restoration of kolleru lake water quality using …thebioscan.in/journals_spl/s314 s. bala...

713

NSave Nature to Survive

ISSN: 0973 - 7049

: Special issue, Vol. 3;

Paper presented in International Conference onEnvironment, Energy and Development (from

Stockholm to Copenhagen and beyond)December 10 - 12, 2010, Sambalpur University

RESTORATION OF KOLLERU LAKE WATER QUALITY USING

ARTIFICIAL WETLAND SYSTEM-A CASE STUDY

S. Bala Prasad et al.

Kolleru

Water quality

Artificial wetland restoration

713-719; 2010

714

S. BALA PRASAD, S. RAMAKRISHNA RAO AND S. A. RAHIMAN*

Dept of Civil Engineering, Andhra University,

Visakhapatnam - 530 003, A.P. INDIA.

E mail:

Kolleru is one of the biggest shallow fresh water lakes in Asia located between the delta of

Krishna & Godavari river in the state of Andhra Pradesh. It extends over about 954 km2 from the

0 to 10.7 ft contour MSL .It lies between longitudes of 810 5’ and 810 20’ East and latitudes of

160 32’ and 160 51’ North in the districts of Krishna and West Godavari. The catchment area

being served by the 16 drains and 14 channels which empty into the lake among which Polaraju

Drain, Ramileru Drain, Chandrayya Drain are major. The outlet of Kolleru Lake into the Bay of

Bengal is Upputeru, in the southeastern of the lake. The total area of the lake converted to

aquaculture ponds accounts for 99.73km2 in 2004 in comparison to 29.95km2 in 1967. The area

under agricultural practice in the wetland also increased from 8.40 km2 in 1967 to 16.62km2 in

2004. Sewage inflow from the towns of Eluru, Gudivada and even Vijayawada and industrial

effluents, pesticides and fertilizers from the Krishna-Godavari delta region contaminate the lake.

Eleven major industries release about 7.2 million liter of effluents into the lake every day.The

lake receives the surface runoff through different drains prominently discharges from western

side of lake. In the upstream areas several anthropogenic activities like -deforestation, industrialization,

inhabitation which pollutes the natural drains. Thus the lake water quality changes due to the

effluents discharged from those activities mentioned above and further from the agriculture and

aquaculture activities carried out in the vicinity. Keepimg in view of the changes in the water

quality it is proposed to reduce the pollution load of the lake by treating the water that is

discharged through drains using artificial wetland system .The artificial wetland system was

thought as solution for treating water being discharge by Chandrayya Drain.A lab Scale model

was design keeping view the characteristics of the drain water and rate of discharges scaling

down to the insitu conditions.It is expected that such an artificial wetland will solve the

euthrophication in the lake resulting in sustainability and conservation of such a wetland system

like kolleru

ABSTRACT

NSave Nature to Survive

*Corresponding author

www.thebioscan.com

715

INTRODUCTION

Kolleru is one of the biggest shallow fresh water lakes in Asia which is located between the delta of Krishna

Godavari river in the state of Andhra Pradesh. It extends over about 954 km2 from the 0 to 10.7 ft contour

MSL. The depth of the lake varies from 1 to 1.6 meters and it reaches 3 to 4 meters during high floods. The

lake covers 7 Mandals in West Godavari District and 2 Mandals in Krishna District. It lies between

longitudes of 810 5’ and 810 20’ East and latitudes of 160 32’ and 160 51’ North in the districts of Krishna and

West Godavari. The lake serves as a natural flood-balancing reservoir for these two rivers. It used to be an

ideal habitat to hundreds of species of birds including migratory birds, 63 species of fishes, fresh water

turtles and amphibians etc. The lake was an important habitat for an estimated 20 million resident and

migratory birds, including the Grey or Spot-billed Pelican (Pelecanus philippines). The lake was notified as

a wildlife sanctuary in November 1999 under India’s Wild Life (Protection) Act, 1972, and designated a

wetland of international importance in November 2002 under the international Ramsar Convention. The

wildlife sanctuary covers an area of 308 km². Sewage inflow from the towns of Eluru, Gudivada and even

Vijayawada and industrial effluents, pesticides and fertilizers from the Krishna-Godavari delta region

contaminate the lake. Eleven major industries release about 7.2 million liter of effluents into the lake every

day.

MATERIALS AND METHODS

Field data and water samples were collected from the field during December, 2009, January and July,

2010.The water samples collected at different drains were also tested in the Public Health Laboratory of

Department of Civil Engineering, Andhra University. The following parameters such as pH, conductivity,

turbidity, TDS, DO, BOD and COD were analysed.

The Chandrayya Drain discharge velocities were measured using current meter at 9 identified locations.The

calculations were made using a calibrated chart. Grab samples were collected from Chandrayya drain at

Peddayeddalgadi Bridge and at Pnenumlanka village .

