On-site Sanitation Facilities Research Articles

Pathogen inactivation from faecal waste via black soldier fly treatment

Sustainable development goal 6.2 advocates for increasing access to equitable and adequate hygiene and sanitation for all by 2030, and its indicator target is to raise the proportion of the population using safely managed sanitation. On the contrary, it is approximated that only 54% of people globally have access to safely managed sanitation, while 2.4 billion lack access. Recent innovations have however seen the development of low-cost technologies that can be customized depending on the region. The container based sanitation (CBS) is one of the options for safely managing the waste compared to conventional sewerage systems that are expensive. However, the need for emptying and transportation of filled fecal sludge (FS) containers on daily basis, leads to high operational costs and increases the operational exposures risks to fecal pathogens amongst the CBS operators. The study determined the performance efficiency of Black Soldier Fly Larvae in inactivation of E.coli via seeded container based sanitation- Urine diverting dry toilet model. Sample was transported to the lab for analysis of E.coli after every 3 days from Seeded households and samples from Non seeded households in replication. One gram of sample was used in serial dilution up to factor 5.The inoculum was plated in Tryptone Bile Glucuronic (TBX) agar for enumeration according to manufacturer’s instructions. Plates with 30-300 colonies were considered viable for counting. The study used statistical analysis IBM SPSS software from the sets of experiments. The E.coli (CFU/ml) mean varied between 7.3±1.3 and 10.1±2.8 for Seeded treatments while non-seed treatments ranged between 7.5±1.6 and 10.4±3.2. A significant variation occurred between the two treatments at p<0.05(SH and NH). Findings from this study showed that there was reduction of E.coli coliforms with Bioconversion of organic waste using the BSF technology has been noted to reduce the E.coli load and reducing the volume of the bio-waste. Sanitation policy makers can apply the findings of this study in formulation of policies on safe handling and disposal of fecal matter from onsite sanitation facilities.

Influence of economic factors on feacal emptying, conveyance and disposal:

Safe management of faecal waste is one of the Sustainable Development Goals (SDGs) which envisions safe sanitation for all. However, although efforts to improve sanitation conditions in slums have been made, faecal emptying, conveyance and disposal still remain a challenge endangering the health of the public. The study examined the influence of economic factors on faecal emptying, conveyance and disposal in on-site sanitation facilities in Meru slums. A convergent design with a mixed methods approach was adopted. Quantitative data was collected using structured questionnaires from a sample of 228 household heads selected using cluster and proportionate simple random sampling techniques. Correlation and regression analysis was carried out to ascertain the association between emptying, conveyance and disposal of faecal waste and the economic factors. Qualitative data was gathered using focus group discussion participants with eight (8) who included four (4) pit operators, 3 household heads and 1 Public Health Officer (PHO) and results analyzed thematically. Findings showed that only 31% of slum dwellers emptied latrine pits and that manual emptying was more common (84%) than mechanical emptying because of its cost efficiency, reliability and the effectiveness in handling plastics, glasses, metal pieces, diapers and sanitary pads contained in pits. Increased cost constrained faecal emptying, conveyance, and disposal (r=0.499, p-value=0.000). Residents who were able to pay for faecal handling services were more likely to practice hygienic faecal emptying, conveyance, and disposal (r=0.524, p-value=0.000). Low level of income for majority of slum dwellers influenced the design of the latrines adopted. Emptying faeces from poorly designed pit latrines was more expensive due to operators’ safety concerns. The study concluded that the inability to meet the costs associated with faecal emptying, conveyance and disposal services facilitated poor sanitation status in slums. There is need to sensitize the slum community on the benefits of practicing safe management of faecal waste. The study recommended development of government policies to regulate mechanical emptying conveyance and disposal of faecal matter.

