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Contamination caused by microbial fecal pollution in water bodies is a serious problem in many countries, especially in low- and middle-income countries. Therefore, fecal source tracking is an important method used to understand the source of fecal contamination and to decrease the hazard of waterborne diseases that occurs in the environment. In this study, a human-associated genetic marker for Escherichia coli (H8) was used to investigate the source of fecal contamination in the Mae Klong River, Thailand. Real-time PCR was performed with this marker for 500 E. coli isolates collected from 10 sampling sites along the river, including MK10 (upstream) to MK1 (downstream). The results showed that the proportions of H8-positive isolates were 46, 14, 10, 18, 14, 38, 12, 26, 32, and 14% at MK10-MK1, respectively. All positive proportions were significantly different between the locations (p < 0.001). The higher occurrence of E. coli with H8 marker detection indicated that domestic wastewater was largely discharged without proper treatment, which is attributable to the high population and the absence of proper sewage treatment in those areas.

Sanitation facility conditions and waste disposal practices are hypothesized to affect the fecal contamination of drinking water and kitchenware. The present study aimed to examine the physical conditions of sanitation facilities and waste disposal locations as well as determine the concentrations of Escherichia coli in drinking water, cups, dishes, flies, toilet floors, and kitchen floors. A total of 336 samples were collected from 17 households in peri-urban Lusaka. Generalized linear mixed models showed that six out of seven physical pit-latrine conditions, waste disposal practices, and kitchen hygiene practices had significant effects on the contamination of either kitchenware or drinking water. The results highlighted that improving the physical pit-latrine conditions, dumpsite location, washing water, and kitchenware-drying location may potentially reduce fecal contamination of drinking water, cups, and dishes.

The world’s sanitation systems must be up to the challenge of addressing the global crises of water shortages and food insecurity in the face of a growing population. To help address these problems, ecological sanitation (Ecosan), which typically involve the use of urine-diverting dry toilets (UDDTs) and the application of excreta in agriculture, can be employed. This paper discusses the challenges and potentials of the Ecosan approach in terms of 3 essential requirements—continuous defecation use, reduction of health risk, and use of excreta—by examining 3 cases of Ecosan use in Vietnam and Malawi. The experience with traditional Ecosan in rural Vietnam suggests that dry sanitation practices that apply Ecosan are effective at reducing fecal contamination in the surrounding water environment, thereby reducing the health risk from unavoidable accidental ingestion of contaminants. However, current sanitization processes involving the application of manure to agricultural products represent a significant health risk challenge. The experience with modern UDDTs in rural Vietnam suggests that they can be continuously used for defecation for long periods of time without intervention, while there remain major challenges to continuous use from physical damage to the UDDT structures. The proper management of fecal chambers can successfully control the offensive odors that are a source of wide concern. In rural Malawi, the introduction of modern UDDTs successfully fostered a demand for the use of feces by raising the perception of its value in agriculture and through an integration of the Ecosan project into an agricultural technology transfer program. Urine use, by contrast, did not gain a wide acceptance, suggesting that raising an awareness of the effects of urine on agriculture is a key challenge. Thus, although some challenges still need to be overcome, 3 cases of Ecosan showed bright potentials of the Ecosan approach from the 3 essential requirement.

Globally, 2.8 billion people use on-site sanitation facilities, which need regular emptying of accumulated fecal sludge. Illegal dumping from informal emptying businesses, one of the major challenges in environmental management, is widely observed. Considering Mandalay, Myanmar, this study aimed to determine why informal emptying businesses are selected and estimate the lost revenue for a formal emptying service provider (FP) due to the informal businesses. We interviewed 400 households on their recognition and experiences regarding emptying services and willingness-to-pay for improved service. Revenue loss was estimated by comparing the present and theoretical maximum revenues. Results showed that 91.0% of households recognized FP only. Among 134 emptying-experienced households, 32.8%, 59.7%, and 4.5% chose FP with legal contact, FP with illegal contact, and informal service providers, respectively. The service fees from FP with illegal contact did not become revenue for FP; this was a major informal emptying business in the city. Differently from previous studies, the major illegal dumping was done by FP in this area. A great financial loss was estimated that FP lost 76.5% of the theoretical maximum revenue due to informal business. Logistic regression analysis indicated people’s intention to shorten the waiting time through illegal contact, even by paying a higher fee. As emptying services are typically required immediately after fecal sludge is over-accumulated, shorter waiting times and faster contact methods were the reasons why the informal business was selected. Less bureaucratic and more customer friendly system could reduce revenue loss, charge more, and increase profits.

