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This paper presents a three-dimensional CFD based hydro-environmental model that simulates fate and transport of bacteria in water bodies. The model numerically solves unsteady incompressible Reynolds-Averaged Navier-Stokes equations on a structured grid. Free-floating and particle-attached bacteria were modelled separately regarding both fate and transport. Therefore, a sediment transport model was integrated into the main model in order to model particle-attached bacteria transport. In addition, Volume of Fluid approach was implemented to capture the water surface movements. Wind effect was also considered in the modelling using shear stress on the water surface. Since stormwater reuse is the source of some public health concerns, a stormwater pond was chosen as the test case for the model. The model was applied to simulate the distribution of bacterial indicator organisms in the Inverness Stormwater Pond in Calgary, Alberta, which is a large T-shaped pond with several inlets and outlets. The bacteria distribution in the pond was simulated for three rain events that occurred in the area. In six locations of the pond the modelled bacteria distribution was compared to collected data using non-dimensional bacteria concentrations. The comparison showed good agreement and indicated that the middle of the pond, close to the surface had the lowest levels of bacteria and thus, was considered the optimal location for withdrawal for reusing pond water. Furthermore, planting a tree barrier on the north bank of the West wing of the pond was shown to mitigate bacteria transport away from the inlets into the pond body and substantially decrease the risk of contamination at the optimal water withdrawal location.

Surface water protection and sustainability is a vital move to enhance public health and ensure food and water security. Pathogen containing wastewater when discharged into water bodies, affects the water quality and poses health risks to the intended users. Even though various disinfection methods of domestic wastewater exist for pathogen control, much work has not been done to compare and ascertain the most effective method(s). A systematic literature review has therefore been conducted on the various available disinfection methods that have been evaluated in laboratory or on pilot scales or employed in full-scale wastewater treatment plants. Approximately 21% of the disinfection studies were conducted at full-scale. The technologies identified included advanced oxidation, microwave-induced electrodeless UV irradiation, ozonation and filtration, tin oxide anode, UV irradiation and peracetic acid. Generally, the combined technologies proved to be more effective than when used on their own. UV irradiation processes or their combination was the most frequently applied wastewater disinfectant method. Many of the disinfection processes proved effective in inactivating some of the pathogens and indicator organisms such as E. coli, total coliforms, C. perfringens, Enterococci and enteric viruses. Nearly all the disinfection methods were able to reduce E. coli and total coliforms.

Fecal indicator organisms (FIOs), such as Escherichia coli and enterococci, are often used as surrogates of contamination in the context of beach management; however, bacteriophages may be more reliable indicators than FIO due to their similarity to viral pathogens in terms of size and persistence in the environment. In the past, mechanistic modeling of environmental contamination has focused on FIOs, with virus and bacteriophage modeling efforts remaining limited. In this paper, we describe the development and application of a fate and transport model of somatic and F-specific coliphages for the Washington Park beach in Lake Michigan, which is affected by riverine outputs from the nearby Trail Creek. A three-dimensional model of coliphage transport and photoinactivation was tested and compared with a previously reported E. coli fate and transport model. The light-based inactivation of the phages was modeled using organism-specific action spectra. Results indicate that the coliphage models outperformed the E. coli model in terms of reliably predicting observed E. coli/coliphage concentrations at the beach. This is possibly due to the presence of additional E. coli sources that were not accounted for in the modeling. The coliphage models can be used to test hypotheses about potential sources and their behavior and for predictive modeling.

Small to medium irrigation ponds provide substantial quantities of water for irrigation in the Mid-Atlantic region of the U.S. The concentrations of the fecal indicator organism Escherichia coli (E. coli) are used to evaluate the microbial water quality of irrigation sources. Little is known about the spatiotemporal variability of E. coli concentrations in pond water and the possible effects on monitoring and management of the microbial quality of irrigation water from these ponds. The objective of this work was to test the hypotheses that (a) spatial patterns of E. coli concentrations exist that are preserved both intra- and interannually, and (b) persistent spatial patterns in water quality parameters exist and correlate with persistent patterns of E. coli concentrations. Sampling was conducted fortnightly during the summer months in 2016 to 2018 and consisted of taking water quality measurements at 23 and 34 locations in ponds P1 and P2, respectively. Interannual variability of E. coli was observed in both ponds as was substantial spatial variability of E. coli concentrations within each year. The mean relative difference (MRD) analysis was used to identify temporally stable patterns of E. coli concentrations within the ponds. These patterns found for individual years showed significant positive correlations with each other and with the overall pattern derived from the 3-year dataset. Correlation coefficients of patterns varied from 0.487 to 0.842 in P1 and from 0.467 to 0.789 in P2 (p

Pasteurisation is an alternative to other disinfection processes such as chlorination, ozonation and UV treatment. It does not produce harmful by-products and may have a lower pre-treatment requirement than other disinfection processes. Pasteurisation has been trialled and implemented in California under their “Title 22” regulations but there is a lack of peer-reviewed scientific literature to support the selection of appropriate surrogates and indicators for the validation of pasteurisation performance. This paper provides a brief review of the available knowledge on the heat inactivation of enteric bacteria, protozoa, viruses and helminths to inform the selection of appropriate surrogates and indicator organisms for pasteurisation disinfection of municipal wastewater. Based on review of the available literature, native Escherichia coli may be a reasonable surrogate for most organisms of interest, as most of the tested bacteria in the literature displayed a greater sensitivity to heat. Escherichia coli may also make a suitable surrogate for protozoa, helminths and some viruses as these have a higher sensitivity to heat than E. coli. Enterococci and FRNA phage (MS2) were found to be less heat sensitive than E. coli, most viruses, and the tested protozoa and helminth species, and could thus make more conservative surrogates for these pathogens.

Bacterial diversity and antimicrobial resistance patterns among the indicator organism Escherichia coli were monitored in wastewater samples collected over one year from a hospital (HW), a community (CW) and the receiving urban (UW) wastewater treatment plant (WWTP). We compared levels of antibiotic resistance in the different types of wastewater, and identified whether resistant strains were endemic in the wastewater system. If so, implementation of local treatment at certain resistance hotspots (e.g. hospital outlets) could be used to decrease the amount of resistant bacteria in the wastewater. E. coli from HW (n = 2644), CW (n = 2525) and UW (n = 2693) were analyzed by biochemical phenotyping (PhenePlate System) and antimicrobial susceptibility testing to nine antibiotics (AREB System). The phenotypic diversities of the total E. coli populations were similar for all three sites (Simpson's Diversity index, Di = 0.973), however for individual samples, HW showed low diversities (Median Di = 0.800) and the E. coli flora was often dominated by strains that may have originated from the fecal flora of single individuals. The diversities in CW samples was higher (Median Di = 0.936), and UW samples showed similar diversities as the whole collection of isolates (Median Di = 0.971). Resistance to at least one of the nine antibiotics was observed in 45% of the HW isolates, 44% of CW isolates, and 33% of UW isolates. Resistance to gentamicin and chloramphenicol was uncommon (3.2 and 5.3%, respectively), whereas resistance to tetracycline and ampicillin was most common (24% and 31%, respectively). Extended-spectrum beta-lactamase-producing E. coli (ESBL-EC) were more common in HW (11.5%) and in CW (6.9%) compared to UW (3.7%). A high diversity (Di = 0.974) was observed among ESBL-EC isolates from UW (n = 99), indicating absence of any clonal structure among these isolates. Common PhP types of ESBL-EC often dominated in each HW sample, but were not identified across different samples, whereas ESBL-EC in CW showed low diversity (Di = 0.857) and were dominated by a specific PhP type that was found across almost all CW samples. The antibiotic resistance rates were highest in hospital wastewater, but surprisingly they were also high in the studied community wastewater, compared to the urban wastewater. The relative contribution of HW seemed low in terms of dissemination of antibiotic resistant bacteria to the WWTP.