Application of machine learning in sanitation management prediction: Approaches for achieving sustainable development goals

Due to lack of understanding about the different conditions of sanitation systems and complexity, mostly in Asia and Africa, the occurrence of unsafely managed sanitation still exists, leading to severe environmental and health impacts. Because of the complexity of this problem, machine learning tools were applied to develop an effective model for health protection and safe sanitation management as a promising way to approach sustainable development goals. This study aimed to examine the incidences of ineffective sanitation management on the prevalence of diarrhea infections using machine learning tools. The prevailing conditions for safely sanitation management were identified, and the effective model to protect the impacts of ineffective sanitation management on the prevalence of diarrhea infections was proposed. Based on information collected from about 1000 households with relatively high diarrhea infections during the period of 2017–2021, factors relating to sanitation facilities for health protection and safe sanitation management were examined. Diarrhea infections and no diarrhea infection were recognized based on actual conditions of the surveyed households and incidences from ground-based observation. Classification tree model as J48 in WEKA was applied for analytic predictive tool using 70:30 ratio of training and validating dataset. The findings showed that the tree model obtained from the training data was with 73% accuracy prediction, while that from the validation data was with 70% accuracy. The correlation of personal hygiene (such as washing hand before meal and drinking water from natural water sources) and sanitation facilities (such as open defecation and distance from on-site sanitation facilities to open drains or storm sewer) was significant with inverse relationship for safely sanitation management and public health protection.

Tracking enteric pathogen contamination from on-site sanitation facilities to groundwater in selected rural areas of Vhembe District Municipality, Limpopo Province, South Africa

Groundwater is valued as a source of potable water, although it is vulnerable to environmental pollution. The aim of this study was to track enteric pathogen contamination from on-site sanitation (OSS) facilities to 70 household boreholes used by four villages of the Vhembe District Municipality. Two objectives were pursued: to measure the lateral distance between the borehole and the sanitation facilities in household yards, and to track the enteric pathogens. The borehole abstraction point and OSS system distance were determined using a steel measuring tape. Real-time PCR was used to track Shigella flexneri, Salmonella typhimurium, Campylobacter jejuni, and enterotoxigenic Escherichia coli (ETEC) from Wastewater (WW) from domestic septic tank and sludge from pit latrines to boreholes. Escherichia coli was used as an indicator of faecal contamination. Results showed that 25% of households kept a distance of ≥50 m between the OSS facilities and the boreholes. In total, 87.5% of household boreholes in the rainy season and 72.5% in the dry season were contaminated with E. coli and pathogenic bacteria: Shigella flexneri, Salmonella typhimurium, and ETEC. The concentrations of the pathogens ranged from 2.03 to 2.12 LogEGC/100 mL. A very weak (r = −0.093) to moderate (r = −0.541) association was found between pathogens in groundwater and on-site sanitation systems (WW from septic tank and sludge from pit latrine). This suggests that the pathogens were not present in the sanitation compartment when they were found in the groundwater and vice versa. Moreover, a very weak (r = 0.007) to moderate (r = 0.525) association was found between the detected contaminants in groundwater and the lateral distance between the OSS facilities and the boreholes. The pathogens detected in all samples showed consistent concentrations, suggesting potential contamination from OSS systems' waste, possibly in groundwater, indicating potential contamination. The siting of OSS facilities at the yards in this study appeared to have a slight influence on the contaminants detected in groundwater. This study calls for an education program to be implemented by the Water and Sanitation Services Authorities to prevent contamination of groundwater and the risk of waterborne diseases.

Characterization and Methanogenic Potential Evaluation of Faecal Sludge: Case of the Kossodo Biogas Plant in Ouagadougou

The use of faecal sludge (FS) in anaerobic digestion (AD) requires a perfect knowledge of their composition. Considered as a very heterogeneous material, the high variability of FS can disturb biodigesters’ functionality and impact biogas production. Unique in West Africa, Kossodo’s biogas plant in Ouagadougou receives sludge from septic tanks and pit latrines. To evaluate the quality of sludge discharged in this treatment plant and its ability for AD, a characterization of 130 FS trucks from several onsite sanitation facilities was carried out. Physico-chemicals, including heavy metals and microbiological parameters, were analyzed using standard protocols. A biochemical methane potential test was employed to evaluate biogas yield. Results showed that raw sludge averaged 1.12% total solids (TS), 54.74% volatile solids (VS), 9253 mg/L chemical oxygen demand (COD), and 1645 mg/L biochemical oxygen demand (BOD). Settled faecal sludge exhibited higher levels of total coliforms, E. coli, helminth eggs, and heavy metals. Heavy metal levels met AD standards defined by VDI 4630, with decreasing toxicity order: Zn > Mn > Cu > Cr > Ni > Pb > As ≥ Hg. The carbon-to-nitrogen (C/N) ratio was 6.7 ± 4.3, indicating unsuitability for AD. Sludge settling increased C/N ratio by 46%, which was still below optimal AD conditions (20–30). Methane yield of raw and settled FS averaged 61 ± 0.2 and 156 ± 3.2 NL CH4/kg VS removed, respectively. Co-substrate addition could enhance the methanogenic yield of these sludges. This study provides a valuable database on the characteristics of FS, supporting sustainable recovery options.

