Eco-Toxicity Dynamics in Compost Prepared From Organic Wastes

Waste accumulation is reported to be one of the serious environmental problems. Organic wastes such as organic fraction of municipal solid waste (OFMSW) or sewage sludge (SS) can be treated using aerobic microbial decomposition called composting. It is important to know when composts obtained in co-treatment processes turns to be safe but not toxic for the environment. In this study, we estimated eco-toxicity in the process of composting of mixture consisting of SS, OFMSW and sawdust polluted by oil (OS). Water flea Daphnia magna, infusorium Paramecium caudatum and higher plant Avena sativa were used in bioassays. The maximal toxicity of the compost mixture for the aquatic test-objects was observed on the 60 th day of the treatment – it was calculated to be 71% for P. caudatum and 80% for D. magna. The minimal toxicity (10% and less) was observed on the 270 th day of the treatment for both test-organisms. The lowest germination indexes of A. sativa were observed on the 30 th and 60 th days of the treatment – 45% and 54%, respectively, and the highest one at the end of the treatment – 98% (day 270). In overall, co-treatment of the municipal wastes permitted to obtain a final product with no toxic but also no fertilizing properties.