Composite sample is collected at an interval of one hour for 6 hrs within a distance of 3000 m. At the

collection point, with the help of “WATER ANALYSIS KIT” parameters like pH, Temperature,

Conductivity, Turbidity, Salinity and Dissolved Oxygen were analysed. The depth of Chandrayya Drain was

measured randomly.

It is observed that the Chandrayya Drain is receiving effluents from various sources like industries, residential

townships, agricultural fields, aquaculture ponds,etc which is ultimately discharged into the lake proper

and finally goes to the sea through Uppeteru Drain. The results suggests that BOD and COD ranges 70-180

mg/L and 120-642 mg/L respectively which can be treated and disposed of into lake proper by constructing

an artificial wetland which is designed to reduce the BOD and COD by 70% using the weeds for uptake of

nutrients .

RESULTS

The range of current of Chandrayya Drain is 0.222 - 0.405 m/sec for the depth of 1.5 to 2 m. pH of the

sample ranges from min-4.84 to max-8.51, basic to acidic as going from Chandrayya Drain to KolleruLake. Salinity level ranges min-0.2 to max-6.19(ppt), decreasing half of the Chandyaaya Drain again itincreasing as going towards the Peddayedagaddi village and atlast to lake.TDS value ranges min-1.07,max-7.41(mg/L), increasing as going towards the Chandrayya Drain to Kolleru Lake. DO value ranges min-2.2,max-6.6(mg/L), decreases as going through Penumalanka Village and increases as going throughPeddayeddalagaddi and to Lake.BOD value ranges min-70,max-180(mg/L), increasing Chandrayya Drain

as going towards the Kolleru Lake.COD value ranges min-120,max-642(mg/L) ,increasing as going towards

the Lake.

RESTORATION OF KOLLERU LAKE WATER QUALITY

716

S. BALA PRASAD et al.,

Sl.

No

Loca

tion

Nam

e of

loca

tion

Tem

p (°

C)

pH

Sal

inity(p

pt)

TD

S(p

pt)

D O

(ppm

)B

OD

CO

D

(mg/L

)(m

g/L

)

1N

16º 3

6’5

04"E

81° 0

9’5

24"

Ped

day

eddal

gad

i b

ridge

226.2

-28.8

°C

4.8

4-7

.45

0.9

-6.1

01.0

7-7

.28

2.4

-6.5

125-1

65

230-4

66

2N

16º 3

5’2

59"E

81° 0

8’2

48"

Pen

um

lanka

tow

er s

ide

28.4

-30.5

°C

5.8

3-8

.21

0.7

6-6

.19

2.2

4-7

.41

3.8

-6.6

110-1

70

120-4

80

3N

16º 3

5’0

72"E

81° 0

8’1

31"

Chan

dra

aya

kal

ava

28.6

-31.6

°C

5.5

1-5

.80.5

7-1

.82

1.7

3-1

.75

2.8

-3.2

72-1

28

386-4

65

4N

16º 3

4’5

60"E

81° 0

7’4

67"

Chan

dra

aya

dra

in29.8

°C

5.5

1-5

.80.5

7-1

.82

1.7

3-1

.75

3.2

-2.8

72-1

28

386-4

65

5N

16º 3

4’3

43"E

81° 0

7’2

71"

Ner

aydu K

alav

a30.4

°C

6.2

-6.4

80.8

6-0

.92

1.1

5-1

.82

2.2

-3.4

76-9

8508-5

20

6N

16º 3

4’1

36"E

81° 0

7’1

31"

Nan

dig

am L

anka

29-2

9.5

°C

5.3

3-6

.10.7

9-0

.81

4.1

2-4

.28

2.7

-3.6

70-1

12

385-4

18

7N

16º 3

5’4

94"E

81° 0

9’5

52"

Chin

nap

adu l

anka

27.8

-29.8

°C

5.5

1-6

.20.2

-0.6

81.7

9-2

.14

2.4

-2.6

165-1

75

410-4

41

8C

om

posi

te s

ample

3m

L

(sam

ple

-2+

3+

4+

5+

6)

29.6

-31°C

7.4

1-8

.51

1.2

-4.8

32.8

9-5

.77

3.8

4-5

.5155-1

80

400-6

42

Table

1:

