On small family farms, dung from stables and farmyards is a prized fertiliser and disposing of it is not a problem.
Current intensive agriculture has separated animals from the land: fields on one side, and on the other hundreds of intensively reared animals, resulting in the problems of getting rid of waste. In most cases, animal dung is collected and composted. This is perfectly acceptable from an environmental point of view but it takes time, space, and significant investment.
An interesting alternative has just been put forward jointly by the ecological engineering company Coind, and Rivoira, which is active in the technical gas sector: a technique for intensive production of humus and other natural fertilisers, which takes advantage of chemical reactions and is therefore known as electro-composting.
Electro-composting originated in the former Soviet Union, where animal effluents were preserved by the climate: since the earth is frozen for 7 or 8 months of the year, it cannot absorb anything.
The Soviet agronomy institute wanted to reduce the volume of the dung by removing the liquid components. The technology has been improved and adapted to Italian conditions by Coind. The partnership with Rivoira was of fundamental importance for removing toxins from the liquid to conform with Italian regulations.
The process involves an initial phase of homogenisation and dissolution of solids in order to achieve pumpable sludge which is then transferred to the electro-chemical reactor and separated into two phases. The first step is a tank with permanent electrodes, where the organic constituents are saturated and oxidised by the OH radicals resulting from electrolysis of the water, producing highly polarised organic molecules. The next step is a tank with surface electrodes where the electric current causes the oxidisation of iron anodes, adding Fe++ ions to the solution. These ions form branched colloidal complexes with the polar molecules formed in the tank.
The resulting solid fertiliser produced in the centrifuge contains about 1% of ammonia nitrogen and 15-20% of organic substances. The process takes 15 to 20 minutes and the equipment takes up much less space than natural composting would.
Info: Coind, www.coindsrl.com - Rivoira, www.rivoiragas.it
(Hi-Tech Ambiente, Italy, www.pubblindustria.com)