Survey of users and providers of recycled water: quality concerns and directions for applied research

Evaluating the impact of water reuse educational videos on water reuse perceptions using EEG/event related potential

As climate change and population growth increasingly stress freshwater resources, government agencies and scientists have recognized the importance of water reuse (the beneficial use of reclaimed or recycled water). While end users (municipalities and farmers) are largely open to exploring water reuse, a barrier to using this water source is the public's negative perception, or the 'yuck factor'. Recognizing that water reuse is becoming a necessity, there is an urgent need to determine how to improve public acceptance of this water source. Increasing knowledge has been identified as a critical method for improving the adoption of sustainable practices, but to date, there has been a lack of outcome studies on the ability of water reuse education materials to change perceptions. Previous studies have relied heavily on self-reported concerns and perceptions which are limited by bias and social expectations, and their results have failed to substantially change water reuse education efforts, and by extension failed to substantially improve water reuse perceptions. We propose the integration of psychology for evaluating the effectiveness of water reuse education and outreach efforts. The purpose of this study was to determine if water reuse educational videos modulate perceptions of water reuse terms. Participants were recruited from a university campus and completed pre-intervention surveys on water reuse knowledge, willingness to use recycled water, and preferred water reuse information sources. We then measured changes in neural activity in response to multiple categories of water reuse terms pre- and post-exposure to water reuse education videos using electroencephalogram (EEG). Through EEG we measured event related potential (ERP), which assesses sustained engagement with the cues (late positive potential (LPP) amplitude), and alpha power. Participants also completed a pre/post exposure battery involving five tasks, in randomized order, presented before and after viewing videos. Sixty-eight percent of survey participants had previously heard of water reuse and 91% reported willingness to use recycled water for at least one activity. Participants reported obtaining water reuse information mostly from the internet (77%) and preferred to receive additional information mainly by watching online videos (73%). We observed significant increases in alpha power, corresponding to feelings of relaxation, in response to seven of eight water reuse term categories post-video exposure. These findings show that water reuse educational videos can change perceptions of water reuse. Our results point to the possibility of validating and increasing the effectiveness of water reuse education materials using sophisticated neurocognitive measures.

Leveraging User Comments for the Construction of Recycled Water Infrastructure-Evidence from an Eye-Tracking Experiment

Building sufficient recycled water infrastructure is an effective way to solve problems related to water shortages and environmental degradation, and is of great strategic significance for saving resources, protecting the ecological environment, and promoting sustainable social and economic development. Although recycled water is environmentally friendly, the public is still skeptical about its use, which has led to the failure of a large number of recycled water infrastructure investments; therefore, increasing the public's willingness to re-use is critical for the construction of recycled water infrastructure. To identify the influence mechanism of user comments on public re-use behaviors, we conducted an eye-tracking experiment in China. The results demonstrated that (1) perceived usefulness, perceived quality, and perceived risk have significant impacts on the public's willingness to buy; (2) user reviews can enhance the public's perceived usefulness of recycled products and increase their willingness to buy; and (3) in the process of consumption, the public tends to pay attention to negative reviews, where user reviews alter the perceived risks and perceived prices of recycled products, thereby affecting the willingness to buy of consumers. This study provides a scientific reference for the construction of recycled water infrastructure and the further promotion of recycled water.

Root system response to salt stress in grapevines (Vitis spp.): A link between root structure and salt exclusion

Accessing freshwater resources for agriculture becomes more complex due to increasing demands and declining water quality. Alternative water sources, such as saline water, require ad hoc solutions. Therefore, understanding roots' response to saline water is crucial for future agriculture. We examined the response of three grapevine rootstocks (Paulsen 1103, Richter 110 and SO4) to salt stress. The rootstocks were subjected to two salinity treatments: 10 mM and 30 mM NaCl (EC = 2 and 4 ds/m, respectively). Root and shoot samples were taken at the end of the experiment for morphologic and ionomic analyses. The specific root area (SRA) increased in response to salinity for all three rootstocks due to root tissue density and average root diameter reductions. Salinity also led to increased root Na⁺ and Cl^- contents and reduced root K⁺/Na⁺ ratio, parallel to increased leaf Cl^- but not Na⁺ contents. SO4 showed improved chloride and sodium exclusion, concomitant with its highest SRA, resulting from the increase in its thin roots' contribution to the total root system surface area. We suggest that enhanced SRA combined with decreased root tissue density and diameter may improve grapevines' salt exclusion by less salt uptake from the soil.

