results suspect.
TO AC POWER

AOUARIUM TYPE

WATER HEATERS

Fig. 4. Testing apparatus used with the waste characterization study.

v

TO AC POWER

v

12 LITERS

NI-13 FREE WATER

32 GALLON

PLASTIC CAN
10

For subsequent attempts, turtles were allowed to "warm up" in the main

tanks by placing them in containers identical in size and color to the

testing containers. The turtle to be tested was kept in this adjustment

container until normal eating habits were observed and then placed under

testing conditions.

At 1:00 p.m. on the day of testing, a turtle from the "warm uptl tub

in the main tank was removed and placed in the prepared test container.

Initial temperature, pH, and salinity wer~ recorded. At 5:00 p.m. on

the test day, the turtle was fed a counted number of food pellets;

thirty minutes later, uneaten food was removed and counted to determine

the number of pellets eaten. This feeding process was again performed

the following day at 9:00 a.m. At 1:00 p.m. on the following day, final

pH was measured, the turtle was removed, weighed, and returned to the

main tanks. Samples of the test water were taken for immediate chemical

analysis.

Partitioning Study

A partitioning study was undertaken to determine the impact of

suspended solids upon water quality. Selected samples from the

excretion studies were split. One aliquot was examined unfiltered,

while the other was pre-filtered through a 4.25 cm glass microfiber

filter apparatus prior to analysis. Filtered samples were analyzed for

BOD and total Kjeldahl nitrogen (TKN), and these values were compared to

values obtained in the same tests on the unfiltered samples. The

purpose of the partitioning study was to determine the maximum effect

that inclusion of a solids settling unit in the treatment scheme could

have on filtration efficiency.
11

System Monitoring

Periodically, a sample of water was withdrawn from the sump in the

turtle holding system. These samples were immediately analyzed for BOD,

total Kjeldahl nitrogen, ammonia nitrogen, and nitrite nitrogen. These

samples were collected in the latter part of the study period after the

system stabilized to represent typical system operation.

Chemical Methods

All data collected in these experiments was obtained from water

quality tests performed according to procedures established in Standard

Methods, 15th edition (APRA, 1980). Water quality parameters included

in the excretion study were: biochemical oxygen demand, total Kjeldahl

nitrogen, ammonia nitrogen, nitrite nitrogen, suspended solids, volatile

suspended solids, and settleable solids. The value of each of these

parameters in aiding filter design is summarized in Table 1. Techniques

and instrumentation used to measure the above-mentioned parameters are

presented in Table 2.

For the excretion study, approximately 5 liters of water was

sampled for analysis after the 24 hour excretion period. Water quality

tests were normally performed on the day of sample collection, with the

exception of the distillation step of the TKN analysis, which was

performed the following morning. The digested samples were kept on the

digestion apparatus overnight. Also, suspended solids and volatile

suspended solids tests were usually performed one or two days after the

sample was collected; the preservation of sample for these tests was

simply refrigeration. Suspended solids samples were filtered through

glass fiber filters with a 0.45 micrometer pore size. Slightly larger

sample volumes were taken for the partitioning and
12

Table 1. Water quality parameters included in the waste characterization study.

Parameter

Biochemical Oxygen Demand

Total Kjeldahl Nitrogen

Ammonia Nitrogen

Nitrite Nitrogen

Suspended Solids

Volatile Suspended Solids

Settleable Solids

Value

Sizing of biological filter, flow

determination

Biological filter selection

Biological filter selection

Contributes to nitrogen mass balance

analysis

Settling tank design

Biological filter solids balance

Settling tank design

Table 2. Water quality tests performed and instruments used (Standard

Methods, 15th edition).

Water Quality

Parameter

Ammonia Nitrogen

Nitrite Nitrogen

Total Kjeldahl

Nitrogen

Biochemical

Oxygen Demand

Settleable Matter

Suspended and

Volatile

Suspended Solids

Test

Distillation plus

Nesslerization

Sulfanilamide-based

colorimetric method

Digestion, Distillation

plus Nesslerization

5-Day BOD Test

Gravimetric Method

Nonfilterable Residue

Method

Instrument

Milton Roy Co. Spectronic

20 Spectrophotometer

Spectronic 20

Spectronic 20

Fisher Accumet pH meter

(Model 815 MP) with Orion

Research Oxygen Electrode

(Model 97-08-00)

Imhoff Cone

Whatman 4.25 cm glass

micro-fiber filters and

filtration flask apparatus, drying oven, muffle

oven, Mettler balance
13

system monitoring tests to compensate for the additional volume used for

filtered analysis and lower dilution factors for the sump analysis.