Exploration of appropriate media to influence sustainable on-site sanitation choices in Sri Lanka– visualization with still images or a video

Pit latrines are the most common form of improved sanitation in many rapidly developing countries. However, they cause the highest amount of groundwater pollution among on-site sanitation (OSS) facilities. Many households in developing countries use groundwater as their main or sub-source, and pit latrines are not a sustainable solution. Thus, the conversion from pit latrines to septic tanks is required.We created two types of media, still images and a video, to illustrate the differences in functions and hygiene risks between pit latrines and septic tanks. Moreover, a survey was conducted in Sri Lanka to determine the media choice that would increase the people's preference for septic tanks as their next OSS, even weeks after the information is presented. The choice of the next OSS participants selected before they were presented with the images was the same as that currently in use, reflecting the belief that the problem of pit latrines was not currently apparent and need not be changed. However, a video presentation of the information made it possible for a larger group of people to choose the usage of septic tanks in the future, especially in suburban areas where the problems were likely to occur.

Analysis of sanitation system and coliform number in groundwater in Wonosari District, Gunungkidul Regency, Indonesia

Sanitation visualizes the environment’s health status, comprising housing, sewage disposal, and clean water provision. In general, sewerage can have on-site and offsite sanitation facilities. The research was conducted to characterize the sanitation system for sewage disposal, determine the water quality from biological parameters, and enumerate coliform bacteria in groundwater for every sanitation system observed in Wonosari District, Gunungkidul Regency, Indonesia. These sets of information can help detect groundwater contamination by coliform that reflects the sanitary characteristics of the sewage disposal to be further considered in sanitation management and treatment policies. The research used purposive sampling, field surveys, interviews with a questionnaire, laboratory analyses, and a descriptive-comparative design. The results showed that the sanitation system for sewage disposal at the study site consisted of individual septic tanks and wastewater treatment plants (WWTPs). In terms of quality, the coliform counts exceeded the existing standards, with the highest presence found in groundwater downstream of improperly maintained WWTPs and substandard septic tanks close to other sources of pollutants.

Process performance evaluation of faecal matter treatment via black soldier fly

Abstract Sustainable management of faecal matter is a prevailing global challenge. In this study, we assessed black soldier fly (BSF) process performance during co-treatment of faecal matter using kitchen waste (FM:KW) to formulate five feeding substrates. About 1 kg of each feed substrate was treated utilizing 5 g of 5-day-old BSF larvae after which 100 larvae were randomly picked at 3-day intervals from each treatment to monitor the larval weight gain across the treatment process. Larval days to 50% pupation, mean pupal yield, waste reduction rate (WR), bioconversion rates (BRs), and feed conversion rates (FCRs) were monitored for the process performance. Study results showed that the substrate 1:1 attained the best measures of high WR, waste reduction index (WRI), BR, FCR, and overall pre-pupal yield within a shorter development time. Further, we modelled the BSF larval weight gain using the modified Gompertz model to assess the least time for optimal biomass conversion for animal feed processing. The BSF larvae exhibited an S-shaped growth curve and the modified Gompertz model adequately quantified the BSF larval growth performance. In the future, our methodology will pave the way for effective treatment and valorization of faecal matter from onsite sanitation facilities, manage organic municipal wastes and provide alternative animal feed and bio-fertilizer.

ICT-based solution for efficient fecal sludge management: An experience from Bangladesh

