On-site Sanitation Research Articles

Raising Awareness for Sustainable Faecal Treatment Using Augmented Reality

Pit latrines—the simplest on-site sanitation system—have been extensively used in developing countries in Asia for a long time. However, pit latrines are pollution and health risk hotspots that can cause widespread contamination. It is preferable to upgrade them to septic tanks, which are more advanced, effective, and simple alternatives. This study encourages the transition from pit latrines to septic tanks by making people aware of the health and environmental risks associated with the use of pit latrines. As decisions about sanitation technologies are mostly made by individual households, it is important to find communication tools for the average household to understand the basic information to make informed decisions. To this end, this study used augmented reality as a communication tool. A survey was conducted with Sri Lankan households that use pit latrines, and experiments were carried out in a university laboratory in Japan. The use of augmented reality increased people’s understanding of the environmental and health risks of pit latrines. This understanding was retained for some time because people found the use of augmented reality ‘enjoyable’. Hence, our findings contribute to the promotion of the transition from pit latrines to septic tanks in low- and middle-income countries.

Critical review on on-site sanitation technologies: Typologies, treatment and transition towards circular economy.

Around 4.2 billion people globally depend on on-site sanitation systems, with 43% relying on basic or unsafe facilities with key challenges of containment, emptying, transport, treatment and resource recovery from faecal sludge. This review paper critically examines faecal sludge characteristics and treatment technologies in terms of urine diversion capability, land requirements and capital as well as operational expenditure based on Indian and international practices. Apart from these, the review also provides reuse-recycle of processed manure, treated effluent and bio-energy from faecal sludge to create environmental and economic benefits. The review also highlights future research on the development of nature-based solutions for solid-liquid separation and treatment, low footprints and on-site treatment for fostering a circular economy. Ultimately this review emphasizes the importance of advancing faecal sludge management to address global sanitation challenges and to create sustainable solutions for environmental protection.

Effluents from septic systems and impact on groundwater contamination: a systematic review.

Globally, 2.2 billion people rely on groundwater for their water supply, and 2.8 billion use onsite sanitation systems for their sanitation needs. Groundwater contamination from septic systems is a critical public health concern, linked with diseases related to water sanitation and hygiene. Despite the severe impacts of septic systems on groundwater quality, comprehensive global studies remain limited. This study conducted a systematic review of articles published between 2012 and 2023 on topics related to septic systems and groundwater contamination, and 82 peer-reviewed articles met the inclusion criteria. The review identified key contaminants, including E.coli, nitrate, Enterococcus spp., total coliform, ammonium, phosphate, chlorides, and pharmaceuticals. Research on microbial indicators is more prevalent in Africa, while research on nutrients is common in North America. Research on organic contaminants including polyfluoroalkyl substances (PFAS), pharmaceuticals, and personal care products (PCPPs) is limited, particularly in low-and middle-income countries. Critical factors contributing to groundwater contamination include soil, hydrogeological conditions, climate, septic system maintenance and functioning, and septic density. The goal of this study was to comprehensively assess the extent of groundwater contamination resulting from septic system effluents by identifying the major contaminants typically found in affected groundwater sources and exploring the factors contributing to contamination. Identifying the major contaminants and factors related to groundwater contamination from septic systems is crucial for developing effective management strategies to protect groundwater sources.

Persistence of respiratory, enteric, and fecal indicator viruses in fecal sludge from on-site sanitation in Dakar, Senegal

ABSTRACT As wastewater-based epidemiology (WBE) broadens to include prevalent diseases with significant global health impact, existing surveillance systems concentrate on sewer-based infrastructure, which excludes the 2.7 billion people using non-sewered systems. To address this gap, our study explores the potential of fecal sludge treatment plants for WBE, emphasizing the stability of virus ribonucleic acid (RNA) targets within pooled fecal sludge. We screened fecal sludge from a centralized treatment facility in Dakar, Senegal for Severe Acute Respiratory Syndrome (SARS)-CoV-2, human norovirus, and microbial source trackers pepper mild mottle virus and tomato brown rugose fruit virus (ToBRFV). Decay kinetics of viral genomic RNA markers were examined at 4, 15, and 30 °C over 70 days. Results indicate the high persistence of viral targets in fecal sludge (T90 value of 3.3 months for exogenous SARS-CoV-2 N1 and N2 and 6.2 months for ToBRFV), with all targets detected throughout the 70-day experiment under various temperatures with limited decay (<90% reduction). This study improves our understanding of virus persistence in on-site sanitation systems by providing essential decay rate constants for effective target detection. Our results indicate that sampling at centralized facilities treating fecal sludge from on-site sanitation could facilitate localized pathogen surveillance in low-income settings.

