Indirect Potable Reuse Research Articles

A comparative evaluation of reverse osmosis membrane performance when combined with anaerobic or aerobic membrane bioreactors for indirect potable reuse applications

The filtration performance and fouling behaviour of reverse osmosis (RO) membranes was investigated for the post-treatment of aerobic (Ae) and anaerobic (An) MBR effluents treating municipal wastewater for potable reuse. Both MBR effluents followed by RO can produce a water quality sufficient for indirect potable water reuse, while fluorescence excitation-emission scan suggests RO can effectively remove disinfection by-products precursors, ensuring the safety for chlorine based reuse water distribution by rejecting the dissolved organic matters in MBR effluents. AnMBR effluent leads to more fouling when compared to the AeMBR effluent with an average membrane fouling resistance of 12.35 × 1013 m−1 and 8.97 × 1013 m−1. Elemental analysis and membrane surface imaging results demonstrate that the foulant deposition sequence is organic and colloidal at first, followed by inorganic substances, while TOC and Ca are the most deposited foulants from both effluents. The unremoved ammonia in the AnMBR effluent may partially go through in the RO permeate and exceed the threshold in Singapore's PUB NEWater standard, while experiencing a significantly higher deposition rate of 13.8 % than the nitrate (0.02 %) from the AeMBR effluent. The findings suggest that the combination of AnMBR with RO offers a more sustainable approach than with the AeMBR but nutrients removal, with the potential of recovery, is recommended before the RO membranes to limit the fouling propensity and achieve a permeate of sufficient quality.

Author Correction: Addressing the contribution of indirect potable reuse to inland freshwater salinization

Author Correction: Addressing the contribution of indirect potable reuse to inland freshwater salinization

Lithium occurrence in drinking water sources of the United States

Lithium (Li) is listed in the fifth Unregulated Contaminant Monitoring Rule (UCMR 5) because insufficient exposure data exists for lithium in drinking water. To help fill this data gap, lithium occurrence in source waters across the United States was assessed in 21 drinking water utilities. From the 369 samples collected from drinking water treatment plants (DWTPs), lithium ranged from 0.9 to 161 μg/L (median = 13.9 μg/L) in groundwater, and from <0.5 to 130 μg/L (median = 3.9 μg/L) in surface water. Lithium in 56% of the groundwater and 13% of the surface water samples were above non-regulatory Health-Based Screening Level (HBSL) of 10 μg/L. Sodium and lithium concentrations were strongly correlated: Kendall's τ > 0.6 (p < 0.001). As sodium is regularly monitored, this result shows that sodium can serve as an indicator to identify water sources at higher risk for elevated lithium. Lithium concentrations in the paired samples collected in source water and treated drinking water were almost identical showing lithium was not removed by conventional drinking water treatment processes. Additional sampling in wastewater effluents detected lithium at 0.8–98.2 μg/L (median = 9.9 μg/L), which suggests more research on impacts of lithium in direct and indirect potable reuse may be warranted, as the median was close to the HBSL. For comparison with the study samples collected from DWTPs, lithium concentrations from the national water quality portal (WQP) database were also investigated. Over 35,000 measurements were collected from waters that could potentially be used as drinking water sources (Cl− < 250 mg/L). Data from WQP had comparable median lithium concentrations: 18 and 20 μg/L for surface water and groundwater, respectively. Overall, this study provides a comprehensive occurrence potential for lithium in US drinking water sources and can inform the data collection effort in UCMR 5.