In Bangladesh, people primarily depend on on-site sanitation facilities (OSSF) with an immense challenge in achieving safe sanitation due to unplanned infrastructure development, improper management of fecal sludge, and inadequate monitoring. The commitment of attaining Sustainable Development Goals (SDG) 6.2 (ensuring safe sanitation for all) by 2030 requires immediate attention in the management of fecal sludge for low-middle income countries. This paper presented the findings, challenges, and possible ways forward from a study conducted to provide data for Information and Communication Technology (ICT)-based fecal sludge management (FSM) at a municipality in the northwest of Bangladesh. A total of 18,808 households and 407 institutions in Saidpur municipality, a non-sewered town in Nilphamari district, were studied to understand the type of containment structures and on-ground desludging practices. The study showed around 10% of containments were connected to the drains illegally, 95% of the people in Saidpur practiced unsafe disposal, and 7% still practiced open defecation. To identify these malpractices, the study also implemented an ICT-based sustainable solution through a web application that enabled the local administrator to have a global look at the sanitation scenario of the municipality. The dashboard was developed to create a total sanitation monitoring system, identify defaulters, allow target-based safe managed sanitation service strategies, and ensure sustainability in FSM. The study highlighted the accessibility of vacuum truck services projecting through a spatial map and identified methods to empty the septic tanks where Vacutag services are unavailable by engaging local pit emptiers. The innovative approach of fecal sludge management will help not only to improve the existing sanitation practices but also raise community awareness to ensure sustainable sanitation system. Altogether, the web system will work as a medium to manage the faecal sludge for the existing co-compost plant where the faeces is converted into organic soil conditioner, creating prospects for a green business mechanism.

Physico-chemical properties of waste derived biochar from community scale faecal sludge treatment plants.

Background: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 "ensure availability and sustainable management of water and sanitation for all" by 2030. Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer. Methods: The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry. Results: Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident. Conclusions: Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.

Situational assessment for fecal sludge management in major cities of Pakistan.

With enhanced focus on global sanitation, access to toilets at the household level is increasing in developing countries although the provision of sewer networks is not expanding at the same pace. This is resulting in the adaptation of on-site sanitation facilities to contain the fecal sludge. The fecal sludge generated by the on-site sanitation facilities requires emptying, treatment, and safe end-use or disposal. In this study, the sanitation situation and need for fecal sludge management was evaluated in major cities of Pakistan including Karachi (provincial capital), Lahore (provincial capital), and Islamabad (national capital). Primary and secondary data were collected from key informant interviews of the stakeholders, national and international reports, research, and review articles. Infographics on wastewater and fecal sludge from origin to disposal were developed using a shit flow diagram tool and enabling environment was evaluated with a modified service delivery assessment tool. The results indicate that sewerage network coverage exists for 60%, 63%, and 50% of the areas in Karachi, Lahore, and Islamabad respectively. The sewerage network in major cities is old, leaking, and insufficient, thus a limited amount of wastewater reaches the treatment plants. Total wastewater treatment in Karachi and Islamabad is 10% and 9% respectively whereas, in Lahore, there is no infrastructure for the same. The safe sanitation in Lahore (8%) and Islamabad (25%) is coming from on-site sanitation systems with fecal sludge buried safely onsite. National level sanitation programs exist in the country but are limited to reducing open defecation and containments of fecal sludge only. The inclusion of complete fecal sludge management related framework, guidelines, and policies can help achieve the goal of safe sanitation for all.

Physico-chemical properties of waste derived biochar from community scale faecal sludge treatment plants

Background: The dumping of untreated faecal sludge from non-sewered onsite sanitation facilities causes environmental pollution and exacerbates poor public health outcomes across developing nations. Long-term mechanisms to treat faecal sludge generated from these facilities are needed to resolve the global sanitation crisis and realize the Sustainable Development Goal (SDG) 6 “ensure availability and sustainable management of water and sanitation for all” by 2030. Pyrolysis of faecal sludge removes pathogens and generates biochar, which can be used as a soil enhancer. Methods: The properties of faecal sludge biochars from three full-scale treatment plants in India were determined via Fourier transform infrared (FTIR) spectroscopy, scanning electron microscopy (SEM), energy dispersive x-ray (EDX) spectroscopy, crystal x-ray diffraction (XRD), proximate analyses, and BET surface area porosimetry. Results: Results showed that all three biochars had low specific surface area, high alkaline pH values, high ash content, and negative surface charge. Fourier transform infrared spectra showed the same surface functional groups present in each biochar. X-ray diffraction analysis showed the mineral composition of each biochar differed slightly. Scanning electron microscopy analysis indicated a porous structure of each biochar with ash particles evident. Conclusions: Slight differences in the ash content, surface area, pH and mineral content was observed between the three biochars.