Fipronil is a highly effective, broad-spectrum insecticide used to control pests, globally. The increased usage has led to contamination of soil, water, fruits, and vegetables. The wide and frequent usage of fipronil across the globe calls for attention regarding risk assessment of undesirable effects on non-target microorganisms. In this context, the present study was carried to understand the impact of fipronil on non-pathogenic Escherichia coli. The non-pathogenic E. coli are important commensal of the intestinal tract of humans and animals and are also indicator organisms in the environment. Our study indicates that exposure of E. coli to fipronil (100 μM concentration) leads to significant reactive oxygen species production, loss of membrane potential and viability. Further, we have witnessed the bioaccumulation and biotransformation of fipronil by E. coli at non-lethal concentrations. The bio-transformed products (fipronil sulfone and fipronil sulfide) are also the major metabolites (along with amide) reported in the feces of the mammals when exposed to fipronil. Thus, there is a possibility that the gut E. coli might play a role in the degradation and thereby removal of fipronil. In addition, the bioaccumulation of fipronil in bacteria is of concern and need to be further explored because it can lead to biomagnification in the higher trophic level and can disturb the ecological balance. In our knowledge, this is the first report on the determination of fipronil and its metabolites in bacteria through GC-MS/MS.

The current microbial water quality standards are based on the monitoring of fecal indicator organisms, which are mainly bacterial indicators (i.e., Escherichia coli, intestinal enterococci), however epidemiological data indicate that viruses are important etiological agents of waterborne illnesses. Among waterborne viruses, human adenovirus can be considered as an index pathogen, owing to its abundance in sewage and persistence in the environment, as well as its potential infectivity. In this study, data on human adenoviruses from different water matrices (the entrance and exit of a water treatment plant, rivers and seawaters) were analyzed, in parallel with traditional fecal bacterial indicators and somatic coliphages. The results showed a 64% frequency of positive adenovirus samples, decreasing from the sewage system (100% at the entrance and 94% at the exit) to rivers (92% and 72% for different rivers) and seawater (21%). Adenovirus concentrations showed a significant correlation with somatic coliphages in one river and seawater, thus supporting the recent inclusion of coliphages as viral indicators in water safety guidelines. The data collected were used to estimate adenovirus to indicator ratios, which could be used as input in Quantitative Microbial Risk Assessment (QMRA) studies.

Terrestrial invertebrates are often used as indicator organisms in ecological risk assessments. However, determining the risk of metals to invertebrates is laborious and time-consuming due to the lengthy testing and ethical approval procedures. In this study, a review of the literature was conducted to provide toxicity data for two standard soils (OECD and LUFA 2.2). An attempt was made to establish models for predicting the toxicity of elements to invertebrates using quantitative ion character-activity relationships (QICARs). In OECD soil, the element toxicity of four groups (Enchytraeus albidus mortality and reproduction, Folsomia candida and Eisenia fetida reproduction) showed significant correlations with atomic number, atomic mass and atomic ionization potential (0.852 ≤ R2 ≤ 0.989, P

On-site wastewater treatment systems are gaining popularity in areas where centralized wastewater treatment is not available. In the current case study a domestic activated sludge system was investigated, where treated effluent was stored in a short-term (1 week turn-over time) and a long-term (over 2–3 months) storage tank and was then used for irrigation. This design provided a unique opportunity to assess the chemical and microbial changes of the effluent upon storage. Long-term storage greatly improved both the chemical quality and the degradation efficiency of most organic micropollutants examined, including petroleum hydrocarbons and the pesticide diethyltoluamide. Taxonomic profile of the core microbiome of the effluent was also influenced upon storage. Relative abundance values of the members of Azoarcus and Thauera genera, which are important in degrading polycyclic aromatic hydrocarbons compounds, clearly indicated the biodegrading activity of these microbes across samples. The abundance of xenobiotics degradation functions correlated with the observed organic micropollutant degradation values indicating efficient microbial decomposition of these contaminants. Functions related to infectious diseases also had the highest abundance in the short-term storage tank corresponding well with the relative abundance of indicator organisms and implying to the significance of storage time in the elimination of pathogens. Based on these results, small, on-site wastewater treatment systems could benefit from long-term storage of wastewater effluent.

Fecal indicator bacteria (FIB) are commonly used to evaluate the pollution impact of combined sewer overflows (CSOs) in urban rivers. Although water quality assessment with FIB has a long tradition, recent studies demonstrated that FIB have a low correlation with pathogens and therefore are not accurate enough for the assessment of potential human hazards in water. Consequently, new eligible and more specific indicators have to be identified, which was done in this study via sequencing of genetic markers from total community DNA. To identify potential microbiome-based indicators, microbial communities in samples from an urban river in Tokyo under different climatic conditions (dry and rainy) were compared with the influent and effluent of three domestic wastewater treatment plants (WWTPs) by analyzing 16 S rRNA gene amplicon libraries. In the first part of this study, physicochemical parameters and FIB quantification with selective culture techniques facilitated the identification of samples contaminated with CSO, sewage, or both. This allowed the grouping of samples into CSO-contaminated and non-contaminated samples, an essential step prior to the microbiome comparison between samples. Increased turbidity, ammonia concentrations, and E. coli [up to (9.37 ± 0.95) × 102 CFU/mL after 11.5 mm of rainfall] were observed in CSO-contaminated river samples. Comparison of dry weather (including WWTP samples) and rainy weather samples showed a reduction in microbial diversity in CSO-contaminated samples. Furthermore, the results of this study suggest Bacteroides spp. as a novel indicator of sewage pollution in surface waters.

Enteric viruses in the aquatic environment are a concern due to the potential for waterborne disease transmission to humans. In Nepal, the Bagmati River serves as a source of drinking and irrigation water; therefore, the detection of waterborne enteric pathogens is integral to maintaining human health. The objective of this study was to quantify the crAssphage marker in surface water samples from the Bagmati River between November 2015 and September 2016. Concentrations of crAssphage were then compared to those of other enteric viruses and indicator organisms found in the samples in order to examine the potential of crAssphage as a marker for fecal contamination. CrAssphage was detected in 17% (1/6) of samples from Sundarijal, 100% (6/6) of samples from Thapathali, and 100% (6/6) samples from Chovar, with the highest average concentrations recorded in May 2016 and the lowest average concentrations recorded in September 2016. Overall, crAssphage was present in 72% (13/18) of samples and was strongly correlated with the presence of fecal indicator bacteria Escherichia coli (r = 0.89) and Enterococcus (r = 0.92) and several enteric viruses. The strongest viral correlations were to salivirus (r = 0.84), pepper mild mottle virus (r = 0.77), Aichi virus 1 (r = 0.75), enteroviruses (r = 0.76), and tobacco mosaic virus (r = 0.71). These results provide evidence for the potential use of crAssphage as a marker for human fecal contamination in river water.

