Urban India is growing fast mainly due to rapid industrialization and various commercial activities. Solid wastes and sewage are also being generated increasingly in cities and the authorities are paying little attention to their proper management.
Urban India is generating about 62 million tons (MT) of solid waste and about 22630 billion liters of sewage per year. Out of the total solid waste generated, more than 25% is not collected and nearly 70% of the urban areas have unsatisfactory and inadequate capacity to manage such waste. Similarly, 80% of the sewage in India is untreated and is discharged directly into the rivers and other water bodies, thereby polluting the main source of drinking water. Due to this, land, water and air are getting highly polluted. Most of the people in urban areas are suffering from various types of water and airborne diseases like asthma, cholera, gastroenteritis, bacterial dysentery, hepatitis and poliomycitis etc.
In addition to this, solid waste is clogging the storm water drainage system and causing flooding of street and houses during rainy season.
The Ganga basin is spread over an area of 861,404 sq. km covering the states of Uttaranchal, Uttar Pradesh, Haryana, Delhi, Madhya Pradesh, Bihar, Jharkhand and West Bengal. There are 223 cities and towns which are generating about 8250 million liters per day (mld) of sewage. At present, treatment facilities are available only for 3500 mld and facilities for treatment of an additional capacity of about 1500 mld are in the pipeline. Thus, there is a big gap between sewage generation and treatment capacity. The situation for other rivers is still worse because of unsatisfactory disposal of solid waste and sewage.
As regards solid waste management, the present practice of landfills in most of the urban areas is unscientific and inadequate resulting in contamination of soil, water and air as well as ground water. The general methods to be adopted for urban solid waste management should take into account the concept of “3Rs” i.e. Reduce, Reuse and Recycle. Minimum waste should be produced and the waste generated should be reused and recycled wherever it is possible. The best system to manage urban solid waste should be to streamline the collection, transport and treatment using modern technology as practiced in many developed countries.
The collection of solid waste should be done properly at suitable sites preferably on the outskirts of the city or town. At first, recyclable waste like metal scraps, plastics, rubber, glasses etc. should be separated and sold to the respective industries for recycling. The building and road construction waste should be utilized in road construction and filling of the low-lying areas. Then the remaining organic waste separated from the rest should be utilised for anaerobic digestion for producing fuel gas as well as compost or by aerobic process to prepare compost which can be sold to the users.
Based on the data for 2000, the average compostable matter is 41.8% of the total amount of solid waste generated per day which amounts to be 48,134 MT. By applying anaerobic bio digestion process, the compost generated should be about 8048 MT and the amount of the biogas generated per day is 161 lakhs m3. Based on this assumption, each ton of solid waste should produce 400 kg of compost and 800 m3 of biogas (containing 55 to 65% of methane). This biogas can generate about 2.4 MW power per 100 ton/day of organic waste.
Similarly, technology is available and is being practiced in most of the developed countries to effectively treat sewage through processes like Activated Sludge Process followed by Chlorination and Dual Media Filtration. The treated sewage produces sludge to make compost and the treated sewage water can be reused for various purposes such as gardening, cooling water make up, road washing, toilet flushing, landscape developing etc. Both solid waste and sewage processing should be carried out on a small scale but in large numbers at suitable sites on the outskirts of the urban area for proper management.
The situation due to mismanagement of solid waste and sewage in almost all our cities and towns is causing alarming environmental pollution and is highly hazardous, resulting in suffering and unnatural deaths of lakhs of urbanites every year. The full and undivided attention of our planners and decision makers for protecting urban environment and aquatic resources from solid waste and sewage is urgently required.
It has recently been reported that the Housing and Urban Affairs Ministry, Government of India, in its programme on urban development in 99 ‘Smart cities’, has made a budget for solid waste management, sludge water treatment and environment management together as only 7.4% whereas those for transport, area and economic development, the amount is 44.3% of the total budget.
Much larger amounts should be assigned for solid waste, sewage and environment management which would enable the respective authorities in the cities to bring a meaningful impact in these three important areas. Better execution of projects in these areas will help the growing urban population to live in a clean and healthy environment and get safe drinking water throughout the year.
Good health and peaceful living of urbanites should be a sign of ‘Smartness’ of urban India.
(Former Director General, Council of Scientific & Industrial Research, India)
(Former, Planning Board Member, Government of Odisha)
Chairman, Institute of Advance Technology & Environmental Studies (IATES) and
president, Natural Resources Development Foundation (NRDF)
