Effects of Addition of MgO and H3PO4 on Turnover and Loss of Nitrogenous Compounds during Composting of Food Wastes

[Objective] The effects of the addition of MgO and H3PO4 on turnover and loss of nitrogenous compounds during the composting of food wastes were investigated.[Method] Static aerobic process was carried out during the composting.The amount of MgO was different.Three kinds of ratio(defined as C0,C1,C2) were used and they were 0,1,3 mol/kg,respectively.At the same time,the same amount of H3PO4 with magnesium oxide was added.[Result]At the end of composting,the accumulative amount of ammonia emissions from food wastes of C0,C1,C2 was 5.77,0.92 and 0.01 g/kg,respectively.The concentration of total nitrogen of treatment C0 decreased by 23.1%,and that of treatment C1 and C2 increase by 14.2% and 33.0%.The lost amount of nitrogen was 48.9%,18.9% and 16.5% of the initial total nitrogen amount.Ammonia volatilization was account for 36.8%,15.8% and 0.2% of the total nitrogen losses.[Conclusion] From the economic and practical value of the compost,the optimum amount of add MgO and H3PO4 was 1mol/kg during the composting of food wastes.