Immersion – KK Nag Industry Visit

The SIIP team visited K. K. Nag industries as part of immersion visits.

K. Nag Pvt. Ltd represents more than half a century of pioneering enterprise. Headquartered in Urse, Near Pune, is renowned for having introduced several innovative plastic products into India for the first time and are a premier Indian manufacturer of EPS (Thermocole), EPP and myriad speciality plastics.

The main line of business of Nag industries is Expanded Polystyrene (EPS) moulded packaging and components. Most of the manufacturing takes place at total 4 locations, 2 in Pune, one each on Puducherry and Chennai. These factories also process other foamed plastics. Company also prepares rotationally moulded products in LLDPE and various other plastics, and has in-house facilities for PU foaming.

Approximately 15 years ago Nag industries ventured into the field of sanitation under the able and passionate leadership of Mr. M. K. Nag (MD, K. K. Nag Pvt. Ltd).

One of their first and iconic products were ‘squatting slabs’. A squatting slab is a plastic moulded slab retrofitted with a steel frame inside to bear the weight of the person. The slab is classically set up on top of a pit latrine. This system is usually used in rural areas and/or in areas affected by natural calamity. The squatting slab is very successful product as it offers an easy sanitation solution and stops the spread of diseases like Diarrhoea, Dysentery, Typhoid and Cholera caused due to open deification. The seepage of such a system into the ground water system can still be a problem and hence this system is not advised unless absolutely necessary.

Their most prominent product in sanitation niche is a bio-digester, devised to disintegrate the faecal matter. Nag industries use 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.

The bio-digester has two key components:

  1. Anaerobic Microbial Inoculum (AMI): Non bio-hazard solution a combination of 150 different type of bacteria. These bacteria break down the faecal matter into water, carbon-di-oxide and methane. Nag Industries have an incubator which makes the AMI, the incubator has a cycle of 100 days in which the bacteria is introduced in the incubator using cow-dung as a carrier and later as food for the bacteria.
  2. Bio-digester tank: A specially designed bio-digester tank makes sure that uses toilet discharge as input and is designed in such a way that it gives bacteria enough time to process the input and break down the faecal matter. Nag industries manufacture these bio-digester tanks sing rotational moulding facility. They have perfected the design to get optimum results.

Nag industries are a license holders from DRDO to use their technology to manufacture and distribute the AMI. The Nag industries’ manufacturing facility is inspected by the DRDO officials every 3 months to evaluate the viability of the AMI after which it is allowed to be distributed to the customers. One of the main clients of Nag industries are Indian Railways. Some other clients involve private societies and bungalows.

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. Bio-digester tanks are a need of the hour, as most of the faecal matter entering in the environment is not disposed for a long time and needs to be managed at the source itself.

Currently, in India use of septic tanks is very common as compared to the a bio-digester tank.


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 odours 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.

  1. Anaemia, malnutrition
  2. Ascariasis (a type of intestinal worm infection)
  3. Campylobacteriosis
  4. Cholera
  5. Cyanobacteria toxins
  6. Dengue
  7. Hepatitis
  8. Japanese encephalitis(JE)
  9. Leptospirosis
  10. Malaria
  11. Ringwormor Tinea (a type of intestinal worm infection)
  12. Scabies
  13. Schistosomiasis
  14. Trachoma
  15. Typhoid and paratyphoid enteric fevers

According to DRDO, the published comparative study of a Septic System Tank system and a Bio-Digester system is as follows:

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


Key advantages of Bio-Digester technology:

  1. No bad smell in toilets from the tanks
  2. No infestation of cockroaches and flies
  3. Faecal matter in the tank not visible.
  4. No clogging of digester.
  5. Effluent is free from offensive odours, solid waste and does not contaminate the ground water / soil like other systems do.
  6. No maintenance required.
  7. Reduction in organic matter by 90%.
  8. No requirement of adding bacteria/ enzyme.
  9. No need of removal of solid waste.
  10. Normal Cleansing Agents like Phenyls, Toilet Cleaners can be used


Design and working of a Bio-Digester system:

More information of K.K. Nag industries and DRDO technology of Bio-Digester tank can be found on the following link: