Developing sanitation planning options: A tool for systematic consideration of novel technologies and systems

Selection of appropriate on-site household sanitation options for rural communities of Zimbabwe - case of Mbire district, Zimbabwe

Selecting an appropriate sanitation option involves multiple stakeholders with often conflicting objectives. A multiple criteria decision analysis (MCDA) framework was developed to inform decision makers on selecting appropriate sanitation options for rural communities. Criteria established from literature were evaluated and weighted on-line by stakeholders. A performance matrix was developed by assigning weights to criteria and scoring alternatives. Selection of alternatives was based on a composite appropriateness index from a rank using the simple multi-attribute ranking technique. The framework was evaluated by verification, validation and sensitivity analysis. Five alternatives were evaluated on 14 decision criteria. The first preferred alternative was the urine diverting dry toilet (72.54) then the Blair ventilated improved pit latrine (67.10). The framework was commented as reasonable and robust. A simple and transparent MCDA framework was developed considering local conditions in a participatory manner to select appropriate alternatives for rural sanitation where a single option is encouraged.

A review of how decision support tools address resource recovery in sanitation systems

Globally, there is increasing interest in recovering resources from sanitation systems. However, the process of planning and implementing circular sanitation is complex and can necessitate software-based tools to support decision-making. In this paper, we review 24 decision support software tools used for sanitation planning, to generate insights into how they address resource recovery across the sanitation chain. The findings reveal that the tools can address many planning issues around resource recovery in sanitation including analysis of material flows, integrating resource recovery technologies and products in the design of sanitation systems, and assessing the sustainability implications of resource recovery. The results and recommendations presented here can guide users in the choice of different tools depending on, for example, what kind of tool features and functions the user is interested in as well as the elements of the planning process and the sanitation service chain that are in focus. However, some issues are not adequately covered and need improvements in the available tools including quantifying the demand for and value of resource recovery products, addressing retrofitting of existing sanitation infrastructure for resource recovery and assessing social impacts of resource recovery from a life cycle perspective. While there is scope to develop new tools or to modify existing ones to cover these gaps, communication efforts are needed to create awareness about existing tools, their functions and how they address resource recovery. It is also important to further integrate the available tools into infrastructure planning and programming processes by e.g. customizing to relevant planning regimes and procedures, to move them beyond research and pilots into practice, and hopefully contribute towards more circular sanitation systems.

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

In resource-limited settings, conventional sanitation systems often fail to meet their goals-with system failures stemming from a mismatch among community needs, constraints, and deployed technologies. Although decision-making tools exist to help assess the appropriateness of conventional sanitation systems in a specific context, there is a lack of a holistic decision-making framework to guide sanitation research, development, and deployment (RD&D) of technologies. In this study, we introduce DMsan-an open-source multi-criteria decision analysis Python package that enables users to transparently compare sanitation and resource recovery alternatives and characterize the opportunity space for early-stage technologies. Informed by the methodological choices frequently used in literature, the core structure of DMsan includes five criteria (technical, resource recovery, economic, environmental, and social), 28 indicators, criteria weight scenarios, and indicator weight scenarios tailored to 250 countries/territories, all of which can be adapted by end-users. DMsan integrates with the open-source Python package QSDsan (quantitative sustainable design for sanitation and resource recovery systems) for system design and simulation to calculate quantitative economic (via techno-economic analysis), environmental (via life cycle assessment), and resource recovery indicators under uncertainty. Here, we illustrate the core capabilities of DMsan using an existing, conventional sanitation system and two proposed alternative systems for Bwaise, an informal settlement in Kampala, Uganda. The two example use cases are (i) use by implementation decision makers to enhance decision-making transparency and understand the robustness of sanitation choices given uncertain and/or varying stakeholder input and technology ability and (ii) use by technology developers seeking to identify and expand the opportunity space for their technologies. Through these examples, we demonstrate the utility of DMsan to evaluate sanitation and resource recovery systems tailored to individual contexts and increase transparency in technology evaluations, RD&D prioritization, and context-specific decision making.

Regulating Citywide Inclusive Sanitation (CWIS) in Colombia

The conventional top-down scope of relying only on centralised sewerage has proven insufficient to reach the entire global population with safely managed sanitation and meet Sustainable Development Goals 6.2. and 6.3 by 2030. Citywide Inclusive Sanitation (CWIS) has emerged as an approach to accelerate progress by considering different technologies and service provision models within the same city to expand sanitation access equitably and sustainably. However, to generate an enabling environment for CWIS to be implemented successfully, regulatory frameworks must be adapted, as they are often unsuited for non-sewered sanitation solutions. By analysing the Colombian case study through a mixed qualitative methodology comprised of a policy review, semi-structured interviews, and workshops with key stakeholders in the urban sanitation sector, the country’s regulatory framework was evaluated to determine if it is adequate to implement CWIS. Regulations were identified to pose barriers for CWIS and produced a disabling environment for its application. This research proposes recommendations to adapt the regulatory framework to allow CWIS application in Colombia based on the encountered barriers. This is the first comprehensive study on regulations for CWIS in the Latin American context and therefore provides the basis for further research to understand the dynamics related to effective regulations for CWIS globally.

Moving Up the Sanitation Ladder: A Study of the Coverage and Utilization of Improved Sanitation Facilities and Associated Factors Among Households in Southern Ethiopia

BACKGROUND

Improved sanitation facilities offer numerous advantages, ranging from the reduction of diarrheal illnesses and helminth infections to the improvement of psychosocial well-being. At the household level, attaining universal access to improved sanitation facilities demands a thorough understanding of the factors that influence their adoption and use. As a result, the purpose of this study was to assess the availability and utilization of improved sanitation facilities, as well as the factors that influence the adoption and proper use of such a facility among households in the Gedeb district of Southern Ethiopia.

METHODS

A community-based cross-sectional household survey was conducted from March to April 2019. A systematic random sampling technique was used to select 630 households at random. A pre-tested questionnaire was used to collect the respondents' self-reported data, which comprised socio-demographic, home characteristics, behavioral, and environmental elements. The factors related to the availability and utilization of improved sanitation facilities were identified using multivariable logistic regression.

RESULT

Improved sanitation facilities were present in 172 (27.3%) of the 630 households surveyed, with 111 (64.5%) of them being used properly. The availability of improved sanitation was associated with educational status [AOR = 2.73, 95% CI (1.59, 4.67)], upper wealth quintile [AOR = 2.18, 95% CI (1.21, 3.93)], ever hearing educational messages about latrines [AOR = 3.9, 95% CI (1.86, 8.18)], favorable attitude toward latrine construction [AOR = 2.81, 95% CI (1.67, 4.74)], and receiving support during construction [AOR = 3.78, 95% CI (2.15, 6.65)]. Furthermore, utilization was associated with the absence of children under the age of 5, knowledge of sanitation-related diseases, and a positive attitude toward latrine use.

CONCLUSION

Both the availability of improved sanitation facilities and the rate at which they were used properly fell far short of the National Hygiene and Environmental Health Strategy's goals. This study contributes to the body of knowledge on how to improve the availability of improved sanitation in Ethiopia.

Closing Water and Nutrient Cycles in Urban Wastewater Management: How to Make an Academic Software Available to General Practice

Appropriate sanitation is crucial to alleviate pressures on environmental and human health hazards. Conventional (sewered) sanitation systems are often not viable in rapidly developing urban areas, where over 70% of the world population is expected to live in 2050. Freshwater is polluted and valuable resources such as nutrients and organics are lost. At present, many alternative sanitation technologies and systems are being developed with the aim to alleviate these pressures through (1) independency from sewers, water, and energy, therefore better adapted to the needs of fast and uncontrolled developing urban areas; and (2) contribute to a circular economy through the recovery of nutrients, energy, and water for reuse. Unfortunately, these innovations hardly find their way into practice because there exists a lack of data and knowledge to systematically consider them in strategic planning processes. To this end, we have developed SANitaTIon system Alternative GeneratOr (SANTIAGO)—a software that provides a comprehensive list of potential technologies and system configurations and quantifies their local appropriateness as well as their resource recovery and loss potentials. The aim is to provide a manageable but diverse set of decision options together with information needed to rank the alternatives and to select the preferred one in a structured decision making process. To make this software useful for practice, an easily accessible interactive user interface is required that (1) facilitates data collection and input; and (2) the exploration and presentation of results. As a first step in creating this user interface, we develop a framework that summarizes (1) the requirements that arise from practical applications of SANTIAGO, and (2) a comprehensive user understanding on the basis of 21 interviews with international practitioners caught in five personas: capacity developers, engineering experts, planners, researchers, teachers and trainers. This framework aids the development of any academic software into a tool useful for practice and policy makers. Here specifically, it enables contribution to sustainable development goals 6 (clean water and sanitation), and 11 (sustainable cities and communities).

An integrated assessment of environmental, economic, social and technological parameters of source separated and conventional sanitation concepts: A contribution to sustainability analysis

Resource recovery and reuse from domestic wastewater has become an important subject for the current development of sanitation technologies and infrastructures. Different technologies are available and combined into sanitation concepts, with different performances. This study provides a methodological approach to evaluate the sustainability of these sanitation concepts with focus on resource recovery and reuse. St. Eustatius, a small tropical island in the Caribbean, was used as a case study for the evaluation. Three source separation-community-on-site and two combined sewerage island-scale concepts were selected and compared in terms of environmental (net energy use, nutrient recovery/reuse, BOD/COD, pathogens, and GHG emission, land use), economic (CAPEX and OPEX), social cultural (acceptance, required competences and education), and technological (flexibility/adaptability, reliability/continuity of service) indicators. The best performing concept, is the application of Upflow Anaerobic Sludge Bed (UASB) and Trickling Filter (TF) at island level for combined domestic wastewater treatment with subsequent reuse in agriculture. Its overall average normalised score across the four categories (i.e., average of average per category) is about 15% (0.85) higher than the values of the remaining systems and with a score of 0.73 (conventional activated sludge - centralised level), 0.77 (UASB-septic tank (ST)), 0.76 (UASB-TF - community level), and 0.75 (ST - household level). The higher score of the UASB-TF at community level is mainly due to much better performance in the environmental and economic categories. In conclusion, the case study provides a methodological approach that can support urban planning and decision-making in selecting more sustainable sanitation concepts, allowing resource recovery and reuse in small island context or in other contexts.

Refining the shit flow diagram using the capacity-building approach - Method and demonstration in a south Indian town

In cities of the Global South, faecal sludge management (FSM) has arisen as an acceptable and economical alternative for managing excreta. Shit flow diagram (SFD) has emerged as the preferred tool for the planning and advocacy of FSM services. Besides context-specific challenges, FSM planning, especially the use of SFD is impeded by the lack of data related to on-site sanitation systems (OSSs) and lack of capacity at the local level. This paper sets out to demonstrate how the capacity-building approach can be extended to overcome these two challenges in planning FSM with a substantial share of the information collected through household surveys. We argue that even the resource-constrained towns in the Global South have access to college students, smartphones and open source applications and demonstrate how they can be harnessed to collect the data in a cost-effective manner. Using the data collected by 150+ university students, participants of a summer school, we prepare a SFD for Alleppey, a town in Kerala, India. We argue such repeated exercises by subsequent batches of students can help understand local problems, arrive at context specific solutions and monitor them to instill better accountability of local governments. We also identify two issues with the current SFD preparation process and find it is necessary to contextualise the output of the tool to use it for planning. We suggest that the methods demonstrated here be incorporated in the future refinements to the SFD tool to make it more useful for planning city-wide FSM services.

Comparative analysis of sanitation systems for resource recovery: Influence of configurations and single technology components

Resource recovery and emissions from sanitation systems are critical sustainability indicators for strategic urban sanitation planning. In this context, sanitation systems are the most often structured using technology-driven templates rather than performance-based sustainability indicators. In this work, we answer two questions: Firstly, can we estimate generic resource recovery and loss potentials and their uncertainties for a diverse and large set of sanitation systems? And secondly, can we identify technological aspects of sanitation systems that indicate a better overall resource recovery performance? The aim is to obtain information that can be used as an input into any strategic planning process and to help shape technology development and system design for resource recovery in the future. Starting from 41 technologies, which include novel and conventional options, we build 101,548 valid sanitation system configurations. For each system configuration we quantify phosphorus, nitrogen, total solids, and water flows and use that to calculate recovery potentials and losses to the environment, i.e. the soil, air, or surface water. The four substances cover different properties and serve as a proxy for nutrient, organics, energy, and water resources. For modelling the flows ex-ante, we use a novel approach to consider a large range of international literature and expert data considering uncertainties. Thus all results are generic and can therefore be used as input into any strategic planning process or to help guide future technology development. A detailed analysis of the results allows us to identify factors that influence recovery and losses. These factors include the type of source, the length of systems, and the level of containment in storage and treatment. The factors influencing recovery are related to interactions of different technologies in a system which shows the relevance of a modelling approach that allows to look at all possible system configurations systematically. Based on our analysis, we developed five recommendations for the optimization of resource recovery: (i) prioritize short systems that close the loop at the lowest possible level; (ii) separate waste streams as much as possible, because this allows for higher recovery potentials; (iii) use storage and treatment technologies that contain the products as much as possible, avoid leaching technologies (e.g. single pits) and technologies with high risk of volatilization (e.g. drying beds); (iv) design sinks to optimise recovery and avoid disposal sinks; and (v) combine various reuse options for different side streams (e.g. urine diversion systems that combine reuse of urine and production of biofuel from faeces).