Investigating the physico-chemical and microbial characteristics of compost obtained from anaerobic digestion of municipal solid waste

BACKGROUND AND ABJECTIVEOver the past decades, the generation of large amounts of municipal solid waste (MSW) due to extensive urbanization has become a serious challenge, especially for large cities in developing countries. The anaerobic digestion (AD) of organic fraction municipal solid waste (OFMSW) is the most promising environmentally friendly method for solving the problem of municipal solid waste. The goal of this study was to investigate the physico-chemical and microbial (fecal coliforms and Salmonella) properties present in a compost of municipal solid waste of Isfahan city via mesophilic AD in a pilot scale.MATERIALS AND METHODSThe investigated parameters included the determination pH, EC, moisture, ammonium, faecal coliform and Salmonella. The determination of fecal coliform and Salmonella in compost was done by the most probable number (MPN) method according to the national standard of Iran No. ۱۳۳۲۱-۳ and ۱۳۳۲۱-۲, respectively.RESULTS AND DISCUSSIONThe pH value varied between ۷ and ۸, EC, moisture and NH۴+ of content compost were ۳.۸ ds/m, ۷۹% and ۳۰۰۰-۵۰۰۰ mg/L, respectively. The amount of fecal coliform and Salmonella in OFMSW entering the anaerobic digester was ۵.۰۲×۱۰ ۷ MPN/g and ۱۶.۱۳ MPN/۴g, respectively. After anaerobic digestion, the amount of fecal coliform and Salmonella in the output of the digester decreased to ۲.۳×۱۰ ۵ MPN/g and ۱.۴۲ MPN/۴g. The results of this study show that anaerobic digestion of waste has positive effective in reducing pathogens.CONCLUSIONThe analyses carried on the composted municipal solid waste by anaerobic digestion showed this compost has usage potential in agriculture. Due to the short time to convert municipal solid waste into compost, this method is a suitable and promising method for urban solid waste management.

کلیدواژه ها:

Anaerobic digestion ، MSW ، Compost ، Coliforms ، Salmonella