India has historically always had advanced sanitation and hygiene systems, the best example being the advanced hydraulic engineering, water supply and sanitation systems built by our ancestors, in the Indus Valley Civilisation and MohenjoDaro. These civilisations had the world’s earliest known system of flush toilets and were connected to a common sewerage system. The urban areas of the Indus Valley civilization had a network of public and private toilets with sewage being disposed through underground drains. These drains were built with precisely laid brick, and a sophisticated water management system. Over the ages things changed, and today we are the world’s most populous country with some of the world’s highest population densities in our cities. Human waste (faecal matter) disposal is an ever growing problem leading to threat of organic pollution & rise of infectious diseases due to contamination of ground water, food chain and drinking water resources. Our Local Govt Bodies have been unable to cope up with the population explosion and as a result we have some unfavourable conventional technologies like Septic Tank Systems which need to be re-looked into so as to preserve and save our environment for the future generations.
The Bio-Digester Technology Toilets have the same look and feel like any other normal toilet. The only difference is in the manner in which the human waste (faecal matter) is treated. In the past few years a variety of treatment solutions have come up in the market but none of them are as popular and efficient as the Bio-Digester Technology developed by DRDO, Ministry of Defence, Govt of India. This technology was initially developed to cater to the needs of Indian soldiers posted in high altitude regions like Siachen. With successful results, the technology is being offered to the entire country under the SWACCH BHARAT MISSION. DRDO is a premier research organisation and has left no stone unturned to ensure that the very best technology is offered to the market. The BIO-DIGESTER TOILET SYSTEM has two key components which perform the task of treating the human waste matter and converting it to safe water fit for irrigation / gardening.
Anaerobic Microbial Inoculum (commonly called as the AMI – Anaerobic Microbial Inoculum) and sometimes referred to as DRDO Bacteria. This is a non hazardous solution which is poured into the Bio-Digester Tank and works round the clock to treat the human faecal matter and converts it to water, carbon di oxide and methane.
A specially designed tank known as the Bio-Digester Tank which contains the AMI and into which flows the Black Water (toilet discharge). This tank can be installed over or under the ground as per the site requirements. It is delivered factory assembled and only the inlet and outlet connections have to be made at the site.
Septic Tank: In India, Septic Tank is a very commonly used product for storage and disposal of Human Faecal matter at places / sites that lack connection to main sewage pipes which normally are provided by local government bodies. Sadly in our country, the sewerage network is missing and in fact most of our urban clusters lack 100% sewage connections thus leading to higher usage of Septic Tanks which is NOT an Eco Friendly Solution. Since Septic Tanks require large drainfields to dispose of the sludge (Human Faecal Matter), they are not suitable for densely built cities and in fact pollute the environment. Periodic preventive maintenance is required to remove solids (faecal matter) that remain and gradually fill the Septic Tank which reduces its efficiency and thus regular pumping out is a must to de-sludge the Septic Tank. If this is not done then the faecal matter (solids) escapes from the Septic Tank and clogs the drainage pipes / surrounding areas thus polluting and creating numerous health hazards. Additives to improve the effluent quality from septic tanks, reduce sludge build-up and to reduce odors have been promoted by some manufacturers, however, these additives – which are commonly based on “effective micro-organisms” – are usually costly in the longer term and fail to live up to expectations of the users. Disadvantages of a Septic Tank:
Septic tanks do not treat the waste but only store it thus they basically just postpone the problem of treating the waste and act as containers of waste material.
In many rural areas no proper equipment is available to pump out the waste matter from the septic tanks and many a times people manually clean the septic tanks which is tantamount to manual scavenging, a practice that is morally repugnant, dehumanising and against the law.
The agencies that “clean” the septic tanks do not treat the waste – they just dump it in the water bodies or ditches, thus polluting the environment.
Environmental concerns due to Septic Tank Systems: Odour and gas emissions: Septic Tank systems typically generate hydrogensulphide, a pungent and toxic gas along with ammonia which is also generated due to breakdown of Nitrates and organic nitrogen compounds. Both these gas emissions are not desirable for human beings and for our environment. Nutrients in the effluent Septic tanks are ineffective at removing nitrogen compounds that have potential to cause algal blooms in waterways into which the septic tank dischargefinds its way. Furthermore the system keeps phosphates in a soluble and mobilized form which can trigger prolific plant growth including algal blooms which also include the blooms of the potentially toxic cyanobacteria. Groundwater pollution In urban areas with high population density, septic tank system pollutes the ground water beyond acceptable limits which in turn pollutes the food chain leading to health hazards. Surface water pollution: In areas adjacent to water bodies, septic tank systems pollute the water thus harming the marine life leading to lower harvest levels (less number of fishes in the water) and ecological destruction. Health Hazards: In India, the extensive usage of Septic Tanks along with Soak Pits / Leach Pits and Open Defecation has led to degradation of our environment posing serious health hazards. The list of diseases that could be reduced with proper sanitation and hygiene practices is very long. For example, in India, 15 diseases have been listed which could be stamped out by proper sanitation practises.
