EXPLOITATION OF DEHYDRATED SLUDGE AND INNOFENSIVE ORGANIC WASTE BY COMPOSTING THEREOF VIA EARTHWORMS AND PARTIAL SOLAR DRYING OF THE COMPOST ON A PLATFORM COVERED WITH AN OPEN-TYPE GREENHOUSE

摘要

Novelty: the exploitation of the dehydrated sludge and innofensive organic waste produced in sludge treatment centers by the composting method using earthworms as well as by partial solar drying of the compost on a platform covered with an open-type greenhouse is disclosed. Compost process: composting is carried out onto concrete platforms for a period of almost 90 days and three periods per year with building material (e.g. hay) and earthworms with population density of 2,5kg/m2 thereabouts; the earthworms disintegrate the sludge and diminishes its humidity by from 80 to 65-70% so that the concentration of pathogenic and heavy metals are efficiently reduced. In the sequel, humidity is reduced by 40% via partial solar drying carried out, under sunshine conditions, on a platform and in an open-type greenhouse having openings at its front and rear side; a 0,1-m thick layer of sludge is spread over the concrete platform, stirred with a tractor-towed milling machine and dried at a solar drying velocity of Udr=9,3kg H20/m2d for at least 120 days per year. Solar drying is accelerated by the above tractor-towed milling machine drying.