INFLUENCE OF MINERAL AND ORGANIC ADDITIONS TO ACTIVATED SEWAGE SLUDGES AND DURATION OF COMPOSTING PROCESS ON THE CONTENT OF CHROMIUM AND NICKEL IN PLANT AND SOIL

摘要

The pot experiment aimed at evaluating the influence of fresh and composted sewage sludge with CaO, brown coal ash, straw, and sawdust fertilization on contents and uptake of chromium and nickel by a test plant. These metal concentrations were also determined in the soil, 3 years after the experiment was completed. The highest contents and the amounts of chromium and nickel uptake in maize were recorded on objects fertilized with sludge plus brown coal ash. Contents and uptakes of examined heavy metals by maize grown on objects fertilized with sewage sludge plus CaO, straw, and sawdust addition were lower as compared to separate sludge applying. In general, composting the sewage sludge from Siedlce and Lukow, as well as their mixtures with the above components, did not significantly differentiate the contents and the amount of chromium and nickel uptaken by maize. Concentrations of determined elements in the soil amended with fresh and composted sewage sludge as well as their mixtures with calcium oxide, brown coal ash, straw, and sawdust, apparently increased, although over-normative levels of soil contamination were not observed.