Dates : 22 -24 Venue : Satish Dhawan Auditorium, Indian...

Lake 2008 : Conservation and Management of River and Lake Ecosystem

BASELINE STUDY OF AN

River and Lake Ecosystem Dates : 22nd- 24th December 2008

Venue : Satish Dhawan Auditorium, Indian Institute of Science, Bangalore 560 012

BASELINE STUDY OF AN ECO-RESTORATION PROCESS ON A

HYPER-EUTROPHIC URBAN WATER BODYHYPER EUTROPHIC URBAN WATER BODYY. Prathishta, JRF, CES, Anna University, Chennai

Dirk Walther, CIM expert, CES, Anna University, ChennaiK. Thanasekaran, Director, CES, Anna University, Chennai, , , y,

ContentsY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Contents

Obj ti & Sit S l ti• Objectives & Site Selection

R t ti t h i• Restoration techniques

Eff t f t t t• Effect of treatment

C l i• Conclusion

IntroductionY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

• Ramsar convention, 1971.

I di 15 illi b di 25 R i• India – 15 million water bodies, 25 Ramsar sites.

• “The National Lake Conservation Plan” (1994) and “TheNational Wetland Conservation Programme” (1995)National Wetland Conservation Programme (1995).

• “Wetland (Conservation and Management) rules 2008”.

• Hypereutrophic pond for the study.

• Technologies used for restoring the pond.

• Utilize the pond for propagation of wildlife.

ObjectivesY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

jThe scope of the project is to developefficient eco-restoration mechanism in a

ll l h d hsmall scale eutrophic pond to reacholigotrophic state

• To Monitor the status of the pond by conducting Physico chemical and biological conducting Physico-chemical and biological analysis.

• Technologies to be urged for rejuvenating the pond by enhancing the oxygen loads the pond by enhancing the oxygen loads and maintaining the mass balance.

Study Area & Sampling Y. Prathishta, Dirk Walther, K. Thanasekaran (2008)

pStrategy

• The pond is located at Besant Nagar (Chennai, Tamil Nadu)

S.No

Frequency of sampling

Type of sampling

1. Before the t ti

Integrated li Tamil Nadu)

• Area - 2,452.8 m2

• Depth -1.6m l l 924 3

restoration process

sampling (H)

2. Aquatic h t

Integrated s li • Total Volume - 3,924 m3

• The pond was overgrown with (Pistia spp.) water

macrophyte removal

sampling (V)

3. During the filtering process

Integrated sampling ( pp )

cabbagesfiltering process sampling

(V)

V - VerticalV VerticalH - Horizontal

Sampling Sites

Y. Prathishta, Dirk Walther, K. Thanasekaran (2008)

DC

B

Sampling Sites 1.85 m

1.89 m

AE

C

1.71 m

1.9 m

2.5 m

Dissolved Oxygen(DO) Profiling with depth

DO in mg/L

0

0.2

0.4

0 1 2 3 4 5 6

DO in mg/L

0.6

0.8

1

1.2

Dep

th in

m

1.4

1.6

Site 'A' Site 'B' Site 'C' Site 'D' Site 'E'

MethodologyY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Pond

Aquatic macrophyte

removalStep 1 Reduces nutrient

concentration

Filtration and re-aerationStep 2 Accelerates and re-aerationStep 2

removes nutrients

Aquatic macrophyte removalY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Aquatic macrophyte removal

Filtration and Re-aeration set upY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Filtration and Re aeration set up

Impacts of RestorationY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Impacts of RestorationBefore

restoration

E i E i M t

After water cabbage removal

During filtration

P t U it M t H E i HEpi- Epi- Meta-limnion limnion limnion

1 pH - 7.1 8.8 7.7 7.7 8.3 7.9 7.62 EC µS/cm 1390 957 950 954 381 375 3743 DO mg/L 3.2 4.4 3 1.2 4.8 3.9 1.9

