Fecal Coliform Concentrations Research Articles

Modeling the Effects of Future Hydroclimatic Conditions on Microbial Water Quality and Management Practices in Two Agricultural Watersheds.

Anticipated future hydroclimatic changes are expected to alter the transport and survival of fecally-sourced waterborne pathogens, presenting an increased risk of recreational water quality impairments. Managing future risk requires an understanding of interactions between fecal sources, hydroclimatic conditions and best management practices (BMPs) at spatial scales relevant to decision makers. In this study we used the Hydrologic Simulation Program FORTRAN to quantify potential fecal coliform (FC - an indicator of the potential presence of pathogens) responses to a range of mid-century climate scenarios and assess different BMP scenarios (based on reduction factors) for reducing the risk of water quality impairment in two, small agricultural watersheds - the Chippewa watershed in Minnesota, and the Tye watershed in Virginia. In each watershed, simulations show a wide range of FC responses, driven largely by variability in projected future precipitation. Wetter future conditions, which drive more transport from non-point sources (e.g. manure application, livestock grazing), show increases in FC loads. Loads typically decrease under drier futures; however, higher mean FC concentrations and more recreational water quality criteria exceedances occur, likely caused by reduced flow during low-flow periods. Median changes across the ensemble generally show increases in FC load. BMPs that focus on key fecal sources (e.g., runoff from pasture, livestock defecation in streams) within a watershed can mitigate the effects of hydroclimatic change on FC loads. However, more extensive BMP implementation or improved BMP efficiency (i.e., higher FC reductions) may be needed to fully offset increases in FC load and meet water quality goals, such as total maximum daily loads and recreational water quality standards. Strategies for managing climate risk should be flexible and to the extent possible include resilient BMPs that function as designed under a range of future conditions.

Comparative Bacteriological and Heavy Metal Toxicity Evaluation of Groundwater Wells Proximal to Pollution Receiving Streams in Ondo City, Nigeria

Background: Groundwater is the main and easily accessible source of water supply. Aside its over-exploitation problems, groundwater has undergone quality challenges-owing to its proximity to pollution sources. Methods and Materials: This study assessed the quality of hand-dug wells situated close to the pollution receiving streams in the Ondo City. Thirty water samples; from fifteen hand-dug wells and fifteen closely associated streams across the city were collected for the study. Physico-chemical, microbial and heavy metals parameters were comparatively analyzed in stream and groundwater samples to assess percolation impact on groundwater quality. Studies were carried out in wet and dry seasons. Results: The results obtained from the wells water show that beside temperature and PH, the mean values of other physicochemical parameters like turbidity (111.47 NTU & 68.77 NTU/), total dissolved solid (474.6 mg/l & 68.77mg/l), and electrical conductivity (822.31 µS/cm & 816.79 µS/cm) in both season respectively were above the World Health Organisation (WHO) highest desirable limits. The highest total coliform (T.col) recorded at 11,200 (cfu/100ml) and 11,300 (cfu/100ml) and Faecal coliform at 8,400 (cfu/100ml) and 12,100 (cfu/100ml) for dry and rainy seasons respectively. Highest level of aluminium, cadmium, lead, and chromium concentrations in well water at 1.632mg/l, 0.820mg/l, 0.079mg/l and 0.079mg/l recorded in the rainy season exceeded WHO’s recommendations. Pearson Correlation analysis between well and stream in the dry season shows positive correlation for all water parameters, with strong significance in PH, turbidity, faecal coliform and chromium concentration (0.544, 0.914, 0.414 &0.597) respectively. Similarly, in the rainy season, both well and stream had positive correlations for most parameter tested with significances in turbidity, electrical conductivity, total dissolved solid and cadmium concentration (0.708, 0.775, 0.766&0.655) respectively. Conclusion: The major outcome of this research revealed most water samples (well and stream) failed quality assessments. The positive correlations between wells and polluted stream parameters suggested that distance contributed significantly to well contaminations.

