A risk-based evaluation of onsite, non-potable reuse systems developed in compliance with conventional water quality measures.
Ontology highlight
ABSTRACT:
SUBMITTER: Schoen ME
PROVIDER: S-EPMC7503949 | biostudies-literature |
REPOSITORIES: biostudies-literature
Similar Datasets
Project description:Onsite non-potable reuse (NPR) is being increasingly considered as a viable option to address water scarcity and infrastructure challenges, particularly at the building scale. However, there are a range of possible treatment technologies, source water options, and treatment system sizes, each with its unique costs and benefits. While demonstration projects are proving that these systems can be technologically feasible and protective of public health, little guidance exists for identifying systems that balance public health protection with environmental and economic performance. This study uses quantitative microbial risk assessment, life cycle assessment and life cycle cost analysis to characterize the human health, environmental and economic aspects of onsite NPR systems. Treatment trains for both mixed wastewater and source-separated graywater were modeled using a core biological process-an aerobic membrane bioreactor (AeMBR), an anaerobic membrane bioreactor (AnMBR) or recirculating vertical flow wetland (RVFW)-and additional treatment and disinfection unit processes sufficient to meet current health-based NPR guidelines. Results show that the graywater AeMBR system designed to provide 100% of onsite non-potable demand results in the lowest impacts across most environmental and human health metrics considered but costs more than the mixed-wastewater version due to the need for a separate collection system. The use of multiple metrics also allows for identification of weaknesses in systems that lead to burden shifting. For example, although the RVFW process requires less energy than the AeMBR process, the RVFW system is more environmentally impactful and costly when considering the additional unit processes required to protect human health. Similarly, we show that incorporation of thermal recovery units to reduce hot water energy consumption can offset some environmental impacts but result in increases to others, including cumulative energy demand. Results demonstrate the need for additional data on the pathogen treatment performance of NPR systems to inform NPR health guidance.
| S-EPMC7490829 | biostudies-literature
Project description:Low molecular weight, uncharged compounds have been the subject of considerable study at advanced treatment plants employed for potable water reuse. However, previously identified compounds only account for a small fraction of the total dissolved organic carbon remaining after reverse osmosis treatment. Uncharged carbonyl compounds (e.g., aldehydes and ketones) formed during oxidation have rarely been monitored in potable water reuse systems. To determine the relative importance of these compounds to final product water quality, samples were collected from six potable water reuse facilities and one conventional drinking water treatment plant. Saturated carbonyl compounds (e.g., formaldehyde, acetone) and α,β-unsaturated aldehydes (e.g., acrolein, crotonaldehyde) were quantified with a sensitive new analytical method. Relatively high concentrations of carbonyls (i.e., above 7 μM) were observed after ozonation of wastewater effluent. Biological filtration reduced concentrations of carbonyls by over 90%. Rejection of the carbonyls during reverse osmosis was correlated with molecular weight, with concentrations decreasing by 33% to 58%. Transformation of carbonyls resulted in decreases in concentration of 10% to 90% during advanced oxidation, with observed decreases consistent with rate constants for reactions of the compounds with hydroxyl radicals. Overall, carbonyl compounds accounted for 19% to 38% of the dissolved organic carbon in reverse osmosis-treated water.
| S-EPMC7755163 | biostudies-literature
Project description:Onsite non-potable water systems (ONWS) collect and treat local source waters for non-potable end uses such as toilet flushing and irrigation. Quantitative microbial risk assessment (QMRA) has been used to set pathogen log10-reduction targets (LRTs) for ONWS to achieve the risk benchmark of 10-4 infections per person per year (ppy) in a series of two efforts completed in 2017 and 2021. In this work, we compare and synthesize the ONWS LRT efforts to inform the selection of pathogen LRTs. For onsite wastewater, greywater, and stormwater, LRTs for human enteric viruses and parasitic protozoa were within 1.5-log10 units between 2017 and 2021 efforts, despite differences in approaches used to characterize pathogens in these waters. For onsite wastewater and greywater, the 2017 effort used an epidemiology-based model to simulate pathogen concentrations contributed exclusively from onsite waste and selected Norovirus as the viral reference pathogen; the 2021 effort used municipal wastewater pathogen data and cultivable adenoviruses as the reference viral pathogen. Across source waters, the greatest differences occurred for viruses in stormwater, given the newly available municipal wastewater characterizations used for modeling sewage contributions in 2021 and the different selection of reference pathogens (Norovirus vs. adenoviruses). The roof runoff LRTs support the need for protozoa treatment, but these remain difficult to characterize due to the pathogen variability in roof runoff across space and time. The comparison highlights adaptability of the risk-based approach, allowing for updated LRTs as site specific or improved information becomes available. Future research efforts should focus on data collection of onsite water sources.
