Defence scientists develop bio-toilets for soldiers
Saturday, 19 February 2011, 13:37 IST | 10 Comments
Bangalore: Indian defence scientists have recruited a small army of bacteria and harnessed solar power to build bio-toilets for managing the human waste of soldiers stationed at glaciers and other low temperature areas. 'Human waste disposal in high altitude and low temperature areas is a burning problem,' a spokesman for the Defence Research and Development Establishment (DRDE) in Gwalior told IANS on phone. 'The problem is further aggravated in glaciers where ambient temperature drops to minus 40 degrees Celsius and lower.' When left buried in the ice, the low temperature prevents natural biodegradation of waste, leading to their accumulation for a long time. Due to heating by direct sunlight, the melting ice takes the waste to rivers, polluting them as well, scientists said. Traditional methods of burying human waste or incineration and chemical treatment are not possible in glaciers. Biological treatment is an attractive approach for solving the problem but micro-organisms that decompose the waste in normal temperatures are inactive at freezing temperatures. Technology developed by DRDE overcomes the problem. The key to DRDE's bio-toilet technology is a consortium of anaerobic bacteria --organisms which do not require oxygen to live and multiply -- that has been formulated and adopted to work at temperatures as low as five degrees Celsius, the scientists said. The bacterial consortium acts as inoculum (seed material) to the biodigester converting the organic waste into methane and carbon dioxide. The biodigester buried below the ground serves as a reaction vessel whose temperature is maintained between 5 and 30 degrees Celsius by solar heating. Charging of the biodigester with the bacterial inoculum is done only once during the entire life of bio-toilet. DRDE scientists say their technology allows the human waste to be disposed of in an eco-friendly manner in places with extremely low temperatures. They claim their process results in treated effluent free from pathogens, and biogas (methane) is generated as a byproduct, which can be used for cooking and room heating. According to scientists, the biodigester developed by DRDE is suitable for below zero temperatures of the Himalayan region and is maintenance free. Around 90 DRDE bio-toilets have been installed at 24 locations, including several places in Leh, Sikkim and at the Base Camp in Siachen glacier, DRDE said. The scientists said as a spin-off, the same technology has been used to develop bio-toilets for Indian Railways. These toilets were successfully run on the Gwalior-Barauni Mail for two years and the technology has been transferred to eight firms, scientists said.