Fabrication and application of novel high strength sulfonated PVDF ultrafiltration membrane for production of reclamation water

Advanced treated water (ATW) produced in wastewater treatment facilities was assessed as an excellent alternative water resource that can be used as reclamation water, such as indirect and direct potable reuse. The development of cutting-edge technology for simple but best practices is essential for the reliable production of safe reclamation water from wastewater. This study prepared a novel high strength sulfonated polyvinylidene fluoride (HSPVDF) ultrafiltration membrane and investigated to produce ATW, and performances were compared to sulfonated PVDF (SPVDF) (which was prepared without thermal treatment) and bare PVDF. To compare the properties of HSPVDF to hydrocarbon polymer, the polyetherimide (PEI) and Sulfonated PEI (SPEI) membrane were prepared. HSPVDF showed excellent membrane morphology, porosity, MWCO, and hydrophilicity, resulting in higher pure water flux (712 ± 6 L m−2 h−1) antifouling properties (Rir 1.3% and FRR 98.6%) compared to PVDF. It is an interesting fact that the tensile strength of the HSPVDF (3.4 ± 0.2 MPa) tremendously increased (3 folders) when compere to PVDF (1.3 ± 0.1 MPa). The HSPVDF membrane showed good removal efficiency up to 96 ± 05% and 97 ± 09% rejection for bovine serum albumin (BSA) and humic acid (HA), respectively. The membrane application studies for wastewater treatment showed that the tertiary HSPVDF UF membrane filtration following the nutrient removal activated sludge (NRAS) process can produce reliable and economic performance (125 ± 2 L m−2 h−1, 0.25 ± 0.05 NTU, no pathogens), suggesting that it can be a best practice technique that can replace the complicated multi-staged tertiary processes to produce reclamation water.

Modeling and Life Cycle Assessment of a Membrane Bioreactor–Membrane Distillation Wastewater Treatment System for Potable Reuse

Wastewater treatment for indirect potable reuse (IPR) is a possible approach to address water scarcity. In this study, a novel membrane bioreactor–membrane distillation (MBR-MD) system was evaluated to determine the environmental impacts of treatment compared to an existing IPR facility (“Baseline”). Physical and empirical models were used to obtain operational data for both systems and inform a life cycle inventory. Life cycle assessment (LCA) was used to compare the environmental impacts of each system. Results showed an average 53.7% reduction in environmental impacts for the MBR-MD system when waste heat is used to operate MD; however, without waste heat, the environmental impacts of MBR-MD are significantly higher, with average impacts ranging from 218% to 1400% greater than the Baseline, depending on the proportion of waste heat used. The results of this study demonstrate the effectiveness of the novel MBR-MD system for IPR and the reduced environmental impacts when waste heat is available to power MD.

Incorporating catalytic ceramic membrane into the integrated process of in situ ozonation, membrane filtration and biological degradation: Enhanced performance and underlying mechanisms

The integrated process comprising of in situ ozonation, ceramic membrane filtration and biologically active carbon filtration has a bright application prospect in wastewater reclamation to confront the global water crisis. Additionally, ceramic membranes of stronger catalytic activity are highly desirable so as to further increase the process cost-efficiency. In this study, a Mn-loaded catalytic membrane was tested by conducting pilot-scale experiments of the integrated process to measure its performance in enhancing pollutant removal and in alleviating membrane fouling. Lab-scale experiments were also conducted in order to investigate the underlying mechanisms in which the conventional Al2O3 membrane was used for comparison. Results showed that the integrated process with an incorporated catalytic membrane performed very well in that at a water flux as high as 80 L/m2/h and an ozone dosage of 5 mg/L, the treated water satisfied the guideline values for indirect potable reuse and membrane fouling was minimal. Reducing the ozone dosage to 4 mg/L can still achieve significant membrane fouling control effects, and maintain good effluent quality. Catalytic ozonation could lead to the generation of hydroxyl radicals, and the catalytic ozonation effect was much stronger when the catalytic membrane was used. Catalytic ozonation took place in both the membrane tank and membrane pores, with comparable contributions to the pollutant removal and membrane fouling control. Redundancy analysis (RDA) of membrane fouling characteristics showed that residual ozone concentration in membrane tank was an essential parameter and catalytic ozonation could be more effective in abating irreversible fouling than reversible fouling. RDA also confirmed that a lower ozone dosage would be sufficient for membrane fouling control when the catalytic membrane was used. This study evidently suggested the advantage of using catalytic ceramic membrane in the integrated process for efficient while economic treatment and reclamation of wastewater.

