Fecal Coliform Concentrations Research Articles

Treating Waste with Waste: Activated Bauxite Residue (ABR) as a Potential Wastewater Treatment.

Bauxite residue (or red mud) is a highly alkaline waste generated during the extraction of alumina. As a result of the substantial accumulation of bauxite residue in tailings facilities, there is a growing interest in exploring the potential for reusing this material for other purposes. The main objective of this study is to evaluate the use of activated bauxite residue (ABR) for remediating oil sands process-affected water (OSPW) and as a supplement to municipal wastewater treatment through bench-scale, proof-of-concept studies. The ABR is produced through a reduction roasting process that alters the physicochemical properties of bauxite residue, resulting in the generation of potentially effective adsorbent media. The treatment performance via chemical and biological activity removals (cytotoxicity, estrogenicity, and mutagenicity) was also assessed. For OSPW, ABR treatment resulted in the effective removal of recalcitrant acid-extractable organics (AEOs), with kinetics following the pseudo-second-order and comparable adsorption capacity to other waste materials (e.g., petroleum coke). ABR also effectively reduced the estrogenicity and mutagenicity of OSPW, albeit cytotoxicity increased at higher dosages, possibly due to some components leaching out of the material (e.g., metals). For municipal wastewater, ABR treatment reduced fecal coliform concentrations (>99%), total phosphorus (up to 98%), total ammonia-nitrogen (63%), estrogenicity (nondetectable), and mutagenicity (nondetectable), especially in the primary effluent. The ultimate end use of ABR is for the recovery of valuable metals (especially iron) and as a construction material, but additional work is needed to optimize the dosage (currently in the g/L range) and maximize the use of ABR as an adsorbent prior to its subsequent uses.

Salinity and microbiological risk assessment in surface runoff and main tributaries to La Vega Dam in Teuchitlán, Jalisco, Mexico.

Objective: This research aimed to evaluate the water quality of the main tributaries to the La Vega Dam for irrigation purposes through the physicochemical and microbiological parameters. Design/methodology/approach: The 10 main tributaries to the La Vega Dam were selected. The variables evaluated were pH, Temperature, Electrical Conductivity, Total Dissolved Solids and Dissolved Oxygen, boron calcium, magnesium, sodium, SAR, and RCS. Results: 50% of samples presented low sodicity risk, 10% medium risk, 20% and 20% very high risk. In the CSR results, only one site (10%) presented a low risk, and the remaining four tributaries (40%) of this area presented a medium risk. Five sites (50%) located east of the dam presented a high risk. Also, high boron concentration was observed, corresponding to El Salado River. Fecal pollution was detected in 100% of sites, limiting their use as irrigation water. Limitations on study/implications: Continuous water quality monitoring of the main tributaries to and into La Vega Dam should be followed up. Findings/conclusions: The most significant contribution of contamination to the dam was observed in the eastern part, with the entrance of El Salado River. High concentrations of boron were also observed. A high concentration of total and fecal coliforms was also found, in addition to the presence of Pseudomonas spp., which indicates fecal contamination. The effluent at the east of La Vega Dam is unsuitable for irrigation.

Analysis of Spatiotemporal Variation and Driving Factors of Water Quality in the Xiangjiang River Basin from 1990 to 2016