| S-EPMC10084472 | biostudies-literature
Project description:Needless to say, the safety of treated water for potable reuse must be definitively ensured. Numerous methods are available for assessing water quality; it's important to understand their challenges and limitations.
| S-EPMC7159541 | biostudies-literature
Project description:An epoxy treatment was applied to a pipeline used to convey advanced treated recycled water from a purification facility to a recharge site. The epoxy treatment was applied to prevent further deterioration (corrosion) of the interior cement mortar lining (CML). A soil column study was conducted to evaluate the effect of the epoxy liner on the clogging potential of water before and after conveyance. The clogging potential was represented by differences in the column's relative hydraulic conductivity and water quality, between the treatment plant and injection site, before and after epoxy lining. Hydraulic conductivity of columns at the injection well site declined rapidly before epoxy and improved considerably after epoxy application. Total suspended solids (TSS) and cellular adenosine triphosphate (cATP) median concentrations improved significantly. Before epoxy, TSS increased with pipeline transit from 0.005 to 0.053 (mg/L) compared with 0.009 mg/L after epoxy. Before epoxy, cATP increased from 0.14 to 1.6 pg/ml across pipeline transit compared with 0.37 pg/ml after epoxy. Aluminum and nitrate followed similar trends. Results indicate that epoxy liner reduced the clogging potential of high purity recycled water, likely due to a decrease in particle and biomass load (clogging constituents) accumulated during pipeline transit. PRACTITIONER POINTS: Clogging potential of advanced treated recycled water increases with pipeline transit. Epoxy lining the pipeline used for conveyance reduces the particulate and microbial loading of the highly purified water. Applying epoxy to pipelines used to convey advanced treated recycled water has the dual benefit of infrastructure protection and improving water quality. Reducing particle and microbial load in the advanced treated recycled water can reduce maintenance frequencies and elongate production periods for MAR applications.
| S-EPMC10107648 | biostudies-literature
Project description:PURPOSE OF REVIEW:With the increasing interest in recycling water for potable reuse purposes, it is important to understand the microbial risks associated with potable reuse. This review focuses on potable reuse systems that use high-level treatment and de facto reuse scenarios that include a quantifiable wastewater effluent component. RECENT FINDINGS:In this article, we summarize the published human health studies related to potable reuse, including both epidemiology studies and quantitative microbial risk assessments (QMRA). Overall, there have been relatively few health-based studies evaluating the microbial risks associated with potable reuse. Several microbial risk assessments focused on risks associated with unplanned (or de facto) reuse, while others evaluated planned potable reuse, such as indirect potable reuse (IPR) or direct potable reuse (DPR). The reported QMRA-based risks for planned potable reuse varied substantially, indicating there is a need for risk assessors to use consistent input parameters and transparent assumptions, so that risk results are easily translated across studies. However, the current results overall indicate that predicted risks associated with planned potable reuse scenarios may be lower than those for de facto reuse scenarios. Overall, there is a clear need to carefully consider water treatment train choices when wastewater is a component of the drinking water supply (whether de facto, IPR, or DPR). More data from full-scale water treatment facilities would be helpful to quantify levels of viruses in raw sewage and reductions across unit treatment processes for both culturable and molecular detection methods.
| S-EPMC6779056 | biostudies-literature
Project description:Potable reuse of municipal wastewater is often the lowest-energy option for increasing the availability of fresh water. However, limited data are available on the energy consumption of potable reuse facilities and schemes, and the many variables affecting energy consumption obscure the process of estimating energy requirements. By synthesizing available data and developing a simple model for the energy consumption of centralized potable reuse schemes, this study provides a framework for understanding when potable reuse is the lowest-energy option for augmenting water supply. The model is evaluated to determine a representative range for the specific electrical energy consumption of direct and indirect potable reuse schemes and compare potable reuse to other water supply augmentation options, such as seawater desalination. Finally, the model is used to identify the most promising avenues for further reducing the energy consumption of potable reuse, including encouraging direct potable reuse without additional drinking water treatment, avoiding reverse osmosis in indirect potable reuse when effluent quality allows it, updating pipe networks, or using more permeable membranes. Potable reuse already requires far less energy than seawater desalination and, with a few investments in energy efficiency, entire potable reuse schemes could operate with a specific electrical energy consumption of less than 1 kWh/m3, showing the promise of potable reuse as a low-energy option for augmenting water supply.