Assessment of Sanitation Services and Practices among Local Community in West B Municipality in Zanzibar Island, United Republic of Tanzania

Good basic sanitation services and practices are essential in maintaining generally accepted standards for personal hygiene and public health. The objective of this paper is to assess the sanitation services and practices among the local community in West B Municipality in Zanzibar Island, United Republic of Tanzania. The study uses a cross-sectional study design. Raosoft online sample calculator was used to determine the sample size while systematic random sampling was applied to select the respondents. Results show that a substantial proportion of the community uses on-site sanitation systems by which excreta and wastewater are collected and stored in containments within the vicinity, requiring emptying when full. Many toilets have security issues as they lack privacy and user comfort. About 28.8% have unlockable doors, 21.2% have fixed clothing curtains and 3.8% are completely open. In the area, Indian-type squat toilets are dominant (78.75%), followed by traditional pit latrines (20%). A slightly large percentage (55%) of households use motorised but the remaining percentage (45%) use non-motorised means of emptying and transportation. The study further found limited or ineffectual use of Personal Protective Equipment (PPE) among the sludge workers, thus risking their health and safety. The conveyed sludge waste is usually taken to a designated treatment plant, disposed of in excavated pits or dumped openly in the forest. This implies that sanitation services and practices in West B are inadequate, leading to disease transmission due to environmental pollution. The study recommends compliance with standards and guidelines, awareness and advocacy, technological innovations, stakeholder involvement and research and development on sanitation services and practices.

Onsite sanitation systems and contamination of groundwater: A systematic review of the evidence for risk using the source-pathway-receptor model

Onsite sanitation systems and contamination of groundwater: A systematic review of the evidence for risk using the source-pathway-receptor model

Indicators to complement global monitoring of safely managed on-site sanitation to understand health risks

Halfway through the Sustainable Development Goal (SDG) period, there has been little research on the criteria for monitoring safely managed sanitation under SDG target 6.2. For reporting against SDGs, global indicators are necessarily limited and exclude many safety aspects from a public health perspective. Primary survey data from 31,784 households in seven countries in Asia and Africa were analysed, comparing estimates of safely managed on-site sanitation based on global indicators with five complementary indicators of safety: animal access to excreta, groundwater contamination, overdue emptying, entering containments to empty and inadequate protection during emptying. Application of additional criteria reduced the population with safely managed sanitation by 0.4–35% for specific indicators, with the largest impact due to the risk of groundwater contamination, animal access, and containments overdue for emptying. Combining these indicators across the service chain, excluding transport and treatment, found almost three-quarters of on-site systems currently assessed as safely managed with global indicators were considered unsafe based on complementary indicators. A more comprehensive assessment of safety of on-site sanitation can be achieved through these indicators, which could be integrated into national monitoring systems and used to inform sanitation investments that address local health-related risks.

Microbiome and antibiotic resistome in bioelectrochemical toilets for onsite treatment of fecal sludge

Effective management of fecal sludge (FS) is essential for preventing environmental and public health risks. Developing safe and efficient FS treatment technology is crucial for reducing the health risks of onsite sanitation systems. In this study, bioelectrochemical toilets (BETs) were developed to treat FS onsite. Compared with the open-circuit BETs (OC-BETs), BETs exhibited higher removal efficiencies for total organic carbon, total nitrogen, and total phosphorus. Specifically, the enhancements in removal efficiencies were 18.82 ± 1.73 %, 7.28 ± 0.32 %, and 11.41 ± 0.05 % for urine, and 19.28 ± 4.08 %, 21.65 ± 1.23 %, and 24.68 ± 0.95 % for feces, respectively. Microbiome analysis indicated that the dominant populations were affiliated with electroactive bacteria (Desulfuromonas and Pseudomonas) in the electrode biofilm of BETs. The species co-occurrence network showed that the electrode biofilm microbiome in BETs had more complex correlations than that in OC-BETs, suggesting that a weak electrical current enhanced the microbiome stability. The relative abundance of antibiotic resistance genes in BETs and OC-BETs reduced by 59.85 ± 1.32 % and 53.01 ± 2.81 % compared with the initial FS, respectively. These findings indicate that BETs are an alternative system for enhancing onsite treatment of fecal sludge and provide a theoretical foundation for the implementation of BETs.

