Natural use of municipal sewage slugde and compost from municipal waste - Fertilizing value contra danger to environment

Taking into account fertilizing qualities of compost made from municipal waste and municipal sewage sludge, they can be foolvaluable fertilizer, provided they do not consist heavy metals above the norm. Then evaluation of quality and quantity content of heavy metals is important criteria in natural recycling of compost and sewage sludge. Finding out chemical connections of metals gives possibility of predicting changes taking place in water and soil environment. This paper present results of physical (pH, humidity, glass and ceramics) and chemical (organic substance, organic carbon, total nitrogen, phosphorus, patassium and heavy metals - total forms and fractions content) investigation on compost from MUT-DANO technology in Katowice (before and after partly segregation of municipal wastes) and Municipal sewage sludge from treatment plant with different sludge treatment. Sewage sludge was collected from: Opole, Zabrze-Rokitnica, Zabrze-Mikulczyce, Zawiercie, Piotrkow Trybunalski, Pulawy, Kozienice, Bytom-Miechowice, Dabrowa Gornicza. In compost and sewage sludge samples total content of heavy metals Cd, Cr, Cu, Ni, Pb, Zn was determined using ASA method. Total content of mercury was also determined in compost samples. Qualitative content of heavy metals (speciation) was also determined in tested samples. Investigations on compost (1993 divided by 2001) proves high fertilizing value. It contains a lot of nitrogen, phosphorus and potassium. Compost from MUT-DANO technology also contains excessive amount of glass, ceramics, heavy metals, especially cadmium, copper, lead and zinc. Only small contents of heavy metals were bound in easy-soluble fractions and highest percentage amount of heavy metals were present in fraction V, which is almost unavailable for plants.