The great expansion in recent years in the use of plant biostimulants has underestimated the possibility of producing environmental risks. The objective of this study was to evaluate the cytotoxicity, genotoxicity, and toxicity of three different biostimulants (A, B, and C) produced and widely marketed in Brazil and exported to other countries on both plant and animal indicator organisms. In Allium cepa (non-target species of these plant biostimulants), the concentrations evaluated for the products A and B (0.0625 at 0.500 mL/L), and C (0.0625 at 0.500 g/L) induced inhibition of cell proliferation on meristems, in at least one time of analysis, characterizing them as cytotoxic. The three biostimulants promoted an expressive number of prophases in detriment to the other phases of cell division. In the test with Artemia salina, different concentrations of the biostimulants were tested, ranging from 1000 to 1.95 ppm, and the toxic potential was evaluated through the LC50. The three products showed high toxicity (LC50

Microplastics are pollutants of concern in the freshwater and marine environments. These microparticles carry biofilm communities unique from the surrounding water. The objective of this study was to investigate the role of source water quality, microparticle type (i.e., different polymers and morphologies), and microparticle size on the resulting biofilm microbial communities. Of particular interest was determining whether microbial agents were concentrated in these biofilm communities. A series of batch reactors were prepared to investigate the microbial communities observed in wastewater or river water compared to those in biofilm on microplastic or glass microspheres via amplicon sequencing. Sampling was performed after 48 h. qPCR was also performed for a fecal indicator organism marker (BacHum) and sul1 antibiotic resistance gene. The biofilm community structures varied as a function of source water and as a function of microparticle type: polystyrene spheres had different microbial community structures from polyethylene microparticles. The differences observed between microparticle types may be due to the morphology/surface texture rather than polymer composition given that some glass microspheres had similar microbial communities to polystyrene microspheres. For a given microparticle type and source water, size (106–125 μm versus 355–425 μm for polystyrene microspheres, 125–250 μm versus 250–500 μm for polyethylene microparticles) did not significantly impact the microbial community structure. While the biofilm microbial communities differed from communities in the surrounding water, the biofilm did not have a higher relative abundance of the indicator organism marker or sul1 genes than the reactor filtrate.

Despite the many recognised benefits, the application of high rate algal ponds (HRAP) to manage wastewater treatment in small communities has been limited. To be incorporated into the South Australian Community Wastewater Management Scheme (CWMS), new wastewater treatment systems are required to undergo validation and obtain regulatory approval from the South Australian Department of Health, Wastewater Management Group. A HRAP system at Kingston on Murray, South Australia, underwent validation to be incorporated into the CWMS. The process was consistent with the Australian National Guidelines which requires the demonstration of the log10 reduction values (LRV) for indicator organisms achieved by the wastewater treatment system. These were required to be measured twice weekly, over a 10 week period in below average solar radiation and temperature conditions, by an independent National Association of Testing Authorities accredited laboratory. The Australian Water Quality Centre was commissioned to assess the removal of Escherichia coli, F-RNA bacteriophage and aerobic spore-forming bacteria. Flinders University of South Australia concurrently monitored the removal of the same organisms and other standard wastewater parameters. While ASFB were shown to be unsuitable indicators of protozoa in natural pond systems, the system effectively removed E. coli and F-RNA bacteriophage with the treated effluent meeting the limits set by the guidelines for effluent reuse for non-food crop irrigation: a 5th percentile LRV of >1.0 for F-RNA bacteriophage and a median E. coli concentration of

The aim of the study was to monitor the operational sustainability and efficacy of rainwater harvesting solar pasteurization (SOPAS) treatment systems installed in a local informal settlement in Stellenbosch, South Africa. Indicator organisms, cations and anions were routinely monitored in the tank water before (untreated) and after SOPAS treatment, while molecular-based techniques were used to identify and quantify pathogens associated with rainwater sources. The operational sustainability of the systems was monitored to determine the volume of water produced, the total water usage by the end-user households and the required system maintenance. Anions and cations analyzed for in the untreated and SOPAS treated rainwater were within national and international drinking water guidelines, with the exception of zinc which exceeded the limits in all samples. Additionally, the total coliform, E. coli, fecal coliform and heterotrophic bacteria counts exceeded drinking water guideline limits in 100%, 55%, 36% and 100% of the unpasteurized tank water samples (n = 11), respectively. However, a minimum pasteurization temperature of 66 °C was required to reduce all indicator organism counts to within drinking water standards. Quantitative PCR analysis confirmed that Legionella spp., Pseudomonas spp. and Salmonella spp. were still detected following SOPAS treatment. Monitoring of the operational sustainability of the systems indicated that minimal system maintenance was required and that the systems were effectively able to provide water to the participating households during the rainfall periods. Based on microbiological indicator analyses, the SOPAS systems may be used in rural areas and informal settlements for the provision of an alternative water source.

Ballast water discharges are potential sources for the spread of invasive and pathogenic aquatic organisms. Ballast waters from six ships docked in the Port of Singapore were tested to determine if indictor organisms fell within proposed standards for ballast water discharge according to regulation D-2 of the Ballast Water Management Convention (BWMC) guidelines. Vibrio species were cultured on media supplemented with beta-lactam antibiotics to determine the presence of antibiotic resistant Vibrio species in the ballast waters of these vessels. Indicator organisms were quantified using culture media Colilert-18 and Enterolert in ballast waters of six ships docked in a tropical harbor, with uptake from different geographical locations. Of the six ships, one had ballast water originating from the Persian Gulf, another from the East China Sea, and four from the South China Sea. Two of the six ships which carried ballast waters from the East China Sea and the South China Sea did not meet the D-2 stipulated requirements of the Ballast Water Management Convention for indicator organisms with Enterococci values more than three times higher than the acceptable limit of100CFU/100mL. Using the most-probable-number-PCR (MPN-PCR) method for Vibrio species detection, non-toxigenic species of V. cholerae (2 MPN/100mL), Vibrio vulnificus (110 MPN/100mL), and Vibrio parahaemolyticus (2 to110 MPN/100mL) were detected in at least one of six ballast water samples. Using thiosulfate-citrate-bile salts-sucrose agar (TCBS) supplemented with beta-lactam antibiotics (meropenem, ceftazidime), 11 different Vibrio species, exhibiting resistance to beta-lactam antibiotics were isolated; with Vibrio campbellii (44%) and Vibrio alginolyticus (15%) the most detected antibiotic resistant Vibrio species. A practical approach of prioritized screening of high-risk vessels should be conducted to ensure that the water quality meets D-2 standards prior to discharge.

A demonstration-scale unit process open-water wetland system was built to treat water from an effluent-dominated river (i.e., a river in which the flow consisted almost entirely of municipal wastewater effluent from May to October). Monitoring of the system over a two-year period indicated effective removal of nitrate, with concentrations decreasing by over 90% during summer. The temperature-independent areal first-order nitrate removal rate constant, k 20 , ranged from 61.7 to 68.1 m yr −1 after the microbial community was established, which is significantly higher than values typically observed in full-scale surface flow wetlands. The beta-adrenergic blockers, atenolol and propranolol, as well as the antiviral drug, acyclovir, were removed by photolysis and biotransformation in the wetland biomat, whereas the antiepileptic drug, carbamazepine, exhibited little removal. The bacterial indicators E. coli and enterococci decreased substantially during summer, mainly through sunlight exposure. Models of contaminant removal based upon measured flow rates and performance data collected at a similar pilot-scale system agreed well with measured data for nitrate and the trace organic contaminants. The model accurately predicted removal of enterococci but systematically over-predicted the removal of E. coli . During the two-year study period, routine maintenance was necessary to prevent colonization of the water surface with duckweed ( Lemna spp.). Unit process open-water (UPOW) wetlands may offer a low-cost means of improving water quality in natural treatment systems that can be integrated with conventional surface-flow wetlands and other managed natural systems. The quantitative models of contaminant removal described in this study can be used to design natural treatment systems that balance the needs for local water quality requirements, available land and site-specific requirements.

