Nămolul orăşenesc din geotuburi – oportunităţi de valorificare în calitate de fertilizant
2014
Plămădeală, V. (Institute of Pedology, Agrochemistry and Soil Protection "Nicolae Dimo", Chisinau (Republic of Moldova) | Rusu, A. | Bulat, L.
This paper describes the advantages of geotube dewatering technology of municipal sewingsludge in comparison with traditional technology on air drying beds. When using geotube technology, dehydrationprocess occurs faster due to reagents that provide clogging sludge. Applying the technology of dehydrating thesludge in geotube leads to reducing: the time required for dehydration from 18 months up to one month; thesurface of land required for the dehydration from 6.0 to 1.25 ha, and respectively, for storage, from 27.7 to 3.65 ha.The emission of toxic gases into the atmosphere is reduced from 1.4 to 6.2 times. Compared with the traditionaltechnology of air drying beds, the sludge dehydrated in geotubes contains 2 times more carbon and totalnitrogen. Total phosphorus content had a slight tendency to decrease, total potassium concentration increaseswith 1.76 times. One ton of dried sewage sludge stored in geotube and stocked for one year has the humidity of65% and contains 151 kg of organic matter, 9.0 kg N, 10 kg P2O5 and 2.9 kg K2O. Heavy metal content is below themaximum limits that are allowed by national regulations from 2008. The application of sewage sludge as a fertilizerprovided a specific increase of the total yield over the two years of 100.5 kg cereal units per 1 ton of sewagesludge at the dose of 18 t/ha and 45.5 kg cereal units per 1 ton of sewage sludge at the dose of 36 t/ha.
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