Forced Aeration Composting System for Swine Manure Treatment

Abstract

A four-phase forced aeration composting process was designed and preliminary trials were conducted to treat swine manure in a pilot-scale forced aeration composting facility (19.6 L×14.0 W m) with 4 thermophilic decomposition compartments (3.92 m×5.0 m) on farm. Corn stalk was used as bulking agent, and volume ratio of swine manure to amendment was determined to be 1:1.5 on farm according to the desired bulk density of mixture. The initial mixture of swine manure and corn stalk was stacked in the first decomposition compartment to form a trapezoid shape pile with a volume of 25.5m3, the pile was weekly remixed and turned to the next compartment one by one, the ingredients stayed in each compartment for 1 week and air was supplied using blower with capacity of 7m3/min and power of 0.25 kWh, the blower operated intermittently with interval of 15min. The preliminary trials were conducted in winter season with daily mean ambient temperature ranging from -10oC to 6oC, the inside temperatures more than 55oC were recorded for 22 consecutive days during the composting process, it could meet the requirement of national sanitary standard for manure non-hazardous, the farmer could have $912 net income from the compost of a pile, which was much higher than the $70 of raw manure marketing. This four-phase composting process is suitable for swine manure treatment in swine farm of China.