Gold Moritz, Harada Hidenori, Therrien Jean-David, Nishida Takahiro, Cunningham Michael, Semiyaga Swaib, Fujii Shigeo, Dorea Caetano, Nguyen Viet-Anh, Strande Linda
a Eawag: Swiss Federal Institute of Aquatic Science and Technology, Sandec: Department of Water , Sanitation and Solid Waste for Development , Duebendorf , Switzerland.
b Graduate School of Global Environmental Studies , Kyoto University , Kyoto , Japan.
Environ Technol. 2018 Dec;39(23):3077-3087. doi: 10.1080/09593330.2017.1374472. Epub 2017 Sep 12.
Dewatering of faecal sludge (FS) is indispensable for adequate FS management. However, comprehensive knowledge is lacking on FS dewatering performance. This study compared the dewatering performance of FS from different countries and onsite sanitation technologies, to assess influential characteristics on dewatering, and to compare dewatering performance of FS with wastewater sludge. We collected 73 FS samples from septic tanks, lined pit latrines, unlined pit latrines and johkasou tanks in Uganda, Vietnam and Japan, and 18 samples of wastewater sludge in Switzerland. Capillary suction time (CST) and total solids (TS) of centrifuged sludge (%TS) were determined as metrics of dewatering rate and dewaterability, respectively, together with relevant sludge characteristics. Data were analysed by bootstrapping comparison of median results of each sample category and by bootstrapping multiple regression analysis to quantify the relative importance of sludge characteristics on dewatering performance. Results showed that the dewatering rate was significantly different between FS from different technologies, whereas dewaterability was significantly different within the same technology. FS had a significantly lower dewatering rate than wastewater sludge. In contrast, FS dewaterability was greater than wastewater sludge. However, this could be attributed to higher concentrations of sand in FS. Electrochemical properties such as NH-N and surface charge had the strongest correlation to dewatering rate, and solid properties such as sand content and total volatile solids to dewaterability. The results identify potential characteristics that could explain and predict the high variability of FS dewatering performance that is observed in the field.
粪便污泥脱水对于粪便污泥的妥善管理至关重要。然而，目前缺乏关于粪便污泥脱水性能的全面知识。本研究比较了来自不同国家的粪便污泥以及现场卫生技术的脱水性能，以评估对脱水有影响的特性，并比较粪便污泥与污水污泥的脱水性能。我们从乌干达、越南和日本的化粪池、有衬砌的坑式厕所、无衬砌的坑式厕所和净化槽中收集了73份粪便污泥样本，以及在瑞士收集了18份污水污泥样本。分别将离心污泥的毛细吸水时间（CST）和总固体含量（%TS）作为脱水速率和脱水性能的指标，并测定了相关污泥特性。通过对每个样本类别的中位数结果进行自助法比较以及通过自助法多元回归分析来分析数据，以量化污泥特性对脱水性能的相对重要性。结果表明，不同技术的粪便污泥脱水速率存在显著差异，而同一技术内的脱水性能存在显著差异。粪便污泥的脱水速率明显低于污水污泥。相比之下，粪便污泥的脱水性能优于污水污泥。然而，这可能归因于粪便污泥中较高的砂含量。诸如NH-N和表面电荷等电化学性质与脱水速率的相关性最强，而诸如砂含量和总挥发性固体等固体性质与脱水性能的相关性最强。这些结果确定了一些潜在特性，这些特性可以解释和预测在实际中观察到的粪便污泥脱水性能的高度变异性。