Each test for BOD, TKN, ammonia, and nitrite was performed by analyzing

one blank, a standard, and two replicates of sample water. Each

replicate was analyzed in triplicate. Values measured for standards

were compared to standard curves for quality control of test results.

Two standard curves were run, the second one performed when new reagents

were prepared for depleted ones.

RESULTS

Behavior

The activity of the turtles during their captivity in the lab

varied as the length of their stay increased. Early restlessness and

anxiety exhibited by thrashing actions of the turtles waned after about

one month. A noticeable behavior pattern that all five turtles

exhibited was a desire to swim into the turbulent current caused by the

spray head returning flow from the sump. Hours would be spent by these

turtles "exercising" in this fashion. Otherwise, the turtles spent the

daytime hours resting with their heads in the cinder block holes or

under the wood dividers.

No major disease or health problems were perceived in any of the

turtles; the only noticeable affliction was a minor skin abrasion on the

front flipper of one turtle, which seemed to be healing fine at the time

of the turtles' return to Galveston. The turtles usually showed

vigorous appetites at both daily feedings, and enjoyed feeding on live

crayfish that were given to them once or twice a week during the last

two months. Based on their weight data, presented later, the turtles

grew at a steady rate while in captivity.
14

Excretion Study

The results of water quality measurements made in the excretion

study are presented in Tables 3 and 4. Table 3 shows results in total

milligrams per day and Table 4 gives values in milligram per gram turtle

mass per day, obtained by dividing values in Table 3 by the mass of the

turtles at testing time. Information on the amount of food eaten during

the 24 hour test period and turtle mass is made available in Table 5.

Ground samples of the Purina Trout Chow were analyzed for BOD-5

(0.084 g-BODS/g-food) and TKN (0.33 g-N/g-food).

Thirteen separate data sets were collected on the five turtles

during their stay. Ten of these tests yielded acceptable data. Three

test samples analyzed early in the study were considered invalid because

the erratic nature of the turtles' eating habits produced inconsistent

test results. Subsequent testing attempts employed the adaption techniques discussed earlier to ease the transition to testing conditions.

Partitioning Study

Table 6 presents a comparison of filtered versus non-filtered

values for the BOD-5 and TKN. The partitioning study was performed on

samples of the final three turtles tested. A larger number of samples

analyzed in this fashion would have been desirable, but results of these

excretion study tests were fairly representative of the data on the

remaining turtles.

System Monitoring

Table 7 displays the results of water quality tests performed on

samples taken from the sump of the prototype holding system. Also

listed is information on the turtle's weight during testing of the sump

water. Flow rate through the filters varied from 5 to 8 gpm. Samples
15

Table 3. Results of the waste characterization study (mg/day).

Water Quality Parameter

Turtle

Ident.

Number Volatile

(Date Ammonia BOD-5 TKN Nitrite Susp. Susp. Settble.

Tested) (mg-N/ (mg-O/ (mg-N/ (mg-N/ Solids Solids Solids

day) day) day) day) (mg/day) (mg/day) (ml/day)

409 351.5 1474.8 631.1 0.940 6240.0 3773.3 25.2

(6/4)

410 507.2 2621.3 1021.5 0.163 12900.0 9360.0 58.8

(6/5)

417 430.8 657.6 776.4 35.9 3540.0 2304.0 51.6

(6/24)

410 399.6 924.0 757.2 27.7 3756.0 2328.0 74.4

(6/26)

420 505.2 1266.0 849.6 11.5 2904.0 1620.0 48.0

(7/1)

409 440.4 1050.0 626.4 15.7 2664.0 1620.0 45.6

(7/3)

423 451.2 594.0 638.4 34.8 2568.0 1380.0 54.0

(7/10)

409 375.6 795.6 636.0 39.1 1860.0 1584.0 46.8

(7/31)

410 519.6 908.4 726.0 0.276 1920.0 1668.0 22.8

(7/31)

417 345.6 878.4 548.4 40.9 1692.0 1356.0 36.0

(8/5)

Statistics (mg/day)

Average 432.7 1117.0 721.1 20.7 4004.4 2699.3 46.3

Std. 64.4 590.9 138.3 16.9 3395.6 2449.4 15.4

Deviatn.

Coeff. of 14.9 52.9 19.2 81.6 84.8 90.7 33.3

Var. (%)
16

Table 4. Normalized results of the waste characterization study

(mg/g-day).

