India’s rivers, groundwater polluted by untreated effluents, sewage dumped in urban stretches

urban groundwaterAn excerpt from “A 21st Century Institutional Architecture for India’s Water Reforms Report”*, submitted by the Committee on Restructuring the Central Water Commission (CWC) and Central Ground Water Board (CGWB), chaired by Dr Mihir Shah to the Prime Minister’s Office:

In India, the number of people living in urban areas is expected to more than double and grow to around 800 million by 2050. This will pose unprecedented challenges for water management in urban India. The demands of a rapidly industrialising economy and urbanizing society come at a time when the potential for augmenting supply is limited, water tables are falling and water quality issues have increasingly come to the fore.

Both our rivers and our groundwater are polluted by untreated effluents and sewage dumped into them. Many urban stretches of rivers and lakes are overstrained and overburdened by industrial waste, sewage and agricultural runoff. These wastewaters are overloading rivers and lakes with toxic chemicals and wastes, consequently poisoning water resources and supplies. These toxins are finding their way into plants and animals, causing severe ecological toxicity at various trophic levels.

In India, cities produce nearly 40,000 million litres of sewage every day and barely 20 percent of it is treated. Central Pollution Control Board’s 2011 survey states that only 2% towns have both sewerage systems and sewage treatment plants. 63 Averaged for 71 cities and towns, groundwater constitutes 48% of the share in urban water supply. In India, 56 per cent of metropolitan, class-I and class-II cities are dependent on groundwater either fully or partially. Unaccounted water in urban areas exceeds 50% according to the CGWB’s report on the groundwater scenario in 28 Indian cities.

Privately driven, individualistic pumping of groundwater in large parts of urban India has provided benefits for filling out the gaps in public water supply schemes. However, it has also led to problems of co-terminal depletion and contamination of aquifers. There are huge gaps in our knowledge about urban aquifers, their characteristics, the significance of their service value and a comprehensive understanding of the competition and conflicts around groundwater resources.

Sustainable management of groundwater is impossible without a much deeper understanding of the types of aquifers within which it is located. Aquifers in large regions of India act as both sources and sinks for various loads, ranging from sullage to sewage and from industrial waste to agricultural residues like pesticide and fertilizer. Groundwater resources in growing urban centres are therefore likely to become contaminated as much by residual contaminants from erstwhile agricultural activities and poor rural sanitation as by contamination from more current haphazard waste-water disposal.

Only 33% urban Indians are connected to a piped sewer system and 13% – roughly 50 million urban Indians – still defecate in the open (Census of India, 2011). Large parts of the modern cities remain unconnected to the sewage system as they live in unauthorised or illegal areas or slums, where state services do not reach. Surveys of groundwater quality in many cities, therefore, reveal a large magnitude of water-borne pathogenic contamination – commonly referred to as bacteriological contamination – clear signs of groundwater contamination by sewage.

Santragachi_Lake_-_Howrah_2012-01-26_1594The following key steps could form the building blocks of an urban aquifer management programme in India:

  1. Identifying status of existing groundwater resources in cities through participatory mechanisms, involving citizens, educational institutions and urban utilities;
  2. Assessment of the groundwater resources through a participatory ‘aquifer mapping’ approach coupled with systematic studies by institutions with appropriate capacities to identify natural recharge areas, groundwater discharging zones and quantification of aquifer characteristics, namely transmissivities, storativities and groundwater quality;
  3. Profiling stakeholders, including users, tanker operators, drilling agencies and developing mechanisms for registering water sources;
  4. Ascertaining quantitative and quality-related groundwater security, including groundwater recharge, which is allied to the protection, conservation and upkeep of water bodies;
  5. Hydrogeology must be considered during waste-disposal, sewage and sullage management and design of sewerage and sewagetreatment;
  6. Developing a framework of regulatory norms around urban groundwater use and protection of urban aquifers by preserving natural recharge areas;
  7. Understand changes in river flows and quality and the precise relationship between aquifers, aquifer systems and the river flowing through a town or city;
  8. Finally, developing an institutional structure required for mapping the aquifers, and initiating groundwater management as an integral part of urban governance.

Currently, according to estimates of the Central Pollution Control Board, the country has installed capacity to treat roughly 30 per cent of the excreta it generates. Just two cities, Delhi and Mumbai, which generate around 17 per cent of the country’s sewage, have nearly 40 per cent of the country’s installed capacity. What is worse, some of these plants do not function because of high recurring costs – electricity and chemicals and 65 others because they do not have the sewage to treat.

In most cities, only a small (unestimated) proportion of sewage is transported for treatment. And if the treated sewage – transported in official drains – is allowed to be mixed with the untreated sewage – transported in unofficial and open drains – then the net result is pollution. Decentralised wastewater management systems can overcome many of these problems by

  • catering to the un-served areas and minimize the pressure of transporting to a single location.
  • reducing the cost of treatment and O&M costs
  • adopting site-specific treatment technologies based on the land use.
  • minimising land requirement for treatment.

What is more, with basic level treatment of sewage, the water can be reutilised in industries and power plants. The water sludge after treatment can also be used as manure in agriculture; this measure may result in revenue generation to ULB. It is in the interest of the city to find ways to find buyers and users for its sewage. In this way it can work out the effluent profile of its treated effluent and segregate its waste to meet the needs of the end-user.

A rapidly emerging element of urban water, which requires much greater focus on recycling and reuse, is industrial water. Indian industry is currently excessively dependent on fresh water and tends to dump its untreated waste into our rivers and groundwater. Overall, the water footprint of Indian industry is too high, which is bringing industry into conflict with other parts of the economy and society.

There is huge scope for reducing the industrial water footprint and this can be done through technologies and investments, which have a very short payback period. Coal-based thermal power plants need massive amounts of water, both for cooling and ash disposal. In case of coastal power plants, the water 66 requirement is normally met from the sea, but for inland TPPs, water is a far more critical issue.

Out of the 192,804 MW with environmental clearance, about 138,000 MW or 72% are inland. TERI has estimated that in 1999–2001 out of a total of about 83,000 million litres per day (MLD) of water discharged by all the industries in India, about 66,700 MLD (~80 per cent) is cooling water discharge from thermal power plants. CSE puts the figure closer to 90%. During the same period, it was estimated that for every MW of power produced, Indian thermal power plants consumed about 8 times more water than those in developed nations.

This is mainly attributed to the once-through cooling system (open loop system). Cooling towers and ash handling are the major water consuming areas and account for about 70 per cent of the water use within the plant. Comprehensive water audits conducted by TERI at some of India’s largest thermal power plants revealed immense scope of water savings in the cooling towers, and ash handling systems. Once-through systems are becoming uncommon in the world.

However, in India, many plants still operate the once-through cooling system. A rough estimate suggests that by converting all the thermal power plants in India to closed-cycle cooling systems, about 65,000 MLD of fresh water can be saved. The payback period for the proposed wastewater treatment and recycling system is less than 3 years. From a national perspective, where a large number of power plants other than NTPC still function on the once-through cooling system, there is considerable scope to improve water-use efficiency and conserve water resources.

The first step in this direction will be to make comprehensive water audits a recurring feature of industrial activity so that we know what is being used by the industrial sector at present and so that changes can be monitored and the most cost-effective basket of water efficiency technologies and processes designed and implemented to reduce water demand and increase industrial value added per unit of water consumed.

We must make it mandatory for companies to include every year in their annual report, details of their water footprint for the year. Simultaneously, we must develop benchmarks for specific water use in 67 different industries and would ensure their application in the grant of clearances for industrial projects.

*Click HERE for full report


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