Yard phytoarchitecture for onsite sanitation of household wastewater containing copper

Copper can be found in various equipment, building materials, and consumer products. When buildings are used, copper can enter wastewater in different ways. It is challenging for occupants to remove copper physically or chemically since they can potentially reduce copper levels through yard phytoarchitecture. This study aims to formulate houseplants' suitability to become decorative plants for the yard phytoarchitecture, simultaneously as onsite sanitation. This study identified the copper deconcentration pathway in wastewater by studying published works-based research. Literature was collected and selected based on recency, accessibility, and the relationship among copper, wastewater, and plants. The study findings show that processing copper by plant has the greatest opportunity to be implemented on a building scale. The yard phytoarchitecture system involves arranging plants in the yard, which serves both as a decorative feature and a way to treat the building's wastewater. It can be used on dry yards or ponds and only requires a small amount of land. The plants used should have low leaf density and high root density. It plays a dual role consisting of onsite sanitation infrastructure and yard aesthetics, which mutually strengthen the environmental health locally and positively effect on a larger scale.

Comparative life cycle assessment of excreta management systems through composting and biomethanization: Case of a low-income tropical country.

Low-income tropical regions, such as Haiti, grapple with environmental issues stemming from inadequate sanitation infrastructure for fecal sludge management. This study scrutinizes on-site sanitation systems in these regions, evaluating their environmental impacts and pinpointing improvement opportunities. The focus is specifically on systems integrating excreta valorization through composting and/or anaerobic digestion. Each system encompasses toilet access, evacuation, and sludge treatment. A comparative life cycle assessment was undertaken, with the functional unit managing one ton of excreta in Haiti over a year. Six scenarios representing autonomous sanitation systems were devised by combining three toilet types (container-based toilets (CBTs), ventilated improved pit (VIP) latrines, and flush toilets (WC)) with two sludge treatment processes (composting and biomethanization). Biodigester-based systems exhibited 1.05 times higher sanitary impacts and 1.03 times higher ecosystem impacts than those with composters. Among toilet types, CBTs had the lowest impacts, followed by VIP latrines, with WCs having the highest impacts. On average, WC scenarios were 3.85 times more impactful than VIP latrines and 4.04 times more impactful than those with CBTs regarding human health impact. Critical variables identified include the use of toilet paper, wood shavings, greenhouse gas emissions, and construction materials.

Option of last resort or pragmatic solution? Social perspectives on onsite wastewater treatment systems in northern Argentina

ABSTRACT The unplanned and rapid expansion of metropolitan areas reduces accessibility to existing and often outdated centralized water and wastewater systems. In this context, sanitation policies that focus exclusively on centralized systems become expensive and unfeasible. Using Q methodology, we identified three different social perspectives on onsite wastewater treatment systems (OWTS) in the metropolitan area of the Lerma Valley in northern Argentina. We focused our analysis on the legal, environmental, and technical aspects of onsite sanitation. The perspectives found were: ‘OWTS have advantages’, ‘Hard path for sewerage’, and ‘Process before technology’. We describe the perspectives identified and we provide an analysis of their differences and similarities to discuss their possible policy implications for our study area and comparable regions in the country and beyond.