In order to explore the spatiotemporal variation characteristics and driving mechanism of water quality in the Xiangjiang River Basin, the data of 16 water quality parameters at 113 stations over 26 years from 1990 to 2016 in the Xiangjiang River Basin were collected for synthetically assessing the water quality and identifying its main pollutants through the water quality index and other methods. The causal mechanism of water quality, especially the driving effect of water level and land use pattern, was analyzed. The results showed that： ① The overall water quality grade of the Xiangjiang River Basin during the study period was "good." However, the water quality deteriorated first （from 1990 to 2003） and then improved （from 2004 to 2016）. The season variation in water quality was not obvious, but the water quality fluctuation of the wet season was larger. The water pollution load of the main stream decreased successively from the middle reaches, downstream reaches, and upstream reaches. The upstream tributaries had the best water quality, whereas areas with poor water quality were mainly distributed at the mouth of the middle and downstream tributaries, especially in areas where multiple tributaries converged. ② Toxic heavy metals had the characteristics of toxicity, persistence, and bioaccumulation. If they exceeded a certain concentration in water, they were difficult to purify, posing great harm to the natural environment and human health. The toxic metal index （CI1） was the leading factor affecting water quality, in which Hg and Cd were the main parameters affecting the overall water quality of the Xiangjiang River Basin. ③ The water level had a positive impact on the water quality of the Xiangjiang River by diluting environmental parameters. Land type had little effect on heavy metal concentration, whereas forest land could improve water quality. Grassland had a negative correlation with permanganate index over a large scale range （≥ 5 km）. The increase in water bodies, arable land, and impermeable surface areas within the watershed increased the probability of high fecal coliform concentration in the water body. ④ With the increase in buffer distance, the water quality explained by the land use pattern increased. On the scale of 10 km buffer zone in the riparian zone, the explanation degree by land use pattern on water quality was the highest, which was an effective scale for water quality control of the Xiangjiang River. This research showed that the driving factors of heavy metal pollution and other pollution were different, but their regional differences were all obvious in the Xiangjiang River Basin. Therefore, pollution control should be classified and taken according to local conditions.

Monitoring microbial safety and evaluation of removal efficiency from drinking water in Ahvaz, Iran

The availability of potable water sources is vital worldwide. Due to the potential for microbial contamination, developing nations focus more research on the existence of microorganisms that are indicators in water than they do on chemical presence. This study was done in order to assess the microbial level of drinking water in Ahvaz city. In this descriptive-cross-sectional study, the measure the microbial tests, two culture mediums, MacConkey broth, and green lactose broth, were used for possible and confirmatory culture respectively. Bioindicators measured in drinking water included fecal coliform and total coliform. Not only the residual chlorine concentration was also measured, but its relationship with bioindicators was also calculated by Spearman's correlation test. Result of this study showed that, the maximum total coliform concentration reported is between 2021 and 2022 (1600 MPN/100 ml). Based on result of this study the average concentration of fecal coliform in 2019, 2020, 2021, and 2022 were 11.88, 10.66, 7.78, and 6.11 MPN/100 ml respectively. The average annual concentration of total coliform and fecal coliform in four years was 28.95 and 9.32 MPN/100 ml, respectively. According result of this study, the Karun River, Ahvaz's main drinking water source, is contaminated by surface water runoff, old facilities, and unfiltered discharge of different wastewater kinds from factories, farms, and communities in Khuzestan.

Intelligent dosing of sodium hypochlorite in municipal wastewater treatment plants: Experimental and modeling studies

Sodium hypochlorite (NaClO), a disinfectant extensively employed in municipal wastewater treatment plants (WWTPs), is frequently overdosed to ensure qualified effluent quality consistently. In light of the escalated disinfectant expenses and detrimental environmental impacts, it is critical to have a precise control model in place to enable intelligent dosing of NaClO. The lack of real-time disinfection evaluation indicators presents difficulties in precisely and swiftly regulating the dosage. Herein, the CT value (the product of residual chlorine concentration and contact time) was initially determined experimentally as a metric for assessing disinfection in municipal WWTPs. Fecal coliform (FC) concentrations become less than 1.0 × 103 MPN/L when the effluent CT value is regulated at 0.20 mg·min/L (calculated as Cl2). In addition, a model employing long short-term memory (LSTM) was developed to predict the dosage, utilizing simplified and suitable parameters such as COD, NH3-N concentration, flow rate, and historical dosage of NaClO as input factors, which demonstrated satisfactory performance (R2 = 0.948). Notably, dosage adjustments were made concurrently in response to CT value feedback. The intelligent dosing model under simultaneous feedforward and feedback control was applied at a full-scale WWTP for nearly two months, considerably reducing disinfectant consumption and meeting the discharge standard of FC.

Assessing the utility of shellfish sanitation monitoring data for long-term estuarine water quality analysis

Regular testing of coastal waters for fecal coliform bacteria by shellfish sanitation programs could provide data to fill large gaps in existing coastal water quality monitoring, but research is needed to understand the opportunities and limitations of using these data for inference of long-term trends. In this study, we analyzed spatiotemporal trends from multidecadal fecal coliform concentration observations collected by a shellfish sanitation program, and assessed the feasibility of using these monitoring data to infer long-term water quality dynamics. We evaluated trends in fecal coliform concentrations for a 20-year period (1999–2021) using data collected from spatially fixed sampling sites (n = 466) in North Carolina (USA). Findings indicated that shellfish sanitation data can be used for long-term water quality inference under relatively stationary management conditions, and that salinity trends can be used to investigate management-driven bias in fecal coliform observations collected in a particular area.

