Converting Municipal Sewage Waste into Bio-Fertilizer

In many metropolitan cities, open, uncontrolled and poorly managed dumping is commonly practiced, giving rise to serious environmental degradation. More than 90 percent  of MSW in cities and towns are directly disposed of on land in an unsatisfactory manner. Such dumping activity in many coastal towns has led to heavy metals rapidly leaching into the coastal waters. In larger towns or cities like Delhi, the availability of land for waste disposal is very limited.

Conventionally sewage treatment plant treats the sewage and the same is dried. The technology developed by Bhabha Atomic Research Centre (BARC) subjects the dried sludge to crushing and exposure to 10 kGy radiation dose. This kills the pathogens in the sludge and makes it safer for use. In the next step, BIO-NPK (Nitrogen Phosphorus Potassium) microorganisms are sprayed on to it to make it bio- fertilizer. The use of such bio-fertilizer provides organic carbon and other nutrients to the soil. The process also helps in recycling of the waste material to useful Bio-fertilizer.

i) A 100 ton/day capacity facility  has  been constructed  at  Ahmedabad  under 

Memorandum of Understanding (MoU) with Ahmedabad Municipal Corporation.

ii) The cold trials have been completed successfully.

iii) The facility is scheduled to be fully operational soon after radiation source loading.

iv) Another similar facility of 100 ton/day capacity will be constructed at Indore  

under   MoU with BARC.

This information was provided by the Union Minister of State (Independent Charge) Development of North-Eastern Region (DoNER), MoS PMO, Personnel, Public Grievances & Pensions, Atomic Energy and Space, Dr Jitendra Singh in written reply to a question in Lok Sabha .

Large amount of sewage sludge is produced in India every day. The sludge is infectious and can spread diseases. It also has essential micro and macro nutrients, especially carbon, useful for soil and crop production. Radiation Technology can be used to hygienise the sludge reliably and affordably and protect health and environment. Addition of useful microorganisms to the hygienised sludge can convert it to a value added manure. Ahmedabad Municipal Corporation (AMC) takes the lead to set up first plant in India to treat 100 tons/day sludge and produce manure using a fully automatic process

Benefits to the farmers/people: Various benefits to farmers on using radiation hygienised sludge are:-

• Increased crop yield - direct benefit to the farmers.
• Improved soil conditions - soil conservation & restoration.
• Reduced health risks associated with sludge, reduces costs of health care system.
• Reduced demand of water due to higher water holding capacity of the sludge.
• The nutrient rich sludge, which otherwise is discarded, can be gainfully recycled for economic gain.
• Improved overall quality of life.

Radiation technology has sound scientific basis and is a practical technology to economically hygienise sewage sludge for agriculture application. The technology and radiation source both are available in our country. Irradiation facility can be utilised to treat whole city sludge at one place in a fully automatic process. The hygienised sludge can benefit farmers and protect environment and human health. The technology has high potential in contributing towards meeting the objectives of Clean India Mission (the Swachh Bharat mission).

The various Advantages of Radiation Hygienisation of Dry Sewage Sludge Process are listed below:

• Process is simple, economic, effective, reproducible and scalable.
• Easy to integrate with conventional sewage treatment facilities.
• Process is fully automatic to avoid manual handling of contaminated sludge.
• Based on the process of radiation sterilization which is well established world over and in India.
• Degrades chemical contaminants and makes sludge safer for use

Rapid industrialization and population explosion in India has led to the migration of people from villages to cities, which generate thousands of tons of MSW daily. The MSW amount is expected to increase significantly in the near future as the country strives to attain an industrialized nation status by the year 2020. Poor collection and inadequate transportation are responsible for the accumulation of MSW at every nook and corner. The management of MSW is going through a critical phase, due to the unavailability of suitable facilities to treat and dispose of the larger amount of MSW generated daily in metropolitan cities. Unscientific disposal causes an adverse impact on all components of the environment and human health . Generally, MSW is disposed of in low-lying areas without taking any precautions or operational controls. Therefore, MSWM is one of the major environmental problems of Indian megacities. It involves activities associated with generation, storage, collection, transfer and transport, processing and disposal of solid wastes. But, in most cities, the MSWM system comprises only four activities, i.e., waste generation, collection, transportation, and disposal. The management of MSW requires proper infrastructure, maintenance and upgrade for all activities. This becomes increasingly expensive and complex due to the continuous and unplanned growth of urban centers. The difficulties in providing the desired level of public service in the urban centers are often attributed to the poor financial status of the managing municipal corporations . In the present study, an attempt has been made to provide a comprehensive review of MSWM for Indian cities to evaluate the current status and identify the problems of MSWM.

In the majority of urban centers, MSW is disposed of by depositing it in low-lying areas outside the city without following the principles of sanitary landfilling. Compaction and leveling of waste and final covering by earth are rarely observed practices at most disposal sites, and these low-lying disposal sites are devoid of a leachate collection system or landfill gas monitoring and collection equipment. As no segregation of MSW at the source takes place, all of the wastes including infectious waste from hospitals generally find its way to the disposal site. Quite often, industrial waste is also deposited at the landfill sites meant for domestic waste. Sanitary landfilling is an acceptable and recommended method for ultimate disposal of MSW. It is a necessary component of MSWM, since all other options produce some residue that must be disposed of through landfilling.

However, it appears that landfilling would continue to be the most widely adopted practice in India in the coming few years, during which certain improvements will have to be made to ensure the sanitary landfilling.