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  1. Smart cities need effective sewage recycling systems

Smart cities need effective sewage recycling systems

While India has rapidly urbanised in recent decades, most towns and cities still lack basic infrastructure like running water or stable electricity. In January this year, the country took a landmark step toward modernising its cities by awarding 20 of them with funds to solve problems from shoddy sewage treatment to snarled traffic.

By: | New Delhi | Updated: August 25, 2016 12:22 PM
Groundwater plays a very important role in meeting the water demand of Indian cities. There is imperative need to have sound planning strategies for managing, protecting and conserving the urban aquifer systems for sustainable extraction of groundwater over a longer period. (Source: Reuters) Groundwater plays a very important role in meeting the water demand of Indian cities. There is imperative need to have sound planning strategies for managing, protecting and conserving the urban aquifer systems for sustainable extraction of groundwater over a longer period. (Source: Reuters)

While India has rapidly urbanised in recent decades, most towns and cities still lack basic infrastructure like running water or stable electricity. In January this year, the country took a landmark step toward modernising its cities by awarding 20 of them with funds to solve problems from shoddy sewage treatment to snarled traffic.

After coming to power over two years ago, Prime Minister Narendra Modi unveiled his vision for creating smart cities across India for a better life for 400 million city dwellers. The Smart Cities Mission is an urban renewal and retrofitting programme to develop 100 cities and make them citizen friendly and sustainable. The Union Ministry of Urban Development is responsible for implementing the mission in collaboration with the state governments of respective cities.

Smart cities are projected to be equipped with basic infrastructure that will offer a good quality of life through smart solutions. Assured water and power supply, sanitation and solid waste management, efficient urban mobility and public transport, robust IT connectivity, e-governance and citizen participation along with safety of its citizens will be the key attributes.

Groundwater plays a very important role in meeting the water demand of Indian cities. There is imperative need to have sound planning strategies for managing, protecting and conserving the urban aquifer systems for sustainable extraction of groundwater over a longer period.

Official figures show that about 62,000 million litres per day (MLD) of sewage is being generated in urban areas, while there is treatment capacity for only 23,277 MLD. Significantly, the actual amount of sewage treated stands at 18,883 MLD as only 522 out of 816 sewage treatment plants listed across India are operational.

Thus, at least 70% of sewage generated in urban India is being dumped in rivers, seas, lakes and wells, polluting water bodies and contaminating fresh water sources. Partially treated or untreated sewage is responsible for large part of the pollution in streams and water bodies. Experts say up to 80% of water bodies could be polluted.

Discharge of untreated sewage is the single most important source of pollution in surface and ground water. There is clearly a large gap between generation and treatment of domestic waste water. The problem is not only that India lacks sufficient treatment capacity, but also that sewage treatment plants that exist do not operate and are not maintained.

Waste water generated in these areas normally percolates into the soil or evaporates. Uncollected wastes accumulate in the urban clusters, causing unhygienic conditions and releasing pollutants that seep down to surface and groundwater.

A total of 114 Indian cities are estimated to be dumping untreated sewage and partially cremated bodies directly into the rivers. Lack of toilets and sanitation facilities leads to people defecating in open. This contributes to surface water pollution, disastrous environmental consequences and diseases.

In the national capital of New Delhi, groundwater salinity is a common problem. However, the depth of interface between fresh and saline water varies from area to area. Highly saline groundwater in the city is mainly due to water logging, low lying areas and discharge zones. Irrigation and water logging also cause concentration of chloride and nitrate ions in the groundwater.

Industrial areas located in the western, southern and eastern parts of the city as well as three thermal power plants are major anthropogenic sources of groundwater contamination. Industrial and domestic effluents increase nitrate concentration in groundwater in some pockets of the west, southwest and northwest districts. These nitrate plumes in the groundwater in southern and northern parts of the city are indication of unplanned urbanisation of these areas.

Contamination of the groundwater by trace metals is due to industrial waste in the Yamuna river catchment areas from Najafgarh drain.  The use of water from Yamuna and associated drainage systems for irrigation of agricultural land leads to accumulation of heavy metals such as chromium, copper, zinc, lead, nickel and cadmium as a result of industrial waste and sewage in the sub-surface.

Much of the water used for domestic purposes does not require potable (suitable for drinking) water quality. For instance, water used for flushing toilets or for washing floors, yards or roads and gardening does not require being potable. However, sewage must necessarily be treated correctly and then re-cycled for various purposes that do not need potable water quality. Installing sewage treatment plants can conserve fresh water supply for drinking.

Vishvaraj’s Orange City Water Project in Nagpur is a prime example of effective water management. Nagpur has now been included in the Smart Cities list.

A lot can be done to make the holy river Ganga clean and upgrade Indian cities to world-class levels. But it is crucial to have various options for sustainable water supply in like augmentation of water supply through rainwater harvesting, conservation and groundwater recharge. This should be supported by groundwater regulation to enable overall improvement of water resources.

In addition there is need for demand management, which the urban policy makers have to emphasise. A decentralised approach with coordination among the state, private sector and civil society is needed for evolving better water supply options in urban India.

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