A research team in the pollution office, Hygienic Faculty, Pyongyang Medical College,
From way back, the soil has been recognized that its purification effect is high from its physicochemical and biological character.
Therefore treating sewage using the soil without special purification equipment and cost became trend in the world but the stockbreeding wastewater is treated with activated sludge method because organic contamination of the stockbreeding wastewater is quite serious. Treatment of the stockbreeding wastewater by soil is going on investigation and test steps in many countries now.
A research team has carried out many investigations and experimentations, which has resolved on scientific and technical methods that can purify the wastewater from medium and small-scale stock farms effectively with the soil.
They have resolved on rational design information of soil biological filter that can satisfy a discharge standard of the wastewater through basic experimentations, and have applied it to 22 stock farms at stockbreeding management board in Rakrang district.
In field condition water quality of the stockbreeding wastewater reached a discharge standard of wastewater and purified water can be used as management water and fish farming water.
As a soil biological filter is laid in the earth and the wastewater is purified by difference of natural pressure, this doesn't invade a land under cultivation and electric power and labor is unnecessary and can be applied anywhere easily, thus this is quite effective economically.
A research team has intensified the investigation for last 10 years, so they provided rational operation condition and foundation that can introduce and generalize throughout the country.
Thus they can make stock farms produce a lot of meet normally with existing facilities of the stock farms and contributed to prevention of environmental contamination by stockbreeding wastewaters and people's health protection.
Investigation on the purification of wastewaters using soil will be continued.
