Graduate School of Natural Science and Technology, Kanazawa University, Kanazawa, Japan.
Department of Civil Engineering, Khulna University of Engineering & Technology (KUET), Khulna, Bangladesh.
J Air Waste Manag Assoc. 2022 Aug;72(8):914-924. doi: 10.1080/10962247.2022.2064936. Epub 2022 Jun 19.
Co-composting of fecal sludge (FS) and solid waste (SW) allows recycling of essential nutrients into agriculture thereby closing the nutrient circle. In this study, temperature variation, the mass balance of forced and passive aeration in the composting process, and the extent of degradation with different stages were investigated. The extent of degradation was determined through the different composting process in the first, second, and third stages with different mix proportion of fecal sludge. Four sets of the initial waste mixture were prepared using SW and FS. SW and FS were mixed at four different ratios for four sets namely 90:10, 85:15, 80:20, and 75:25 (SW:FS). Forced aeration and passive aeration composting tests were done using a series of reactors according to a planned experimental program. The results show that (i) the mean maximum temperature of the first and second stage were 65°C and 56°C of passive, 67°C and 60°C of forced aeration, respectively which raised within seven days. (ii) According to the mass balance, total mass, moisture content, and volatile solids always decreased at every stage for passive and forced aeration processes, the degradation of the volatile solid in the composting process using forced aeration was more than in the passive aeration process. (iii) For the passive and forced aeration processes, the total BVS degradation of ranged between 82% and 89%, and 73% and 91%, respectively after 60 days. Therefore, it can be concluded that the percentage of BVS degradation in forced and passive aeration was not significantly different. The extent of degradation was determined through different composting processes in the three stages with different mixture proportion of fecal sludge and organic solid waste. The study showed that maximum temperature in composting ranged from 57°C to 67°C within one week. Co-composting process with passively and forced aeration process of peak temperature were almost same. Reduction of volatile solids at first stage was greater than second and third stages. Biodegradable volatile solids reduction in passive and forced aeration processes were not significantly different. The final product of composting was used in agricultural land.
粪便污泥（FS）和固体废物（SW）的共堆肥可将重要养分回收再利用于农业，从而形成养分循环。本研究中，我们调查了堆肥过程中的温度变化、强制和被动通风的质量平衡，以及不同阶段的降解程度。通过在第一、二、三个阶段使用不同比例的粪便污泥进行不同的堆肥过程，确定了降解程度。四组初始废物混合物使用 SW 和 FS 制备。SW 和 FS 以四种不同的比例混合用于四组，分别为 90:10、85:15、80:20 和 75:25（SW:FS）。根据计划的实验方案，使用一系列反应堆进行强制通风和被动通风堆肥测试。结果表明：（i）第一阶段和第二阶段的平均最高温度分别为 65°C 和 56°C（被动），67°C 和 60°C（强制通风），均在七天内升高。（ii）根据质量平衡，被动和强制通风过程中，总质量、水分含量和挥发性固体始终在每个阶段下降，强制通风过程中挥发性固体的降解量大于被动通风过程。（iii）对于被动和强制通风过程，在 60 天后，总 BVS 降解率分别在 82%至 89%和 73%至 91%之间。因此，可以得出结论，强制和被动通风过程中 BVS 降解的百分比没有显著差异。通过不同混合物比例的粪便污泥和有机固体废物在三个阶段进行不同的堆肥过程，确定了降解程度。研究表明，堆肥过程中的最高温度在一周内从 57°C 到 67°C 不等。被动和强制通风过程的堆肥峰值温度几乎相同。第一阶段挥发性固体的减少量大于第二和第三阶段。被动和强制通风过程中生物可降解挥发性固体的减少量没有显著差异。堆肥的最终产物用于农业用地。