Seasonal contributions of water and pollutants to Lake St. Charles, a drinking water reservoir

Surface waters are widely used as sources of drinking water in Canada. The identification of the main sources of pollutants to surface waters, often associated with increasing urbanization, is needed to improve management strategies. We used stable water isotopes (δ18O and δD), and nutrient and fecal coliform mass fluxes to estimate the seasonal contributions of water and pollutants of different inflows to Lake St. Charles (LSC). Our results indicate that out of six identified LSC water sources, groundwater (GW), Hurons River (HR) and small stream tributaries (SSTs) represent the major contributors (in terms of water volume). The three other water sources, including two wastewater treatment plants (WWTPs), Delage Lake (DL) and precipitation (rain and snow), represent smaller seasonal contributions. During the high-flow seasons (spring and fall), LSC receives water mainly from SSTs and HR, while during the low-flow season (summer), the lake relies mainly on GW inflows. Estimates of point source (WWTPs) versus non-point source (primarily septic installations) concentrations of nutrients and fecal coliforms show that the latter represents a seasonally variable and greater source of pollutants (5% WWTPs vs. 95% septic installations). HR and SSTs, draining densely occupied areas of single housing units with individual septic installations, are categorized as non-point sources, and as such are considered major nutrient and fecal coliform contributors. The higher precipitation in spring and fall caused increased fluxes of nutrients and fecal coliforms through higher stream discharge. Due to the seasonally variable and difficult to predict discharge dynamics of SSTs and HR, these two sources represent a potentially larger threat to LSC water quality. We advocate that improved management requires reducing the number of individual septic installations in the LSC watershed.

Solar Septic Tank: Next Generation Sequencing Reveals Effluent Microbial Community Composition as a Useful Index of System Performance

Septic tanks are widely deployed for off-grid sewage management but are typified by poor treatment performance, discharge of polluting effluents and the requirement for frequent de-sludging. The Solar Septic Tank (SST) is a novel septic tank design that uses passive heat from the sun to raise in-tank temperatures and improves solids degradation, resulting in a cleaner effluent. Treatment has been shown to exceed conventional systems, however, the underlying biology driving treatment in the system is poorly understood. We used next generation sequencing (Illumina Miseq (San Diego, CA, USA), V4 region 16S DNA) to monitor the microbiology in the sludge and effluent of two mature systems, a conventional septic tank and an SST, during four months of routine operation in Bangkok, Thailand, and evaluated the ecology against a suite of operating and performance data collected during the same time period. Significant differences were observed between the microbiome of the sludge and effluent in each system and the dominant taxa in each appeared persistent over time. Furthermore, variation in the microbial community composition in the system effluents correlated with effluent water quality and treatment performance parameters, including the removal of chemical and biochemical oxygen demand and the concentration of fecal and total coliforms in the effluent. Thus, we propose that a wide-scale survey of the biology underlying decentralised biotechnologies for sewage treatment such as the SST could be conducted by sampling system effluent rather than sampling sludge. This is advantageous as accessing sludge during sampling is both hazardous and potentially disruptive to the anaerobic methanogenic consortia underlying treatment in the systems.

Effect of Irrigation with Municipal Wastewater on Heavy Metal and Fecal Coliform Concentrations in Plant and Soil

<p>In order to investigate the effect of treated wastewater on heavy metals and fecal coliform in plant and soil, a field experiment was conducted in RCBD with three treatments in four replications during 2016-2017 in Borkhar, Isfahan (Iran). Treatments including well water, semi-treated wastewater and combination of well water and wastewater were applied in consecutive cultivation of wheat and forage corn. The amount of heavy metals in the soil did not change after two seasons of wastewater application compared to well water. The amount of fecal coliform in both plants was increased in the irrigation water treatment compared to the well water, which was more evident in the corn plant, which is related to the high moisture content of this plant at harvest stage. Due to the improvement of soil nutrient concentrations after two seasons of continuous application of wastewater and no increase in the amount of heavy metals in the soil, the use of wastewater for agricultural production is permissible. But according to the fecal coliform index, it is recommended not to be used for the production of crops harvested at high humidity and conditions for the survival of pathogens.</p>

