Influence of different temperature and aeration regulation strategies on respiration in composting of organic household waste

A laboratory scale composting reactor was constructed for systematic studies of the effects of oxygen levels and temperature on carbon and nitrogen turnover in household waste compost. The reactor was equipped for independent control of oxygen level and temperature. The results presented showed that the performance of the reactor concerning uniform regulation of temperature and O2 level in the compost matrix, gas and over time was good. The effect of three temperature regimes performed at the constant level of 16% O2 in the compost gas was studied in eight experimental runs in the compost reactor. The effect of reduced O2 levels of 2.5 and 1% in the compost gas was studied in two experimental runs for one of the above temperature regimes. It was found that the highest rate of degradation was achieved when the temperature was actively regulated to below 40°C during a low pH phase. The lowest degradation was obtained when the temperature was already regulated to 55°C from the start. It was further found that reduced O2 levels of 2.5 and 1% in the compost gas reduced the degradation rate and enhanced methane emission.