Influence of zeolite and lime as additives on greenhouse gas emissions and maturity evolution during sewage sludge composting.

This study aimed to evaluate the role of different amount of zeolite with low dosage of lime amendment on the greenhouse gas (GHGs) emission and maturity during the dewatered fresh sewage sludge (DFSS) composting. The evolution of CO2, CH4, NH3 and N2O and maturity indexes were monitored in five composting mixtures prepared from DFSS mixed with wheat straw, while 10%, 15% and 30% zeolite+1% lime were supplemented (dry weight basis of DFSS) into the composting mass and compared with treatment only 1% lime amended and control without any amendment. The results showed that addition of higher dosage of zeolite+1% lime drastically reduce the GHGs emissions and NH3 loss. Comparison of GHGs emissions and compost quality showed that zeolite amended treatments were superior than control and 1% lime amended treatments. Therefore, DFSS composting with 30% zeolite+1% lime as consortium of additives were found to emit very less amount of GHGs and gave the highest maturity than other treatments.