Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia.
Centre for Solid Waste Bioprocessing, Schools of Civil and Chemical Engineering, The University of Queensland, St. Lucia, Queensland 4072, Australia; Department of Environmental Sciences, Faculty of Natural Resources, University of Tehran, Karaj, 31536, Iran.
Waste Manag. 2018 Jun;76:364-373. doi: 10.1016/j.wasman.2018.02.029. Epub 2018 Mar 7.
An examination of the processes contributing to the production of landfill greenhouse gas (GHG) emissions is required, as the actual level to which waste degrades anaerobically and aerobically beneath covers has not been differentiated. This paper presents a methodology to distinguish between the rate of anaerobic digestion (r), composting (r) and CH oxidation (r) in a landfill environment, by means of a system of mass balances developed for molecular species (CH, CO) and stable carbon isotopes (δC-CO and δC-CH). The technique was applied at two sampling locations on a sloped area of landfill. Four sampling rounds were performed over an 18 month period after a 1.0 m layer of fresh waste and 30-50 cm of silty clay loam had been placed over the area. Static chambers were used to measure the flux of the molecular and isotope species at the surface and soil gas probes were used to collect gas samples at depths of approximately 0.5, 1.0 and 1.5 m. Mass balances were based on the surface flux and the concentration of the molecular and isotopic species at the deepest sampling depth. The sensitivity of calculated rates was considered by randomly varying stoichiometric and isotopic parameters by ±5% to generate at least 500 calculations of r, r and r for each location in each sampling round. The resulting average value of r and r indicated anaerobic digestion and composting were equally dominant at both locations. Average values of r ranged from 9.8 to 44.5 g CO m d over the four sampling rounds, declining monotonically at one site and rising then falling at the other. Average values of r ranged from 10.6 to 45.3 g CO m d. Although the highest average r value occurred in the initial sampling round, all subsequent r values fell between 10 and 20 g CO m d. r had the smallest activity contribution at both sites, with averages ranging from 1.6 to 8.6 g CO m d. This study has demonstrated that for an interim cover, composting and anaerobic digestion of shallow landfill waste can occur simultaneously.
需要对导致垃圾填埋场温室气体（GHG）排放的过程进行考察，因为尚未区分垃圾在覆盖物下厌氧和好氧降解的实际水平。本文提出了一种通过为分子物种（CH、CO）和稳定碳同位素（δC-CO 和 δC-CH）开发的质量平衡系统来区分填埋场环境中厌氧消化（r）、堆肥（r）和 CH 氧化（r）速率的方法。该技术应用于垃圾填埋场倾斜区域的两个采样点。在该区域上方放置了 1.0 m 厚的新鲜废物和 30-50 cm 厚的粉质粘壤土后，进行了四轮采样，历时 18 个月。静态室用于测量表面的分子和同位素物种通量，土壤气体探针用于收集深度约为 0.5、1.0 和 1.5 m 的气体样本。质量平衡基于表面通量和最深采样深度处分子和同位素物种的浓度。通过随机将化学计量和同位素参数变化 ±5%，考虑计算速率的灵敏度，为每个采样轮的每个位置生成至少 500 次 r、r 和 r 的计算。两个位置的 r 和 r 的平均计算值表明，厌氧消化和堆肥同样占主导地位。四个采样轮中 r 的平均值范围为 9.8 至 44.5 g CO m d，在一个地点单调下降，在另一个地点先上升后下降。r 的平均值范围为 10.6 至 45.3 g CO m d。尽管在初始采样轮中出现了最高的平均 r 值，但所有后续 r 值都在 10 到 20 g CO m d 之间。r 在两个地点的活动贡献最小，平均值范围为 1.6 至 8.6 g CO m d。本研究表明，对于临时覆盖层，浅层垃圾填埋场废物可以同时发生堆肥和厌氧消化。