To protect water resources, the WHO recommends assessing land use influence on water quality, taking into consideration residential development and waste disposal amongst others. Thus, we investigated the impact of unconstructed plots, an informal settlement, an urban residential area, and an industrial area on the microbiological and physicochemical quality of two main tributaries within the Klein Jukskei catchment, Johannesburg, South Africa, to identify areas where immediate resource management strategies were needed. Water samples collected from the tributaries’ sources and upstream and downstream from each land use type (Winter and Spring) were analysed for E. coli (indicator organism), using the Colilert ® 18 system. Physicochemical parameters (Temperature, pH, dissolved oxygen, electrical conductivity, turbidity and total dissolved solids) were measured using multiparameter instruments. The tributaries’ sources had the lowest E. coli counts (Sandspruit – 0.74; North Ridingspruit – 1.18 log 10 MPN/100 mL) during the study. After flowing through the various land uses, mean E. coli counts reached 5.98 (Sandspruit) and 4.85 log 10 MPN/100 mL (North Ridingspruit). E. coli values and all physicochemical parameters (but for pH) downstream from most of the land uses did not meet the South African drinking water quality guidelines. The informal settlement had the most negative impact on the microbial and physicochemical quality of the water within the tributaries. Thus, providing informal settlements with appropriate sanitation facilities is likely to prevent pollution of the water bodies. Protection of the sources should also be implemented while industrial wastes need to be monitored for conformity with water quality guidelines before discharge.

The microbial quality of urban recreational water is of great concern to public health. The monitoring of indicator organisms and several pathogens alone is not sufficient to accurately and comprehensively identify microbial risks. To assess the levels of bacterial pathogens and health risks in urban recreational water, we analyzed pathogen diversity and quantified four pathogens in 46 water samples collected from waterbodies in Beijing Olympic Forest Park in one year. The pathogen diversity revealed by 16S rRNA gene targeted next-generation sequencing (NGS) showed that 16 of 40 genera and 13 of 76 reference species were present. The most abundant species were Acinetobacter johnsonii, Mycobacterium avium and Aeromonas spp. Quantitative polymerase chain reaction (qPCR) of Escherichia coli (uidA), Aeromonas (aerA), M. avium (16S rRNA), Pseudomonas aeruginosa (oaa) and Salmonella (invA) showed that the aerA genes were the most abundant, occurring in all samples with concentrations of 104–6 genome copies/100 mL, followed by oaa, invA and M. avium. In total, 34.8% of the samples harbored all genes, indicating the prevalence of these pathogens in this recreational waterbody. Based on the qPCR results, a quantitative microbial risk assessment (QMRA) showed that the annual infection risks of Salmonella, M. avium and P. aeruginosa in five activities were mostly greater than the U.S. EPA risk limit for recreational contacts, and children playing with water may be exposed to the greatest infection risk. Our findings provide a comprehensive understanding of bacterial pathogen diversity and pathogen abundance in urban recreational water by applying both NGS and qPCR.

Faecal-derived microbial pollution of fresh surface waters is a global problem. Water quality models can play an important role in the management of microbial pollution; however, most existing models are too complex and require a large amount of observed data for calibration, thereby excluding their use in data-scarce catchments. The Water Quality Systems Assessment Model (WQSAM) is a water quality water model structured on the concept of requisite simplicity, thereby limiting the complexity and data requirements of the model. Here, microbial water quality simulation functionality was added to WQSAM, with the aim of assessing whether a simplified representation of processes affecting microbial water quality is sufficiently accurate for purposes of water resource management. Simulations of microbial water quality were based on the inputs and fate of an indicator organism, Escherichia coli. Non-point source inputs were modelled by assigning microbial water quality ‘signatures’ to incremental flow components, whereas a similar signature was assigned to point source inputs. The instream fate of E. coli was based on a first-order rate equation, moderated by salinity and water temperature. The model was validated by application to the upper to middle Crocodile River Catchment, Mpumalanga, South Africa, for historical conditions. Model simulations were obtained that were representative of the variability of observed temperature, salinity and microbial water quality data. The simulations of E. coli were found to be most sensitive to the decay rate k 0. It is argued here that the uncertainty in model results due to the use of a relatively simple model structure would be no more, or even less that that due to the application of a complex model to a catchment with insufficient observed data for adequate model calibration.

The efficiency of two large-volume batch solar reactors [Prototype I (140 L) and II (88 L)] in treating rainwater on-site in a local informal settlement and farming community was assessed. Untreated [Tank 1 and Tank 2-(First-flush)] and treated (Prototype I and II) tank water samples were routinely collected from each site and all the measured physico-chemical parameters (e.g. pH and turbidity, amongst others), anions (e.g. sulphate and chloride, amongst others) and cations (e.g. iron and lead, amongst others) were within national and international drinking water guidelines limits. Culture-based analysis indicated that Escherichia coli, total and faecal coliforms, enterococci and heterotrophic bacteria counts exceeded drinking water guideline limits in 61%, 100%, 45%, 24% and 100% of the untreated tank water samples collected from both sites. However, an 8 hour solar exposure treatment for both solar reactors was sufficient to reduce these indicator organisms to within national and international drinking water standards, with the exception of the heterotrophic bacteria which exceeded the drinking water standard limit in 43% of the samples treated with the Prototype I reactor (1 log reduction). Molecular viability analysis subsequently indicated that mean overall reductions of 75% and 74% were obtained for the analysed indicator organisms (E. coli and enterococci spp.) and opportunistic pathogens (Klebsiella spp., Legionella spp., Pseudomonas spp., Salmonella spp. and Cryptosporidium spp. oocysts) in the Prototype I and II solar reactors, respectively. The large-volume batch solar reactor prototypes could thus effectively provide four (88 L Prototype II) to seven (144 L Prototype I) people on a daily basis with the basic water requirement for human activities (20 L). Additionally, a generic Water Safety Plan was developed to aid practitioners in identifying risks and implement remedial actions in this type of installation in order to ensure the safety of the treated water.

Combined sewer overflow (CSO) negatively impacts water quality during wet weather. An end-of-pipe treatment train with settleable particle removal and peracetic acid (PAA) disinfection was ...

The high frequency and intensity of urban floods caused by climate change, urbanisation and infrastructure failures increase public health risks when the flood water contaminated from combined sewer overflows (CSOs) or other sources of faecal contamination remains on urban surfaces. This study contributes to a better understanding of the effects of urban and recreational surfaces on the occurrence of waterborne pathogens. The inactivation of selected indicator organisms was studied under controlled exposure to artificial sunlight for 6 h followed by 18 h in dark conditions. Concrete, asphalt, pavement blocks and glass as control were inoculated with artificial floodwater containing, as indicator organisms, Escherichia coli bacteria, which are common faecal indicator bacteria (FIB) for water quality assessment, Bacillus subtilis spores chosen as surrogates for Cryptosporidium parvum oocysts and Giardia cysts, and bacteriophages MS2 as indicators for viral contamination. On practically all the surfaces in this study, E. coli had the highest inactivation under light conditions followed by MS2 and B. subtilis, except asphalt where MS2 was inactivated faster. The highest inactivation under light conditions was seen with E. coli on a concrete surface (pH 9.6) with an inactivation rate of 1.85 h−1. However, the pH of the surfaces (varying between 7.0 and 9.6) did not have any influence on inactivation rates under dark conditions. MS2 bacteriophage had the highest inactivation under light conditions on asphalt with a rate of 1.29 h−1. No die-off of B. subtilis spores was observed on any of the surfaces during the experiment, neither in light nor in dark conditions. This study underpins the need to use different indicator organisms to test their inactivation after flooding. It also suggests that given the sunlight conditions, concentration of indicator organisms and type of surface, the fate of waterborne pathogens after a flood could be estimated.

