Excreta Matters: Monthly newsletter on Remedies start in small doses | Centre for Science and Environment


Excreta Matters: Monthly newsletter on Remedies start in small doses

 

Editorial: Remedies start in small doses

Last month, I suggested drastic surgery – open up the Yamuna River’s floodplains into one gigantic wetland, as in Kolkata, to improve water quality. It found little resonance with the government, maybe because there isn’t enough engineering (a person who had studied at IIT Delhi assured me it had) but it was too radical. But doesn’t a humungous problem call for drastic solutions? OK, so let’s propose something less radical, something that’s happening in dribs and drabs. Something that may even happen at a scale to make a difference.

So the Yamuna's 22 km stretch in Delhi gets sewage from 18 drains. It has no fresh water flows downstream of the wazirabad barrage in the lean months. It is a sewer. If we cannot operate on the main stem, we must on the feeder streams. Some have tinkered with the idea of using drains for sewage treatment and there are a couple of small projects to ‘try out’ the concept. It is time we moved ahead more aggressively to convert all drains into treatment zones. A few prerequisites, though, are in order.

First, small-scale units that electroplate or reprocess batteries and engine oil, dump their waste in drains. These eventually join one of the trunk drains that join the river. This is unacceptable and has to stop. One way is to move them to an industrial cluster fitted with a common effluent treatment plant. They will not pay and shutting them down is next to impossible. These units that employ a lot of people should be given a safer, better environment to operate. They do not pay taxes, operating under the government’s radar. While providing them a better place, the government should not ask questions, just stipulate their waste must be treated in a central location. If necessary, the government should operate the cluster and charge the units for power and water. If this is done sensibly, it can remove toxic waste from the equation.

Second, uncover the drains that were entombed in cement during an ill-conceived project of the Common Wealth Games. This was to hide the ugliness and eliminate the stench, but the end result is even higher levels of toxicity in the drains and the danger of concentrations of toxic gases trapped underneath that may build up dangerously. In their natural state, the drains provided a modicum of pollution abatement; covering them has deprived them of this.

Third, pick a large stretch, or the entire drain for treatment. Bits and pieces will not do since fresh pollution enters the drain downstream of the treated section, negating its benefits. We can use a mix of non-conventional treatment options for optimum results depending on the volume of water, rate of flow, aeration, composition of waste water, the area available for treatment, etc. The mix can change with the season, depending on what works best in summer or winter.

The treatment options include bio-remediation with enzymes or bacteria, soil biotechnology, constructed wetlands and green bridges. Each has its own advantages and disadvantages, science and costs. Each drain has unique characteristics that will need to be evaluated before picking a particular approach. These are, in the view of the government, experimental technologies that have been used in different circumstances. True, but they have been mostly effective in these circumstances and therefore, merit larger trials.

One problem is tendering for these technologies, a problem that crops up any time there is a new way to do something. It is easy to circumvent this by stating these are experimental and need to be tried to develop usage protocols from which tendering can evolve. There are large field trials running for each of these approaches that have been studied, and can inform the tendering process. There a constructed wetland and a soil biotechnology plant, each with a capacity to treated two million litres a day; a green bridge has been installed in Udaipur and bio-remediation has been used at several locations. An analysis of these will help decide a suitable mix of non-conventional approaches for in-situ treatment of sewage in drains.

There are many advantages of this approach. The drains will be cleaner and not stink or be eyesores. The water that seeps into aquifers from these drains will be cleaner and help reduce groundwater contamination from sewage. The drains can also become transport channels with paths for non-motorised transport as some architects and agencies have suggested, contributing to improving the quality of urban life. Finally, by improving the water quality in these drains, this work will ultimately help bring the Yamuna River back to life.

 
Nitya Jacob, CSE
 
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Text: Bharat Lal Seth
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Guest Blog
Restoration of Chilika Lake with ecosystem approach
Chilika Lake is the largest wetland along the east coast of India. The lake is a unique assemblage of marine, brackish and fresh water eco-systems with estuarine characters. This fragile ecosystem is known for its amazing biodiversity and is a designated Ramsar site. It is an avian grandeur and the wintering ground for more than one million migratory birds. The highly productive lake eco-system with its rich fishery resources sustains the livelihood of more than 0.2 million-fisher folk who live in and around the lake.

The long shore sediment transport along the coast of Bay of Bengal estimated to be 0.1 million metric tonnes annually tend to shift lake mouth opening to the sea every year.  The spatial and temporal salinity gradients resulting from the freshwater flow from the drainage basin and the seawater influx; gave it the unique characteristics of an estuarine eco-system, exercising a continuous and selective influence on its biota. The open use of the common property resources, illegal shrimp culture and the hydrological alterations by way of manmade construction upstream resulted in change in its ecological characters and it was added to the list the Montreux Record (threatened list of Ramsar sites) in 1993 by Ramsar Secretariat.

The principle adopted for restoration and management of Chilika Lake by Chilika Development Authority (CDA) has been largely based on the Ramsar guidelines, which recommend a diagnostic approach based on a critical evaluation of ecological, economic and socio-cultural features to identify objectives and operational limits including factors for restoration and effective management of wetland ecosystems. Based on the hydrodynamics modeling and wide consultation CDA carried out a hydrological intervention by way of opening of an inlet in 2000. Considering the sensitive ecosystem of the lake, for tracking the lake ecosystem, sensors mounted on buoys have been deployed at 10 strategic locations of the lake that transmit the water quality data on real-time basis to the CDA laboratory.

As a response to the hydrological intervention, several positive changes are being observed; the lake fisheries have revived significantly from 1,747 MT in 2000 to 14,228 MT in 2012, 6 species of fish reappeared following the restoration of the salinity gradient, an increase in tidal flux, expansion of sea grass meadows and species diversity and an expansion of the habitat of the critically threatened Irrawaddy dolphin. The amelioration of the biodiversity created community-based eco-tourism. The Mangalajodi marshes of northern Chilika offer a true example of ecotourism, here, reformed bird hunters guide small groups of tourists quietly through a watery wonderland.

Due to successful restoration, Chilika was removed from the Montreux record by the Ramsar bureau with effect from 11th November 2003. Chilika Lake is the first wetland from Asia to be removed from Montreux record. The restoration of Chilika demonstrates how restoring ecological character of a wetland can result not only in amelioration of biodiversity, but can sustain the livelihood of local communities due to increase in productivity and ecosystem services.

Fortunately, many communities have now begun to realise the need for responsible and wise use of resources. Chilika cannot be seen merely as a source of livelihood for humans. Its biological diversity is a priceless heritage that must be preserved. If managed with care, this vibrant lake can provide an enduring future, both for its people and its life forms.

Dr. Ajit Kumar Pattnaik (IFS),
Chilika Development Authority
 
 
 
 
 
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