Water scarcity and alternative water sources in South Africa: can information provision shift perceptions?

ABSTRACT Consumer perceptions are key to the success of strategies to address water scarcity. A decision pathway survey was used to investigate attitudes amongst South Africans (N = 668) in urban areas towards four alternative water sources. Results showed that storm and rainwater harvesting was the most (49.7%), and reclaimed wastewater the least acceptable options (15.7%). Direct potable reuse was the most supported alternative (26.6%), followed by indirect potable reuse (22.2%), reuse with additional piping (18.3%), direct non-potable reuse (8.3%), and indirect non-potable reuse (6.8%). Importantly, information provision led to a >66% increase in reclaimed wastewater acceptance amongst those initially opposed to it. In contrast, support for desalinated water and water restrictions decreased. Information provision also led to greater acceptance for direct relative to indirect reuse in situations of severe water scarcity. Together, the data suggest a role for information in influencing attitudes towards alternative water sources amongst consumers.

Development of a fluorescence EEM-PARAFAC model for potable water reuse monitoring: Implications for inter-component protein–fulvic–humic interactions

Measuring the surrogate parameters total organic carbon and dissolved organic carbon (TOC/DOC) is not adequate, alone, to reveal nuances in organic character for optimizing treatment in potable water reuse. Alternatively, analyzing each organic compound contributing to the surrogate measurement is not possible. As an additional analytical tool applied between these extremes, the use of excitation-emission matrix fluorescence spectroscopy with PARAllel FACtor (EEM-PARAFAC) analysis was investigated in this research to track categories (components) or families of organic compounds during treatment in recycled water schemes. Although not all organic molecules fluoresce, many do, and fluorescence helps track their fate through water treatment processes. The sites investigated in this research were Lake Lanier, in Gwinnett County, Georgia, USA; the F. Wayne Hill Water Resources Center (FWH WRC) advanced wastewater treatment facility; and two pilot facilities operated in parallel representing the current indirect potable reuse (IPR) scheme as well as a pilot that evaluated direct potable reuse (DPR). A four-component nonnegativity PARAFAC model—elucidating protein-like (including tyrosine- and tryptophan-like fluorescence in a single component), soluble microbial product (SMP)-like, fulvic-like, and humic-like components—was fitted to the data. Each of the four components was spectrally and mathematically separated, implying that the fluorescing SMP-like component was not comprised of protein-, fulvic-, or humic-like components. PARAFAC excitation loadings with dual (double) pairs of fluorescing regions centered at the same emission wavelengths but different excitation wavelengths oriented parallel to the excitation axis and perpendicular to the emission axis were attributed to individual PARAFAC components. Significantly, the observation of PARAFAC emission loadings with multiple peaks—where the protein-like component exhibited fluorescence in both protein and fulvic/humic regions—is proposed to signify an intermolecular energy transfer (< 10 nm). Correct identification of EEM-PARAFAC components is fundamental to understanding water treatment.

Indirect Potable Water Reuse to Face Drought Events in Barcelona City. Setting a Monitoring Procedure to Protect Aquatic Ecosystems and to Ensure a Safe Drinking Water Supply

Indirect Potable Water Reuse to Face Drought Events in Barcelona City. Setting a Monitoring Procedure to Protect Aquatic Ecosystems and to Ensure a Safe Drinking Water Supply

A Comparative Evaluation of Reverse Osmosis Membrane Performance When Combined with Anaerobic or Aerobic Membrane Bioreactors for Indirect Potable Reuse Applications

A Comparative Evaluation of Reverse Osmosis Membrane Performance When Combined with Anaerobic or Aerobic Membrane Bioreactors for Indirect Potable Reuse Applications

Progress on legal and practical aspects on water reuse with emphasis on drinking water – an overview