| S-EPMC8640112 | biostudies-literature
Project description:Wastewater reclamation and reuse have the potential to supplement water supplies, offering resiliency in times of drought and helping meet increased water demands associated with population growth. Non-potable water reuse represents the largest potential reuse market. Yet economic constraints for new water reuse infrastructure and safety concerns due to microbial water quality, and especially viral pathogen exposure, limit widespread implementation of water reuse. Cost-effective, real-time methods to measure or indicate viral quality of recycled water would do much to instill greater confidence in the practice. This manuscript discusses advancements in monitoring and modeling of viral health risks in the context of water reuse. First, we describe the current wastewater reclamation processes and treatment technologies with an emphasis on virus removal. Second, we review technologies for the measurement of viruses, both culture- and molecular-based, along with their advantages and disadvantages. We introduce promising viral surrogates and specific pathogenic viruses that can serve as indicators of viral risk for water reuse. We suggest metagenomic analyses for viral screening and flow cytometry for quantification of virus-like particles as new approaches to complement more traditional methods. Third, we describe modeling to assess health risks through quantitative microbial risk assessments (QMRAs), the most common strategy to couple data on virus concentrations with human exposure scenarios. We then explore the potential of artificial neural networks (ANNs) to incorporate suites of data from wastewater treatment processes, water quality parameters, and viral surrogates. We recommend ANNs as a means to utilize existing water quality data, alongside new complementary measures of viral quality, to achieve cost-effective strategies to assess risks associated with infectious human viruses in recycled water. Given the review, we conclude that technologies are ready for identifying and implementing viral surrogates for health risk reduction in the next decade. Incorporating modeling with monitoring data would likely result in more robust assessment of water reuse risk.
| S-EPMC10448804 | biostudies-literature
Project description:In the search for sustainable drinking water, many countries are weighing up the benefits of advanced treatment technologies as a proactive measure to assist with the transformation of treated wastewater into a source of water used for the production of potable water. We investigated the biological effects along a pilot plant with an advanced water treatment process, using zebrafish embryos at different stages of development. The study took an innovative approach, comparing phenotypic observations with whole genome responses. This enabled us to keep an open mind about which chemicals might be influencing the biological activity. There was no evidence of acute toxicity at any stage of treatment, but distinctive abnormalities – skeletal, cardiovascular and pigmentation – occurred in a small proportion of embryos along the treatment process, and in a tap water, that were not detected in the aquarium water control. Reverse osmosis (RO) reduced the concentration of measured chemical contaminants in the water the most, whilst eliminating the occurrence of abnormalities detected in the fish. In contrast, advanced oxidation appeared to reverse the benefits of RO treatment by increasing the frequency of teratogenic and sub-lethal abnormalities seen in embryos. Genomic analysis found alterations to the retinoid system, which was consistent with the teratogenic abnormalities observed. In addition, we found evidence of changes to metabolic pathways, including tryptophan metabolism associated with the production of melatonin required for the control of normal circadian rhythms. Although we cannot extrapolate these preliminary findings in zebrafish embryos to human or environmental health, we show that underexplored forms of biological activity (that existing Test Guidelines are not designed to capture) occur in treated wastewater effluent, and/or may be created depending on the type of advanced treatment process used. Although the identity of the culprit chemicals are unknown at this time, our innovative approach highlights the need for more research into the effects of chemicals on the retinoid system (and metabolism).
2020-11-30 | GSE152131 | GEO
Project description:Although reclaimed water for potable applications has many potential benefits, it poses concerns for chemical and microbial risks to consumers. We present a quantitative microbial risk assessment (QMRA) Monte Carlo framework to compare a de facto water reuse scenario (treated wastewater-impacted surface water) with four hypothetical Direct Potable Reuse (DPR) scenarios for Norovirus, Cryptosporidium, and Salmonella. Consumer microbial risks of surface source water quality (impacted by 0-100% treated wastewater effluent) were assessed. Additionally, we assessed risks for different blending ratios (0-100% surface water blended into advanced-treated DPR water) when source surface water consisted of 50% wastewater effluent. De facto reuse risks exceeded the yearly 10-4 infections risk benchmark while all modeled DPR risks were significantly lower. Contamination with 1% or more wastewater effluent in the source water, and blending 1% or more wastewater-impacted surface water into the advanced-treated DPR water drove the risk closer to the 10-4 benchmark. We demonstrate that de facto reuse by itself, or as an input into DPR, drives microbial risks more so than the advanced-treated DPR water. When applied using location-specific inputs, this framework can contribute to project design and public awareness campaigns to build legitimacy for DPR.
| S-EPMC5486321 | biostudies-literature