关键词: 沼渣, 牛粪, 玉米秸秆, 混合堆肥, 生命周期评价

Abstract: In order to realize  the highvalue utilization of straw biogas residue and livestock manure, the effect of cocomposting corn straw biogas residue and cow manure was studied, and the environmental benefits of mixed compost were analyzed by life cycle method. And the effects of different mixing ratios and composting time on the water content, pH value, total carbon, total nitrogen, volatile solid content and electrical conductivity of the pile were analyzed, the environmental benefits of cocomposting was also calculated. The results showed that the mixing ratio had a significant effect on the characteristics of the heap. With the ratio of cow dung and corn stover biogas residue increased from 2∶1 to 6∶1, the moisture content of the heap increased significantly, but when the ratio exceeded 4∶1, the effect of mixed composting on the moisture content of the pile gradually decreased. The straw biogas residue had a great influence on the pH value of the pile at the initial stage, and the change rule was not obvious, but when the fermentation time exceeded 40 days, the pH of the pile body showed a significant decreasing trend; increasing the proportion of cow dung helped to increase the pH value of the pile after composting. With the addition ratio of cow manure increasing from 2∶1 to 6∶1, the pH value of the reactor increased from 8.2 to 8.4, the total carbon content of the reactor increased from 35.34% to 36.81% after 60 days of decomposition, the volatile solids content decreased significantly from 46.96% to 3766%, and the electrical conductivity increased from 8.3ms/cm to 9.4ms/cm. At the same time, cocomposting of cow manure and biogas residues significantly reduced the emissions of CO2, CH4, N2O, NOX, NH3, SO2, PO43- and other pollutants in the compost substrate compared with direct emissions.

Key words: biogas residue, cow dung, corn stover, cocomposting, life cycle assessment