The country has got its first toilet-to-tap Waste Water Treatment Plant treatment, in the national Capital Delhi. As the name suggests the plant turns sewage water into drinking water. About One Lakh litres of clean drinking water can be produced by this plant, every day.
The plant is located at Keshopur Jal Board and has been set up by Absolute Water, a Division of Indo-American Chemicals in association with Delhi Government.
“As much as 85% of the raw sewage water, once taken through the correct processes, can be converted to safe drinking water,” says Sunil Singhal, president, Indo American Chemicals.
“Our system will go a long way in alleviating the sewage treatment problems for Delhi. If other states want we can replicate the same model. The treated water can be used for recycling thereby augmenting the dwindling water supply. Similar processing and recycling of water is being carried out in Singapore and Australia among other countries and it is perfectly safe,” added Singhal.
The process works on the principal of vermi-filtration wherein specially bred worm species and a mix of bacteria are added to the sewage water. These organisms act on the suspended and dissolved solids in the raw sewage and biologically degrade in an environmentally safe manner. Another feature of the biofilter is that it produces no sludge, and has very low operating cost. Moreover, it is also quite environment-friendly uses no aeration, chemicals or polymers and has been designed to work on solar power.
The drinking water supply and sanitation in India is grossly inadequate. Water in most rivers in India is largely not fit for drinking.Much of Ganga remains polluted with a high count of coliform bacteria (coliform bacteria are an indicator of sanitary quality of foods and water; the high the count the high is contamination) at many places.
As per the World Health Organization (WHO) estimates, 97 million Indians lack access to safe water today, second only to China. According to the 2011 census, India has only 1,000 cubic meters of water per person, which is pretty low.
Further as per WHO standards, nitrate levels in drinking water should be below 50 milligrams per liter but in Delhi they have been recorded at as high as 1,500 milligrams per liter. This high level is due to the “combined effect of contamination from domestic sewage, livestock rearing, landfills and runoff from fertilized fields, unlined drains, and cattle sheds.
The Absolute Water process can be used to treat the sewage at locations near the Ganga or Yamuna, and clean water discharged into the river to maintain their ecological flow while making them safe for bathing, aquatic life, etc.
The Biomass used in the plant is to be changed once in six months and the reject biomass is excellent Humus for soil rejuvenation. The final stage is the membrane filter, a non-R.O. System, with a high recovery of 85% of water. The Reject water is very high in nutrients and acts as a liquid fertilizer.
Bio-filtration is a continuous process, with the raw sewage filtering through the seven layers of biomass based filter media. And the entire process time is less than seven minutes.
“If this project is up-scaled in a de-centralised manner, every home will get sewer and water connections in the next three to four years,” says Delhi CM Arvind Kejriwal.