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Asian Tribune is published by World Institute For Asian Studies|Powered by WIAS Vol. 12 No. 2707

A new research by a Sri Lankan Engineer: Technology to manufacture organic fertilizer by rapid digestion of organic waste

Sunil C. Perera - Reporting from Colombo

Colombo, 07 October, ( Ever increasing human population and booming commercial entities generate huge amounts of waste, contributing tremendously towards the Urban Solid Waste problem. Unplanned and disorganized dumping of waste has polluted the soil, air and water and has also provided breeding grounds for unhealthy micro-organism creating an unhealthy environment.

Eng. S.A.S.Perera ,a Senior Lecturer and a former Head of the Department of Chemical and Process Engineering of the University of Moratuwa, has developed a patented technology to manufacture organic fertilizer by rapid digestion of organic waste. The process described here brings dual benefits to the country by giving a rapid solution to the urban solid waste problem and by producing a cheap organic fertilizer.

The process involves converting plant wastes, such as leaves, saw dust, tea waste, straw, paddy husk, salvinia, weeds, fruit peels, seeds and animal wastes, such as offal, feathers, bones, skin, (in other words any type of organic waste) etc., into organic fertilizer, with a high content of Nitrogen (N), Phosphorous (P) and Potassium (K), within 1 to 2 days. The automatic generations of high temperature keep the waste free from various germs such as bacteria, virus, and fungus that can cause illness to people, animal and plants. The process has a potential application through out the globe.

A digestive fluid called Delta-D achieves rapid digestion of organic waste. The composition of the digestion fluid varies according to the composition of the organic waste, level of disinfections and the required rate of digestion. The composition of the digestion fluid required to digest saw dust, straw or paddy husk will be different to that required to digest fruit and vegetable waste which in turn will be different to that required to digest fish and meat waste. Further the digestion temperature depends on the type of waste etc, such as rotten meat, fish, sewage, and clinical waste to destroy the harmful pathogens.

The digested waste will take the form of thick, brownish, acidic slurry which is neutralized using a mineral powder mix. The composition of the mineral powder will depend on the required composition of the final product, which will be an organic fertilizer containing water soluble N, P, K, Mg, Ca and other nutrients.

The raw materials that are used to manufacture the digestive fluid and it includes Eppawela Rock Phosphate (Apatite),Phosphoric Acid, Sulphuric Acid, Acetic Acid ,Citric Acid and Saw Dust / Rice Straw or Paddy Husk.

Raw materials used to produce the Mineral Powder Mix are Eppawela Rock Phosphate (Apatite), Dolomite, Calcite, Powdered Mica and Powdered Quartz. The digestion process is human controlled and not micro organic controlled as in the case of natural composting, biogas generation or land filling.

Microorganisms digestion are slow conventional processes that take several months and require large areas of land, while the patented rapid digestion process can convert all types of organic solid waste into organic fertilizer in a few hours.

Process does not produce any leachate, which is a major problem in micro organic processes. The use of Eppawela Rock Phosphate, dolomite and other locally available minerals to convert organic solid waste into organic fertilizer is another unique feature in this process.

Through the new process straw, paddy husk as well as any other plant and animal refuse can be converted into organic fertilizer in 1-3 days, whereas, traditional composting processes require more than 3 months.

Hence, if all the straw and other plant and animal wastes are converted to mineral rich organic fertilizer by this process, it can replace imported fertilizers, such as urea by more than 50%. This will- reduce the burden on the government imposed fertilizer subsidy, and will provide a cheap mineral rich organic fertilizer that is produced in Sri Lanka using local material. It will be the beginning of an agricultural revolution in the country.

If these systems are not adopted, large extents of land will have to be allocated because; garbage has to be stockpiled for 3-4 months. As an example, if the daily collection of garbage is 500 MT at any given time, 45000 to 60000 MT will be in garbage stock piles, undergoing digestion. In land filling and composting processes a leachate is produced, which has a very high BOD value, and which contaminates soil and water.

The cost of fertilizer produced from this process will be Rs. 3.00 – 4.00 per kg and will be richer in N, P and K than traditional compost. In fact, an organic fertilizer of any desired N:P:K ratio can be produced from the process. The fertilizer can be sold to the local market at a price of Rs. 8000.00 per MT.

Moreover, this process leads to automatic separation of other non-degradable material, such as plastics, glass and metal from the organic fertilizer, in a germ free condition, so that they can be recycled.

This process has been tested with all types of waste material. The fertilizer obtained has been successfully tested for various crops, including, rice, coconut and vegetables. Steps have been taken to test it on tea.

The process has been demonstrated at several government institutions that include University of Moratuwa, Horana Urban Council, Maharagama Urban Council, The Central Environmental Authority, and several leading private companies, such as The Lodge Habarana, The Confifi Group of Hotels, Horana Plantations, CIC Fertilisers and several poultry farms. Many institutions such as the Horana UC, Lodge Habarana and Horana Plantations, are willing to carryout the process to convert organic waste into fertilizer on a commercial basis.

- Asian Tribune -

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