Fertiliser Value and Trace Element Content of Composts Produced from Different Wastes

Composting process provides a valuable material improving physical and chemical properties of soil. The quality of the obtained compost depends to a great extent on the kind of material subjected to stabilisation. Composting biodegradable products may result in the end product exceeding heavy metal limits that cannot be used in agriculture. The studies included composts produced in the compost plant in Kołobrzeg, the Municipal Waste Recovery and Storage Plant in Leśno Górne and the Waste Managemant Plant in Wardyń Górny. Composts were made from municipal solid waste, sewage sludge with straw and sawmill waste, and from urban green waste. The following determinations were determined: morphological composition, total content of macroelements and microelements and the level of these elements soluble in HCl at the concentration of 0.5 mol∙dm-3. The examined composts contained the amounts of total Pb, Ni and Cd allowing for their use in agriculture and the compost from sewage sludge, straw and sawmill waste, turned out to have the best utilisation properties.