Water Quality Parameter

Turtle

Ident.

Number Volatile Settb1e.

(Date Ammonia BOD-5 TKN Nitrite Susp. Susp. Solids

Tested) (mg-N/ (mg-O/ (mg-N/ (mg-N/ Solids Solids (mg/

g-day) g-day) g-day) g-day) (mg/g-day) (mg/g-day) g-day)

409 0.178 0.746 0.319 0.00048 3.16 1.91 0.013

(6/4)

410 0.213 1.099 0.428 0.00006 5.41 3.93 0.025

(6/5)

417 0.188 0.288 0.339 0.016 1.55 1.01 0.023

(6/24)

410 0.152 0.352 0.289 0.011 1.43 0.888 0.028

(6/26)

420 0.213 0.534 0.358 0.005 1.22 0.683 0.020

(7/1)

409 0.190 0.453 0.270 0.007 1.15 0.699 0.020

(7/3)

423 0.211 0.278 0.299 0.016 1.20 0.646 0.025

(7/10)

409 0.146 0.310 0.248 0.015 0.725 0.617 0.018

(7/31)

410 0.168 0.293 0.234 0.00009 0.620 0.538 0.007

(7/31)

417 0.128 0.327 0.204 0.015 0.629 0.504 0.013

(8/5)

Statistics (mg/g-day)

Average 0.179 0.468 0.299 0.009 1.71 1.14 0.019

Std. 0.030 0.266 0.066 0.007 1.49 1.06 0.007

Deviatn.

eoeff. of 16.8 56.8 22.1 77.7 87.1 93.0 36.8

Var. (%)
17

Table 5. Test conditions encountered during the excretion study.

Turtle Weight at Food

Ident. Test Time (g) Eaten

Num. (g)

409 410

Consumption (g/g)

409 1977 23.6 0.012 8.8 7.1

410 2385 15.0 0.006 8.6 7.7

417 2287 15.2 0.007 8.5 7.4

410 2623 20.1 0.008 8.6 7.2

420 2373 13.9 0.006 not taken 7.6

409 2319 12.5 0.005 8.9 7.2

423 2136 9.2 0.004 8.9 7.3

409 2566 7.7 0.003 8.1 7.4

410 3098 12.6 0.004 8.2 7.4

417 2690 17.5 0.007 8.6 7.7

Average 2445 14.7 0.006

Table 6. Comparison of non-filtered vs. filtered samples.

Turtle Identification Number/

Water Quality Parameter

Sample

Ident.

Initial pH Final pH

(of test (of test

water) water)

417

TKN BOD-5 TKN BOD-5 TKN BOD-5

(mg/1) (mg/1) (mg/1) (mg/1) (mg/1) (mg/1)

Non- 53.0 70.0 60.5 75.7 45.7 73.2

Filtered

Filtered 38.3 12.7 50.8 8.1 39.8 22.4

Percent 27.7 81.9 16.0 89.3 12.9 69.4

Removal
18

Table 7. Water quality tests on prototype holding system.

Water Date Tested

Quality

Parameter 7/21 7/22 7/24 7/25 8/12

Temperature 24.5 24.5 24.5 24.5 23.0

(Celsius)

pH 7.1 7.0 6.8 7.3 7.3

Salinity (ppt) 15 15 15 14 18

Turtle Mass 10,735 10,735 10,735 10,735 14,890

in System (g)

BOD-5 (mg/l) -- -- 2.6 1.3 2.4

TKN (mg-N/l) 7.34 6.44 5.81 5.05 6.01

Ammonia (mg-N/l) 0.515 0.430 0.339 0.259 0.657

Nitrite (mg-N/l) 0.363 0.402 0.219 0.306 0.634

were taken from the sump on five days near the end of July and early

August. The system held only four turtles in July while the fifth

turtle was held in another system. The fifth sample was taken when all

five turtles were in the system.

Initially, dolomitic limestone was used as filter media in both

filters, but clogging problems developed early in the study due to

solids loading. For this reason, the first filter of the double filter

system was modified to hold oyster shells, which eliminated clogging

difficulties. The visual quality of the water and filter performance

deteriorated significantly when uneaten food was not removed from the

water immediately after feeding. The system water developed a yellow

tint during the final months, a minor annoyance considering that the

water was not changed for the entire study period.
19

Otherwise, if uneaten food was promptly removed after feeding, the water

was clear. No turbidity problems ever developed.