Disinfection by-products formation and acute toxicity variation of hospital wastewater under different disinfection processes

Hospital wastewater (HWW) contains a large number of pathogenic microorganisms; therefore disinfection is an indispensable unit for its treatment. This study compared the formation and formation potential of disinfection by-products (DBPs) and assessed the variations of acute toxicity for both of first physical treatment effluent (FPTE) and second biological treatment effluent (SBTE) of HWW under five different disinfection processes, including free chlorine (Cl2), chlorine dioxide (ClO2), ozone (O3), ultraviolet (UV) and ultraviolet/chlorine (UV/Cl2). Firstly, the optimal parameters of each disinfection process for FPTE and SBTE were determined respectively based on the required disinfection efficiency (i.e., controlling the concentration of fecal coliforms). The amounts of total DBPs in different disinfection processes under the optimal disinfectants dosage followed the order of Cl2 > UV/Cl2 > ClO2 > UV ≈ O3, which demonstrated that the amount of DBPs formation was closely related to the dosage of chlorine. Meanwhile, the amounts of total disinfection by-products formation potential (DBPFP) under the optimal disinfectants dosage followed the order of UV/Cl2 > UV ≈ Cl2 > O3 > ClO2. Besides, it was found that with the reduction of chlorine dosage, the formed DBPs in UV/Cl2 disinfection process decreased. However, UV/Cl2 disinfection process might degrade organic compounds into more DBPs precursors, leading to higher DBPFP than that in Cl2 disinfection process. Significantly, some specific DBPFPs such as haloketones-FP (HKFP), chloral hydrate-FP (CHFP) and trichloronitromethane-FP (TCNMFP) in O3 disinfection process were found higher than that in Cl2 disinfection process, which could be attributed to the formation of O3 oxidation by-products, for instance aldehydes, methyl ketones and trivalent nitrogen compounds. Additionally, apart from O3, the growth inhibition rate of Chlorella vulgaris increased in all the other disinfection processes and the order of the acute toxicity in each disinfected effluent was consistent with that of DBPs formation.

Microbial quality of wild shellfish in a tropical estuary subject to treated effluent discharge

Elevated faecal indicator levels in beaches around Darwin Harbour including near effluent outfalls have led to concerns about the safety of popular, locally harvested aquatic foods. To address these concerns, the impact of treated effluent discharge on the microbial quality of aquatic foods was assessed using culture-based and molecular tools.Seawater, shellfish (mangrove snails Telescopium and Nerita balteata, the local black lip oyster Saccostrea cucullata) and mud crabs (Scylla serrata) were collected from 13 sites close (impacted) and distal (reference) to two effluent discharge locations, in creeks and coastal areas. Sampling occurred over two dry seasons and one wet season.E. coli, typical sewage related pathogens, Salmonella and norovirus, and the molecular faecal marker Bacteroides, as well as naturally occurring marine bacteria, Vibrio parahaemolyticus and Vibrio vulnificus were tested in biota. E. coli and faecal coliforms were measured in water in water.The highest concentration of faecal coliforms in water was from the Buffalo Creek discharge site. At sites located in creeks including reference creeks, the highest concentrations of faecal coliforms in water were measured in the wet season compared to the dry season, whereas in coastal sites, no or only few (<10) faecal coliforms were detected.E. coli concentrations in both snail species were significantly higher in the wet season compared to the dry season (P < 0.0001) at both the treated effluent discharge sites and reference sites with some samples exceeding the acceptable Australian and New Zealand Food Standards (ANZFS) level based on E. coli levels in bivalves.E. coli concentrations in all of the S. cucullata samples were either below the detection limit or below the ANZFS limit for E. coli. No E. coli exceedances occurred in cooked mud crabs although low E. coli levels were measured in 3 cooked mud crab samples.Only one shellfish sample (T. telescopium) was positive for Salmonella. Norovirus and Bacteroides were not detected in any of the shellfish samples tested.V. parahaemolyticus and V. vulnificus were significantly more prevalent in shellfish samples during the wet season. Twelve virulent strains of V. parahaemolyticus were detected in T. telescopium and two in N. balteata. There was no significant difference in V. parahaemolyticus prevalence between sites. V. parahaemolyticus was detected in cooked S. serrata samples from three sites in the wet season and once in the 2016 dry season.V. vulnificus was detected in both T. telescopium and N. balteata, but not in any of the S. cucullata samples. One cooked crab meat sample from a reference site was positive for V. vulnificus. The prevalence of V. vulnificus was significantly higher at the reference sites compared to the discharge or potential impact sites.The lack of correlation between E. coli and targeted faecal pathogens in biota confirm that traditional faecal markers are not suitable surrogates for faecal pollution, at least not in the tropics.The higher prevalence of E. coli, V. parahaemolyticus and V. vulnificus in biota during the wet season compared to the dry season irrespective of treated sewage influence suggests that marine snails should not be harvested and consumed from creeks during the wet season. Any future aquaculture involving shellfish should consider these data when developing appropriate shellfish quality assurance protocols and for making decisions on where to situate farms.

