Uptake of heavy metals by natural zeolite during agitated pile composting of water hyacinth composting

The studies were carried out on heavy metal bioavailability and leachability during water hyacinth composting mixed with cattle manure, sawdust and natural zeolite. The water hyacinth, cattle manure and sawdust were taken in the 6:3:1 ratio with 5, 10 and 15% natural zeolite and composted for 30 days. The concentrations of nutrients and total heavy metals were increased during the process. Due to addition of natural zeolite initial pH of the compost mixture was increased slightly in comparison to control, resulting a decrease in bioavailability and toxicity characteristics leaching procedure (TCLP) extractable metal concentration in the final compost. Water solubility of Ni, Pb and Cd, and diethylene triamine penta acetic acid (DTPA) extractablity of Pb and Cd were not found during the composting process. Addition of natural zeolite significantly reduced the bioavailability and leachability of heavy metals during water hyacinth composting process.