Summary

Figures 5 and 6 summarize the results of the waste characterization

for the key water quality parameters of total Kjeldahl nitrogen (TKN)

and BOD-5. These figures project the total waste loading in a typical

rearing tank at the Galveston facility for the 1985 year class of

turtles. These curves were constructed by combining the results of

Tables 4-6 with unpublished data collected by Dr. Charles Caillouet on

the growth pattern of the 1985 year class of turtles held in the

Galveston lab. The growth curves for other year classes are similar

(Caillouet and Koi, 1985). Dr. Caillouet provided the following equation

relating turtle weight with age obtained by performing an overall lumped

regression on 1985 data on turtle weights:

ln(W) = ln(l.95) + 0.299 (T)i (1)

where W is the turtle weight in grams and T is the turtle age in days

2

(n = 6,020; r = 0.95).

These figures dramatically illustrate the impact of increasing

turtle age (and biomass) on the loading regime. The top curve represents total loading to the system assuming a 10 percent overfeeding

rate. The middle curve estimates the loading in the system assuming

100 percent of the food presented to the turtles is consumed (the conditions under which the excretion studies were conducted). The bottom

curve reflects the dissolved loading to the system assuming a mechanism

for 100 percent removal of the suspended solids is implemented.

Several observations can be made by analyzing these loading curves.

Filtration systems will become heavily loaded late in the year. The
20

50 250 300

---- WITH 10% OVERFEEDING

-- - EXCRETION

WITH SOLIDS REMOVAL

50 100 150 200 250 300

TURTLE AGE (Days)

projected biochemical oxygen demand loading curves for 105

Kemp's ridely sea turltes based upon average growth

patterns for the 1985 year class (Caillouet and Koi, 1985)

and mean, weight normalized, nitrogen excretion rates

derived from the yearling turtles.

8

2

6

o

o

12

10

z

~ 4

I24

20

....-..

~

0 16

"0

"

Ol

- 12

LO

J

a

8

0

CD

4

Figure 6.

100 150 200

TURTLE AGE (Days)

Figure 5. Total Kjeldahl nitrogen loading curves projected for 105

Kemp's ridely sea turtles based upon average growth

patterns for the 1985 year class (Caillouet and Koi, 1985)

and mean weight normalized, nitrogen excretion rates

deri ved from the year ling turtles.
21

exponential nature of BOD-5 and TKN loading with time displayed by the

curves permits more than one raceway to be treated by a single filter

early in the growth year. Additional filtration units can be brought on

line as turtle size increases. Such optimization can result in significant energy savings.

Allowing uneaten food to remain in the system substantially

increases the nitrogen loading, unnecessarily increasing ammonia

loadings. Consequently, screens should be included in the filtration

design to trap uneaten food for immediate removal after feeding.

Figure 6 illustrates the dramatic reduction in BOD-5 loading that could

be realized by including a solids removal unit ahead of the biological

filtration units.

The high nitrogen levels remaining after solids removal revealed by

the bottom curve of Figure 5 dictate the inclusion of a biological

treatment unit. This unit should support nitrification of the toxic

nitrogen forms of ammonia and nitrite to the relatively harmless

nitrate. Submerged rock filters with a gravel or oyster shell media and

fluidized sand bed filters are two economically feasible biological

treatment units capable of supporting nitrification. However, clogging

problems in the submerged rock filters due to excessive bacterial growth

may make fluidized bed filters easier to maintain.

INTERIM DESIGN RECOMMENDATIONS

Additional research is needed to determine the best treatment

scheme for the rearing tanks. Table 8 presents the functions of several

treatment units considered for inclusion in the prototype filtration

system. The research team was hesitant to recommend implementation of

innovative treatment schemes without prior testing. Thus, the
22

Table 8. Treatment components considered for inclusion in

the Ridley turtle treatment system.

Component

Screen Separator

Settling Tank

Rapid Sand Filter

Submerged Rock Filter

Fluidized Bed Reactor

Trickling Filter

Foam Fractionator

Ozonation

Function

Removal of uneaten food pellets

Solids removal

Solids removal

BOD and ammonia oxidation

BOD and ammonia oxidation

BOD and ammonia oxidation

Removal of oils and greases,

aeration

Bacterial reduction, color

removal, oxidation of refractory

compounds

interim, a design employing submerged rock filters similar to those used

in the experimental system is provided along with suggestions for an

improved raceway design. The prototype design will adequately treat

recirculated waters, but more cost efficient treatment schemes can be

developed with further research. Installation of the prototype design

is only recommended as an interim measure until more effective designs

can be developed. The prototype system will provide the Galveston staff

operational experience with a closed system. This experience will

demonstrate the potential benefits of closed system operation, allowing

development of sound recommendations for full scale implementation.

