Author – Shreya Mathur
It has been more than one year since the launch of ‘Swachh Bharat Abhiyan’ and yet sanitation facilities in India are alarming. Half of India’s population does not have an access to toilets and people are forced to defecate in the open. Moreover, in regions with low temperatures and high altitudes, the natural biodegradation of human waste is halted, leading to its accumulation. This poses serious health hazards, raises environmental concerns and water contamination. Untreated human waste or exposed fecal matter is a grave threat to the well-being of our society and the environment.
This problem is glaringly evident in public places such as bus stations, railway stations, etc., which stink with the smell of urine and are filled with garbage. Particularly, when train toilets unload human excreta and urine directly onto the tracks, the stench emanating from the filth is unbearable at times. Apart from the environmental problem posed by these toilets, corrosion of the railway tracks is another major issue.
Solution – DRDO Bio-toilet
Indian Railways requested the Defence Research & Development Organisation (DRDO) to develop an eco-friendly innovative technology for hygienic disposal of human waste. DRDO came up with the idea of ‘Bio-toilet’, which is a self-contained device for disposal of human waste through the help of anaerobic bacteria placed inside a tank.
The main constituents of DRDO Bio-toilet are a pre-fabricated shelter and a bio digester tank that is filled with 125 liters of water. Toilets with this bio-digester are welded to railway passenger coaches. The bio-digester tank has an inlet pipe for human excreta and an outlet for Biogas. The temperature inside the biodigester is maintained at around 25-30 degree Celsius for the ‘cold-active’ bacteria. A microbial reaction takes place that converts 90% of human solid waste into harmless and odorless methane and carbon dioxide and water. The gases are released into the atmosphere and the water is discharged on to railway tracks after chlorination. All the foul smell and disease causing organisms are eliminated in the process.
The question is, how are these DRDO Bio-toilets better than the current system of pit-latrines or open disposal? Bio toilets treat human waste at the source itself, eliminating the need for its transportation. Thus, there is no environmental pollution. There is no infrastructure required, which reduces the burden on daily management. There are other benefits of bio-toilets as well. The system emits pathogen-free water and methane gas, which can be collected and put to use. This water can be used for irrigation and gardening, while biogas can be used for cooking and heating. Since they do not require any sewage pipes, these DRDO Bio-toilets can be installed anywhere irrespective of land terrain or water availability. The bio-toilet system meets all regulatory and environmental standards.
Looking at the cost benefit analysis, installation and maintenance of such biodegradable toilets is not an expensive affair. Installation of one DRDO bio-toilet costs around INR75,000-80,000, which is a one-time cost for 25 years. However, regular maintenance is required to clear the toilet chute in case of choking by tea cups, cloths, napkins, plastic bags etc. and charging of chlorine tablets in the chlorinator.
These DRDO bio-toilets could a blessing for rural India where only 30% of population has private toilets. The technology has been adapted successfully for use in all terrains. While 12,000 units in Lakshadweep islands are using DRDO’s Bio-toilet technology, the railways which faced severe criticism for stinking platforms and unsightly human waste littered tracks, are also using these toilets. For the fiscal year 2015-16, Indian Railways has set the target to fit 17,000 bio-toilets in long-distance trains as part of its ‘Swachh Rail – Swachh Bharat’ program. Till November 2015, 7,621 DRDO bio-toilets have been fitted in 2,144 coaches.
However, bio-toilets have faced some opposition because of certain disadvantages. Scientists from IIT-Kanpur believe that such toilets are suitable for houses but not for trains stating that because a large number of people will need to use them in a short span of time. The ‘cold-active’ bacteria will not be able to treat waste fast enough to break down the sludge and therefore excreta will be directly discharged on railway tracks even after expensive redesigning of the existing conventional toilets in coaches.