Irrigation of a golf course with UV-treated wastewater: effects on soil and turfgrass bacteriological quality

This research was carried out to assess the impact of treated wastewater irrigation on soil bacteriological and physicochemical properties and turfgrass bacteriological quality. Two golf courses were studied: a golf course A irrigated with freshwater (FW) and a golf course B irrigated with UV-treated wastewater (UV-TW). The physicochemical parameters (electrical conductivity and pH) of the soil were determined. FW, UV-TW, lake-stored water (LSW), turfgrass, and soil were collected, and their bacteriological parameters were determined. These parameters include: Escherichia coli, faecal enterococci, and faecal coliform. The results showed that the soil irrigated with treated wastewater (S-TW) showed a significant increase in the pH when compared with the soil irrigated with freshwater (S-FW). However, no significant difference was recorded in soil electrical conductivity. Faecal indicators concentration of the irrigation water samples varied considerably, and the concentrations in LSW frequently exceed those of the water at the output of the treatment plant (UV-TW). The comparison of the faecal contamination between the two golf courses indicates no significant difference in E. coli and faecal coliform concentrations. However, a significant difference was detected in faecal enterococci contamination. This study confirms that, under appropriate conditions, treated wastewater produced by M’zar wastewater treatment plant can be used as an alternative water resource for golf courses irrigation in Agadir city, Morocco.

Groundwater quality and underground flow in southern Amazon, Brazil

The aim of this study was to evaluate the physical, chemical and microbiological groundwater parameters as well as the mapping of groundwater flow in an urban area of Presidente Médici county in Rondônia State, Southern Amazon. The water samples were collected in 11 wells in April and June of 2017, which corresponds to the dry season in the studied region. Groundwater was acidic, with a large range of nutrients concentration, low turbidity and presence of fecal coliforms in most sampled wells. The parameters that were in disagreement with Consolidation Ordinance No 05/2017/MS and CONAMA no 396/08 Resolution, were pH, turbidity, total coliforms, Escherichia coli, and nitrate. Regarding the microbiological parameter, most of the sampling sites were in disagreement with the established by the legislation that it recommends to be absent in 100mL, when it is destined for human consumption. Densities found were higher than 112,000UFC/100mL for total coliforms and higher than 56,000UFC/100mL for Escherichia coli. The pH ranged from 4.1 to 6.4, and the turbidity showed a maximum value of 6.7 uT. The nitrate concentrations were above the established level (10 mg.L-1) in April in 72.7%, and in June 50% of the wells, with a maximum of 48.5 mg.L-1. The study of the direction of the underground flow demonstrated the predominance of the flow towards the nearest river, as well as potential contributors of microbiological influences. The results indicate contamination of the groundwater by domestic sewage, being proved by the presence of coliforms and nitrate, being the water unfit for human consumption without adequate treatment.