In developing countries, many tons of valuable nutrients (mainly nitrogen (N) and phosphorus (P)) are lost as waste derived from daily life and agriculture. Nutrient load quantification is an early step for recognizing environmental pollution, and a basic requirement for planning environmental sanitation options. Material flow analysis (MFA) has been used in the environmental sector in many cities of developing countries. In Mandalay, under rapid urbanization, environmental problems have risen to an alarming level. In this study, a nitrogen and phosphorus flow model was developed with a focus on organic waste. The system boundary was five urban townships of Mandalay city and components included in the system were agriculture, livestock, industry, and household. Household surveys, and farmer, livestock owner and industry manager interviews were conducted along with collecting secondary data to develop the model. Results showed that 304 ton-N/year and 258 ton-P/year were discharged from household to the environment as food waste, excreta and greywater. Approximately 3, 200 ton-N from on-site sanitation were also annually released to the environment as toilet effluent/leakage and fecal sludge. Animal manure (83 ton-N/year and 16 ton-P/year) and market waste (456 ton-N/year and 71 ton-P/year) were also observed as losses of valuable resources. Applying nutrients from animal manure, fecal sludge, and organic solid waste in the agricultural sector can reduce the pollution load to the environment, and reduce the chemical fertilizer demand in the city.

This study investigated the occurrence of Escherichia coli pathotypes in sanitary wastewater and drinking water in a Bangladeshi urban slum and the potential associations between these sources. We examined 621 E. coli isolates from sanitary wastewater and stored drinking water by multiplex PCR and dual‐index sequencing, classifying them into eight pathotypes based on 14 virulence genes and additionally evaluating the possession of the human‐specific E. coli genetic biomarker H8. The proportions of pathogenic E. coli were significantly different (P < 0·001) between wastewater (18·6%) and drinking water (1·7%). StIb‐positive enterotoxigenic E. coli (ETEC) were predominant in wastewater, indicating that people in the site carried ETEC. In contrast, no ETEC was present in drinking water and the proportion of H8‐positive isolates was significantly smaller (7·8%) than that in wastewater (16·3%) (P = 0·001). Our findings indicate that sanitary wastewater from the slum was heavily contaminated with pathogenic E. coli, posing a great health risk. Furthermore, E. coli contamination of drinking water could be derived from not only human but also other sources.

Infectious disease transmission is frequently mediated by the environment, where people's movements through and interactions with the environment dictate risks of infection and/or illness. Capturing these interactions, and quantifying their importance, offers important insights into effective interventions. In this study, we capture high time-resolution activity data for twenty-five Vietnamese farmers during collection and land application of human excreta for agriculture. Although human excreta use improves productivity, the use increases risks of enteric infections for both farmers and end users. In our study, the activity data are integrated with environmental microbial sampling data into a stochastic-mechanistic simulation of E. coli contamination on hands and E. coli ingested. Results from the study include frequent and variable contact rates for farmers' hands (from 34 to 1344 objects contacted per hour per hand), including highly variable hand-to-mouth contact rates (from 0 to 9 contacts per hour per hand). The frequency of hand-to-mouth contacts was substantially lower than the widely-used frequency previously reported for U.S. Office Workers. Environmental microbial contamination data highlighted ubiquitous E. coli contamination in the environment, including excreta, hands, toilet pit, handheld tools, soils, surfaces, and water. Results from the simulation suggest dynamic changes in E. coli contamination on hands, and wide variation in hand contamination and E. coli ingested amongst the farmers studied. Sensitivity analysis suggests that E. coli contamination on hands and ingested doses are most influenced by contamination of handheld tools, excreta, and the toilet pit as well as by frequency of hand-to-mouth contacts. The study findings are especially relevant given the context: no farmers reported adequate storage time of human excreta, and personal protective mask availability did not prevent hand-to-mouth contacts. Integrating high time-resolution activ