Space-temporal analysis of groundwater quality in three areas of the state of Yucatán, México, and its relationship with existing anthropogenic activity.

Groundwater in the Yucatan State is the only source of water. The karst aquifer in Yucatan is vulnerable to pollution. Anthropic activities in Yucatan, such as pig farming, are usually related to high wastewater discharges and water pollution. Administrative and logistical issues in developing on-site sampling to evaluate water quality are common in Mexico. The RENAMECA database provides official data related to groundwater quality. However, no analysis based on this database has been reported. A groundwater quality evaluation based on five reference pig farms and the effect of spatial and temporal anthropic activities in the study area was developed. Eighteen wells based on their location concerning the selected pig farms were studied. On-site sampling and laboratory analysis of the supply water and wastewater in the study case farm were done. Fecal coliforms (FC) values (maximum 2850 MPN [100mL] -1) in most cases for supply water wells exceeded the allowed limit by NOM-127-SAA1-2021. The year of monitoring was significant (P < 0.05) on FC concentrations. Population density and the proximity of wells to population centers affect negatively the presence of total dissolved solids (TDS) and total nitrogen (TN). TDS (maximum value 2620mg L -1) and phosphorus presence could be related to agricultural activities, human settlements, and local aquifer conditions. A local wastewater treatment issue is evident. Groundwater is not quality for consumption without treatment. Regarding the issues in on-site water monitoring, database analysis provides an approximation of the real situation of groundwater quality.

Enhancing pollutant removal efficiency in urban domestic wastewater treatment through the hybrid multi-soil-layering (MSL) system: A case study in Morocco.

This paper evaluates the performance and potential of a full-scale hybrid multi-soil-layering (MSL) system for the treatment of domestic wastewater for landscape irrigation reuse. The system integrates a solar septic tank and sequential vertical flow MSL and horizontal flow MSL components with alternating layers of gravel and soil-based material. It operates at a hydraulic loading rate of 250 L/m2/day. Results show significant removal of pollutants and pathogens, including total suspended solids (TSS) (97%), chemical oxygen demand (COD) (88.57%), total phosphorus (TP) (79.93%), and total nitrogen (TN) (88.49%), along with significant reductions in fecal bacteria indicators (4.21 log for fecal coliforms and 3.90 log for fecal streptococci) and the pathogen Staphylococcus sp. (2.43 log). The principal component analysis confirms the effectiveness of the system in reducing the concentrations of NH4, COD, TP, PO4, fecal coliforms, fecal streptococci, and fecal staphylococci, thus supporting the reliability of the study. This work highlights the promising potential of the hybrid MSL technology for the treatment of domestic wastewater, especially in arid regions such as North Africa and the Middle East, to support efforts to protect the environment and facilitate the reuse of wastewater for landscape irrigation and agriculture.

Modeling climate change effects on transport and fate of pathogens in an urban coastal area of Lake Michigan

Abstract Infrastructure renewal and public health efforts require prediction of climate change effects on the occurrence of pathogens in the Great Lakes' urban coastal waters. This paper presents an investigation that addressed the climate change effects on transport and the fate of bacteria in Milwaukee's urban coastal area. This investigation was part of a study on climate change risks and impacts that included downscaling of climate change data for meteorological stations around Lake Michigan, and implementation of a hydrologic model that predicts tributary flows and bacteria loads. A method to select scenarios appropriate to link watershed and lake transport processes is presented. For the watershed, the sensitivity of bacterial loads with respect to changes in spring-season precipitation and air temperature is critical, while for lake transport, the most important driver is the wind field. Watershed and lake processes are linked by using spring-season watershed loading in the simulation of coastal transport. Scenarios for hydrodynamic modeling were developed by selecting climate projections that yielded high-and-low percentile projected spring-season wind speed. The patterns of bacteria transport showed significant changes under climate change conditions, and the changes in fecal coliform concentration at critical locations were explained by changes in current vector fields.