Significant benefits could be realized by improving the hydraulic

configuration of the rearing tanks. A critical function of flow through
23

the raceway is removal of solids and uneaten food. This function can

most efficiently be achieved by creating a serial flow pattern. Serial

flow can be accomplished by adding partitions in the rearing tanks, such

as presented in Figure 7, which illustrates a conceptual raceway design

capable of rearing 78 turtles. Maintaining a sufficient transport

velocity through the partitions for solids removal will be performed by

the slotted partition design as detailed in Figure 8. Forcing the

system flow through areas of small cross sections will create conditions

of high velocity flow capable of transporting floating food pellets

through the top slots and settled solids through the holes at the

partition bottoms. Dimensions for slots have been estimated and may

require further refinements to assure head losses through the raceway

are not excessive.

By decreasing the pump's flow rate, water level in the raceway for

normal operation and during feeding can be kept below the slots in the

partition tops. This flow will keep food within the partitions during

feeding periods and also maximize velocities for settled solids removal

through the bottom holes. Immediately following feeding, flushing the

system to remove uneaten floating flood can be accomplished by

increasing the flow rate to raise the water level over the top slots.

Figure 9 shows raceway outlet details which features a PVC standpipe

apparatus. This apparatus drains system water through the bottom 2 inch

pipe during normal operation and allows overflow through the top 4 inch

pipe for,flushing operations. The fittings within the turtle tank

should not be glued until the hydraulic operation of the raceway is

confirmed. The size of the reducer for the lower overflow pipe may

require adjustment.
0--000,

41' TO

FILTRATION

UNIT

1 1Y2" FROM

SUMP

Fig. 7. Conceptual design of a partitioned turtle raceway system.
a-3z4"SLOTTED HOLES

@ 31' 0. C.

Fig. 8. Typical turtle compartment within the partitioned raceway system.

OD

U1

0

,OC, 4,G
TO

FILTER

4' MALE ADAPTER (P )

4" FEMALE ADAPTER (PVC)

EXTERIOR FIBERGLASS

RACEWAY

COMPARTMENT

SEPARATOR

Fig. 9. Outlet detail in the partitioned raceway system.

do 1 -0

OPERATING WATER LEVEL

q FLUSHING

RUBBER "0 of

RING LEVEL

4" PVC PIPE

A 4" TEE

(PVC)

6

1 4 9 to

2

1

2 " PVC PIPE

4" x 2" REDUCER' BUSHING (PVC)
27

Filtration will be performed by two sequentially connected submerged rock filters (Spotte, 1979; Wheaton, 1977), oyster shells being

used for media in the first filter and #67 dolomitic limestone used in

the second filter, followed by a sump tank for dilution volume and pump

intake. Three 60 cubic foot tanks available at the Galveston lab will

be used for filter and sump tanks (Figure 10). The oyster shell filter

will act as a solids trap. To prevent filter clogging, annual breakdown

of the filter will be required to remove accumulated solids. For this

reason, the researchers recommend that the oyster shells be loosely

packed in plastic tubular netting such as Duronet (TM), manufactured by

Naltex of Texas, so that the netted shells can be easily removed from

the filter and rinsed free of solids. Whole oyster shells should be

placed loosely in bag nets so that adjacent bags will conform closely to

each other. Gaps between tightly filled bags would cause the filter to

short circuit defeating its solids removal function. Small bags should

be used for easy handling.

Figure 11 shows details of the filter design, underdrain system,

and piping. The first filter requires a minimum volume of 37 cu. ft. of

rinsed oyster shell media for a 108 turtle system, representing a

2.5 ft. depth of shells in the 60 cu. ft. tank. The loosely packed

tubular netting is placed on top of the PVC underdrain system. A

90 degree 4 in. PVC elbow, placed on the end of the raceway outlet pipe,

will empty onto the oyster shell filter. The screening device for

solids removal should be placed at the pipes' end to screen raceway

effluent to the filter. The screening device could be constructed by

placing a rectangular wooden frame lined with a fine mesh nylon screen

under the effluent pipe's discharge, as shown in Figure 11. Daily
1

1'2" CONTROL VALVE

1/2' HP 50 GPM PUMP

1'2 INLt I

NOTE:

HINGED LIDS NOT

SHOWN FOR

CLARITY

.67

OYSTER LIMESTONE

SHELL FILTER

FILTER

Fig. 10. System layout for the proposed raceway.

