Department of Water Resources Engineering, College of Engineering and Technology, University of Dar es Salaam, P. O. Box 35131, Dar es Salaam, Tanzania.
Lund University Centre for Sustainability Studies, Lund University, Box 170, SE-221 00, Lund, Sweden.
J Environ Manage. 2021 Oct 1;295:112924. doi: 10.1016/j.jenvman.2021.112924. Epub 2021 Jun 18.
In unplanned urban settlements, where onsite sanitation systems are the norm, desludging of faecal sludge (FS) containments is a necessity because of the lack of land space to enable new construction. Poorly designed toilet facilities however may jeopardize the progress towards attainment of safely managed sanitation. This study examined FS characteristics and containment design and their effect on safe desludging with a case of two selected unplanned settlements of Dar es Salaam, Tanzania. The analysis focused on design features for the strength of the containment, access to the containment, and desludging characteristics of the FS. The Desludgeability potential of FS was determined on basis of flow behaviour explained in terms of moisture content and volatile solids. Research results showed that partially lined pits, lack of containment access holes and solid wastes are design and usage features which negatively affect containment strength and potential for safe desludging. The analysis further found that, only 54.8% of containments studied have FS that can be desludged by either mechanized or hand pumps. Pour flush toilets and septic tanks indicated a slightly higher potential for safe desludging compared to traditional pit latrines, however, the difference is not statistically significant (P = 0.180). Thus, safe desludging is a problem across all types of containments. To enhance safe desludging in Dar es Salaam, three key design features and usage ought to be urgently addressed: first, a requirement to ensure that all pits are fully lined inside, second, the mandatory presence of an access hole for FS desludging and third, limitations on solid waste entering the pits.
在非计划性城市住区中，由于缺乏土地空间来进行新的建设，原位卫生系统是常规做法，因此必须对粪便污泥（FS）进行清淤。然而，设计不当的厕所设施可能会危及安全管理卫生的实现进展。本研究以坦桑尼亚达累斯萨拉姆的两个选定非计划性住区为例，考察了 FS 的特性和容器设计及其对安全清淤的影响。分析侧重于容器强度的设计特点、进入容器的通道以及 FS 的清淤特性。FS 的可清淤性潜力是根据水分含量和挥发性固体解释的流动行为来确定的。研究结果表明，部分衬砌坑、缺乏容器进入孔和固体废物是设计和使用特点，这些特点会对容器强度和安全清淤的潜力产生负面影响。分析还发现，在所研究的容器中，只有 54.8%的 FS 可以通过机械或手动泵进行清淤。冲水马桶和化粪池与传统的坑式厕所相比，具有稍高的安全清淤潜力，但差异无统计学意义（P=0.180）。因此，所有类型的容器都存在安全清淤问题。为了加强达累斯萨拉姆的安全清淤，有三个关键的设计特点和使用方面需要紧急解决：首先，必须确保所有坑内都完全衬砌；其次，必须为 FS 清淤设置进入孔；第三，限制固体废物进入坑内。
