Somjai Karnchanawong - Department of Environmental Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand
SiriWan Nissaikta - Department of Environmental Engineering, Faculty of Engineering, Chiang Mai University, Chiang Mai 50200, Thailand

Background The effects of microbial inoculation withtwo commercial inoculants and mature compost on thecomposting of household organic wastes were investigatedusing five 200-L passive aeration compost bins. Foodscraps and dry leaves (1.6 kg total) with a ratio of 1:0.14(wet weight) were added to each bin once a day, for60 days, and then further composted for an additional94 days. The temperature in each bin was recorded daily.Weekly to biweekly, a composite sample of the compostfrom each bin was analyzed.Results The C/N ratios of composts in the un-seeded andseeded bins stabilized at 81 days and 67–74 days, respectively.The highest volatile solid mass reduction wasachieved in the bin seeded with 5 % mature compost.Conclusions The study revealed that it might not benecessary to add commercial inoculants to facilitate compostingof household organic waste. Mature compost canbe used as a seed starter to improve composting.

Household organic waste Passive aeration bin Inoculation Mature compost Commercial inoculants