RACEWAY

V-110" HIGH

SUPPORT

4" OUTLET

SCREEN

"'SUMP
29

NOTE:

GRAVEL NOT

SHOWN FOR

CLAR ITY

2'-0"

2'-0"

%" HOLES

SECTION A-A

4

MPVC

INTAKE

,

I~M CHECK

VALVE

FLOAT

LEVEL

I

1'2" PUMP PICK-UP

SUMP

tll __ HINGED LID

I

/I~" PVC RETURN

{ TO RACEWAY

II

I

'2 HP 50 GPM

-

-

:5 "

V4 AERATION

LINE

CONTROL f

VALVES- t

A ~

.M PERFORATED

PVC NETWORK

OYSTER SHELL NO.57 LIMESTONE

FILTER FILTER

FROM RACEWAY)

3'-0· 1 .--

L£

Fig. 11. Details of the filter design, underdrain

system, and piping required for the

proposed raceway system.
30

removal of the screening device for emptying solids captured after

feeding can easily be accomplished.

The underdrain system consists of perforated 4 in. PVC pipe as

shown in section A-A of Figure 11. Pipe fittings do not require gluing.

Holes, 3/8 in. diameter, should be drilled evenly spaced over the entire

surface of the 4 in. PVC pipe. The standpipe is non-perforated and

functions during normal operation as an effluent pipe for filtered water

passing through the bed. Should clogging conditions develop, the

standpipe provides for bypass to the second filter. The effluent of the

oyster shell filter will freely empty onto the water surface of the

second filter.

The second filter contains #67 dolomitic limestone and serves as a

mechanism for nitrification and BOD reduction. The third tank acts as a

sump for dilution volume, storage for surge volume when the pump is not

operating, and pump intake reservoir. The tanks may be buried to protect system water temperature from seasonal temperature extremes. It is

recommended that the tanks be buried to 3/4 of tank depth. Hinged lids

should be attached to the tops of all tanks for safety purposes.

The second filter will require a minimum of 33 cu. ft. of rinsed

dolomitic limestone media for a 108 turtle system, representing about a

2.5 ft. depth in the 60 cu. ft. tank. The filter will perform better

if the #67 limestone is sifted through hardware cloth to remove stones

less than 1/2 inch in diameter. The smaller stones can cause premature

clogging of the filter bed. The gravel should be placed on top of the

filter's underdrain system which is similar to the first filter. Upon

exiting the second filter, flow will empty onto the water surface of the

sump.
31

As shown in Figure 11, the sump will contain the pump intake

strainer, which will be constructed of 4 in. perforated PVC pipe. A

1.5 in. reducer will be fitted to the 4 in. strainer for reduction into

the 1.5 in. pump intake pipe. A 1.5 in. check valve shall precede the

pump to prevent loss of pump prime should the pump be turned off. A

float valve should be placed on the reservoir's side to replace water

lost from evaporation. This float valve should be connected to a fresh

water source. A 1/2 horsepower self-priming pump capable of providing a

flow rate of 50 gallons per minute is recommended for installation.

The recirculation line returning filtered flow to the raceway will

consist of a 1.5 in. PVC pipe fitted with a 1.5 in. ball valve placed

near the raceway influent for controlling pump flow rate to the raceway.

A 3/4 in. aeration line with 3/4 in. control valves will be fitted to

the 1.5 in. raceway recirculation line and will send return flow to both

filters to provide increased filtration and aeration of system water.

Three 1/8 in. diameter holes should be drilled into the PVC caps

attached to the ends of the 3/4 in. aeration lines. Recirculated flow

will spray onto the water surface of both filters, achieving the

aeration needed for oxidation of the wastewater.

Operation and Maintenance Guidelines

The 1.5 in. control valve placed in the raceway recirculation pipe

will be located near the raceway influent for convenient flushing

operation following feeding. During normal operation, water level in

the raceway should be kept just below the slots in the partition tops to

provide maximum velocity of flow through holes in partition bottoms for

efficient removal of settled solids. Immediately following feeding, the

control valve should be adjusted to raise the raceway level above the
32

bottom of the top slots to facilitate removal of the uneaten floating

food pellets. When flushing is complete, water level should be returned

to the original level by adjusting the control valve. Uneaten flood and

settled solids will be flushed onto the screening device located under

the raceway effluent pipe in the oyster shell filter. The screen should

be checked daily for solids accumulation and emptied when appropriate.