Anthropogenic Gadolinium Anomalies in an Alluvial Plain with On-site Wastewater Treatment Systems in Campinas, SP, Brazil

Gadolinium anomalies have become a well-established marker for the pollution caused by wastewater, but there is not yet a standardized method to estimate the anomaly. Here, we compare four different published equations, distinct threshold values and reference normalizing values to estimate Gd anomalies by applying them to the results of a hydrochemical investigation in an alluvial aquifer with on-site sanitation systems. We measured traditional wastewater markers (such as electric conductivity, NO3_N, NH4–N, Cl-) and REE in groundwater samples collected from hand-dug wells in two seasons. The ratios of Gd normalized measured concentrations to Gd normalized geogenic concentrations (GdSN/Gd*) estimated with the various methods ranged from 0.7 to 2.8. It turned out that the choice of the equation and the threshold value can affect the decisions about anthropogenic pollution’s occurrence (or not). The normalizing values did not play a significant role in the decision. Based on measurement uncertainties and on the interpretation of hydrogeological conditions in the study area, a threshold value of 1.3 for defining anthropogenic Gd anomalies was deemed adequate for the study area. The occurrence of Gd anomalies higher than 1.8 in two wells, one in each season, reinforces the hypothesis that the groundwater is contaminated by the on-site sanitation systems in the study area, as intermittent detection of anthropogenic Gd is a characteristic of this pollution source.

Septic tank usage and its faecal sludge management in Cuenca, Ecuador

ABSTRACT On-site sanitation systems such as septic tanks are widely used for treating domestic wastewater in urban and rural areas which lack sewage systems. However, a large portion of these systems do not properly treat human excreta. A main challenge to improve this is the absence of comprehensive data regarding the usage, emptying and maintenance. In this study, records of septic tank desludging frequency during 2009–2022 and the sewerage coverage updated to 2022 were used to investigate their spatial and temporal utilisation, and the persistence of septic tank usage in areas with sewer networks and uncover the current state of Faecal Sludge Management in Cuenca, Ecuador. The spatial behaviour revealed that OSSs are still in use besides the presence of a sewer network. In 2022, there were 109 septic tanks in urban areas with 14.7% in sectors with sewerage service. In rural areas, 469 septic tanks were recorded with 7.8% situated in areas with sewer networks. Although there is no specialised infrastructure in place for the treatment and disposal of faecal sludge, the city has effectively managed it with the existing sanitation facilities. This assessment contributes to the formulation of a secure framework for a safely managed sanitation.

Effects of Climate Change-Induced Flooding on Onsite Sanitation Services: A Case Study of Kanyama, Compound in Lusaka, Zambia

The study underscores the absence of a comprehensive assessment of flooding effects on onsite sanitation systems in Kanyama, exacerbating existing issues like inadequate facilities, poor maintenance, and improper waste management. Conducting both qualitative and quantitative methods, the research engaged 210 respondents from six wards in Kanyama, using systematic random sampling for households and purposive sampling for key informants. Employing predictive models (Root Mean Square Error and R-squared values) in SPSS Version 22, the findings revealed negative effects on onsite sanitation systems, including contamination of water, infrastructure damage, and overflowing of pit latrines/septic tanks. Key statistics include 68% of respondents witnessing temperature changes, 63% understanding climate change, and 73% acknowledging changes in rainfall patterns. For flooding, 72% observed increased floods, with a statistical analysis yielding R-squared values of 0.431, 0.427, and 0.373 for water contamination, infrastructure damage, and overflowing of pit latrines/septic tanks, respectively. These values represent the percentage of variation explained by flood-related variables. Chi-squared statistics values of 234.16, 214.564, and 152.132 highlight a significant effect of flood-related variables on observed outcomes. Qualitative data identified themes such as awareness of climate change effects, diverse beliefs, varying community awareness, and the need for tailored education. The study proposed a Sustainability model, emphasizing drainage systems, awareness campaigns, infrastructure development, waste management, and partnerships to enhance community resilience against climate change-induced flooding

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.

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.