Two field studies were conducted to determine the effect of anaerobic digestion (AD) on the presence and levels of pathogens in post-AD materials. In the first study, samples of pre-AD liquid, post-AD liquid, and post-AD solid were assayed bi-weekly, for six sampling events from a continuous mix and plug-flow AD. In the second study, samples were taken from multiple locations pre-AD and post-AD before and after liquid-solid separation. Samples were assayed for generic E. coli (GEC), Enterococci, Mycobacterium avium subsp. paratuberculosis (MAP), bovine Enterovirus, Campylobacter spp., and Salmonella spp., Escherichia coli O157:H7. Anaerobic digestion resulted in declines of 99% for GEC and 85 to 95% for Enterococci. Twenty-five samples of composted solid manure from the plug-flow digesters indicated a reduction of > 99% for GEC and > 99% for Enterococci. Bovine Enterovirus and MAP were isolated on numerous occasions from both pre- and post-digestion samples and composted material. Salmonella spp. and Campylobacter were found in 50 to 92% both post-digestion, and remained at a detection level of 21 to 96%, respectively, in liquid manure immediately post-AD. Composting of AD solids did reduce the detection of Salmonella to 10% and Campylobacter to 0%. While substantial quantitative reductions occurred for GEC and Enterococci, the minimal survival of these indicator organisms along with the frequent survival of Enterovirus and MAP indicates that AD, even followed by composting, would not remove all biosecurity hazards.

This study compared light and dark disinfection of faecal bacteria/viral indicator organisms (E. coli and MS2 (fRNA) bacteriophage) and human viruses (Echovirus and Norovirus) in Wastewater Treatment Pond (WTP) mesocosms. Stirred pond mesocosms were operated in either outdoor sunlight-exposed or laboratory dark conditions in two experiments during the austral summer. To investigate wavelength-dependence of sunlight disinfection, three optical filters were used: (1) polyethylene film (light control: transmitting all solar UV and visible wavelengths), (2) acrylic (removing most UVB 5-log E. coli and MS2 phage removal (from ~1.0 × 106 to

Highlights • Indicator organisms do not tell the whole story for the safety of water and sanitation systems. • Considering only fecal indicator groups may provide a falsely reduced sense of risk. • Consideration of pathogens matters for meeting SDG6., Water and wastewater utilities, water and sanitation hygiene (WASH) practitioners, and regulating bodies, particularly in developing nations, rely heavily on indicator microorganisms, as opposed to pathogens, for much of their regulatory decisions. This commentary illustrates the importance of considering pathogens and not relying only on indicator organisms when making decisions regarding water and sanitation, especially with respect to meeting the current targets of the Sustainable Development Goal (SDG) 6. We use quantitative microbial risk assessment (QMRA) to present three common scenarios that WASH and public health practitioners encounter to illustrate our point. These include 1) chlorination of surface water for drinking, 2) land application of latrine waste as a fertilizer, and 3) recreation/domestic use of surface waters impacted by wastewater discharge. We show that the calculated probabilities of risk of infection are statistically significantly higher when using treatment/survival information for pathogens versus using indicator species data. Thus, demonstrating that relying solely on indicators for sanitation decision making is inadequate if we truly want to achieve the SDG6 targets of safely managed water and sanitation services., Graphical abstract Image, graphical abstract

This study investigated the occurrence of various opportunistic pathogens (OPs) through four drinking water treatment and distribution systems in eastern China. Conventional treatment trains involving coagulation/sedimentation, filtration, and disinfection efficiently removed total coliforms from 1700 to 2300 CFU/L in the influent to undetectable levels in treated and tap water. However, culture-independent qPCR analysis detected Legionella spp., Mycobacterium spp., Mycobacteria avium, Pseudomonas aeruginosa and the amoeba Acanthamoeba spp. in all water samples, reaching maximum tap water concentrations of 5.33, 4.87, 1.63, 3.85, and 4.32 log (gene copies/mL), respectively. Thus, OPs were abundant in tap water despite total coliforms met applicable microbiological standards in China (GB 5749–2006). Occurrence of OPs correlated positively with turbidity and chemical oxygen demand (COD), and negatively with chlorine residual. Turbidity removal by coagulation and COD removal by ozonation (O3) followed by biological activated carbon (BAC) filtration was the treatment train with the highest OPs removal efficiency, and ClO2 was a more effective disinfectant than NaClO. OPs significantly rebounded in the tap water (up to 11-fold for P. aeruginosa and 21-fold for M. avium in tap water). However, quantitative microbial risk analysis (QMRA) showed that the potential infection risks in tap water were still below WHO (10−3) and even EPA (10−4) benchmarks. Overall, likely underestimation of the pathogenic risk by culture-dependent quantification of indicator organisms makes it prudent to use molecular approaches to periodically revisit the safety of water distribution systems.

Dumpsites and garbage collection areas can act as reservoirs of highly resistant bacterial strains and facilitate the dissemination of Multidrug resistant strains to those living and work on or near the dumpsites and garbage collection areas. The objective of this study was to determine the potential of garbage collection areas and dumpsites in different parts of Nairobi as possible sources of resistant strains using E. coli and Klebsiella as indicator species. The study design was a cross-sectional survey. Sample collection was carried out at different days in seventeen different areas. A total of 126 samples were collected during the sampling period. The samples were then transported to the laboratory for analysis. The samples were cultured on MacConkey agar. Gram staining was done on discrete isolates based on colony characteristics. Biochemical tests were performed on colonies from primary cultures for final identification of the isolates. Antimicrobial disc susceptibility tests and pathogenicity tests were also carried out on the indicator isolates. A total of 121 E. coli and 165 Klebsiella were isolated from all the sampled sites. The highest bacterial burden was recorded from Muthurwa estate dumpsite, with a mean viable count of 8.2 × 1010 cfu/gm while the least was from Dandora dumpsite with a mean count of 1.1 × 1011 cfu/gm. Overall, gentamicin was the most effective antibacterial agent on Klebsiella and meropenem was the most effective on both E. coli and Klebsiella strains. The isolates showed high resistance to ampicillin, streptomycin, and trimethoprim-sulfamethoxazole. It is concluded that municipal waste dumpsites and garbage collection areas bear heavy burdens of potentially resistant bacteria which may constitute major public health hazards, not only to the immediate communities but also to the families of such site workers.

Although Canada has abundant freshwater resources, many cities still experience seasonal water shortage. Supply-side and demand-side management is a core strategy to address this water shortage. Under this strategy, reclaimed water, which the Canadian public is willing to use for non-potable purposes, is an option. However, no universal guidelines exist for reclaimed water use. Despite the federal government's long-term goal to develop guidelines for many water reuse applications, guidelines have only been prescribed for reclaimed water use in toilet and urinal flushing in Canada. At the provincial level, British Columbia (BC) has promulgated guidelines for wide applications of reclaimed water but only at broad class levels. This research has investigated and proposed probabilistic risk-based recommended values for microbial quality of reclaimed water in various non-potable urban reuses. The health risk was estimated by using quantitative microbial risk assessment. Two-dimensional Monte Carlo simulations were used in the analysis to include variability and uncertainty in input data. The proposed recommended values are based on the indicator organism E. coli. The required treatment levels for reuse were also estimated. In addition, the recommended values were successfully applied to three wastewater treatment effluents in the Okanagan Valley, BC, Canada. The health risks associated with other bacterial pathogens (Campylobacter jejuni and Salmonella spp.), virus (adenovirus, norovirus, and rotavirus), and protozoa (Cryptosporidium parvum and Giardia spp.), were also estimated. The estimated risks indicate the effectiveness of the E. coli-based water quality recommended values. Sensitivity analysis shows the pathogenic E. coli ratio and morbidity are the most sensitive input parameters for all water reuses. The proposed recommended values could be further improved by using national or regional data on water exposures, disease burden per case, and the susceptibility fraction of population.