The 3/4 in. control valves on the aeration lines should be adjusted

to maintain enough flow for aerating of the filter water while allowing

sufficient flow through the 1.5 in. recirculation line for raceway flow

requirements. Oxygen levels in the effluents from filters #1 and #2

must remain above 2.0 mg/l. Failure to maintain effluent oxygen levels

above 2.0 mg/l will lead to system failure. The nitrification bacteria

responsible for ammonia and nitrite oxidation are strict aerobes

(Manthe et al. 1984). Rapid buildups of ammonia and nitrite will occur

if oxygen levels are not maintained. Oxygen levels in the filters are

controlled by the total volume of water passing through the filters

(Manthe et a1. 1985) and by the vigor of the aeration action induced by

the spray heads. If temporary excess flow is needed for raceway

operations, the aeration flow may be temporarily reduced to permit the

full flow to reach the raceway.

The biological filters must be permitted to acclimate for 30-45

days to the loading regime before they will contain sufficient bacteria

populations to assure treatment (Malone and Manthe, 1985). If unacceptable water quality conditions develop during this acclimation period,

the water in the system should be replaced with fresh sea water. Once

acclimated, water quality in the system should be consistently good.

Ammonia and nitrite levels should remain below 1 mg-N/l. BOD-5 levels
33

should be below 5 mg/l. The water should be clear, although it may

yellow with age as refractory dissolved organic accumulate.

The only drawback to the submerged rock filters is its tendency to

clog. In the first filter, the oyster shell filter, this will most

likely occur as the result of a long term accumulation of refractory

solids. Should oyster shells in the first filter become clogged,

wastewater flow will be bypassed to the second filter overflow into the

first filter's standpipe. As soon as the first filter bypasses, the

netted shells should be removed and rinsed. If clogging conditions

develop in the second filter, overflow will be diverted by its standpipe

into the sump. Clogging of the second filter can be expected during

periods of very high loading. If water quality remains acceptable, no

action need be taken. If system water quality becomes unacceptable, the

second filter should be broken down by removing limestone gravel for

rinsing of both the gravel and PVC underdrain system.

The filtration system presented here will effectively control

planktonic algal growth. The system will not, however, discourage the

growth of attached algae on the turtles' backs or on the side walls of

the raceway system. It is suggested that the growth of attached algae

will be best controlled by shading the raceway so that the light

intensity is below that required for the algae's proliferation. No

algae problem was observed in the LSU prototype system. The turtle

tanks received only indirect flourescent lighting. Growth of attached

algae in the filter boxes is not harmful. Excessive growths may require

removal if they interfere with the pump intake in the sump.

Filter design was performed for a single existing raceway of 108

turtles for immediate implementation to existing rearing facilities;
34

however, overdesign of the system will permit additional loading should

filter performance prove satisfactory for one raceway. The loading of a

single raceway theoretically represents only one-half of the filtration

system's capacity. If improved raceways are constructed following the

raceway design of Figure 7, the filter should be capable of treating

wastewater from at least two raceways filled with yearling turtles.

Filter design was based on a worst case analysis utilizing waste characterization data and maximum observed weight (2.5 kg) collected on the

LSU lab animals. Weights of the LSU animals were significantly higher

than weights predicted by Dr. Caillouet's weight formula for the 1985

class (eq. 1) so an additional safety factor is provided for most of the

year.

CONCLUSIONS

1. The Kemp's Ridley turtles can be successfully held for extended

periods of time in closed or semi-closed recirculating systems

without any adverse impact.

2. The nitrogen excretion rate of the Kemp's Ridley turtle was a

relatively constant 0.3 mg-N/gm turtle-day. Ammonia was the

principle nitrogen excretion product found in the water at the end

of a 24 hour period.

3. Due to the high nitrogen content of the Purina floating trout

food fed to the turtles, uneaten food has a major impact on the

nitrogen loading to the system. Overfeeding must be avoided or

excess food rapidly removed if ammonia and nitrite levels are to be

successfully controlled.
35

4. The BOD-5 excretion rate was highly variable, averaging nearly

0.5 mg/gm turtle-day. The BOD-5 loading rate to the system is

controlled by the solid excretion rate to the system.

5. The high solids loading rate and associated BOD suggest that an

effective solids removal mechanism included in the treatment system

for the recirculating system would greatly improve filter efficiency and increase filter loading capacity.