Preliminary Study on the Potential Use of Fly Ash as a Ventilated Improved Pit Latrine Additive

This study describes the results of a series of laboratory experiments on aimed at developing of a protocol for the use of fly ash as a pit additive in the ventilated improved pit latrines (VIPs) in South Africa. Model VIP vaults were prepared in the laboratory and filled with synthetic faecal sludge; and dosed with fly ash in amounts ranging from 5 to 20 % (w/w). The maximum leachable chemical oxygen demand (COD) accounted for 3.2 % of the total organic matter, while the maximum leachable ammonium accounted for 1.4 % of the leachable ammonium present in the synthetic faecal sludge. All phosphate in the synthetic faecal material was leachable. Mixing of the 20 % dose of fly ash into the synthetic faecal sludge resulted a minimum 98.9 % reduction (or about two log units) in the faecal coliform concentration after 28 days of incubation. As a result, addition of fly ash can decrease microbial threats to public and environmental health threats from the VIP faecal wastes, but can cause environmental contamination with phosphate. The fly ash dose and the duration of the faecal sludge treatment require further optimisation. Relationship between the chemical composition of the fly ash used as an additive to stabilise the VIP faecal sludge and the leaching of phosphorus from the sludge will also have to be investigated further.

Bacterial indicators reveal water quality status of Rangkui River, Bangka Island, Indonesia

Rangkui River flows across Pangkal Pinang City, the capital of Bangka Belitung Province. Land uses vary and can inevitably be pollution hot-spots for this river. This study aimed to investigate the current status of Rangkui River based on bacterial indicators in association with other water quality parameters. The sample collection was completed in March 2017 within 6 stations. Water quality parameters observed were temperature, TSS, turbidity, pH, DO, salinity, BOD, COD, Nitrate and Phosphate. The results of faecal coliform observation indicated that the stations closer to upstream (station 1, 2, 3) showed lower faecal coliform concentration (530-940 MPN/100 ml) as compared to those closer to downstream (station 4, 5, 6) which had the amount of ∼11,000 MPN/100 ml. Phylogenetic study emphasized that isolates of interest were more similar to Escherichia group. The water from Rangkui River could be classified from Class I to Class IV according to Indonesia Government Regulation No.82/2001. PCA revealed Station 3 and 6 obviously separated from other stations so that more concerns should be given to improving water quality in these areas.

Evaluation of Occurrence, Concentration, and Removal of Pathogenic Parasites and Fecal Coliforms in Three Waste Stabilization Pond Systems in Tanzania.

In Tanzania, waste stabilization ponds (WSPs) are employed to treat wastewater, and effluents are used for urban agricultural activities. The use of untreated or partially treated wastewater poses risks of disease transmission, including parasitic and bacterial infections, to exposed communities. Little is known about the occurrence, concentration, and removal of parasites and fecal coliform (FC) bacteria in WSPs in Tanzania. This study evaluates the occurrence and concentration of parasites and FCs in wastewater, the efficiency of WSPs in removing parasites and FCs, and the validity of using FCs as an indicator of parasites. This was a cross-sectional study conducted between February and August 2018. Wastewater samples were collected from three WSPs located in the Morogoro, Mwanza, and Iringa regions. APHA methods were used to test physicochemical parameters. The modified Bailenger method and Ziehl–Neelsen stain were used to analyse parasites. Membrane filtration method was used to analyse FCs. Data were analysed using IBM SPSS version 20. Helminth egg removal ranged from 80.8% to 100%. Protozoan (oo)cyst removal ranged from 98.8% to 99.9%. The Mwanza WSP showed the highest FC reduction (3.8 log units (100 mL)−1). Both the parasites and FCs detected in the effluents of assessed WSPs were of higher concentrations than World Health Organization and Tanzania Bureau of Standards limits, except for helminths in the Morogoro WSP and FCs in the Mwanza WSP. FCs were significantly correlated with protozoa (p < 0.01) and predicted protozoa occurrence well (p=0.011). There were correlations between physicochemical parameters, parasites, and FC bacteria in the WSP systems. Inadequate performance of these systems may be due to lack of regular maintenance and/or systems operating beyond their capacity. FC indicators were observed to be a good alternative for protozoa monitoring, but not for helminths. Therefore, during wastewater quality monitoring, helminths should be surveyed independently.