Fish is the main source of animal protein and micronutrients for inhabitants in the lower Mekong River basin. Consumption of fish in the basin ranges from 41 to 51 kg capita−1 year−1. Thus, concerns of human health impacts caused by daily intake of metals contained in fish, and the incidence of bacterial contamination from Listeria and Escherichia coli have been raised. This study was conducted to 1) determine concentrations of metals, fecal indicator organisms, and Listeria spp. in cultivated common diet fish, and 2) assess human health risks as results of fish consumption on a daily basis. The results showed significant impacts of metal accumulation in fish especially from the intensive aquaculture. Chemical use to promote the rapid allometric growth of fish was expected to be the explanation for this finding. Concentrations of metals contained in different fish species were not statistically different with the exceptions of Na, Mn, and Zn. This might be due to the mobility of elements in aquaculture farms. Listeria and E. coli log CFU/g were 1.36 ± 0.11 (standard error) and 1.57 ± 0.1 s.e., respectively with higher counts observed in samples collected in market sites. Lastly, for human health risk assessment via fish consumption, it was found that hazard quotients of consuming As, Cu, and Zn contained in all fish species could contribute adverse health effects to the local residents (hazard quotients higher than 1). Therefore, risk management measures must be promoted and implemented in all study areas to reduce potential risks to local Vietnamese residents.

The present study investigated the prevalence of pathogenic organisms (Salmonella spp, Vibrio cholerae, and Shigella spp) and their correlation to the abundance of faecal indicator organisms in water and riverbed sediments in the Apies River, South Africa. In all, 558 water and sediment samples were collected from 10 sites in the river (May 2013–February 2014) and analysed through culture and molecular (real-time PCR) techniques. Concentrations of faecal indicator organisms in sediments reached 1.39 × 105 (±standard deviation) CFU/100 mL. All three pathogens were detected in water and sediments. Pathogens were mostly detected in sediments at sites influenced either by wastewater treatment works or by informal settlements. During the wet and dry seasons (water column), a strong positive correlation was observed between E. coli and all pathogens; C. perfringens only correlated with V. cholerae. Within sediments, strong positive correlations were only observed between E. coli and Salmonella spp, E. coli and V. cholerae (dry season); E. coli and V. cholerae and E. coli and Shigella spp (wet season). No correlation was observed between sediments C. perfringens counts and all the pathogens. Thus, sediments of the Apies River harbour pathogenic organisms. Correlation between E. coli and pathogenic organisms in the sediments suggests that E. coli could also be an indicator of pathogens’ presence. However, the lack of a correlation between E. coli and some pathogens in sediments and between C. perfringens and all the pathogens highlights the need to investigate for more indicators of pathogens’ presence in this complex matrix.

The introduction of aquatic non-indigenous organisms and pathogens via ships ballast water is considered as a great treat to global marine ecosystems, costal economy and public health. This issue can be efficiently addressed by electrolytic treatment technology. In this work, the effects of organic compounds on inactivation efficacy of neutral electrolyzed water were studied by bench scale test and land-based test with Artemia salina as an indicator organism. In bench scale test, both glucose and chitosan significantly accelerated TRO decay of neutral electrolyzed water, while the other kinds of dissolved organic compounds (sodium citrate and sucrose) and particle organic compounds (corn starch) had no significant effect on TRO decay. Both glucose and chitosan weakened the inactivation efficacy of neutral electrolyzed water, especially at 24 h. The results of land-based test also indicated that the inactivation efficacy of ballast water management system not only depended on TRO initial concentration, but also on the property of organic compounds. The presence of glucose and chitosan indicated the need of high level of initial TRO concentration to reach good inactivation efficacy. The results of this study may be useful to decide the initial TRO concentration in ballast water treatment with electrolysis technology.

The Bogota River receives untreated wastewater from the city of Bogota and many other towns. Downstream from Bogota, water from the river is used for irrigation of crops. Concentrations of indicator organisms in the river are high, which is consistent with fecal contamination. To investigate the probability of illness due to exposure to enteric pathogens from the river, specifically Salmonella, we took water samples from the Bogota River at six sampling locations in an area where untreated water from the river is used for irrigation of lettuce, broccoli, and cabbage. Salmonella concentrations were quantified by direct isolation and qPCR. Concentrations differed, depending on the quantification technique used, ranging between 107.7 and 109.9 number of copies of gene invA per L and 105.3 and 108.4 CFU/L, for qPCR and direct isolation, respectively. A quantitative microbial risk assessment model that estimates the daily risk of illness with Salmonella resulting from consuming raw unwashed vegetables irrigated with water from the Bogota River was constructed using the Salmonella concentration data. The daily probability of illness from eating raw unwashed vegetables ranged between 0.62 and 0.85, 0.64 and 0.86, and 0.64 and 0.85 based on concentrations estimated by qPCR (0.47-0.85, 0.47-0.86, and 0.41-0.85 based on concentrations estimated by direct isolation) for lettuce, cabbage, and broccoli, respectively, which are all above the commonly propounded benchmark of 10-4 per year. Results obtained in this study highlight the necessity for appropriate wastewater treatment in the region, and emphasize the importance of postharvest practices, such as washing, disinfecting, and cooking.

Agro-pastoral operations have the potential to threaten public health with loading of diverse pathogens into surface waters through overland flow; increasing awareness of the limitations of fecal indicators has led to development of a number of advancements in detection, source tracking and predictive modeling of public health risk. These tools and techniques are beginning to be integrated into management strategies. The objective of this review was to determine the status of current knowledge and challenges of the fate and transport of Escherichia coli in overland flow and their interaction within vegetative filter strip (VFS) as one of these implemented best management practices and to critically evaluate its use in that setting as an indicator organism. With few studies directly focusing on VFS removal of E. coli from overland flow, we critically evaluated the available data on movement of E. coil from fecal source loading to retention and decay or re-release for potential contamination of water ways and pointed out potential limitations in both pathogen-specific removal and its use as an indicator organisms within overland flow and VFS. Critical areas of focus for future studies to reduce gaps in knowledge were identified, and the integration of newer approaches in source tracking, alternative indicators and the use of non-pathogenic surrogates for field testing of existing VFS models was encouraged. With VFS as a growing field of interest as an economical conservation practice and as an avenue for conservation of resources for small-scale agro-pastoral operations, management strategies to reduce initial fecal load from either applied manure constituents or shedding from free-range animals will continue to test the limits in the applications of models to overland flow and VFS management strategies. Further studies at the microscale in understanding discrepancies between low and high pathogenicity strains of E. coil and between E. coil and other fecal pathogens in the context of VFS will be critical. However, nuanced studies are needed to understand either biological or environmental differences in the fate and transport of the diverse types of fecal pathogens within these settings

Knowledge of pathogen removal in stormwater biofilters (also known as stormwater bioretention systems or rain gardens) has predominately been determined using bacterial indicators, and the removal of reference pathogens in these systems has rarely been investigated. Furthermore, current understanding of indicator bacteria removal in these systems is largely built upon laboratory-scale work. This paper examines whether indicator organism removal from urban stormwater using biofilters in laboratory settings are representative of the removal of pathogens in field conditions, by studying the removal of Escherichia coli (a typical indicator microorganism) and Campylobacter spp. (a typical reference pathogen) from urban stormwater by two established field-scale biofilters. It was found that E. coli log reduction was higher than that of Campylobacter spp. in both biofilters, and that there was no correlation between E. coli and Campylobacter spp. log removal performance. This confirms that E. coli behaves significantly differently to this reference pathogen, reinforcing that single organisms should not be employed to understand faecal microorganism removal in urban stormwater treatment systems. The average reduction in E. coli from only one of the tested biofilters was able to meet the log reduction targets suggested in the current Australian stormwater harvesting guidelines for irrigating sports fields and golf courses. The difference in the performance of the two biofilters is likely a result of a number of design and operational factors; the most important being that the biofilter that did not meet the guidelines was tested using extremely high influent volumes and microbial concentrations, and long antecedent dry weather periods. As such, the E. coli removal performances identified in this study confirmed laboratory findings that inflow concentration and antecedent dry period impact overall microbial removal. In general, this paper emphasizes the need for the validation of stormwater harvesting systems, namely, the testing of treatment systems under challenging operational conditions using multiple indicators and reference pathogens.