Spatio-temporal dynamics of ecological, bacteriological, and overall water quality of the Damodar River, India.

Assessing river water quality is crucial for human and ecological needs because of the deterioration of the river and escalated water pollution under the threats of anthropogenic activities. In order to assess river water quality, the Damodar River water was evaluated from the perspectives of spatio-temporal dynamics of ecological (organic pollution index or OPI and eutrophication index or EI), bacteriological (coliform count and comprehensive bathing water quality index or CBWQI), and overall water quality assessments (water quality index or WQI and comprehensive pollution index or CPI). The OPI reveals that 44.66% of water samples have heavy organic pollution; however, EI depicts that almost all water samples of Damodar River have severe eutrophication, especially in the pre- and post-monsoon seasons. Moreover, the fecal coliform count and CBWQI indicate the unsuitability of river water for bathing. The overall WQI portrays that 21.56%, 33.59%, and 22.47% of water samples have heavy pollution in pre-monsoon, monsoon, and post-monsoon, respectively. Moreover, 73.39% of water samples have low CPI indicating slight comprehensive pollution. This study also reveals that the pollution level in the Damodar River downstream of the Durgapur barrage is high among the other stations. The major reasons behind the severe contamination of Damodar River water are urban-industrial and agricultural effluents mixing into the river that lead to higher concentrations of BOD, DO, fecal coliform, COD, fluoride TSS, and turbidity in the river water. Thus, this study carries appreciated information on policy recommendations for the different stakeholders of the Damodar River basin including regional planners, agri-engineers, and ecological river engineers for sustainable river management.

Alternativa para el incremento de la actividad enzimática y liberación de azúcares en residuos sólidos orgánicos durante un proceso de degradación aerobia

The impact of inoculum (mature compost) was assessed in an aerobic system for the rapid degradation of organic solid waste, with a focus on the release of reducing sugars. Isothermal (35 and 55 °C) and non-isothermal (35-55 °C) treatments were conducted. Key indicators, including the rate of oxygen consumption (O2) and carbon dioxide production (CO2), were measured to assess microbial activity. Additionally, the concentration of reducing sugars, pH, enzymatic activity, and the presence of pathogens were evaluated. Treatments with inoculum at 35 °C and without inoculum at 55 °C exhibited an increase in oxygen consumption and CO2 production, indicating heightened microbial activity and, consequently, greater mineralization of organic matter. The treatment without inoculum at 35-55 °C presented the highest concentration of reducing sugars (160 mg/g dry weight), suggesting its potential as a pretreatment for bioconversion processes aimed at generating value-added products. At a temperature of 55 °C, there was a reduction of 84.4, 87.28, and 67.33 % in the concentrations of fecal coliforms, Escherichia coli, and parasites, respectively. This result suggests that elevated temperature contributes to the effectiveness of pathogen elimination.

A Comprehensive Assessment of Water Quality and Mass Balance of the Bhairab River, Khulna