Abstract The present study highlights the evolution, progress and prospects of future practices of water reuse in the world. The objective was to produce a comprehensive timeline on the global evolution and progress of water reuse. This was achieved through the analysis of the state of the art on the subject. The present study is a qualitative research, where three aspects have been considered to highlight the global evolution of water reuse: i) Regulations, Standards, Criteria or Guidelines (RSCG); ii) Indirect Potable Reuse Projects (IPR); and iii) Direct Potable Reuse Projects (DPR). The study focused on both legal and practical aspects of water reuse and considered three timelines in the context of RSCG, IPR and DPR: 29 RSCG instruments, institutionalized from 1918 to 2020, where only four instruments were solely dedicated to drinking water reuse; 10 IPR projects; five DPR projects. To achieve good, effective results, the regulatory framework must support the objectives of a structured water reuse policy in addition to guaranteeing legitimacy and maintaining public confidence. Integrated water and wastewater management, based on technological and scientific advances, has become a relevant aspect for implementation of more adequate measures by decision makers to address future global water challenges.

Protozoa reduction through secondary wastewater treatment in two water reclamation facilities

The State of Nevada, USA Administrative Code requires a 12-log enteric virus reduction/inactivation, 10-log Giardia cyst reduction, and 10-log Cryptosporidium oocyst reduction for Category A+ reclaimed water suitable for indirect potable reuse (IPR) based on raw wastewater to potable reuse water. Accurately demonstrating log10 reduction values (LRVs) through secondary biological treatment prior to an advanced water treatment train enables redundancy and resiliency for IPR projects while maintaining a high level of public confidence. LRVs for Cryptosporidium and Giardia resulting from secondary biological treatment are not fully established due to a wide range of performance variabilities resulting from different types of secondary biological treatment processes employed in water reclamation. A one-year investigation of two full-scale northern Nevada (e.g. ≤4 mgd; 1.5 × 107 L/day) water reclamation facilities (WRFs) was conducted to monitor Cryptosporidium oocysts and Giardia cysts in untreated wastewater and secondary effluent. This study aimed at establishing secondary treatment LRVs, monitor WRF performance and attempted to correlate performance to protozoan reduction. California's IPR regulations, in which Nevada IPR regulations were modeled after, were based on a maximum concentration of 5-logs (cysts/L) of Giardia and 4-logs (oocysts/L) of Cryptosporidium. The recovery-corrected Giardia and Cryptosporidium concentrations measured in untreated influent (20 samples each at each WRF) were below 5-log cysts/L at the 99th percentile (maximum 4.4-log cysts/L) and 4-log oocysts/L (maximum 2.7 log oocysts/L), respectively. Both secondary treatment WRFs produced secondary effluent that is consistently better than federal and the State of Nevada requirements and perform within an operating envelop for other secondary facilities. Given the results, it appears that a minimum conservative estimate for LRVs for well-operated secondary activated sludge treatment plants (at the 5th percentile) of 0.5 LRV credit for Cryptosporidium and 2.0 LRV for Giardia is warranted. These minimum LRVs are consistent with a conservative review of the available literature.

Granular activated carbon‐based treatment and mobility of per‐ and polyfluoroalkyl substances in potable reuse for aquifer recharge

AbstractHampton Roads Sanitation District recently initiated an indirect potable reuse project to recharge the Potomac Aquifer in southeastern Virginia, USA. Source control and granular activated carbon (GAC) treatment are employed to minimize per‐ and polyfluoroalkyl substances (PFAS) content in this water. Final purified water maintained low long‐chain perfluoroalkyl acids (PFAAs; &lt;8 ppt sum of PFOA, PFNA, PFDA, PFHxS, PFOS) and moderately low short‐chain PFAAs (&lt;118 ppt of sum PFBA, PFPeA, PFHxA, PFHpA, PFBS). High mobility of low concentrations of five PFAS (PFBS, PFPeA, PFHxA, PFHpA, PFOA) in the Potomac Aquifer was observed. Despite low concentrations relative to current guidelines, PFAS breakthrough and mobility support strict source control and the use of surrogates like total organic carbon to guide GAC operation at the installation.Article Impact StatementSource control and granular activated carbon operation targeting 4 mg/L total organic carbon in effluent maintained low per‐ and polyfluoroalkyl substances concentrations in indirect potable reuse water.