Solar pasteurization is effective in reducing the level of indicator organisms in stored rainwater to within drinking water standards. However, Legionella spp. were detected at temperatures exceeding the recommended pasteurization temperatures using polymerase chain reaction assays. The aim of the current study was thus to apply EMA quantitative polymerase chain reaction (EMA-qPCR) to determine whether the Legionella spp. detected were intact cells and therefore possibly viable at pasteurization temperatures70°C. The BacTiter-Glo™ Microbial Cell Viability Assay was also used to detect the presence of ATP in the tested samples, as ATP indicates the presence of metabolically active cells. Chemical analysis also indicated that all anions and cations were within the respective drinking water guidelines, with the exception of iron (mean: 186.76 μg/L) and aluminium (mean: 188.13 μg/L), which were detected in the pasteurized tank water samples at levels exceeding recommended guidelines. The BacTiter-Glo™ Microbial Cell Viability Assay indicated the presence of viable cells for all pasteurized temperatures tested, with the percentage of ATP (in the form of relative light units) decreasing with increasing temperature [70-79°C (96.7%); 80- 89°C (99.2%); 90-95°C (99.7%)]. EMA-qPCR then indicated that while solar pasteurization significantly reduced (p0.05) the genomic copy numbers of intact Legionella cells in the pasteurized tank water (~99%), no significant difference (p0.05) in the mean copy numbers was detected with an increase in the pasteurization temperature, with 6 × 10(3) genomic copies/mL DNA sample obtained at 95°C. As intact Legionella cells were detected in the pasteurized tank water samples, quantitative microbial risk assessment studies need to be conducted to determine the potential health risk associated with using the water for domestic purposes.

More than 270,000 km of rivers and streams are impaired due to fecal pathogens, creating an economic and public health burden. Fecal indicator organisms such as are used to determine if surface waters are pathogen impaired, but they fail to identify human health risks, provide source information, or have unique fate and transport processes. Statistical and machine learning models can be used to overcome some of these weaknesses, including identifying ecological mechanisms influencing fecal pollution. In this study, canonical correlation analysis (CCorA) was performed to select parameters for the machine learning model, Maxent, to identify how chemical and microbial parameters can predict impairment and F-somatic bacteriophage detections. Models were validated using a bootstrapping cross-validation. Three suites of models were developed; initial models using all parameters, models using parameters identified in CCorA, and optimized models after further sensitivity analysis. Canonical correlation analysis reduced the number of parameters needed to achieve the same degree of accuracy in the initial model (84.7%), and sensitivity analysis improved accuracy to 86.1%. Bacteriophage model accuracies were 79.2, 70.8, and 69.4% for the initial, CCorA, and optimized models, respectively; this suggests complex ecological interactions of bacteriophages are not captured by CCorA. Results indicate distinct ecological drivers of impairment depending on the fecal indicator organism used. impairment is driven by increased hardness and microbial activity, whereas bacteriophage detection is inhibited by high levels of coliforms in sediment. Both indicators were influenced by organic pollution and phosphorus limitation.

viii CHAPTER 1: GENERAL INTRODUCTION 1 CHAPTER 2. LITERATURE REVIEW 3 Pathogens and water quality 3 Waterborne disease and water impairment 3 Fecal indicator organisms and water quality standards 4 TMDLs and modeling of bacterial transport 6 Bacterial attachment 7 Definition of bacterial attachment 7 Bacterial attachment in the environment 9 Partitioning methods for bacterial attachment 10 Properties impacting bacterial attachment 12 References 17 CHAPTER 3. DIVERSITY IN PROPERTIES OF E. COLI DERIVED FROM STREAM WATER AND SEDIMENT 23 Abstract 23 23 Introduction 24 Materials and Methods 26 E. coli sampling and analysis 26 Computer-assisted rep-PCR DNA fingerprint analysis 27 Cell Properties 28 Data analyses 30 Results and Discussion 31 E. coli strain selection and dendrogram 31 E. coli property comparison between two environmental habitats 31

Under normal operation, membrane bioreactors (MBRs) produce high quality effluent leading to common application in water recycling schemes. When hazardous events, outside of normal operation, occur strategies must be in place to ensure that microbially safe water is consistently produced. Limited literature is available to quantify the consequence of hazardous events on microorganism log removal value (LRV) by MBRs. As a result, current MBR risk management practices cannot be based on sufficient quantitative evidence. In this study, MBRs were subjected to hazardous events designed to reflect a range of potential severe feed water variations and process failures. During these challenge events, removal of four microbial indicator organisms representing viruses, bacteria and protozoa were quantified. Hazardous event impacts were benchmarked against the 5th percentile of normal process LRV, determined via probabilistic techniques. Severe feed water variation decreased the efficacy of bio-predation due to adversely affected activated sludge performance. However, overall LRV was preserved due to the onset of fouling, aiding rejection by the membrane. Overall FRNA bacteriophage LRV significantly decreased to 0.3 log units below the 5th percentile (LRV=4.1) after the NaCl shock, most likely due to inhibition of adsorption mechanisms. Fibre breakage resulted in a significant reduction in LRV, but was mitigated by suspended solids plugging the membrane lumen within 15 min. The findings presented here can inform risk management strategies for MBRs by permitting control strategy prioritisation according to quantified event consequences.

Point-of-use water treatment has received widespread application in the developing world to help mitigate waterborne infectious disease. This study examines the efficacy of a combined filter and chemical disinfection technology in removing bacterial contaminants, and more specifically changes in its performance resulting from seasonal weather variability. During a 12-month field trial in Chennai, India, mean log-reductions were 1.51 for E. coli and 1.67 for total coliforms, and the highest concentration of indicator bacteria in treated water samples were found during the monsoon season. Analysis of variance revealed significant differences in the microbial load of indicator organisms (coliforms and E. coli) between seasons, storage time since treatment (TST), and samples with and without chlorine residuals. Findings indicate that the bacteriological quality of drinking water treated in the home is determined by a complex interaction of environmental and sociological conditions. Moreover, while the effect of disinfection was independent of season, the impact of storage TST on water quality was found to be seasonally dependent.

Enteric pathogens are typically inferred from the presence of surrogate indicator organisms such as thermotolerant (faecal) coliforms (TTCs). The analysis of TTCs requires time-consuming incubation in suitable laboratories, which can limit sampling resolution, particularly during critical pollution events. Here, we demonstrate the use of in-situ fluorimeters targeting tryptophan-like compounds as a rapid, reagentless indicator of TTCs in groundwater-derived potable water supplies in Africa. A range of other common indicators of TTCs were also determined including nitrate, turbidity, and sanitary risk survey scores. Sampling was conducted during both the dry and wet seasons to investigate seasonality. Tryptophan-like fluorescence was the most effective predictor of both presence/absence and number of TTCs during both seasons. Seasonal changes in tryptophan-like fluorescence in deeper supplies suggest it is transported more efficiently through the aquifer than TTCs. Moreover, the perennial elevated concentrations in some wells suggest it is more resilient than TTCs in groundwater. Therefore tryptophan-like fluorescence could also be a better indicator of some smaller, more easily transported, and long-lived, pathogenic enteric viruses. These sensors have the potential to be included in real-time pollution alert systems for drinking water supplies throughout the world, as well as for mapping enteric pathogen risks in developing regions.