Human and livestock waste, i.e., excreta, were intensively used in crop cultivation in Asia over the years. However, rapid economic growth induced changes in excreta management and subsequently in nutrient flow. In northern Vietnam, a large amount of excreta have been traditionally applied to paddy fields, but much of them are currently discharged to ponds for fish farming. This study investigated the historical changes in excreta management and clarified the impact of fish ponds on nutrient flow as a case study in an agricultural community of suburban Hanoi, Vietnam. A material flow model of nitrogen and phosphorus was applied to the study area. The results showed that the crop-livestock system that intensively used excreta for agriculture was transformed between 1980 and 2010 into the crop-livestock-fish system that discharges a significant amount of livestock excreta to fish ponds. Nutrients inputs to ponds were 41.7 kg-N/ha and 9.8 kg-P/ha in 2010, which were 7.2- and 6.2-fold higher than those in 1980, respectively. Beside, 41 % of nitrogen and 82 % of phosphorus released to ponds still remained in the sediment or discharged unintentionally after heavy rainfall. The use of pond sediment as a source of nutrients in paddy fields would improve the material cycle.

Recently, perfluorohexanoic acid (PFHxA), an emerging contaminant, has been detected at a high level in the water environment. Its possible presence in drinking water treatment process thus suggests that removal technique should be developed. In this study, one reverse osmosis (RO) membrane, two nanofiltration (NF) membranes and two ultrafiltration (UF) membranes were tested to reject PFHxA (100 - 300 ng/L) in pure water. The measured molecular weight cut-off (MWCO) of two NF membranes were as large as 10, 000 and 27, 000 Da, while they were still able to reject 96.3% and 95.3% PFHxA in pure water, respectively. This indicates PFHxA rejection rate was not dependent on the MWCO of membrane. Results also show that membrane with more negative zeta-potential tends to have higher rejection rate to PFHxA in pure water, suggesting that electrical repulsion between PFHxA and membrane might play an important role in PFHxA rejection. In conclusion, NF membranes would be a better option for removing PFHxA from drinking water than RO membrane because of their larger pure water permeability and NaCl transmission.

Nanofiltration was thought to be a good option for the recovery of perfluorohexanoic acid (PFHxA) from industrial wastewater. In this study, two commercially available nanofiltration (NF) membranes (NF 270 and NTR-7450) were tested to concentrate the PFHxA in aqueous solution. Filtration test was conducted in crossflow filtration mode. Membrane flux and PFHxA rejection rate were monitored throughout the filtration test. The impact of initial feed water pH on membrane performance was investigated. Results demonstrated that the two NF membranes showed different response to the change of initial feed water pH, which was caused by the intrinsic properties of membrane material. The flux performance of NF 270 was stable, while its rejection rate of PFHxA was very sensitive to the change of initial feed water pH. Opposite result was obtained with NTR-7450. It had a very good stability on rejection rate, while its flux was very sensitive to the change of initial feed water pH. The mechanisms behind these phenomena were also discussed. The results obtained in this study should be very useful for the process design in practical engineering.

Perfluorooctane sulfonate (PFOS) and perfluorooctanoic acid (PFOA) are two perfluorinated compounds (PFCs) used to produce everyday goods, including clothing, carpets, textiles, upholstery, paper, packaging and cleaning products. PFOS and PFOA belong to the class ofchemical contaminants known as persistent organic pollutants (POPs). They are particularly difficult to deal with once released into the environment because they do not break down easily, they can travel long distances in the air or water supply and they can accumulate in human and animal tissue. Scientists have linked these chemicals, which can be toxic for both humans and wildlife, with serious environmental and health risks. Researchers have reported PFC contamination in river, tap and bottled water in Japan, the US, Europe and in developing countries such as Thailand, Malaysia and Vietnam. Conventional treatment technologies do not remove PFCs effectively from our water supplies, compounding the problem. Some advanced methods have been found to be effective in treating PFOS and PFOA in the water environment. However, these technologies have yet to be applied on a large scale due to regulative and economical constraints on their development.