Wastewater-based epidemiological surveillance to monitor the prevalence of SARS-CoV-2 in developing countries with onsite sanitation facilities

Wastewater-based epidemiology (WBE) has emerged as a valuable approach for forecasting disease outbreaks in developed countries with a centralized sewage infrastructure. On the other hand, due to the absence of well-defined and systematic sewage networks, WBE is challenging to implement in developing countries like Bangladesh where most people live in rural areas. Identification of appropriate locations for rural Hotspot Based Sampling (HBS) and urban Drain Based Sampling (DBS) are critical to enable WBE based monitoring system. We investigated the best sampling locations from both urban and rural areas in Bangladesh after evaluating the sanitation infrastructure for forecasting COVID-19 prevalence. A total of 168 wastewater samples were collected from 14 districts of Bangladesh during each of the two peak pandemic seasons. RT-qPCR commercial kits were used to target ORF1ab and N genes. The presence of SARS-CoV-2 genetic materials was found in 98% (165/168) and 95% (160/168) wastewater samples in the first and second round sampling, respectively. Although wastewater effluents from both the marketplace and isolation center drains were found with the highest amount of genetic materials according to the mixed model, quantifiable SARS-CoV-2 RNAs were also identified in the other four sampling sites. Hence, wastewater samples of the marketplace in rural areas and isolation centers in urban areas can be considered the appropriate sampling sites to detect contagion hotspots. This is the first complete study to detect SARS-CoV-2 genetic components in wastewater samples collected from rural and urban areas for monitoring the COVID-19 pandemic. The results based on the study revealed a correlation between viral copy numbers in wastewater samples and SARS-CoV-2 positive cases reported by the Directorate General of Health Services (DGHS) as part of the national surveillance program for COVID-19 prevention. The findings of this study will help in setting strategies and guidelines for the selection of appropriate sampling sites, which will facilitate in development of comprehensive wastewater-based epidemiological systems for surveillance of rural and urban areas of low-income countries with inadequate sewage infrastructure.

Adequacy of vacuum and non-vacuum technologies for emptying faecal sludge from informal settlements of Kampala City

Over 90% of the population in Kampala Informal settlements is served by onsite sanitation facilities (septic tanks and pit latrines). These fill up fast, leaving emptying as the most viable option for their sustained reuse. This study fills the gap for the limited information about different emptying technologies suitable for informal settlements and limitations they face while carrying out operations. The study compared adequacy of vacuum and non-vacuum emptying technologies used in informal settlements of Kampala. 111 questionnaires (78 for vacuum and 33 for non-vacuum) were administered to obtain data about faecal sludge (FS) source and time estimates, while an additional 37 samples were used in characterising emptied FS. The results showed that FS emptied by vacuum trucks was 43.6% from lined pits, of which 28.2% are from informal settlements. 56.4% is emptied from septic tanks by vacuum technology, where informal settlements contribute 12.8%. FS emptied by non-vacuum technologies was 9.1% from lined pit latrines, 30.3% septic tanks and 60.6% unlined pit latrines (42.4% from informal settlements). Vacuum trucks of capacity 3.6 m3 were the mostly used in informal settlements, while large vacuum trucks (7.2–14 m3) exclusively operated outside informal settlements. The most critical event is the time spent during containment emptying, where non-vacuum can take up to 3 h and less than an hour for vacuum technologies. Such longer emptying times by non-vacuum technologies can be reduced through enforcing minimum standards of containment facilities and preventing dumping of solid wastes in pits. In addition, there is a need to sanction non-compliant operators in observation of PPEs and SOPs in order to improve their safety.

Cesspits as Onsite Sanitation Facilities in the Non-Sewered Palestinian Rural Areas: Users’ Satisfaction, Needs and Perception

The main aim of this research was to assess the problems of using cesspits in the non-sewered areas in the West Bank of Palestine by the means of a questionnaire, with a sample size of 485 households, targeting the cesspits’ owners. People who use cesspits for house onsite wastewater management are not satisfied with them, and most of them complain about high disturbance during discharge of the cesspits (75.5%). Emptying cesspits represents a financial burden, costing 6% of the households’ monthly income. The frequency of cesspits’ emptying decreases substantially when there are onsite GWTPs. People accept that constructing a house with an onsite GWTPs when supported by external funding, and to a much lesser extent when they need to fund them themselves. The majority of people prefer sewerage networks for wastewater management(74.8%), followed by onsite GWTPs (15.5%), and cesspits are the least preferable (9.5%). Therefore, a more technically sound individual home onsite wastewater management system should be applied to replace cesspits so as to solve their negative implications on the socio-economic, environmental, and health aspects in the Palestinian rural communities.