This study aimed to investigate the fate of faecal indicator organisms and to characterize microbial diversity dynamics in dairy manure and in aerated liquid manure in different treatment reactors in a series of continuously fed aerated tank reactors using low intensity aeration and ammonia-reduced feedback. The bacterial diversity in the treatment reactors was also compared with that in the soil from which the process inoculant originated. The fate of enteric indicator organisms was studied by the enumeration of viable counts. Total bacterial community DNA was extracted, amplified using 16S rRNA primers, cloned, sequenced and identified by comparison to known sequences. At best over 90% reduction was observed in the numbers of enteric indicator organisms. However, the result obtained varied depending on treatment run and indicator organism. Firmicutes were the dominating phyla of the untreated slurry; whereas; Proteobacteria and Deinococcus-Thermus dominated in the treatment tanks. Soil had the broadest phylogenetic diversity: the major phylums were Acidobacteria, Proteobacteri and Gemmatimonadetes. At the genus level, raw manure and treatment tanks shared a number of sequences. Soil, the origin of the inoculant, and treatment tanks did not share any sequence at the genus level, although some was observed at the family level.

Investigations into the microbiological impacts of urban runoff on receiving water bodies, especially during storm conditions, have yielded general paradigms that influence runoff abatement and control management strategies. To determine whether these trends are present in other runoff sources, the physical, chemical, and microbiological components of residential runoff from eight neighborhoods in Northern and Southern California were characterized over the course of five years. Sampling occurred regularly and during storm events, resulting in 833 data sets. Analysis of runoff data assisted in characterizing residential runoff, elucidating differences between dry and storm conditions, and identifying surrogates capable of assessing microbiological quality. Results indicate that although microbial loading increases during storm events similar to urban runoff, annual microbial loading in these study sites principally occurs during dry conditions (24% storm, 76% dry). Generated artificial neural network and multiple linear regression models assessed surrogate performance by accurately predicting Escherichia coli concentrations from validation data sets (R2 = 0.74 and 0.77, respectively), but required input from other fecal indicator organism (FIO) variables to maintain performance (R2 = 0.27 and 0.18, respectively, without FIO). This long-term analysis of residential runoff highlights characteristics distinct from urban runoff and establishes necessary variables for determining microbiological quality, thus better informing future management strategies.

The xenobiotics introduced into the environment are the effect of human activities. It is especially soil contamination that leads to degradation of soils, which may finally be referred to the biological imbalance of the ecosystem. Normally chemical methods are used for the assessment of soil’s quality. Unfortunately, they are not always quick and inexpensive. Therefore, the practice and the science at environmental monitoring more frequently employ biological methods. Most of them meet the above mentioned conditions and become a supplement of routine laboratory practices. This publication shows an overview of selected common biological methods used to estimate the quality of the environment. The first part of the paper presents biomonitoring as a first step of environmental control which relies on the observation of indicator organisms. The next section was dedicated to the bioassays, indicating the greater or lesser practical applications confirmed by literature on the subject. Particular attention has been focused on phytotests and the tests based on the invertebrates.

Domestic sewage discharge and live stocks are the main sources of pathogenic contaminations in rivers. The river Tamiraparani in southern India is affected by such non- point source pollution throughout the year. We collected a total of 264 samples (water and sediment) from 22 locations in 2-month intervals during a period of 1 year. Bacteriological analysis such as total viable counts (TVC), total coliform (TC), total Streptococcus (TS), Vibrio like organisms (VLO) and five pathogens as well as 12 geochemical parameters (pH, EC, TDS, Cl, HCO3, Ca, Mg, Na, K, PO4, other nutrients and total hardness) were studied. Principal Component Analysis (PCA) and correlation analysis proved that micro- bial communities were separated with geochemical parameters in order to gain their efficacy. Factor analysis confirmed separate loading rates of microbial (32.3 %) and geochemical (32.7 %) parameters representing 'allochthonous - geochemical' and 'fecal matters - microbial' interactions, respectively. We used geographical information systems (GIS) for mapping the occurrence of indicator organisms from non-point sources throughout the river basin.

The present investigation focused on the evaluation of vermifiltration process using different natural ingredients as a media. The vermifilter was evaluated using different natural ingredients viz river bed material, wood coal, glass balls, mud balls and employing Eisenia fetida as an earthworm species. The complete study was carried out for 90 days. The average COD removal for different material i.e. river bed material, wood coal, glass balls and mud balls was found as 72.3, 64.6, 61.5 and 59.8% while average BOD removal was observed as 81.2, 74.5, 72.7 and 70.9%, for respective filter media. Similarly, the total suspended solid removal was observed as 75, 64, 59 and 55%, respectively for above mentioned different media. The river bed material revealed maximum reduction of indicator organisms like total coliform (3.6 ± 0.90 log unit), fecal coliform (3.4 ± 0.67 log unit), fecal streptococci and Escherichia coli (2.5 ± 0.51 log unit). At the end of the run vermicompost obtained through vermifiltration process as a byproduct were found to be rich in nitrate (31.2 ± 5.9 mg/L), phosphate (18.1 ± 4.6 mg/L) which could be exploited in sewage farming.

Biosolids are nutrient-rich organic residuals that are currently used to amend soils for food production. Treatment requirements to inactivate pathogens for production of Class A biosolids are energy intensive. One less energy intensive alternative is to treat biosolids to Class B standards, but it could result in higher pathogen loads. Quantitative microbial risk assessments models have been developed on land application of Class B biosolids but contain many uncertainties because of limited data on specific pathogen densities and the use of fecal indicator organisms as accurate surrogates of pathogen loads. To address this gap, a 12-mo study of the levels and relationships between Cryptosporidium, Giardia, and human adenovirus (HAdV) with fecal coliform, somatic, and F-RNA coliphage levels in Class B biosolids from nine wastewater treatment plants throughout the United States was conducted. Results revealed that fecal coliform, somatic, and F-RNA coliphage densities were consistent throughout the year. More important, results revealed that HAdV ( x = 2.5 × 10 3 genome copies dry g -1 ) and Giardia ( x = 4.14 × 10 3 cysts dry g -1 ) were in all biosolids samples regardless of treatment processes, location, or season. Cryptosporidium oocysts were also detected (38% positive; range: 0-1.9 × 10 3 oocysts dry g -1 ), albeit sporadically. Positive correlations among three fecal indicator organisms and HAdV, but not protozoa, were also observed. Overall, this study reveals that high concentrations of enteric pathogens (e.g., Cryptosporidium, Giardia, and HAdV) are present in biosolids throughout the United States. Microbial densities found can further assist management and policymakers in establishing more accurate risk assessment models associated with land application of Class B biosolids.

Combined sewer overflows (CSOs) are a known source of human fecal pollution and human pathogens in urban water bodies, which may present a significant public health threat. To monitor human fecal contamination in water, bacterial fecal indicator organisms (FIOs) are traditionally used. However, because FIOs are not specific to human sources and do not correlate with human pathogens, alternative fecal indicators detected using qPCR are becoming of interest to policymakers. For this reason, this study measured correlations between the number and duration of CSOs and mm of rainfall, concentrations of traditional FIOs and alternative indicators, and the presence of human pathogens in two urban creeks. Samples were collected May–July 2016 and analyzed for concentrations of FIOs (total coliforms and E. coli) using membrane filtration as well as for three alternative fecal indicators (human Bacteroides HF183 marker, human polyomavirus (HPoV), pepper mild mottle virus (PMMoV)) and nine human pathogens using qPCR. Four of the nine pathogens analyzed were detected at these sites including adenovirus, Enterohemorrhagic E. coli, norovirus, and Salmonella. Among all indicators studied, human Bacteroides and total coliforms were significantly correlated with recent CSO and rainfall events, while E. coli, PMMoV, and HPoV did not show consistent significant correlations. Further, human Bacteroides were a more specific indicator, while total coliforms were a more sensitive indicator of CSO and rainfall events. Results may have implications for the use and interpretation of these indicators in future policy or monitoring programs.