Impact of sanitation and socio-economy on groundwater fecal pollution and human health towards achieving sustainable development goals\xa0across India from ground-observations and satellite-derived nightlight

Globally, ~1 billion people, mostly residing in Africa and South Asia (e.g. India), still lack access to clean drinking water and sanitation. Resulting, unsafe disposal of fecal waste from open-defecation to nearby drinking water sources severely endanger public health. Until recently, India had a huge open-defecating population, leading declining public health from water-borne diseases like diarrhoea by ingesting polluted water, mostly sourced to groundwater. However, in recent past, sanitation development to achieve Sustainable Development Goals (SDGs) has been encouraged throughout India, but their effect to groundwater quality and human health conditions are yet-unquantified. Here, for the first time, using long term, high-spatial resolution measurements (>1.7 million) across India and analyses, we quantified that over the years, groundwater fecal coliform concentration (2002–2017, −2.56 ± 0.06%/year) and acute diarrheal cases (1990–2016, −3.05 ± 0.01%/year) have significantly reduced, potentially influenced by sanitation development (1990–2017, 2.63 ± 0.01%/year). Enhanced alleviation of groundwater quality and human health have been observed since 2014, with initiation of acceletated constructions of sanitation infrastructures through Clean India (Swachh Bharat) Mission. However, the goal of completely faecal-pollution free, clean drinking water is yet to be achieved. We also evaluated the suitability of using satellite-derived night-time light (NLan, 1992–2013, 4.26 ± 0.05%/year) as potential predictor for such economic development. We observed that in more than 80% of the study region, night-time light demonstrated to be a strong predictor for observed changes in groundwater quality, sanitation development and water-borne disease cases. While sanitation and economic development can improve public health, poor education level and improper human practices can strongly influence on water-borne diseases loads and thus health in parts of India.

Management Scale Assessment of Practices to Mitigate Cattle Microbial Water Quality Impairments of Coastal Waters

Coastal areas support multiple important resource uses including recreation, aquaculture, and agriculture. Unmanaged cattle access to stream corridors in grazed coastal watersheds can contaminate surface waters with fecal-derived microbial pollutants, posing risk to human health via activities such as swimming and shellfish consumption. Improved managerial control of cattle access to streams through implementation of grazing best management practices (BMPs) is a critical step in mitigating waterborne microbial pollution in grazed watersheds. This paper reports trend analysis of a 19-year dataset to assess long-term microbial water quality responses resulting from a program to implement 40 grazing BMPs within the Olema Creek Watershed, a primary tributary to Tomales Bay, USA. Stream corridor grazing BMPs implemented included: (1) Stream corridor fencing to eliminate/control cattle access, (2) hardened stream crossings for cattle movements across stream corridors, and (3) off stream drinking water systems for cattle. We found a statistically significant reduction in fecal coliform concentrations following the initial period of BMP implementation, with overall mean reductions exceeding 95% (1.28 log10)—consistent with 1—2 log10 (90–99%) reductions reported in other studies. Our results demonstrate the importance of prioritization of pollutant sources at the watershed scale to target BMP implementation for rapid water quality improvements and return on investment. Our findings support investments in grazing BMP implementation as an important component of policies and strategies to protect public health in grazed coastal watersheds.