Abstract: Water is a vital component for all organisms on Earth. Water is essential for the survival of all living organisms on Earth. Water is vital for life, much like oxygen, since no kind of life can survive without it. Water often includes several physical, chemical, and biological contaminants. Surface water sources mostly consist of rivers, lakes, ponds, glaciers, and precipitation. The sources are becoming degraded due to contemporary urbanization, escalating population, domestic trash, and industry. The Bhairab River is not far from the sick worry. The water quality of the area is rapidly deteriorating due to the significant influx of contaminants it gets. This research focuses on evaluating the water quality and mass balance of the Bhairab River. In order to achieve the current objective of the research, a stretch of 22.9 kilometers from Jailkhana Ferighat to Shuvorada Kheya Ghat, Fultola, was split into 10 sample sites. The water samples were collected monthly from each monitoring site during the year of 2021 for laboratory analysis. A total of nine water quality indicators, including Fecal Coliform, Temperature, Biochemical Oxygen Demand (BOD), pH, Turbidity, Total Solids (TS), Phosphate, Dissolved Oxygen (DO), Nitrate, and Chloride, were analyzed using standardized methods. The water quality evaluation was conducted by calculating the WQI using the National Sanitary Foundation (NSF) technique. The mass balance has been determined by means of analysis. The current study is being undertaken using both primary and secondary data sources. The investigation reveals that the primary parameters exhibit varying degrees of correlation with each other. In December, the temperature reached a minimum of 16.8 °C, while in May, it peaked at 37.5°C. The pH reached its peak at 8.80 in August, while it had its lowest point at 7.94 in January. The pH variation is minimal and similar throughout the board. The measured turbidity level was 564 NTU, which is the average value. The maximum total solids (TS) concentration recorded was 3346 mg/L, while the minimum concentration was 2460 mg/L. The phosphate content reached its peak at 8.12 mg/L in S5, while it was at its lowest at 4.26 mg/L in S4. The maximum nitrate concentration measured was 26.4 mg/L, while the minimum concentration was 12.80 mg/L. The maximum biochemical oxygen demand (BOD) recorded was 1.80 mg/L at location S6, whereas the minimum BOD was 0.60 mg/L at location S3. The concentration of BOD was consistently low during each month. The highest fecal coliform (FC) concentration observed in November was 1024 N/100ml, while the lowest concentration was 572 N/100ml. The drinking water quality standard for fecal coliform (FC) in Bangladesh is zero per 100 milliliters. The greatest, average, and lowest values surpass the allowable limit set by BDS. The water quality index determined for the year 2021 for Ten Stations has an average value of 43, indicating a similar level of water quality throughout the stations. According to the range of NSF water quality index, the Bhairab River has a poor quality rating. Therefore, this water is not safe for drinking without undergoing treatment. The Bhairab River has a Mass Balance value of 362349.09 gallons per day

Wastewater treatment by infiltration percolation process using fine sand and activated carbon

This study was conducted to find an efficient and inexpensive wastewater treatment system in poor regions and countries. For this purpose, two filtration systems were used to treat wastewater from a WWTP in Morocco, the first one is the intermittent sand filter (ISF) based on fine sand, and the second one is called the modified infiltration percolation (MIP) based on activated carbon. Physico-chemical and bacteriological analyses were carried out before and after passing the water through the filters. The results showed a significant decrease in the physicochemical parameters such as Suspended matter (SM) with an abatement rate of 99.6% for ISF and 99.4% for MIP, Chemical oxygen demand (COD) with an abatement rate of 17.7% for ISF and 55% for MIP, Biochemical oxygen demand (BOD5) with an abatement rate of 7.14% for the first filter, and a significant decrease with an abatement rate of 100% by MIP. These two filters decreased the concentration of fecal coliforms with a respective removal rate of 98.2% for ISF and 99% for MIP, except that this concentration exceeds the standards. The physicochemical analyses were within the norms, and the filtration systems showed an important efficiency, contrary to the bacterial load of coliforms which exceeded the standards. To this effect, another treatment is necessary to reduce the bacterial load of the wastewater.

Quantitative health risk assessment of microbial hazards from water sources for community and self-supply drinking water systems

In low and medium income countries (LMIC) drinking water sources (wells and boreholes) often contain a high number of pathogenic microorganisms, that can pose significant human and environmental health risks. In this study, a quantitative microbial risk assessment approach based on existing literature was conducted to evaluate and compare the quantitative health risks associated with different age groups using various drinking water supply systems. Results showed that both community-supply and self-supply modes exhibit similar levels of risk. However, the self-supply water source consistently showed higher risks compared to the community-supply one. Borehole water was found to be a more suitable option than well water, consistently showing between 5 and 8 lower health risks for E. coli and fecal coliform levels, respectively. The sensitivity analysis further showed the importance of prioritizing the reduction of E. coli concentration in well water and fecal coliform concentration in borehole water. This study offers a fresh perception on quantifying the impact of exposure concentration and age groups, shedding light on how they affect environmental health risks. These findings provide valuable insights for stakeholders involved in the management and protection of water sources.

