What removals of pathogen indicators can be expected within large-scale wastewater treatment facilities in the context of wastewater reuse in Paris conurbation?

The fate of pathogen indicators (Escherichia coli – EC, intestinal enterococci – IE, RNA-F bacteriophages and SSR) was extensively studied in Parisian large-scale wastewater treatment plants (WWTPs), based on conventional activated sludge, biofiltration or MBR processes. 14–87 campaigns were performed between 2014 and 2018 in 5 WWTPs. High removals of 3 log for both EC and IE, and lower removals of 1–2 log for SSR and RNA-F bacteriophages, were observed in conventional activated sludge and biofiltration WWTPs. The MBR WWTP achieves notably greater removals of 4.5–5.5 log for faecal bacteria and 3–4 log of SSR and RNA-F bacteriophages. This WWTP is the only already in compliance with reuse standards, the other ones being non-compliant because of SSR and RNA-F bacteriophages. The implementation of a micro-grain activated carbon process would increase the WWTPs removals of 0.8 log for faecal bacteria, due to particles retention, with no significant effect on both other pathogens. Ozonation (0.9–1.3 g O3/gDOC) or performic acid (0.8–1.2 ppm) would have greater benefits with additional removals of 1.5–2.5 log for EC, 1–2 log for IE and 0.5–1 log for SSR and RNA-F bacteriophages. Correlations between pathogen indicators removals and initial concentrations were found, as well as a significant decrease of RNA-F bacteriophages concentrations in Parisian raw wastewater, below 2 log. Thus, RNA-F bacteriophages could be a real issue to evaluate the compliance of Parisian wastewater with reuse. The time evolution of removals demonstrated that SSR is the most problematic parameter regarding reuse in conventional activated sludge and biofiltration WWTPs, as its initial concentration is high (5 log) but removals insufficient (<2 log). In contrary, removals of RNA-F bacteriophages greater than 2 log can be obtained within WWTPs completed or not with a tertiary treatment when the initial concentration in raw wastewater is sufficient. Correlations were also found between the removals of pathogen indicators and the removals of physico-chemical parameters, but they are not good enough to allow performances predictions.

Increased (Antibiotic-Resistant) Pathogen Indicator Organism Removal during (Hyper-)Thermophilic Anaerobic Digestion of Concentrated Black Water for Safe Nutrient Recovery

Source separated toilet water is a valuable resource for energy and fertilizers as it has a high concentration of organics and nutrients, which can be reused in agriculture. Recovery of nutrients such as nitrogen, phosphorous, and potassium (NPK) decreases the dependency on energy-intensive processes or processes that rely on depleting natural resources. In new sanitation systems, concentrated black water (BW) is obtained by source-separated collection of toilet water. BW-derived products are often associated with safety issues, amongst which pathogens and antibiotic-resistant pathogens. This study presents results showing that thermophilic (55–60 °C) and hyperthermophilic (70 °C) anaerobic treatments had higher (antibiotic-resistant) culturable pathogen indicators removal than mesophilic anaerobic treatment. Hyperthermophilic and thermophilic anaerobic treatment successfully removed Escherichia coli and extended-spectrum β-lactamases producing E. coli from source-separated vacuum collected BW at retention times of 6–11 days and reached significantly higher removal rates than mesophilic (35 °C) anaerobic treatment (p < 0.05). The difference between thermophilic and hyperthermophilic treatment was insignificant, which justifies operation at 55 °C rather than 70 °C. This study is the first to quantify (antibiotic-resistant) E. coli in concentrated BW (10–40 gCOD/L) and to show that both thermophilic and hyperthermophilic anaerobic treatment can adequately remove these pathogen indicators.

Investigation of Pathogenic Bacterial Transport by Waterbirds: A Case Study of Flooded and Non-Flooded Rice Systems in Mississippi

Waterbirds may facilitate pathogen transport in rice fields from autumn to winter. This study investigated pathogen dynamics in two types of rice fields, those considered conventionally managed and a low-external-input-sustainable-agriculture (LEISA) rice system in the Mississippi Alluvial Valley, winter 2017–2018. In each system, fields were (1) left unflooded or (2) flooded from November to March. Fecal indicator and pathogenic bacteria (enterococci, Clostridium perfringens, Escherichia coli, Salmonella spp., and Campylobacter spp.) were quantified in soil before and after winter flooding, and bird fecal matter estimated on both farm types. Water samples were tested for enterococci, C. perfringens and E. coli before fields were drained. The LEISA flooded fields had greater detections of C. perfringens in the soil than conventional non-flooded fields. There was an observed decreasing trend of C. perfringens detection associated with lower bird abundances among treatment groups. All observed pathogen levels in both systems were below EPA standards. Results suggest that long-term waterbird stopovers can influence pathogen indicators in soil, but not at levels to threaten human and environmental health standards. Future studies should focus on long-term monitoring of pathogen introduction in rice fields that harbor wintering waterfowl or other waterbirds.

Detection of Pathogenic Viruses, Pathogen Indicators, and Fecal-Source Markers within Tanker Water and Their Sources in the Kathmandu Valley, Nepal

Tanker water is used extensively for drinking as well as domestic purposes in the Kathmandu Valley of Nepal. This study aimed to investigate water quality in terms of microbial contamination and determine sources of fecal pollution within these waters. Thirty-one samples from 17 tanker filling stations (TFSs) and 30 water tanker (WT) samples were collected during the dry and wet seasons of 2016. Escherichia coli was detected in 52% of the 31 TFS samples and even more frequently in WT samples. Of the six pathogenic viruses tested, enteroviruses, noroviruses of genogroup II (NoVs-GII), human adenoviruses (HAdVs), and group A rotaviruses were detected using quantitative PCR (qPCR) at 10, five, four, and two TFSs, respectively, whereas Aichi virus 1 and NoVs-GI were not detected at any sites. Index viruses, such as pepper mild mottle virus and tobacco mosaic virus, were detected using qPCR in 77% and 95% out of 22 samples, respectively, all of which were positive for at least one of the tested pathogenic viruses. At least one of the four human-associated markers tested (i.e., BacHum, HAdVs, and JC and BK polyomaviruses) was detected using qPCR in 39% of TFS samples. Ruminant-associated markers were detected at three stations, and pig- and chicken-associated markers were found at one station each of the suburbs. These findings indicate that water supplied by TFSs is generally of poor quality and should be improved, and proper management of WTs should be implemented.

High-rate stabilization of primary sludge in a single-chamber microbial hydrogen peroxide producing cell

High-rate sludge stabilization of wastewater primary sludge was achieved in single-chamber microbial peroxide producing cells meeting the requirements of pathogen indicators and vector attraction reductions for class B biosolids.

Role of microbial cell properties on bacterial pathogen and coliphage removal in biochar-modified stormwater biofilters

Bacterial pathogens and pathogen indicators suspended in stormwater are removed to a greater extent in biochar-augmented sand biofilters than sand biofilters; the processes governing the removal are distinct.