6. Submerged rock filters would provide nitrification sufficient for

the recirculation system, but may require periodic breakdown to

remove accumulated solids.

7. There are no insurmountable technical obstacles to developing a

completely automated rearing system providing for automatic

feeding, heating, lighting, water exchange and water quality

treatment for the turtles.

RECOMMENDATIONS

1. It is recommended that this research effort be continued. There

appear to be no serious obstacles to using recirculating systems

for rearing of the Kemp's Ridley sea turtle.

2. Selected findings of this initial study need to be reconfirmed.

Additional testing of the food and additional partition studies

should be undertaken to assure findings in these areas are

statistically sound.

3. At least one of the rearing tanks at the Galveston lab should be

converted to a recirculating format this spring, implementing the

interim prototype treatment system design in this report. This

system should be monitored and evaluated by the Galveston staff.
36

4. A fully automated prototype rearing system employing the most

advanced design concepts should be set up on the LSU campus for

testing and refinement. Following evaluation, selected components

of this unit will be installed on a second rearing tank at the

Galveston lab for staff evaluation.

5. An analysis of the cost and benefit of the selected treatment and

automation options should be undertaken by the research team.

6. Recommendations for a permanent full scale implementation should be

developed by the Galveston lab staff working in collaboration with

the research team following evaluation of the prototype systems.

ACKNOWLEDGEMENTS

This research was supported by the Louisiana Sea Grant College

Program. This program is an element of the National Sea Grant Program,

under the direction of NOAA, U.S. Department of Commerce. We gratefully

acknowledge the assistance of Dr. Charles W. Caillouet and Clark T.

Fontaine of the National Marine Fisheries Service's Southeast Fisheries

Center Galveston Laboratory for providing the turtles and guidance in

handling required for this project. We also owe our appreciation to

Dr. Ronald L. Thune of the Louisiana State University Department of

Veterinary Microbiology and Parasitology for his assistance in monitoring the health of the experimental animals. Figures in this report

were originally drafted by David Kurjan. Daniel G. Burden provided

training and supervision for the analytical work conducted in the waste

load allocation.
37

LITERATURE CITED

APHA. 1980. Standard Methods for the Examination of Water and Wastewater.

15th Edition, American Water Works Association, Water Pollution Control

Federation, and American Public Health Association, Washington, D.C.,

USA.

Caillouet, C. W., and D. B. Koi. 1985. Patterns and variability in the

first year growth in the weight of captive-reared Kemp's Ridley sea

turtle: a graphical analysis. NOAA Tech. NMFS-SEFC-164, 4 pp. + 52

figs.

Fontaine, Clark T. and Charles W. Caillouet, Jr. 1985. The Kemp's ridley

sea turtle head start research project: an annual report for fiscal

year 1984. NOAA Technical Memorandum NMFS-SEFC-152, ii plus 13 p. and

3 tables.

Fontaine, C. T., K. T. Marvin, T. D. Williams, W. J. Browning, R. M.

Harris, K. L. Indelicato, G. A. Shattuck, and R. A. Sadler. 1985. The

husbandry of hatchling to yearling Kemp's Ridley sea turtles

(lepidochelys kempi). NOAA Tech. Mem. NMFS-SEFC-158, 24 pp.

Malone, R. F., and D. P. Manthe. 1985. Chemical addition for accelerated

nitrification of biological filters in closed blue crab shedding

systems. Pages 41-47 in National Symposium on the Soft-Shelled Blue

Crab Fishery, H. M. Perry and R. F. Malone (eds.).

Manthe, D. P., R. F. Malone, and H. M. Perry. 1983. Water quality fluctuations in response to variable loading in a commercial closed blue

crab shedding facility. Journal of Shellfish Research, 3:175-182.
38

Manthe, D. P., R. F. Malone, and S. Kumar. 1984. Limiting factors associated with nitrification in closed blue crab shedding systems.

Aquacultural Engineering, 3:119-139.

Manthe, D. P., R. F. Malone, and S. Kumar. 1985. Elimination of oxygen

deficiencies associated with submerged rock filters used in closed,

recirculating-aquaculture systems. Pages 49-55 in National Symposium

on the Soft-Shelled Blue Crab Fishery, H. M. Perry and R. F. Malone

(eds.).

Spotte, S. 1979. Fish and Invertebrate Culture, Water Management in

Closed Systems. 2nd Edition, Wiley-Interscience, New York, USA, 177

pp.

Wheaton, F. W. 1977. Aquacultural Engineering. Wiley-Interscience, New

York, USA, 708 pp.