Seventy per cent of municipal sewage and effluents from over 900 cities and towns is being discharged untreated into rivers that are a major source of drinking water, according to a recent study by the Central Pollution Control Board
Indian cities and towns together are generating an estimated sewage load of 38,254 million litres per day (MLD) and are treating only 11,787 MLD, which shows a capacity gap of 26,467 MLD, says a new report by the Central Pollution Control Board (CPCB) on water consumption and sewage disposal patterns across the country.
Delhi tops the list -- the national capital generates over 3,800 MLD of sewage per capita. Mumbai is the second big polluter with 2,671 MLD, and Kolkata third with 705 MLD. The study shows that only eight cities -- Hyderabad, Ahmedabad, Delhi, Mumbai, Pune, Ludhiana, Chennai and Vadodara -- treat more than half their sewage.
The fourth report in a series based on data available in 2008, of 498 Class I cities (with over 1 lakh population) and 410 Class II towns, shows that the biggest cities in India are only treating 50% of the sewage they generate. Not only is the rest going into rivers -- the source of drinking water -- it is also polluting the sea.
Kolkata, Mumbai and Chennai account for 60% of sewage spewed into the sea. Cities like Kolkata, Patna, Kanpur, Dehra Dun and Allahabad dispose of huge amounts of waste directly into the river Ganga.
According to the report, of the total 38,254 MLD sewage, the greatest contribution of over 35,000 MLD comes from Class I cities while the remaining 2,696 MLD is from Class II towns. Against this, the total sewage treatment capacity of Class I cities (498) is 11,553.68 MLD, which is only 32% of the sewage generation.
“Out of an 11,553.69 MLD sewage treatment capacity, 69% (8,040 MLD) is treated in 35 metropolitan cities, thus indicating that other than metropolitan cities, the capacity of 462 Class I cities is only 31%,” the report says.
“This evidently indicates the ominous position of sewage treatment, which is the main source of pollution in rivers and lakes, and hence there is an urgent need for implementing an action plan to arrest the pollution of rivers,” the report notes.
While the current state of sewage disposal poses a huge health problem, it is also a waste of resources. “Sewage water has nutrients like nitrogen and phosphorus. The nutrient value of this water is between Rs 75 per hectare per annum and Rs 400 per hectare per annum. The only way out is to set up systems wherein this water can be used for irrigation and fertilisation in fields and horticultural areas,” said a senior scientist from the CPCB.
Despite funds from the Ministry of Environment and Forests, and under the Jawaharlal Nehru National Urban Renewal Mission, sewage treatment plants do not function to their full capacity. The study suggests that if an economic value were to be assigned to the fertilising potential of this wastewater, Rs 1,091 million was being lost annually.
Source: The Indian Express, January 11, 2010
Press Trust of India, January 10, 2010
The Economic Times, December 25, 2009