Parameters Units Meta-limnion

Hypo-limnion

Epi-limnion

Hypo-limnion

S. No

g4 Temp ºC 24.7 30.6 29.5 29.2 31.1 29.2 29.15 TDS mg/L 922 1180 1250 1090 1283 1093 12876 TSS mg/L 131 257 149 210 140 1200 13957 TS mg/L 1050 1440 1200 1370 1423 107 1088 T bidit NTU 14 9 120 30 69 1 28 9 17 2 17 78 Turbidity NTU 14.9 120 30 69.1 28.9 17.2 17.79 NH4-N mg/L 15.4 BDL BDL BDL 1.4 0.8 1.1

10 NO2-N mg/L BDL BDL BDL BDL BDL BDL BDL11 NO3-N mg/L BDL 0.1 0.1 0.1 BDL BDL BDL12 TKN N /L 23 8 9 8 7 4 2 9 8 4 2 4 212 TKN-N mg/L 23.8 9.8 7 4.2 9.8 4.2 4.213 Chlorophyll a mg/m3 80.5 39 13.9 1.1 371 21.3 17.114 PO4

3- P mg/L 1.1 0.4 0.5 0.3 1.4 0.9 0.915 COD mg/L 168 96 92 86 45 45 9416 BOD (20ºC) /L 52 30 27 23 14 14 2816 BOD5(20ºC) mg/L 52 30 27 23 14 14 2817 Fecal coliform MPN/100ml 1.13*105 2.33*105 1.13*104 7.79*104 6.79*104 3.79*104 5.02*104

18 Total coliform MPN/100ml 1.13*105 1.13*105 6.79*103 5.22*104 5.02*104 1.13*104 3.79*104

Y. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Changes during restorationChange in water quality during restoration in metalimnionChange in water quality during restoration in epilimnion

3

7

0 5

3.9

0.8

4.2

0.91

234

56

78

conc

entr

atio

n in

mg/

L

3.2

15.4

23.8

4.4

9.8

4.8

9.8

5

10

15

20

25

once

ntra

tion

in m

g/L

0.150.5

01

DO NH4-N TKN PO43—P

parameters

c

after w ater cabbage removal during f iltration

3.21.10.15 0.41.4 1.4

0

5

DO NH4-N TKN PO43—P

parameters

c

before restoration after w ater cabbage removal during f iltration

Change in water quality during restoration in metalimnion

92

4360708090

100

on in

mg/

L

Change in water quality during restoration in epilimnion

371

250

300

350

400

n m

g/L

27

13.914

43

21.3

01020304050

BOD COD chlorophyll a

parameters

conc

entr

atio

after w ater cabbage removal during f iltration

52

168

80.5

30

96

3914

45

0

50

100

150

200

250

BOD COD chlorophyll a

parameters

conc

entr

atio

n in

after w ater cabbage removal during f iltrationbefore restoration after w ater cabbage removal during f iltration

Changes during restorationY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Changes during restoration

Change in water quality during restoration in hypolimnion

1.2

4.2

0 3

1.9

1.1

4.2

0.91

1.52

2.53

3.54

4.5

once

ntra

tion

in m

g/L

DO profiling with depth

0 000 2 4 6 8

DO in mg/L

0.1 0.3

00.5

DO NH4-N TKN PO43—P

parameters

co

after w ater cabbage removal during f iltration

0.00

0.25

0.50

0 75m

Change in water quality during restoration in hypolimnion

86

94

60708090

100

n in

mg/

L

0.75

1.00

1.25

1.50

Dep

th in

m23

1.1

28

17.1

01020304050

BOD COD chlorophyll a

parameters

conc

entr

atio

f bb l d i fil i

1.75

2.00A E C D B

after water cabbage removal during filtration

DO increaseY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Production of oxygen during re-aerationFl 5 L/

DO increase

• Flow rate = 5 L/s• Volume of water per hour = 18 cubic meter• DO level in the pond = 0.79 mg/L• DO level in the outlet = 4 93 m/L• DO level in the outlet = 4.93 m/L• DO production in the outlet = 4.14 mg/L or 4.14g/m3

• Filtration process = 23.8 kg of O2

BOD reduction during aeration

• After water cabbage removal = 97.9 kg of BODf g g f• During filtration = 69 kg of BOD• Reduction of BOD = 28.9 kg of BOD• Reduction percentage = 30%