Per‐ and polyfluoroalkyl substance removal in carbon‐based advanced treatment for potable reuse

AbstractThe persistence of perfluoroalkyl acids (PFAAs) in wastewater effluent highlights the need for active monitoring and targeted removal of these compounds in potable reuse applications. The City of Altamonte Springs' permanent potable reuse demonstration facility, pureALTA, employs a carbon‐based advanced treatment process using multiple treatment barriers to provide potable water that meets state and federal regulatory requirements and health guidelines for unregulated contaminants. The combination of ozonation, biological activated carbon filtration (BAC), ultrafiltration (UF), granular activated carbon adsorption (GAC), and UV advanced oxidation process (UV AOP) showed complete removal of long‐chain PFAAs (perfluoroalkyl sulfonic acids with ≥6 carbons and perfluoroalkyl carboxylic acids with ≥7 carbons) with federal health guidelines, such as perfluorooctanoic acid and perfluorooctane sulfonate in the advanced treated water while maintaining total organic carbon (TOC) levels below 3 mg/L, the regulatory limit in Florida for indirect potable reuse. Ozone, BAC, and UF showed increases in PFAAs to varying levels based on the transformation of precursors. GAC was the critical process for both TOC and PFAA removal; as anticipated GAC media's age defined the extent of removal of short‐chain PFAAs such as perfluoropentanoic acid and perfluorohexanoic acid. Because of regulatory limits on TOC in Florida potable reuse projects and the absence of regulations on short‐chain PFAAs, TOC continues to dictate GAC media change‐out frequency and operating cost. However, the performance control strategy for GAC at pureALTA may change if stringent limits are set for short‐chain PFAAs in the future. As of May 2021, pureALTA has been in operation for more than 4 years and continues to operate, providing an opportunity for continued research and community engagement.Article Impact StatementThe study represents the first pilot‐scale evaluation of perfluoroalkyl acid removal and correlation to total organic carbon in a carbon‐based advanced treatment process for potable reuse in Florida.

An investigation into the biological effects of indirect potable reuse water using zebrafish embryos

Advanced treatment technologies are being assessed as a proactive measure to assist with the transformation of treated wastewater into a source of water for potable water production. We investigated the biological effects along an advanced water treatment pilot plant, using zebrafish embryos throughout early development. The study compared phenotypic observations with global transcriptome responses, enabling us to keep an open mind about the chemicals that might influence the biological activity. There was no evidence of acute toxicity at any treatment stage, but skeletal, cardiovascular and pigmentation changes occurred in a small proportion of embryos along the treatment process, and in a tap water; not detected in the aquarium water control. Reverse osmosis (RO) reduced the concentration of measured chemical contaminants in the water the most, while eliminating the occurrence of abnormalities detected in fish embryos. Conversely, advanced oxidation reversed the benefits of RO treatment by increasing the frequency of teratogenic and sub-lethal abnormalities seen. Using the molecular responses of zebrafish embryos to different IPR water, we report the bioactivity within the water at different stages of advanced treatment and associate these to perturbed biological functions. Transcriptomic analysis revealed alterations to the retinoid system, which was consistent with the observed teratogenic effects. Changes to tryptophan metabolism (associated with the production of melatonin required for the control of normal circadian rhythms) and somatolactin-beta (associated with normal pigmentation in fish) were also found. We show that underexplored forms of biological activity occur in treated wastewater effluent, and/or may be created depending on the type of advanced treatment process used. By integrating the available analytical chemistry we highlight chemical groups associated to this response. Our study shows that more detailed and in-depth characterisation of chemicals and biological pathways associated with advanced treatment water systems are needed to mitigate possible risks to downstream organisms.

