Muck to moolah
THE urban perception of wastewater management has essentially been that of pollution control. Conversely, rural communities in many of the poorer parts of the world recognise municipal wastewater as a nutrient pool to be used in fisheries and agriculture.
Taking into account the latter view, under the Ganga Action Plan (GAP) in West Bengal, a number of low-cost wastewater treatment and resource recovery projects are being designed and implemented. These projects draw lessons from the world's largest ensemble of fisheries and agriculture using city wastewater (the East Calcutta wetlands). They also take a unified approach by involving the local people, the village panchayat and the implementing authority for setting up a new agenda in wastewater conservation. In a small way, these grass roots projects mark the beginning of a turn around. There should be lessons for the future from here.
The projects are an outcome of one of the earliest efforts in developing community-based technology for river sanitation. Here, the conventional option in wastewater treatment has been replaced by an ecological design-wise use of wetlands. Wastewater is viewed as a recyclable resource which can produce revenue by taking advantage of the nutrient- enriched effluent to promote fisheries and agriculture. In this way, the present project links wastewater treatment with the livelihood of the local community, unlike the conventional sewage treatment plant.
The design of the wetland system is based on a pragmatic manipulation of the existing framework of policy and regulatory controls. For example, in these projects, though the pond areas are calculated on the basis of widely used guidelines for designing stabilisation ponds (anaerobic, facultative and maturation), they improve the efficiency of the system by introducing fish in the admissible water areas. This is because, firstly, the fish population acts as an ecological manipulator by grazing on the algae, which would have otherwise caused algae bloom and secondly, fish production brings adequate entrepreneurial incentive to operate the system efficiently and productively.
Therefore, while the GAP, with its conventional treatment plants has a dedicated objective of river sanitation, the present approach, in addition to cleaning the river, draws in its fold the task of enhancing food security and developing livelihood for the rural poor surrounding the project site. Completion of the wetland project will result in the supply of enriched irrigation water. In addition, pisciculture units already ich form a part of the system.
ihere are many other benefits to implementing this project as opposed to the conventional method of treating wastewater. Firstly, this project is based on an environmentally sound design. Wastewater ponds are basically solar reactors and complete most of the biochemical reactions with the help of solar energy. Therefore, consumption of conventional energy is minimised.
Secondly, wetland projects are much more reliable and have a much longer life-span than conventional sewage treatment facilities. The laiter are prone to damage and frequent breakdowns, causing huge financial liabilities to the parent municipal authority. Op the other hand, the wetland project is a revenue earner. Since it is a non-structural option, the problem of damage and breakdown hardly arises and the system can continue to work for any length of time without any major disorder.
Thirdly, an outstanding feature of the wetland project is its strong emphasis on th@ ideology of Agenda-21. Unlike conventional mechanieal, sewage treatment plants, the wetland project, in accordance'with Agenda-21, ensures local participation and therefore decentralises management and decision- making. After completion of the project local rural authorities can be given the responsibility of the day-to-day maintenance of the system.
And lastly, the wetland option is the least expensive. The expenditure can be less than rupees three million per million litres of wastewater per day. The major cost of the project is the land, which should preferably be a low-lying area at the fringe of the municipal boundary. These lands, which are cheap and generally produce only one crop a year, provide a source of enhanced steady income for the farmers.
For all of these reasons, municipalwaste water should predominantly be viewed as a resource instead of a pollutant. Wastewater management should essentially be a task of conservation rather than pollution control, and the knowledge of the village folk should get accommodated in the making of a new subjective base.
Dhrubajyoti Ghosh is an environmentalist and currently works with the Calcutta Municipal Water and Sanitation Authority. He is also the coordinator of the West Bengal Environment Improvement Programme