Development and evaluation of treatment options for recycling ablution greywater

This study aimed to develop and evaluate five simplified AGW treatment options with or without low-cost ceramic filters, including direct ceramic filtration, alum coagulation–sedimentation, alum coagulation–sedimentation–ceramic filtration, alum coagulation–sedimentation–activated carbon, adsorption–sedimentation, and ceramic filtration–activated carbon adsorption–sedimentation. In raw AGW, concentrations of turbidity (14.8 NTU), TSS (24 mg/L), COD (63.2 mg/L), BOD (37.0 mg/L), and fecal coliform (884 MPN/100 mL) exceeded the greywater reuse standards for unrestricted irrigation, toilet flushing, and firefighting. In laboratory experiments, first three treatment options produced almost similar effluent with residual turbidity 1.5 NTU, COD 35 mg/L, and BOD 20 mg/L. Addition of the activated carbon to the last two treatment options enhanced the BOD and COD removals (< 12 mg/L). Multicriteria decision-making was performed to evaluate all the AGW treatment options against effluent water quality, treatment cost, land requirements, and need of skilled operators. Criteria weights were estimated using Entropy method, while the technique for order preference by similarity to ideal solution was used to final ranking of AGW treatment options. Results found direct filtration as the most feasible option to reuse AGW for restricted irrigation, and for unrestricted irrigation, toilet flushing, and firefighting, the ceramic filtration–activated carbon adsorption–sedimentation treatment process would be the more feasible option.

Nexus between sanitation and groundwater quality: case study from a hard rock region in India

Abstract Groundwater quality in the towns of Namakkal and Erumaipatti in India was studied to understand the nexus between surface sanitation and groundwater quality in hard rock regions. In total, 32 wells, both shallow open and deep bore wells, were monitored over a two-year period. The presence of fecal coliforms (FCs) up to 600 CFU/100 mL in wells as deep as 100 m showed that bacteriological contamination had reached deep aquifers through fractures and fissures. Statistical analyses showed that bore wells located in Namakkal were bacteriologically more contaminated than those in Erumaipatti (p = 0.017 for FC) because of urbanization, the type of top soil and the shallow groundwater table. Wells in densely toileted areas of Namakkal were more contaminated than those located in open defecation areas. After replacing a soak pit with a septic tank, concentrations of FC and chemical oxygen demand (COD) in the leachate at a depth of 2.1 m reduced from 2,500 to 1,000 CFU/100 mL and from 200 to 50 mg/L, respectively, after 150 days of the construction of septic tanks. To improve the hygiene and sanitation, the provision of toilets along with on-site waste management systems, capable of achieving required effluent quality, are essential.

Quality of Drinking Water from Springs in Palestine: West Bank as a Case Study.

The shortage of fresh water creates acute challenges in the West Bank of Palestine. Springs provide a main water resource in the West Bank. Investigating springs' water quality is essential step for promoting their public use. The aim of this research is to assess the microbiological and physiochemical quality parameters of drinking water from springs. The study methodology included sampling through field work and laboratory testing for water quality parameters using standard procedures. The study area covered all locations containing licensed springs by the Palestinian Water Authority in the West Bank of Palestine. The number of collected samples was 127 covering 300 springs. The chemical, physical, and biological parameters for each sample were measured. Then, the obtained characteristics were evaluated based on national and international quality standards (PSI and WHO). The investigated parameters included temperature, pH, EC, total hardness, concentrations of nitrate, sodium ions, total chlorine, residual chlorine, turbidity, and total and faecal coliforms. Most of investigated physical and chemical parameters were within the acceptable standard limits. However, the turbidity and chloride and nitrate concentrations exceeded standard limits. The findings indicate that only a minor fraction of the samples (2%) requires chlorination treatment, while most of the springs (97% of samples) are classified as possessing no risk.