Addressing the contribution of indirect potable reuse to inland freshwater salinization

Inland freshwater salinity is rising worldwide, a phenomenon called the freshwater salinization syndrome (FSS). We investigate a potential conflict between managing the FSS and indirect potable reuse, the practice of augmenting water supplies through the addition of highly treated wastewater (reclaimed water) to surface waters and groundwaters. From time-series data collected over 25 years, we quantify the contributions of three salinity sources—a water reclamation facility and two rapidly urbanizing watersheds—to the rising concentration of sodium (a major ion associated with the FSS) in a regionally important drinking-water reservoir in the Mid-Atlantic United States. Sodium mass loading to the reservoir is primarily from watershed runoff during wet weather and reclaimed water during dry weather. Across all timescales evaluated, sodium concentration in the reclaimed water is higher than in outflow from the two watersheds. Sodium in reclaimed water originates from chemicals added during wastewater treatment, industrial and commercial discharges, human excretion and down-drain disposal of drinking water and sodium-rich household products. Thus, numerous opportunities exist to reduce the contribution of indirect potable reuse to sodium pollution at this site, and the FSS more generally. These efforts will require deliberative engagement with a diverse community of watershed stakeholders and careful consideration of the local political, social and environmental context. Freshwater salinization syndrome is an emerging threat to freshwater globally. Here the authors quantify the contribution of indirect potable reuse to sodium pollution and suggest a variety of behavioural and technological interventions to address this growing environmental problem.

Fate and Transport of Viruses within a High-Rate Plug-Flow Biofilter Designed for Non-Membrane-Based Indirect Potable Reuse Applications

Numerous chronic health effects might be caused by the presence of chemical constituents in reclaimed water; however, an acute risk for water-borne diseases is mostly associated with pathogens. For...

Quantitative microbial risk assessment of a non-membrane based indirect potable water reuse system using Bayesian networks.

Risk-based approaches are used to define performance standards for water and wastewater treatment to meet health-based targets and to ensure safe and reliable water quality for desired end use. In this study, a screening level QMRA for a non-membrane based indirect potable reuse (IPR) system utilizing the sequential managed aquifer recharge technology (SMART) concept was conducted. Ambient removals of norovirus, Campylobacter and Cryptosporidium in advanced water treatment (AWT) steps were combined in a probabilistic QMRA utilizing Bayesian networks constructed in Netica. Results revealed that all pathogens complied with disease burden at the 95th percentile, and according to the assumptions taken about pathogen removal, Cryptosporidium was the pathogen with the greatest risk. Through systematic sensitivity analysis, targeted scenario analysis, and backwards inferencing, critical control points for each pathogen were determined, demonstrating the usefulness of Bayesian networks as a diagnostic tool in quantifying risk of water reuse treatment scenarios.

Tracking Wichita Falls' Path From DPR to IPR

The City of Wichita Falls, Texas, made international news in 2014 when its water system became a water reuse pioneer. In response to a historic drought, the city simultaneously planned and implemented direct potable reuse (DPR) and indirect potable reuse (IPR) systems to see it through the drought and respond to future water shortages. Now, the city is a role model for water utilities around the world.

Community education and perceptions of water reuse: a case study in Norman, Oklahoma

The success of municipal wastewater reuse programs is often dependent on public willingness to use recycled water. Psychological reactions that contribute to behavioral intention have varying levels of influence, with the reaction of disgust or “yuck factor” creating the primary behavioral barrier. Factors influencing disgust reactions to recycled wastewater are of interest to psychologists and water managers alike. Research has shown that community education initiatives can increase willingness to support water reuse projects. A two-part study was carried out with a total of 114 participants in Norman, Oklahoma, where the local government is interested in implementing wastewater reuse to supplement water supply during drought. Participants were asked about their willingness to use this water and their feelings of disgust, as well as their trust of public officials before and after touring the Norman Water Reclamation Facility. Results found that willingness and disgust are inversely related. Political affiliation, education, and previous knowledge of the program had significant effects on willingness to use recycled wastewater. Community education significantly increased willingness to use that water and to support an eventual ballot initiative to expand indirect potable reuse. These results suggest community education can overcome initial reactions of disgust that contribute to behavioral intention.