Effect of dissolved ozone flotation thickening process on coliform bacteria and antibiotics simultaneous abatement: A pilot-scale study

This study focused on the removal of the total coliforms, fecal coliforms and four target antibiotics in the dissolved ozone flotation (DOF) thickening sludge process. Additionally, the thickened effluent chromaticity and its effect on thickened sludge hydrolysis process were investigated. Ozonation in the DOF process could inactivate coliforms by oxidizing cellular components and destroying genetic material, as well as altering the chemical structure of antibiotics, leading to the degradation of antibiotics. At an O3 dosage of 16 mg/g TS, the concentration of total coliforms and fecal coliforms decreased by 2.2 log and 2.4 log, corresponding to an overall removal rate of 99.4 % and 99.7 %, respectively. The total degradation rate of four target antibiotics (tetracycline (TC), oxytetracycline (OTC), norfloxacin (NOR), ofloxacin (OFL)) were 66.5 %, 68.8 %, 53.3 % and 57.5 %, respectively. The chromaticity removal rate of the thickened effluent reached 95 %. Analysis of fluorescence spectra indicated alterations in the fluorescence properties of dissolved organic matter, resulting in a decrease in fluorescence intensity by ozonation. The thickened sludge had higher hydrolysis rates, resulting in a greater production of volatile fatty acids (VFAs). This was mainly attributed to the increased amount of soluble protein and carbohydrate in the substrate after DOF treatment, which was more conducive for the rapid conversion of hydrolysis into VFAs during the initial stage. These results provided new ideas for upgrading and transforming the thickening process of wastewater treatment plants (WWTPs).

An Analysis of the Effects that South Africa’s Informal Settlements have had on the Country’s River Systems

The quality of surface water has a significant impact on human health and the entire ecological system. Sewer spillages from the surrounding informal settlements discharging into the river, carrying high concentrations of fecal coliforms, are one of the major causes of extreme pollution in the rivers of South Africa. These informal settlements are common in many developing countries, and they are usually located near waterways to compensate for basic demands for water, sanitation, and recreational space, where municipal infrastructure lags behind urban growth. One major problem has been poor sanitation and poor waste disposal practices in the informal settlements, which has led to the contamination of water resources. This study aims to assess the extent to which poor sanitation in informal settlements impacts the water quality of South African rivers, given the rapid rise in population and unemployment rate. The study also highlights health and environmental issues in the local regions caused by poor sanitation. Contamination of water bodies is associated with serious health problems and fatalities. Therefore, there is a need for frequent monitoring and management of waste products discharged into the neighboring aquatic environments.

Advanced steam explosion as thermal hydrolysis process for high solids anaerobic digestion and enhanced methane yield: Proof of concept

Sewage sludge management is one of the major issues faced by wastewater treatment plant (WWTP) operators. Though anaerobic digestion (AD) is one of the most preferred sludge management techniques, the complex microbial floc structure of the sludge creates physical and chemical barriers that limit the rate of microbial degradation resulting in a longer hydraulic retention time (HRT) of 25–30 days. The thermal hydrolysis process (THP) can be used as a pretreatment technique to enhance the rate of biodegradation which results in reduced retention time and increased methane yields. This work investigated the effects of the THP on the semi-continuous anaerobic digestion of high solids sludge (15% total solids, TS) obtained from a municipal wastewater treatment plant (WWTP) operating at higher solids retention time (SRT) of 40 days. The thermal hydrolysis process achieved the effective release of organics into the liquid phase resulting in 37% chemical oxygen demand (COD) solubilization. Two semi-continuous digesters, one fed with untreated sludge (control digester, 5% TS) to mimic the conventional anaerobic digester and the other fed with THP sludge (160 °C, 30 min, 6 bar, 10% TS) were operated under a mesophilic regime and a hydraulic retention time (HRT) of 15 days. The methane yield from the THP digester (0.366 ± 0.010 m3/kg VSadded, 70 ± 1.13% CH4) was 47% higher than the control digester (0.248 ± 0.013 m3/kg VSadded). The volatile solids removal (VSR) was 51 ± 0.6% in the THP digester, i.e., 43% higher over control digester (35.7 ± 1.3%). The fecal coliforms concentration in the digestate of control and THP digesters were 9200 and 200 MPN/g, respectively. Thus, the THP sludge meets the Class A biosolids criteria (<1000MPN/g). THP integrated anaerobic digestion achieved higher solids reduction with enhanced energy recovery, high solids loading with shorter retention time, and generated Class A biosolids.