An examination of the microbial community and occurrence of potential human pathogens in rainwater harvested from different roofing materials

While harvested rainwater can serve as an alternative water supply, microbial contaminants within the collection system can negatively affect water quality. Here, we investigated the impact of roofing material on the microbial quality of rainwater freshly harvested from pilot-scale roofs (concrete tile, cool, green, Galvalume® metal, and asphalt fiberglass shingle). The microbial quality of freshly harvested rainwater from six rain events over two years was analyzed by high-throughput sequencing and culture-dependent and -independent techniques. The concentrations of total coliform were significantly different among rainwaters harvested from the various roofing materials (p-value >0.05). However, the fecal coliform concentrations and the copy numbers of Enterococcus 23S rRNA genes and total Bacteria 16S rRNA genes did not vary by type of roofing material in a statistically significant way. Potential human pathogens such as Legionella, Escherichia coli O157:H7, Shiga-toxin-producing Escherichia coli, and adenovirus were detected at least once in rainwater harvested from the different roofing materials, even though the lowest occurrence of those potential human pathogens was noted from the metal roof. Also, substantial variation in the microbial communities from the different roofing materials was observed at the family and genus levels. These results demonstrate that the type of roofing material affects the microbial quality of freshly harvested rainwater, indicating that the choice of roofing material could shape the microbial community structure entering a rainwater storage tank. Given that detection of potential pathogens in the freshly harvested rainwater also differed between roofing materials, the type of roofing used to capture rainwater needs to be considered in rainwater harvesting system design, particularly if the water is intended for potable use.

Implications of poor-regulated wastewater treatment systems in the water quality and nutrient fluxes of a subtropical coastal lagoon

Sewage treatment is a way of controlling coastal eutrophication worldwide. Yet is it enough to ensure water quality and avoid the effects of eutrophication? In this study, we hypothesize that sewered and non-sewered regions of Conceição lagoon (Southern Brazil) have similar water quality, due to the poorly designed sewerage system and the lack of effective public policies. The LOICZ (Land–Ocean Interactions in the Coastal Zone) biogeochemical model was used to understand how the lagoon responds to nutrient inputs from the watershed. There was no significant difference in the water quality between the urbanized rivers. Both regions (sewered and non-sewered) showed high concentrations of phosphate, ammonium and fecal coliform. The percentage of urbanization was directly correlated with deoxygenation, nutrients and coliform. Lower concentrations of nutrients and oxic waters were found in the non-urbanized rivers and in the lagoon. As such, biogeochemical and physical processes counterbalance the nutrient inputs. However, the sewage runoff might be fueling the dead zone of the lagoon, since the water residence time and nutrient retention are high. Our results indicate that the sewage treatments are inefficient in preventing the input of organic matter and nutrients to the system. Additionally, new management strategies are required to revert eutrophication, such as the expansion of the serviced area by the sewage system and the improvement of its technology.

Investigation of the fecal coliform plumes induced by river discharge and wind stress using a three-dimensional model

A three-dimensional hydrodynamic, suspended sediment, and fecal coliform transport model was developed and applied to characterize the fecal coliform plume in the Danshuei River estuarine system and its adjacent coastal sea. The numerical model was calibrated and validated with time-series water levels and spatial distributions of suspended sediment and fecal coliform concentrations in 2012 and 2013, respectively. Three indices (i.e., mean absolute error, root-mean-square error, and skill score) were used to compare the predicted results and measured data for assessing the performance of the model. Quantitatively, there was good agreement between the simulation and the measurement results. The validated model was later applied to explore the influence of river discharge and wind stress on the fecal coliform plume in the Danshuei River coastal area. In the absence of wind stress, no cyclonic circulation occurs as a result of river discharge under flood conditions. However, anticyclone circulation occurs on the east coast of the Danshuei River mouth at low river discharge. The plume distances of fecal coliform from the Danshuei River mouth reach 17 km and 5 km under flood flow and Q50 flow conditions, respectively. In the absence of river discharge, the plume distance of fecal coliform is confined to the Danshuei River mouth. Consequently, the wind directions control the upwelling and downwelling plumes. If the river discharge and wind stress are included in the model simulations, the surface fecal coliform concentrations are flushed out of the Danshuei River mouth and move to the southwestern coast as a result of the wind’s favoring downwelling. Conversely, the fecal coliform concentrations are flushed out of the Danshuei River mouth and flow to the northeastern coast, with the wind favoring upwelling. Comparing simulated results with and without wind stresses, the plume distance/area of fecal coliform decreases with the inclusion of wind stress.