- Anaemia, malnutrition
- Ascariasis (a type of intestinal worm infection)
- Campylobacteriosis
- Cholera
- Cyanobacteria toxins
- Dengue
- Hepatitis
- Japanese encephalitis(JE)
- Leptospirosis
- Malaria
- Ringwormor Tinea (a type of intestinal worm infection)
- Scabies
- Schistosomiasis
- Trachoma
- Typhoid and paratyphoid enteric fevers
Polio is another disease which is related to improper sanitation and hygiene. To counter the problems faced due to the above scenario, DRDO (Defence Research and Development Organisation), Ministry of Defence, Govt of India has developed and commercialised the Bio-Digester Technology for treatment of human faecal matter. Dr Lokendra Singh of DRDE, Gwalior is credited with the invention of this technology that was initially deployed in the Defence sector and now is being promoted under the SWACCH BHARAT MISSION program.
Bio-Digester Systems versus Septic Tank Systems
| Working Features | Septic Tank | Bio-Digester |
| Waste Degradation | Aerobic dominant | Anaerobic |
| Waste Decomposition | Only 30% pathogen reduction | Up to 99% pathogen reduction |
| Additives | Periodic addition required | One time charge of Bacterial Inoculum. |
| Sludge Formation | Yes | No |
| Maintenance | Periodic removal of sludge, to be emptied every 2 years or earlier as per IS 2470 norms. High Maintenance Costs. | Maintenance-free. |
| Discharge from Tank | Odorous (hydrogen sulphide and ammonia gases), sludge formation and hazardous waste . Discharge water is unsafe for any kind of use and has to be disposed of safely. The discharged water contaminates the ground / water bodies. | Odourless, colourless and hazard-free waste (water only)Discharge water is safe to be used for irrigation, gardening or to be let off into water bodies or over the ground. It does not contaminate. |
| Sensitivity towards Cleaning Agents | Cannot tolerate toilet cleaning agents | Bacteria conditioned to remain unaffected by cleaning agents up to permitted limits |
| Size of the system | Three times bigger than the Bio-Digester, hence costly to construct and occupies more space a major constraint in the urban areas | One third the size of the Septic Tank, hence economical and has a smaller footprint leading to lower construction cost. |
| Impact on Environment | Significant | No impact…100% Eco-Friendly system |
| EFFLUENT TEST RESULTS – COMPARISION | ||
| Parameter | Septic Tank | Bio-Digester |
| pH | 6.7-7.5 | 7.0-7.2 |
| Turbidity (NTU) | 500-800 | 70-90 |
| Total Suspended Solids (mg/L) | 150-300 | 90-120 |
| TDS (mg/L) | 500-850 | 350-450 |
| VS (mg/100ml) | 50-60 | 20-30 |
| COD (mg/L) | 1200-2000 | 250-300 |
| BOD 5 (mg/L) | 350-500 | 70-120 |
| Coliforms (MPN/ml) | > 3,000 | 300-350 |
Listed below are the key advantages of Toilets build using the BIO-DIGESTER Technology as compared to the conventional treatment systems such as Septic Tank, Soak Pit, Open Drainage, Two Pit Latrine, etc…
No bad smell in toilets from the tanks
No infestation of cockroaches and flies
Faecal matter in the tank not visible.
No clogging of digester.
Effluent is free from offensive odours, solid waste and does not contaminate the ground water / soil like other systems do.
No maintenance required.
Reduction in organic matter by 90%.
No requirement of adding bacteria/ enzyme.
No need of removal of solid waste.
Normal Cleansing Agents like Phenyls, Toilet Cleaners can be used
Specifications of Bio-Digester Tanks:
Rotationally moulded, factory assembled, ready for installation
Material of construction: Polyethylene
Tank wall thickness: 7 mm (minimum)
Heavy-duty poly-grass matting to ensure good formation of bacterial colonies
3 compartment design for complete digestion of faecal matter
Lifting hooks for ease of handling
Inbuilt vent pipe