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Central Institute of Freshwater Aquaculture (Indian Council of Agricultural Research)
Po: Kausalyaganga, BBSR
Ph.: 0674-2465421
Fax: 0674-2465407
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| ETS - Introduction |
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| Introduction: |
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The productive utilization of coastal areas for shrimp aquaculture has received priority attention in India since early 1980s. The country has about 1.2 million hectares of brackish water area and presently about 0.14 million hectares are used for shrimp farming in the coastal States and some Union Territories. Of this, one third of the area is presently under traditional methods of farming and the rest is under improved traditional and extensive methods of aquaculture. More than 90 per cent of the shrimp farmers own less than 2.0 hectare water area and farms below 5.0 hectare occupy 65 per cent of the total area of shrimp farms in the country.
However, the wastewater produced during the post-harvest cleaning operation of shrimp farms can have a much greater impact on the ecology of the open waters, although it may be for a shorter period. Similarly, the impact can be significant where large number of shrimp farms are established in areas with poor flushing capacity
In India, overcrowding of shrimp farms in certain areas and limited carrying capacity of the creeks/estuaries serving such farms has been a matter of concern (e.g. Kandeleru Creek in Nellore District, Andhra Pradesh). Similarly, certain areas in Orissa also have concentration of shrimp farms. Presently, most of the farms lack effluent treatment system for treating the waster water before it is released in to the open waters. The farms which do have such facility also do not conform to the scientific requirements. The integration of effluent treatment systems, based on best management practices in the shrimp farms will therefore assist the farmers to improve the waste water quality and make their farming practices more sustainable.
Existing Legal Provisions
Government regulations are important component of management in supporting aquaculture development, maintaining environmental quality, reducing negative environmental impacts, allocating natural resources between competing users and integration of aquaculture into coastal zone management. Presently, the following legal provisions are available to exercise appropriate control on discharge of wastewater generated by the shrimp farms and other developmental activities.
The Water (Prevention and Control of Pollution) Act, 1974 was enacted for maintaining and restoring the wholesomeness of water and to promote cleanliness of stream and wells. Under this Act, the stream includes sea or tidal waters as well and hence this Act has much relevance to the brackish water aquaculture. To keep the coastal waters clean and free from pollution, the water bodies are classified according to the use and the use may be termed as “designated best use” in that stretch. The use classes of marine coastal waters of India, based on designated best uses are:
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Designated Best Use
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Class
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Salt pans, shell fishing, Mari culture
and ecologically sensitive zone
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SW I
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Bathing, contact water sports and commercial fishing
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SW II
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Industrial cooling, recreation (non contact) and aesthetics
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SW III
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Harbour
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SW IV
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Navigation and controlled waste disposal
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SW V
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Based on the designated best use, the primary water quality criteria was developed and notified under the Environment (Protection) Act, 1986 as standards. Any deficiency in the ambient water quality from the assigned class category in any zone would require appropriate control on the discharge reaching the zone.
The Environment (Protection) Act, 1986 is an umbrella legislation that provides for the protection of the environment by taking necessary measures for protecting and improving the quality of environment and prevention, control and abatement of environmental pollution by laying down standards for the quality of environment, emission or discharges of environmental pollutants from any sources.
The Ministry of Environment and Forests under the Environment (Protection) Act, 1986 has declared the coastal stretches as Coastal Regulation Zone (CRZ). The CRZ includes the coastal stretches of seas, bays, estuaries, creeks, rivers and backwaters, which are influenced by tidal action (in the landward side) for regulating the activities. Thus, the Water (Prevention and Control of Pollution) Act, 1974, Environment (Protection) Act, 1986 and Coastal Regulation Zone Notification 1991 as amended in 1994, 1997 and 1998 are the prevailing legislations to support the orderly development of coastal aquaculture in the country.
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The Ministry of Agriculture in its Guidelines for Sustainable Development and Management of Brackish Water Aquaculture has prescribed standards for the waste water discharged from the shrimp farms. A comparison of the parameters prescribed for shrimp farm waste water for release into the open waters in India and Thailand indicates that the Indian standards are fairly stringent, especially in the case of free ammonia and nutrients (Table 2).
Table 2. Guidelines/standards for waste water from coastal aquaculture farms in India and Thailand
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No.
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Parameters
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INDIA
Final Discharge Point
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THAILAND
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Coastal marine waters
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Creeks/estuaries- when the same inland water courses are used as water source and disposal point
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1
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PH
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6.0 – 8.5
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6.0 – 8.5
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7.0 – 8.7
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2
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Suspended Solids mg/1
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100
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100
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100
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3
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Dissolved Oxygen mg/1
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Not less than 3.0
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Not less than 3.0
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More than 4.0
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4
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Free Ammonia (as NH3-NN) mg/1
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1.0
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0.5
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1.8 – 2.9
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5
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Bio-chemical Oxygen Demand (BOD) (5 days at 20ºC) mg/1
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50
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20
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10
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6
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Chemical Oxygen Demand (COD) mg/1
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100
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75
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7
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Dissolved Phosphate (as P) mg/1
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0.4
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0.2
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0.4
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8
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Total Nitrogen (as N) mg/1
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2.0
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2.0
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4.0
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To achieve the wastewater quality standard prescribed above, proper treatment of the farm effluents is a prime requisite. The effluent treatment system (ETS) detailed in the present guidelines will help the shrimp farms to achieve the objectives.
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