Li Danyang, Yuan Jing, Ding Jingtao, Wang Huihui, Shen Yujun, Li Guoxue
Institute of Energy and Environmental Protection, Academy of Agricultural Planning & Engineering, Ministry of Agriculture and Rural Affairs, Beijing, 100125, China; Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Science, China Agricultural University, Beijing, 100193, China.
Beijing Key Laboratory of Farmland Soil Pollution Prevention and Remediation, College of Resources and Environmental Science, China Agricultural University, Beijing, 100193, China.
J Environ Manage. 2022 Dec 1;323:116093. doi: 10.1016/j.jenvman.2022.116093. Epub 2022 Sep 12.
There are several issues such as low maturity degree of compost product and severe pollution gas emissions during the composting process. Carbon/Nitrogen (C/N) ratio and aeration rate (AR) are the most important factors affecting the composting performance. According to the results of previous studies, the proper C/N ratio and AR were 20-30:1 and 0.1-0.4 L kg DM·min, respectively. Therefore, a lab-scale experiment was conducted to investigate the effects of C/N ratio and AR on sheep manure composting process and associated gaseous emissions. The initial C/N ratio in this experiment were set at 23, 26 and 29 to simulate the C/N ratio at low, medium and high levels. The AR were decided at 0.12, 0.24 and 0.36 L kg DM·min to simulate the aeration at low, middle and high levels. The results showed that as the C/N ratio or AR increased, the methane (CH) and hydrogen sulfide (HS) emissions decreased. The nitrous oxide (NO) emission peaked at the low C/N ratio or AR treatments. The total greenhouse gas (GHG) emissions decreased with the increase of C/N ratio or AR, and the maximum value occurred in the treatment with C/N ratio 23 and AR 0.24 L kg DM·min. In the treatment with C/N ratio 26 and AR 0.36 L kg DM·min, the GI value of compost product was the highest (about 250%), and the total greenhouse effect was the lowest (2.36 kg CO2-eq·t DM). Therefore, considering reduction of pollution gas emissions and improvement of the quality of compost products comprehensively, the optimum conditions were initial C/N ratio 26 and AR 0.36 L kg DM·min during the co-composting of sheep manure and cornstalks. In addition, the key physicochemical factors and eight key bacterial communities were determined to regulate compost maturity and pollution gas emissions during the sheep manure composting, which could provide scientific support and theoretical reference for controlling pollution gas emissions and obtaining high quality sheep manure compost products.
堆肥过程中存在堆肥产品成熟度低和污染气体排放严重等问题。碳氮比（C/N）和曝气速率（AR）是影响堆肥性能的最重要因素。根据以往研究结果，适宜的C/N比和AR分别为20 - 30:1和0.1 - 0.4 L kg DM·min。因此，进行了一项实验室规模的实验，以研究C/N比和AR对羊粪堆肥过程及相关气体排放的影响。本实验中初始C/N比设定为23、26和29，以模拟低、中、高水平的C/N比。AR设定为0.12、0.24和0.36 L kg DM·min，以模拟低、中、高水平的曝气。结果表明，随着C/N比或AR的增加，甲烷（CH）和硫化氢（HS）排放减少。氧化亚氮（NO）排放在低C/N比或AR处理时达到峰值。总温室气体（GHG）排放随着C/N比或AR的增加而减少，最大值出现在C/N比为23和AR为0.24 L kg DM·min的处理中。在C/N比为26和AR为0.36 L kg DM·min的处理中，堆肥产品的GI值最高（约250%），总温室效应最低（2.36 kg CO2-eq·t DM）。因此，综合考虑减少污染气体排放和提高堆肥产品质量，羊粪与玉米秸秆共堆肥的最佳条件是初始C/N比为26和AR为0.36 L kg DM·min。此外，确定了关键理化因素和八个关键细菌群落来调节羊粪堆肥过程中的堆肥成熟度和污染气体排放，这可为控制污染气体排放和获得高质量羊粪堆肥产品提供科学支持和理论参考。
