Namolul orasenesc din geotuburi  oportunitati de valorificare in calitate de fertilizant | Municipal sewage sludge from geotubes  valorization opportunities as a fertilizer
2014
Plamadeala, V. | Rusu, A. | Bulat, L.
This paper describes the advantages of geotube dewatering technology of municipal sewing sludge in comparison with traditional technology on air drying beds. When using geotube technology, dehydration process occurs faster due to reagents that provide clogging sludge. Applying the technology of dehydrating the sludge in geotube leads to reducing: the time required for dehydration, from 18 months up to one month; the surface of land required for the dehydration from 6.0 to 1.25 ha, and respectively,for storage, from 27.7to 3.65 ha. The emission of toxic gases into the atmosphere is reduced from 1.4 to 6.2 times. Compared with the traditional technology of air drying beds, the sludge dehydrated in geotubes contains 2 times more carbon and total nitrogen. Total phosphorus content had a slight tendency to decrease, total potassium concentration increases with 1.76 times. One ton of dried sewage sludge stored in geotube and stocked for one year has the humidity of 65% and contains 151 kg of organic matter, 9.0 kgN, 10 kg P2O5 and2.9 kg K2O. Heavy metal content is below the maximum limits that are allowed by national regulations from 2008.The application of sewage sludge as a fertilizer provided a specific increase of the total yield over the two years of 100.5 kg cereal units per 1 ton of sewage sludge 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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