Addendum of data related to drying of faecal sludge from on-site sanitation facilities and fresh faeces

The present document consists of an addendum of data to the Handbook of Methods for Faecal Sludge Analysis. It is part of a project funded by the Bill & Melinda Gates (BMGF) through the OPP1164143, untitled “Characterization of faecal material during drying”. This project was granted for funding after the 5-years Transformative Technologies convening at the BMGF headquarters in 2016, where drying was recognized as a gap in the transformative technologies for the implementation of innovative sanitation technologies. The addendum of data compiles the results from experiments directly related to drying or having indirect implications in the process. The data was obtained from experimental work conducted from 2013 to date, and involving several research institutions. As the addendum of data is an initiative led by the Pollution Research Group at the University of KwaZulu-Natal, most of the data come from this research group. Partner institutions adhered to this initiative and shared their data, including: (i) Swansea University through the SPECIFIC research group; (ii) Cranfield University through their Bioenergy laboratory; (iii) Duke University through their WASH-AID centre; (iv) Laval University through their Civil and Water Engineering department; (v) Victoria University through their Public & Environmental Engineering laboratory; (vi) Swiss Federal Institute of Aquatic Science and Technology (EAWAG) through their Sanitation, Water and Solid Waste for Development (SANDEC) department. In the addendum, the data is organized in datasheets that are categorized in different thematics according to the content. In each datasheet, the data is displayed as graphs and includes an interpretation. In addition to this, the datasheets contain the basic information that is required to understand how the data was obtained, including the information about the feedstock, laboratory equipment, experimental conditions and performed analysis. The datasheets also offer the bibliographic references about where the results can be found in literature and the hyperlink to access to the raw files with the data. Moreover, this document includes a background with a landscape about faecal sludge drying, description of the fundamentals aspects from faecal sludge drying to understand better the significance and applicability of the data, and a summary of the analysis from results from the datasheets with their practical implications in the field. The datasheets were categorized into eight groups: thermodynamics, kinetics, physiochemical properties, morphology, mechanical properties, dewaterability, disinfection, gas emission. Different types of faecal samples were involved on the generation of the data: fresh faeces and faecal sludge from various types of onsite sanitation facilities, among which ventilated improved pit (VIP) latrines, urine diversion dry toilets (UDDT), anaerobic baffled reactor (ABR) from a decentralized wastewater treatment plant (DEWAT).

Time and motion assessment of pit-emptying operations in Kigali, Rwanda

Abstract To ensure sanitation for all by 2030, fecal sludge collection services in low-income urban areas with no sewer connections need improvement. One of the major issues is the gap between low-income households' willingness to pay and the cost of emptying services in low-income areas. One way of lowering the cost of these services is through process optimization. In this regard, we conducted a time and motion study to better understand the bottlenecks associated with the collection of fecal waste from different types of on-site sanitation facilities. Our results show that emptying pit latrines, which make up 53% of the market for emptying services in Kigali, takes twice as long as emptying septic tanks. 33% of households that requested the service were located in an informal settlement with no access to road and could only be served by a semi-mechanized method which required use of barrels, and a portable pump. In general, interventions related to minimizing trash disposal in pits and septic tanks can go a long way in making the emptying process more time- and cost-efficient. Additionally, developing effective and efficient pumping technologies that are suitable for use in inaccessible areas should be prioritized.

Faecal contamination pathways of shallow groundwater in low-income urban areas: implications for water resource planning and management

Abstract Shallow groundwater is vulnerable to faecal contamination, especially in low-income urban areas where use of on-site sanitation facilities is high. This paper explores statistical relationships between potential factors influencing contaminant pathways (i.e., variables) and observed faecal contamination of shallow groundwater, represented by nitrate concentrations and counts of Escherichia coli (i.e., response function) in a small, growing town in Uganda over dry and wet seasons in 2018 and 2019. A statistically significant (p = 0.004) multiple linear regression model from dry-season E. coli counts in 2018 identifies medium sanitary risk levels and modes of construction as significant pathways (p = 0.01). Water source depth (<20 m) and proximity (>10 m) to a pit latrine were also significant (p<0.05) in both hydrogeological formations. No significant linear regression models were established for NO3 during both seasons due to low pH and rapid infiltration velocities; inconsistent sample timing during the wet season impaired the significance of the statistical models of E. coli counts. We show that modes of construction of water sources and pit latrines play key roles in determining the quality of the shallow groundwater in urban environments. Greater emphasis is therefore required to improve the functionality and sustainability of on-site water sources and pit latrines.

