Effect of aeration rate, aeration pattern, and turning frequency on maturity and gaseous emissions during kitchen waste composting
Lijuan Peng, Ruolan Tang, Guoying Wang, Ruonan Ma, Yanming Li, Guoxue Li, Jing Yuan
Abstract
Currently, the increasing output of kitchen waste makes its treatment an urgent problem to be solved. Based on the principle of resource utilization, we consider improving various process parameters, including aeration rate, aeration mode and turning frequency, analyzing physicochemical indicators, maturity indicators and gas emissions, to propose comprehensive process parameters that can quickly compost, promote maturity and reduce emissions. The results showed that high aeration rate (> 0.3 L kg −1 DM min −1) reduced the temperature of the matrix and increased the electrical conductivity and germination index of compost, thereby inducing strong emissions of odors and greenhouse gases. Compared with continuous aeration, intermittent aeration was more effective in reducing gaseous emissions under the same total aeration volume but was characterized by lower maturity. Moreover, it was found that non-turning reduced gaseous emissions substantially, while excessively high (once every 2 days) or too low (once every 6 days) turning frequency increased gaseous emissions to varying degrees. Most turning frequencies did not significantly promote compost maturity. The above results indicated that the rapid kitchen waste composting processes that yielded best results were an aeration rate of 0.2∼0.3 L kg −1 DM min −1, continuous or intermittent aeration pattern, and a turning frequency of once every three days. This research was of great significance to the improvement of kitchen waste combined process.