Effect of TreatmentY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Effect of Treatment

Trophic Level IndexY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

pTrophic state

Nutrient enrichment category

Trophic Level Chla (mg/m3)

Secchi depth (m)

TP (mg/m3)

TN(mg/m3)

Ultramicro-trophic

Practically Pure 0.0 to 1.0 < 0.33 >25 < 1.8 <34

Micro- Very Low 1 0 to 2 0 0.33- 25 15 1.8- 34 73trophic Very Low 1.0 to 2.0 0.82 25-15 4.1 34-73

Oligo-trophic Low 2.0 to 3.0 0.82 -

2.0 15 - 7 4.1-9.0 73-157

Meso-trophic Medium 3.0 to 4.0 2 - 5 7-2.8 9 - 20 157-337

Eutrophic High 4.0 to 5.0 5 - 12 2.8-1 1 20-43 337-7251.1

Super-trophic Very High 5.0 to 6.0 12 - 31 1.1-

0.4 43-96 725-1558

HyperHyper-trophic Saturated > 6.0 > 31 < 0.4 > 96 > 1558

Source: Rotorua (2002)

Status of the PondY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Layers Chl a (mg/m3) OP (mg/m3)* TN (mg/m3) SD (m)

Epilimnion (BR) 80.5 1100 23800 1.01

Epilimnion (AMR) 39.0 400 9800 0.74

Metalimnion (AMR) 13.9 500 7000 0.86

Hypolimnion (AMR) 1.1 300 4200 0.77

E ili i (DF) 371 0 1400 9800 0 86Epilimnion (DF) 371.0 1400 9800 0.86

Metalimnion (DF) 21.3 900 4200 0.97

Hypolimnion (DF) 17 1 900 4200 0 96Hypolimnion (DF) 17.1 900 4200 0.96

Ultramicro-trophic

Micro-trophic

Oligo-trophic

Meso-trophic Eutrophic Super-

trophicHypereu-trophicp p

* TP > OP

BR – Before restoration, AMR – Aquatic macrophyte removal, DF – During filtration

Comparing techniquesY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

S.No

Aerators Oxygenproduction(kg/KWh)

Operationalcost (Rs)

Location

1.

2.3.

CP 150 (natural aeration)Surface low- speedSurface high speed

0.7

0.70.7

2,210

221+7000*221+7000*

Surface

SurfaceSurface

4.

5.

Submerged turbinewith sparger

Horizontal rotar

0.2

0.5

773.5+7000*

309.4+7000*

Submerged

Submerged

* H ti t

S.No

Aerators Cost perm3

Effect

* - Harvesting cost

1.2.3.4.

CP 150 (natural aeration)Surface low- speedSurface high speedSubmerged turbine with

0.670.060.060.23

Aeration &filtrationAerationAerationAeration

5.

gsparger

Horizontal rotar 0.09 Aeration

Achievements of restorationY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Parameters Initial load (kg)

Load after aquatic macrophyte removal (Kg)

Efficiency%

Load during filtration (Kg)

Efficiency%

removal (Kg)BOD 204 97.9 52 69 66COD 659 326.2 51 225.7 66TKN 153 8 24 4 83 52 5 66TKN 153.8 24.4 83 52.5 66OP 4.3 1.3 70 3.9 9

Efficiency of the restoration process

5060708090

cy %

01020304050

Effic

ien

BOD COD TKN Orthophosphate

Parameters

Aquatic macrophyte removal During filtration& re-aeration

ConclusionY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Conclusion

• From the studies the pond is • Aeration in combination withfilt ti f bi i

pSuper-hypereutrophic (TLI)

• The average saturation level

filtration of biomass is aneffective technique inrestoring an hypereutrophicpond.g

of DO before and after therestoration processes werealmost doubled.

pond.

• Using similar aeration andfiltration technique will help

• Efficiency of bothtechniques in reducing the

f q pin restoring large scalewaterbodies.

techniques in reducing thenutrient concentration andrestoring a pond.

• Simultaneous harvesting ofalgae is effective inrestoring the pond

Future TreatmentY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Future Treatment

• Harvesting of algae by (1) cutting or uprooting Harvesting of algae by (1) cutting or uprooting and removing the weeds from the pond.

