Structured Approach for Comparison of Treatment Options for Nutrient-Recovery From Fecal Sludge

Abstract

The aim of this study is to present a structured approach for comparing possible nutrient-recovery fecal sludge (FS) treatment systems in order to support transparent decision-making. The approach uses a multi-dimensional sustainability assessment of treatment technologies for nutrient recovery from FS, using a typical case of Kampala City, Uganda. A synthesized list of 22 treatment technologies was prepared from literature. This list included wastewater treatment technologies, which could be adapted to treat fecal sludge, and established fecal sludge treatment technologies that are available or potentially applicable in Kampala. Based on the local situation, the list was reduced to eight possible options, which were carried forward into a multi-dimensional sustainability assessment that incorporated input of stakeholders. The technologies included in the final assessment were optimization of the existing system, lactic acid fermentation (LAF), composting, vermicomposting, Black-Soldier Fly (BSF) composting, ammonia treatment, alkaline stabilization and solar drying. Optimization of the existing system performed well against the set criteria and is a recommended short-term solution. This will require e.g., adding narrower screens to remove more trash from the incoming sludge and respecting storage times prior to selling the sludge. To maximize the agricultural value of the recovered product, while respecting the need for safe reuse, a combination of technologies becomes relevant; the use of a combination of BSF, and subsequent ammonia or alkaline treatment of the remaining organic fraction would allow for maximized safe nutrient recovery and can be the aim for long-term sanitation planning in Kampala. The results of this process provide supporting information for a discussion of trade-offs between stakeholder groups as part of a decision-making process within a larger planning context.

Small-scale on-site treatment of fecal matter: comparison of treatments for resource recovery and sanitization

“…Currently, the common practices are not considering treatment or resource recovery and rely on subsequent storage or disposal (Strande and Brdjanovic 2014;Tilley et al 2014). Dry composting toilets are considered one of the best current options for on-site treatment in terms of resource recovery (Orner and Mihelcic 2018;McConville et al 2020). However, composting is not always successful, and the resulting material is usually neither stabilized nor sanitized (Niwagaba et al 2009;Hill et al 2013).…”

DMsan: A Multi-Criteria Decision Analysis Framework and Package to Characterize Contextualized Sustainability of Sanitation and Resource Recovery Technologies

“…The results of the literature review were used to inform the methodologies, criteria, and indicators used within the DMsan package. Decision-support techniques were identified for each paper, with some papers using multiple techniques. ,,, Out of the 35 papers, MCDA was the most common decision-support technique (22 papers) ,,,− ,− followed by LCA (seven papers). − ,,,, Other techniques included cost–benefit analysis (CBA; four papers); − appropriateness assessment (AA; two papers); , strengths, weaknesses, opportunities, and threats (SWOT) analysis (one paper); agent-based modeling (ABM; one paper); probabilistic model (one paper); and decision-support systems (one paper; Figure A). Within MCDA, the most widely used ranking methodologies were the technique for order of preference by similarity (TOPSIS; nine papers) ,,,,,,,, and analytical hierarchy process (AHP; nine papers; ,,,,,,,, Figure B).…”

“…Within MCDA, the most widely used ranking methodologies were the technique for order of preference by similarity (TOPSIS; nine papers) ,,,,,,,, and analytical hierarchy process (AHP; nine papers; ,,,,,,,, Figure B). Other MCDA methods observed outside of TOPSIS and AHP included elimination of choice translating reality (ELECTRE; three papers), ,, multi-attribute utility theory (one paper), qualitative MCDA (one paper), and choosing by advantage (one paper) . MCDA methods were often combined to increase the robustness of the decision making framework by leveraging the advantages of multiple approaches, such as AHP paired with TOPSIS , or AHP paired with ELECTRE .…”

Toward Zero Hunger Through Coupled Ecological Sanitation-Agriculture Systems

“…Managing sanitation in a changing climate is a challenge, particularly when systems rely on large quantities of fresh water and centralized, extensive infrastructure that requires significant capital and trained management (Kohlitz et al, 2017). Global efforts to enhance access to adequate sanitation under SDG 6 are driving demand for innovative non-sewered sanitation services, particularly in regions that are rapidly urbanizing and where water resources are scarce (Russel et al, 2019;McConville et al, 2020).…”