Faecal sludge continues to pollute Yamuna despite ban on defecation
Septage has high contents of phosphorus, nitrogen, pathogen, BOD and suspended matter. Experts claimed the DJB’s policy demands that septage should be treated by STPs.delhi Updated: Jul 08, 2017 10:07 IST
The National Green Tribunal might have banned open defecation on Yamuna’s flood plains but faecal sludge from lakhs of septic tanks that are emptied into drains is regularly reaching the river and polluting it, warn experts.
According to the 2011 census, around 60% of Delhi’s households have water closets and nearly 30% of the households have septic tanks and pits. But where does the waste go from these tanks and pits?
“Privately owned tankers, after collecting the waste from septic tanks, dump them almost anywhere – neighbourhood fields, open drains and even water bodies. The sludge ultimately reaches Yamuna through the drains,” said Pawan Kumar Jha, a sanitation expert and a former consultant of the World Bank and union water and sanitation ministry.
The Delhi Jal Board in its policy on sewage management had suggested that such waste should be emptied into sewage pumping stations from where it should reach the sewage treatment plants.
But that is seldom done. In almost all cases, the tankers are taken to nearby drains, agricultural fields, local ponds and the waste is poured. The problem is more acute in peripheral areas such as Aya Nagar, Chattarpur and Sangam Vihar.
“Most of the tankers in Aya Nagar discharge waste in a drain on MG Road. That drain opens into a bigger drain which joins the Yamuna,” said Ved Pal local councillor of Aya Nagar.
The entire faecal sludge cleaning industry is operated by private players and government has hardly any control over them. An estimate by the Centre for Science and Environment said around 400-500 such tankers are operating in the city. They collect around four million litres of septage every day.
“The pumping station is quite far and we usually empty the waste in a drain near Batra Hospital. We can complete a few more rounds by saving time. Disposing the waste is a big problem,” said Vicky Singh, a tanker operator who operates in Sangam Vihar.
Septage has high contents of phosphorus, nitrogen, pathogen, BOD and suspended matter. Experts claimed the DJB’s policy demands that septage should be treated by STPs.
“But the problem is that most of the STPs in Delhi are already overloaded and can’t treat such highly polluted waste. The discharged water coming out of the STPs is often polluted and goes into the river,” said Jha.
Experts said the government has to come up with better faecal sludge management guidelines. This would include construction of proper septic tanks with two chambers and soak pits.
- Najafgarh and Shahdara drains biggest contributors as far as discharge and biochemical oxygen demand (BOD) is concerned
- Together these two contribute around 74% of the BOD load and 82% of the discharge
- High Nitrogen: Could lead to eutrophication of water and dissolved oxygen loss. Can lead to a range of diseases among humans – particularly pregnant ladies and children
- High Phosphorus: Could lead to eutrophication and dissolved oxygen loss
- Pathogen: Parasites, bacteria and virus trigger communicable diseases
- Biodegradable organics: Can deplete the dissolved oxygen in surface waters harming aquatic life
“Faecal sludge management is the big missing picture. It is a part of the puzzle we need to crack so that we can have cleaner rivers. We need to plan for it,” said Sunita Narain, head of CSE.