Creating clean, reusable water from human waste

The Rs32 lakh Ecosan (Ecological Sanitation) project is experimented, with help from Mumbai Metropolitan Region (MMR) Environment Society, at Adarsh College at Kulgaon-Badlapur by Ram Patkar, President, KBMC. The technical assistance to the project that was started in 2008 is given by GTZ – Germany, Waterworks Association and Ecosan Foundation, Pune.

At Adarsh Vidya Mandir, from two separate toilet blocks used by 1500 male and female students, human excreta with grey or black water is directed into a biogas settler and a siphoning plant. From there it is directed to the compensation chamber and then, to the anaerobic baffle-reactor and anaerobic upflow filter plant. The biogas thus prepared is guided to a stove where it is used to cook khichdi for the students. Three biogas settlers and one baffle reactor generate 2000 (800 and 1200 respectively) litres of biogas between them.

Urine flows to urine collection tanks. Its odour is removed at the source using membrane technology and is then guided through pipes to the garden to water plants. Water that had collected in the siphoning tanks flows to a wet land and then to water polishing pond. Its impurities get settled there. This is then used for gardening and washing.

Mineralised sludge is propelled out of the treatment system after two years to be used as compost with other organic materials which further amends the soil.

“The pots are designed in such a way that faeces falls directly in the hole below and toilets do not need washing till the evening,” says Patkar. In the evenings when the toilets are cleaned (they are cleaned only once – in the evenings), only 7000 litres of water is used as against the 19,000 litres used in a normal system. Urine from only boys’ toilets is used in the storage tank.

The principle in Ecosan is simple: Urine and faeces are separated at source and not mixed with water. This way, it becomes easier to recover and recycle the nutrients like phosphorus and nitrogen. Plus, it stops the contamination of large volumes of water with pathogens. This separated urine can be used in the soil as a hygienic fertilizer after diluting or processing.

The same way, faeces can be composted. “It allows the integration of organic waste treatment into food production.” In Ecosan toilets, the urine and excreta are collected and disposed off separately and no water is used for flushing. The entire structure is constructed above ground and does not have below ground process.

The unique project has been noticed by the United Nations which has awarded the KBMC with the UN Water Conservation Award. Ecosan offers low and high technology solutions for rural and urban areas. The solutions can be dry and/or waterborne depending on the situation. “I had attended an Ecosan presentation at Leela Kempinski two years ago that changed my way of thinking on water and waste management. I think it is important for us to look at sustainable and eco-friendly measures when it comes to natural resources. That way, we can save money and overcome the scarcity of natural resources,” says Patkar.

Ecosan toilets are effective in areas having a high water table and also those that experience water scarcity. According to the statistics supplied by the Food and Agriculture Organisation (FAO) on food, the average excretion of nutrients per capita per year in India is about 2.7kg nitrogen, 0.4kg phosphorous and 1.5kg potassium.

According to Ecosan ideology, human excreta and household wastewater are resources that can be recovered, treated safely and reused along with enabling the recovery of nutrients. By recycling and redirecting them to agriculture, the soil fertility is improved. It is claimed that biogas systems have the potential to produce renewable energy.