An Overview of Bio-Digesters / Bio Toilets

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 Defence Research & Development Establishment, Ministry of Defence.

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.

Technology allows the human waste to be disposed of in an eco-friendly manner in places with extremely low temperatures. The 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,


Advantages of Bio-toilets

Bio-toilets have emerged as a very innovative and eco-friendly solution to the problem of human waste disposal. The most important advantage of a bio-toilet is that it disposes and degrades human waste in a completely safe manner, without causing any hazards to the environment. . The pathogens and other disease-causing harmful organisms are eliminated completely.

Another plus point of a bio-toilet is that it generates colourless, odourless inflammable bio-gas which has numerous uses for household and industrial purposes. The water thus released is absolutely clear and odourless. It is full of nutrients and minerals and hence it becomes good for irrigation of nearby gardens, lawns etc. 

The assembling of a bio-toilet does not require a separate connection with a septic tank ora sewage tank. It is just connected with a bio-digester tank which makes it 100% maintenance free and economically viable. Regular cleaning with kerosene, phenyl and soap do not harm the surface of bio-toilets.

Bio-toilets play an important role in conservation of natural resources like water and energy and also save on money and time, thus promoting health and hygiene. 


Salient Features

Bio-toilets are environment-friendly and apt for disposing human waste. The best feature of a bio-toilet is that it is perfect for areas of sub-zero temperature (like the Himalayan region and the glacier areas), public places (like railway coaches, buses and highways), metro cities, remote areas and other busy places like sea ports and mining areas. 

Bio-toilets are suitable for mobile toilet applications and hence they are quite portable, even for the hilly areas. No transportation and installation hassles are involved. In fact, it can be installed instantly and made operational within 12hours only. 
Bio-toilets are not depended on the conventional sources of energy. Rather, it is a continuous biological process and there is no additional cost incurred for maintaining the same. The inoculum (a constituent of the bio-toilet) also needs charging just once during the life-time of the bio-toilet. 

Bio-toilets degrade human waste in a completely safe and environment-friendly way.They generate colourless, odourless inflammable bio-gas which again has its own uses.

Bio-toilets do not require a separate connectivity with a septic tank ora sewage tank. Even a separate outlet for sludge disposal is also not required. It is just connected with a bio-digester tank, making it economically viable. Bio-toilets can be cleaned with the regular cleaning chemicals like kerosene, phenyl and soap.

The special feature of the bio-digester toilets installed at Vivekananda Nidam is that the Bacteria Anaerobic Digestion process keeps clean and odourless the water emanating from the toilets and whihc can be used for plants.

Below the toilets, a special kind of bacteria is put in the digester tank, which makes the water from the toilets clean and odourless.

The bio-digester toilets are already in use in express trains across India.


Types of Bio Toilets

Based on their uses, bio-toilets are categorised as follows –

1. ST Series
2. IMMT Series
3. TMMTC Series

These series of bio-toilets have been identified based on their area of uses. “ST Series” comprises of Stationery toilets. Similarly “IMMT Series” comprises of Independently Mounted Mobile Toilets and “TMMTC Series” ofTrailer Mounted Mobile Toilet Cluster. Stationery Bio-toilets have been further sub-categorised as “Non Temp Controlled” and “Temp Controlled”. The Non Temp Controlled Stationery Bio-toilets are mainly used in plain areas. These Bio-toilets are available in various readymade options like single pan, 2pan and 4pan. 

The Temp Controlled Stationery Bio-toilets are solar powered. They are used inhilly and cold regions.Like the former, these Bio-toilets are also available in three standard readymade options like single pan, 2pan and 4pan. 

The IMMT Series or the Independently Mounted Mobile Toilets are used in transport industry. As the name suggests, these independent mobile toilets are mounted on railway coaches, buses, ships and boats.

The TMMTC Series or the Trailer Mounted Mobile Toilet Clusters are a cluster of 4-16 single toilet cabins. Depending on the customer’s requirement, these clusters are mounted on tractor trailer, jeep trailer or trucks and thus can be transported to the destination.