Physi

co-c

hem

ical

chara

cter

isti

cs o

f C

handra

yya D

rain

The

follow

ing t

able

s sh

ow

the

data

wit

h r

egard

to t

he

physi

co-c

hem

ical

para

met

ers

mea

sure

d i

n t

he

sam

pling l

oca

tions

Figure 2: Q0 C

0 = Inlet COD Concentration, Q

1 C

1 = COD Concentration

during treatment, Ce = COD concentration in the effluent

Qo2 Co Q

1

Co Ce

Figure 3: Top View of the artificial wetland

Figure 1: Total Size = Length x width x height: 1.5m x 0.3m x 0.6m; Zone 1 and 3

= 0.3m x 0.3m x 0.3m; Zone 2 = 0.9m x 0.3m x 0.6m

Inlet settling

zone

Floaling and

emergted

plants

Zone 1

Fully vegetetedZone 2

Open water surface

Variable level

outletZone 3

Fully vegeteted

Efflu

en

t

outletZone

Protrolord

logoon

influent

Submergedgrowth plant

Flooting and

emergent plant

717

Table 2: Flow rates recorded in Chandrayya Drain discharges into Kolleru lake

Sl No Date/ Name of Location Location Depth(m) Current flow

Time (m/sec)

1 17-07-10,09:30 AM Chandrayya Drain N 16º 35’463” E 81° 08’543” 0.405
















18 18-07-10,12:30 PM Chandrayya Drain N 16º 35’297” E 81° 08’274” 0.222

1. Basin Embankment

2. Filtering Media

3. Higher Aquatic Plants4. Root Rhizome

5. Covered Drain

6. Drainage Wate Collector7. Water Supply Pipes

8. Water Level Regulation Device

9. Inlet10. Water Level Measurement Device

11. Outlet

12-13 Water Flow Measurement Device14. waterproof liner

Figure 4: Cross Section of Artificial Wetland

Figure 5: Section showing the components in the artificial wetland

DISCUSSION

The kolleru lake water quality was studied by Krishna (1990).The water quality model was develop by

Ramakrishna Rao and Sujatha in 1996.The wetland characteristics and bio energitics was reported by

Ramakrishna Rao in 1986.An integrated approach to restore the water quality of the lake was suggested by


718

Ramakrishna Rao et al., in 1986. The lake receives water through seven small and large drains out of which

Chandrayya Drain is most polluted Since domestic and industrial discharges are carried from the upstream

areas.The results indicate that the BOD load goes to 180 mg/L which can be treated and discharged. It is

observed that physico chemical characteristics are in concurrence with the findings of earlier investigators

Design of artificial wetland

Advantages of Constructed wetlands

Constructed wetlands are simple, inexpensive, environment friendly, provide food, habitat for wildlife,

differ from natural wetlands in several ways.Remain constant in size, Not directly connected with groundwater,

Accommodate greater volumes of sediment, Quickly develop the desired diversity of plants and associated

organisms.

The design details of the proposed constructed wetland lab model

Per flux sheet box of 5ft in length ,1ft in width was made with 2 ft depth was made .The whole ecosystem

was created using the soil, flora and fauna from the lake. The water of the lake was also brought and the

experiment conducted in open to sky environment. The evaporation losses were measured the rate of flow

was maintained as 24 liters per 24 hr.

The Model Setup

The model was constructed using the Perplex sheet measuring of 5ft in length, 1ft in width and 2 ft depth.The mini Kolleru Lake is created using the Materials brought from Kolleru Lake itself. The model is filledwith the benthic soil and the continuous flow was maintained using the water brought from the ChandrayyaDrain .The floating the submerged and emergent weed vegetation is planted in the tank .The flow rates ofwater are controlled using hydraulic reservoir. The rate of flow is fixed approximately 25 L for 24 hr. thesystem is kept open to the sky Samples are collected from the artificial wetland in the inlet samples andoutlet samples twice in a day for the parameters mentioned above in the methodology. The rates of evaporationsare also measured by calculating losses incurred in a known sample kept for 24 hr. The changes due torainfall during the period of study is also recorded. The following is the data with regard to water quality

with respect to parameters mentioned in the inlet and outlet after detention in the model.

ACKNOWLEDGEMENTS

The authors thank Department of Science and Technology, New Delhi for the sanction of the project to

carryout the work. The authors also acknowledge the help extended by Prof.P.Rajendra Prasad, Technical

Co-ordinator and Prof.K.Gopal Reddy, Director for Center of Bay of Bengal, Andhra University.

S. BALA PRASAD et al.,

Figure 6: Final setup of Artificial wetland

719

REFERENCES

Krishna, A. 1990. “Studies on some aspects of the ecology of a fresh water wetland, Kolleru lake of Andhra

Pradesh State, Doctorial Thesis p 136.

Ramakrishna Rao, S. Krishna, A. and Rama Rao, R. V. 1986. on, “An integrated approach for the restoration

of polluted Lake Kolleru” Published by International conference of the Israel Society for Ecology and Environmental

quality Sciences Bar Ilan University Press, Isreal.

Ramkrishna Rao, S. 1986. “ Bioenergitics of weeds in Kolleru Lake wetland system Project report submitted to

Department of Biotechnology,New Delhi.

Ramakrishna Rao. S. 1996. Lakshmi Sujatha, B. Ecological Modelling of Kolleru Lake transformations, M Tech

Thesis. p. 97.


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