• This step requires labour and cost, so further restoration steps should be taken to improve the

lit f th d quality of the pond.

• Probiotic consortium culture synergistically • Probiotic consortium culture synergistically works to inhibit the growth of pathogenic harmful bacterial through competitive exclusion. g p

Dissolved Oxygen(DO) Profiling with depth

DO in mg/L

00 1 2 3 4 5 6

DO in mg/L

0.2

0.4

0.6

0.8

pth

in m

1

1.2

Dep

t

1.2

1.4

1 61.6

Site 'A' Site 'B' Site 'C' Site 'D' Site 'E'

B

A

D

C

A

E

Change in water quality during restoration in epilimnion

23.8

20

25

L

15.415

20

n in

mg/

9.8

4 8

9.810

cent

ratio

3.21.1

4.4

0.15 0.4

4.8

1.4 1.4

0

5conc

0DO NH4-N TKN PO43—P

parameterspbefore restoration after w ater cabbage removal during f iltration

Change in water quality during restoration in epilimnion

371

350

400

250

300

in m

g/L

168

96150

200

entr

atio

n

5280.5

30

96

3914

4550

100

conc

e

0BOD COD chlorophyll a

tparameters

before restoration after w ater cabbage removal during f iltration

Change in water quality during restoration in metalimnion

77

8

L

3 94.2

5

6

n in

mg/

L

3

3.9

2

3

4

cent

ratio

n

0.150.5

0.8 0.9

0

1

2

conc

0DO NH4-N TKN PO43—P

parameters

after w ater cabbage removal during f iltration

Change in water quality during restoration in metalimnion

92

8090

100

L

607080

n in

mg/

L

27

43

21.3304050

cent

ratio

n

13.914

01020

conc

0BOD COD chlorophyll a

parameters

after w ater cabbage removal during f iltration

Change in water quality during restoration in hypolimnion

4.2 4.2

44.5

L

2 53

3.5

n in

mg/

L

1.2

1.9

1.1 0.91.5

22.5

cent

ratio

0.1 0.3

0 9

00.5

1

conc

0DO NH4-N TKN PO43—P

parameters

after w ater cabbage removal during f iltration

Change in water quality during restoration in hypolimnion

86

94

90100

L

607080

n in

mg/

L

2328

304050

entr

atio

n

23

1.1

17.1

0102030

conc

0BOD COD chlorophyll a

parametersp

after water cabbage removal during filtration

Efficiency of the restoration processEfficiency of the restoration process

90

5060708090

cy %

20304050

ficie

nc

01020Ef

f

BOD COD TKN Orthophosphate

Parameters

Aquatic macrophyte removal During filtration& re-aeration

Changes during restorationY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Change in water quality during restoration in epilimnion

Change in water quality during restoration in epilimnionesto at o ep o

23.8

20

25

mg/

L

p

371350400

mg/

L

15.4

9.8 9.810

15

20

ntra

tion

in

168

96

257

13180 5

140150200250300350

atio

n in

m

3.21.1

4.4

0.4

4.8

1.40.15 1.4

0

5

10

conc

e 523096

391445

80.5

050

100150

BOD COD chlorophyll TSSco

ncen

trDO NH4-N TKN PO43—P

parameters

BOD COD chlorophylla

TSS

parametersbefore restoration after w ater cabbage removal during filtrationbefore restoration after w ater cabbage removal during f iltration before restoration after w ater cabbage removal during f iltration

Changes during restorationY. Prathishta, Dirk Walther, K. Thanasekaran (2008)

Change in water quality during restoration in metalimnion

Change in water quality during restoration in metalimnion

7

3 9 4 25678

in m

g/L

92

149

107125150175

on in

3

0 5

3.9

0.8

4.2

0.92345

cent

ratio

n

27

92

14

43

13.9 21.3255075

100

conc

entra

tim

g/L

0.50 80.15

01

DO NH4-N TKN PO43—P

parametersco

n

025

BOD COD chlorophylla

TSS

c

parameters

after water cabbage removal during filtration

parameters

after water cabbage removal during filtration