Fecal Sludge Management in Low Income Settlements: Case Study of Nakuru, Kenya.

Introduction: In order to meet the sustainable development goals targets of sanitation, countries aim to increase access to safely managed sanitation services for its citizens. Safely managed sanitation services refers to improved sanitation technologies that are not shared with other households and where excreta is treated and disposed; or stored, transported and treated off-site. In most Sub-Saharan Africa (SSA) countries, on-site sanitation facilities such as latrines and septic tanks are common, with low-income urban settlements mainly using pit latrines. However, little is documented about the management of sludge from these facilities, especially in low income settlements in secondary and emerging cities. This lack of data is a major hindrance to public health, development and planning efforts by governments and planning agencies. This study specifically assesses practices and challenges along the sanitation value chain related to containment, emptying, transportation, treatment and recycling of fecal sludge.Methods: The study was carried out in low income settlements in Nakuru, a secondary city in Kenya. Over half the population in Nakuru live in low income areas and majority of these residents use pit latrines. A case study design was selected for this study and data was collected using qualitative methods. Data was collected through In-depth interviews and Focus Group Discussions using in depth interview guide and focus group discussion guides that had questions on sanitation practices along the value chain, challenges, opportunities available, and recommendations for improvement. Analysis was done through content analysis by reading the transcripts multiple times to gain a sense of the flow of the discussion. Thereafter, coding was done by following emergent issues and thereafter categories were identified which formed the basis for providing a picture of FWM practices in the settlements.Results: On site sanitation facilities are dominant in the settlements, but they are few and are shared by several households. These facilities were unclean, and they filled up at a fast rate because of the high number of users. The latrines were emptied by manual emptiers who used mechanized equipment but complemented with manual emptying using buckets. Sludge was transported to a central collection point using large and small scale means of transportation, before transfer to the treatment site for final treatment and disposal. Various stakeholders are involved in capacity building of emptiers as well as in the transportation, treatment and disposal of fecal sludge in the settlements. Challenges along the stages of the value chain included negative community perceptions and attitudes toward fecal sludge management.Conclusion: The results highlight the need to address the challenges along the chain by involvement of state and non-state actors. Low income areas have high populations and thus contribute huge amounts of fecal sludge. Deliberate efforts to consolidate such data from low income areas will result in availability of data, and informed decision making for stakeholders at national and international levels.

Inhibition of ammonia and hydrogen sulphide as faecal sludge odour control in dry sanitation toilet facilities using plant waste materials

On-site dry sanitation facilities, although cheaper than wet sanitation systems, suffer from high malodour and insect nuisance as well as poor aesthetics. The high odour deters users from utilizing dry sanitation toilets as an improved facility leading to over 20% open defecation in Sub-Saharan Africa. To address this malodour concern, this study first assessed odour levels, using hydrogen sulphide (H2S) and ammonia (NH3) as indicators, on two dry sanitation facilities named T1 and T2. The potential of using biomass (sawdust, rice husk, moringa leaves, neem seeds), ash (coconut husk, cocoa husk) or biochar (sawdust, rice husk, bamboo) as biocovers to remove or suppress odour from fresh faecal sludge (FS) over a 12-day period was investigated. Results showed that the odour levels for H2S in both T1 (3.17 ppm) and T2 (0.22 ppm) were above the threshold limit of 0.05 ppm, for unpleasantness in humans and vice versa for NH3 odour levels (T1 = 6.88 ppm; T2 = 3.16 ppm; threshold limit = 30 ppm limit). The biomasses exhibited low pH (acidic = 5–7) whereas the biochars and ashes had higher pHs (basic = 8–13). Basic biocovers were more effective at H2S emission reduction (80.9% to 96.2%) than acidic biocovers. The effect of pH on suppression of NH3 was determined to be statistically insignificant at 95% confidence limit. In terms of H2S and NH3 removal, sawdust biochar was the most effective biocover with odour abatement values of 96.2% and 74.7%, respectively. The results suggest that biochar produced from locally available waste plant-based materials, like sawdust, can serve as a cost-effective and sustainable way to effectively combat odour-related issues associated with dry sanitation facilities to help stop open defecation.