Microbial hazards in real-world alternating dual-pit latrines treated with storage and lime in rural Cambodia

Abstract Achieving safely managed sanitation (SMS) in rural areas has spurred innovation in toilet designs that provide on-site treatment of fecal sludge (FS), including the development of International Development Enterprise (iDE)’s alternating dual-pit latrine upgrade (ADP). ADPs treat FS by inactivating pathogens using storage treatment with lime; however, ADPs’ reduction in pathogenicity (and thus their associated public health benefit) has not yet been described in real-world pits at scale. We thus enumerate the fecal indicator bacteria Escherichia coli (E. coli) and fecal coliforms in 147 pits after two years of storage treatment with lime and compare detected concentrations to relevant standards. E. coli and fecal coliform concentrations indicated a risk to human health in 31% and 42% of sampled pits, respectively. Regression models described relationships between fecal indicator bacteria concentrations and measured factors (e.g., sludge pH, temperature) but did not reveal any meaningful associations. High rates of pit ineligibility also indicate that many ADPs are not operated as recommended. Results indicate a one-in-three chance that a household emptying their own pit would be exposed to health hazards and call into question the effectiveness of the standard two-year storage treatment in real-world applications. To improve rural SMS, various evidence-based recommendations are made.

The Physico-Chemical and Bacteriological Characterization of Domestic Wastewater in Adétikopé (Togo, West Africa)

Wastewater represents a health risk for the population. For sanitary safety, it is important to know its physico-chemical and microbiological qualities in order to better understand the risks incurred by the population. The aim of this study was to analyze Adétikopé’s domestic wastewater from a microbiological and physico-chemical standpoint. Twelve wastewater samples were taken in Adétikopé from December 2022 to February 2023. Physico-chemical parameters were determined in accordance with AFNOR and the French NF standard. In microbiology, AFNOR was used as a reference for the detection of germs contaminating wastewater. Results were assessed in relation to European Union Criteria 98/83/EC. The wastewater analyzed has a pH close to neutral, with an average pH of 7.05. The pollutant load generated ranged from 32 mG/L to 201 mg/L for BOD5, from 660 mG/L to 900 mG/L for COD and from 408 mG/L to 2080 mG/L for suspended solids. The highest levels of germs were detected in the samples taken, with values of 68,000 CFU/100 mL and 47,000 CFU/100 mL for thermotolerant coliforms and fecal streptococci, respectively. The results show that fecal contamination originates from both animal and human sources. Concentrations of fecal coliforms and fecal streptococci are very high, far exceeding WHO guidelines. While a short-term solution would be to disinfect household sanitation systems on a daily basis, in the long term, the construction of collective sanitation systems, backed up by environmental education, remains a sustainable solution for the health and safety of populations.

Occurrence and removal of fecal bacteria and microbial source tracking markers in a stormwater detention basin overlying the Edwards Aquifer recharge zone in Texas.

The Edwards Aquifer is the primary water resource for over 2 million people in Texas and faces challenges including fecal contamination of water recharging the aquifer, while effectiveness of best management practices (BMPs) such as detention basins in mitigating fecal pollution remains poorly understood. For this study, the inlet and outlet of a detention basin overlying the aquifer's recharge zone were sampled following storm events using automated samplers. Microbial source tracking and culture-based methods were used to determine the occurrence and removal of fecal genetic markers and fecal coliform bacteria in collected water samples. Markers included E. coli (EC23S857), Enterococcus (Entero1), human (HF183), canine (BacCan), and bird (GFD). Fecal coliforms, EC23S857, and Entero1 were detected following each storm event. GFD was the most frequent host-associated marker detected (91% of samples), followed by BacCan (46%), and HF183 (17%). Wilcoxon signed rank tests indicated significantly lower outlet concentrations for fecal coliforms, EC23S857, and Entero1, but not for HF183, GFD, and BacCan. Higher GFD and BacCan outlet concentrations may be due to factors independent of basin design, such as the non-point source nature of bird fecal contamination and domestic dog care practices in neighborhoods contributing to the basin. Mann-Whitney tests showed marker concentrations were not significantly higher during instances of fecal coliform water quality criterion exceedance, except for E. coli, and that fecal coliform concentrations were not significantly different based on marker detection. Overall, results suggest that the detention basin is effective in attenuating fecal contamination associated with fecal coliforms and the general markers, but not for host-associated markers. Consequently, management efforts should focus on mitigating dog and bird-associated fecal pollution in the study region.