Effect of different techniques of composting on stability and maturity of municipal solid waste compost

Abstract

Three methods for composting, aerobic, anaerobic and mixed type were compared in three locally fabricated composters of 20 L each, for their effect in accelerating compost maturity and stability using municipal solid waste. The composting process was monitored through determining the changes in temperature, pH, ammonium‐N (NH+ 4‐N), nitrate‐N (NO− 3‐N), carbon/nitrogen (C/N) ratio, NH+ 4‐N/NO− 3‐N, total carbon, nitrogen (TN), potassium (TK), phosphorous (TP), humification index (HI), degree of polymerization (DP), humification rate (HR), CO2, humic acid (HA), fulvic acid (FA), and cation exchange capacity (CEC). Temperature increased rapidly from the mesophilic to the thermophilic stage and gradually decreased near the maturation phase. A similar behaviour was recorded for pH, which become slightly alkaline at the maturity level. The composting process decreases the concentration of total carbon, NH+ 4‐N, C/N ratio, and CO2, and increases CEC, HI, DP, HA, TP, TK, and TN. All three composting methods used in this study produce mature compost at different time intervals. A high statically significant correlation was found between the total carbons, C/N ratio, HA, FA, DP, HI, HR, CEC, and ammonium nitrate ratio.