A Landlord/lady Perspective on Emptying and Transportation of Faecal Sludge in informal settlements of Eldoret town, Uasin Gishu County, Kenya

Emptying, transportation and disposal of faecal sludge in informal settlements of Eldoret Kenya is still a big challenge. This study aimed to identifying actors and factors determining emptying costs and constraints limiting improvement in service provision with the use of a questionnaire and a review of secondary data. A total of 35 respondents were issued questionnaires. The data showed that most of the households were using septic tanks as the preferred method of Onsite Sanitation Systems (OSS). The study also noted that there were no price regulations for faecal sludge emptying services. Through the study, it was found that the private exhausters were charging the customers exorbitantly and there was a need to create a regulatory framework to manage the costs. It was also found that due to the high-water table within the environs of Eldoret and Uasin Gishu County at large, there was a risk of groundwater contamination, especially for the neighbors who solely depended on water from their wells for their daily household use. It was established that the emptying charges were directly proportional to the capacity of the exhauster and the haulage distance to the wastewater treatment plant. In summary, the paper recommends adequate allocation of funds, the involvement of all key stakeholders, the creation of awareness and education in the FSM and the creation of a legal framework or policy governing the management and disposal of FS as we move towards the realization of SGD 6.

Sanitation in urban areas may limit the spread of antimicrobial resistance via flies.

Synanthropic filth flies are common where sanitation is poor and fecal wastes are accessible to them. These flies have been proposed as mechanical vectors for the localized transport of fecal microbes including antimicrobial resistant (AMR) organisms and associated antimicrobial resistance genes (ARGs), increasing exposure risks. We evaluated whether an onsite sanitation intervention in Maputo, Mozambique reduced the concentration of enteric bacteria and the frequency of detection of ARGs carried by flies collected in household compounds of low-income neighborhoods. Additionally, we assessed the phenotypic resistance profile of Enterobacteriaceae isolates recovered from flies during the pre-intervention phase. After fly enumeration at study compounds, quantitative polymerase chain reaction was used to quantify an enteric 16S rRNA gene (i.e., specific to a cluster of phylotypes corresponding to 5% of the human fecal microflora), 28 ARGs, and Kirby Bauer Disk Diffusion of Enterobacteriaceae isolates was utilized to assess resistance to eleven clinically relevant antibiotics. The intervention was associated with a 1.5 log10 reduction (95% confidence interval: -0.73, -2.3) in the concentration of the enteric 16S gene and a 31% reduction (adjusted prevalence ratio = 0.69, [0.52, 0.92]) in the mean number of ARGs per fly compared to a control group with poor sanitation. This protective effect was consistent across the six ARG classes that we detected. Enterobacteriaceae isolates-only from the pre-intervention phase-were resistant to a mean of 3.4 antibiotics out of the eleven assessed. Improving onsite sanitation infrastructure in low-income informal settlements may help reduce fly-mediated transmission of enteric bacteria and the ARGs carried by them.

Improved Child Feces Management Mediates Reductions in Childhood Diarrhea from an On-Site Sanitation Intervention: Causal Mediation Analysis of a Cluster-Randomized Trial in Rural Bangladesh

BackgroundThe WASH benefits Bangladesh trial multi-component sanitation intervention reduced diarrheal disease among children < 5 years. Intervention components included latrine upgrades, child feces management tools, and behavioral promotion. It remains unclear which components most impacted diarrhea.MethodsWe conducted mediation analysis within a subset of households (n = 720) from the sanitation and control arms. Potential mediators were categorized into indicators of latrine quality, latrine use practices, and feces management practices. We estimated average causal mediation effects (ACME) as prevalence differences (PD), defined as the intervention’s effect on diarrhea through its effect on the mediator.ResultsThe intervention improved all indicators compared to controls. We found significant mediation through multiple latrine use and feces management practice indicators. The strongest mediators during monsoon seasons were reduced open defecation among children aged < 3 and 3–8 years, and increased disposal of child feces into latrines. The strongest mediators during dry seasons were access to a flush/pour-flush latrine, reduced open defecation among children aged 3–8 years, and increased disposal of child feces into latrines. Individual mediation effects were small (PD = 0.5–2 percentage points) compared to the overall intervention effect but collectively describe significant mediation pathways.DiscussionThe effect of the WASH Benefits Bangladesh sanitation intervention on diarrheal disease was mediated through improved child feces management and reduced child open defecation. Although the intervention significantly improved latrine quality, relatively high latrine quality at baseline may have limited benefits from additional improvements. Targeting safe child feces management may increase the health benefits of rural sanitation interventions.

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.