Soil degradation kinetics of oxybenzone (Benzophenone-3) and toxicopathological assessment in the earthworm, Eisenia fetida

A preponderance of recent evidence indicates that oxybenzone and other personal-care product chemicals threaten the biota inhabiting various ecological niches. What is understudied is the ecotoxicological impact of oxybenzone, a UV filter in sunscreens and anti-aging products, to terrestrial/soil organisms that are keystone species in these habitats. In the present study, acute exposure (14-day) to oxybenzone resulted in earthworm mortality (LC₅₀ of 364 mg/kg) and growth rate inhibition. Environmentally relevant concentration of oxybenzone (3.64, 7.28 and 36.4 mg/kg) at exposures of 7-day, 14-day, 28-day induced oxidative stress and neurotoxicity followed by perturbations in reproduction processes and changes in vital organs. Decreased levels of superoxide dismutase (SOD) and catalase (CAT) activity were statistically lower than controls (p < 0.05) on day 14 for all three concentrations, while glutathione-s-transferase (GST) activity was significantly elevated from controls on days 7 and 14. On day 28, SOD and CAT activities were either not significantly different from the control or were higher, demonstrating a temporal multiphasic response of anti-oxidant enzymes. GST activity on day 28 was significantly reduced compared to controls. Acetylcholinesterase levels across the three-time points exhibited a complicated behaviour, with every exposure concentration being significantly different from the control. Chronic exposure negatively influences earthworm health status with elevated biomarker values analysed using IBRv2 index. This, in turn, impacted higher levels of hierarchical organization, significantly impairing reproduction and organismal homeostasis at the histological level and manifesting as decreasing cocoon formation and successful hatching events. Thus, the overall findings demonstrate that oxybenzone is toxic to Eisenia fetida at low-level, long-term exposure. Based on the concentration verification analysis and application of the EPA PestDF tool, oxybenzone undergoes single first-order kinetics degradation in OECD soil with DT50 and DT90 as 8.7-28.9 days, respectively.

Public Awareness and Risk Perceptions of Endocrine Disrupting Chemicals: A Qualitative Study

Endocrine disrupting chemicals (EDCs) are exogenous chemicals found in food, consumer products, and the environment. EDCs are ubiquitous in modern life and exposure is associated with many negative health effects, such as reproductive disorders, metabolic disorders, and cancer. Scientists have deemed EDCs as a serious public health risk, yet the public's perceptions of these chemicals is poorly understood. This study aimed to qualitatively explore how aware the public is of EDCs and their attitudes, beliefs, and perceptions of EDC risk. Thirty-four participants (aged 19-65 years) took part in the six focus groups. Discussions were transcribed verbatim and Nvivo 11 was used for thematic analysis. Our results indicated that awareness of EDCs was low. Themes of EDC risk perception included perceived control, perceived severity, and similarity heuristics. Risk alleviation strategies were also discussed. Future research should use quantitative methodology and a larger sample size to validate the findings from this study. Findings from this study may aid the development of effective risk communication strategies and public health interventions.

A review on microbial contaminants in stormwater runoff and outfalls: Potential health risks and mitigation strategies

Demands on global water supplies are increasing in response to the need to provide more food, water, and energy for a rapidly growing population. These water stressors are exacerbated by climate change, as well as the growth and urbanisation of industry and commerce. Consequently, urban water authorities around the globe are exploring alternative water sources to meet ever-increasing demands. These alternative sources are primarily treated sewage, stormwater, and groundwater. Stormwater including roof-harvested rainwater has been considered as an alternative water source for both potable and non-potable uses. One of the most significant issues concerning alternative water reuse is the public health risk associated with chemical and microbial contaminants. Several studies to date have quantified fecal indicators and pathogens in stormwater. Microbial source tracking (MST) approaches have also been used to determine the sources of fecal contamination in stormwater and receiving waters. This review paper summarizes occurrence and concentrations of fecal indicators, pathogens, and MST marker genes in urban stormwater. A section of the review highlights the removal of fecal indicators and pathogens through water sensitive urban design (WSUD) or Best Management Practices (BMPs). We also discuss approaches for assessing and mitigating health risks associated with stormwater, including a summary of existing quantitative microbial risk assessment (QMRA) models for potable and non-potable reuse of stormwater. Finally, the most critical research gaps are identified for formulating risk management strategies.

Precipitation influences pathogenic bacteria and antibiotic resistance gene abundance in storm drain outfalls in coastal sub-tropical waters

Stormwater contamination can threaten the health of aquatic ecosystems and human exposed to runoff via nutrient and pathogen influxes. In this study, the concentrations of 11 bacterial pathogens and 47 antibiotic resistance genes (ARGs) were determined by using high-throughput microfluidic qPCR (MFQPCR) in several storm drain outfalls (SDOs) during dry and wet weather in Tampa Bay, Florida, USA. Data generated in this study were also compared with the levels of fecal indicator bacteria (FIB) and sewage-associated molecular markers (i.e., Bacteroides HF183 and crAssphage markers) in same SDOs collected in a recent study (Ahmed et al., 2018). Concentration of FIB, sewage-associated markers, bacterial pathogens and many ARGs in water samples were relatively high and SDOs may be potentially hotspots for microbial contamination in Tampa Bay. Mean concentrations of culturable E. coli and Enterococcus spp. were tenfold higher in wet compared to dry weather. The majority of microbiological contaminants followed this trend. E. coli eaeA, encoding the virulence factor intimin, was correlated with levels of 20 ARGs, and was more frequently detected in wet weather than dry weather samples. The bla_KPC gene associated with carbapenem resistant Enterobacteriaceae and the beta-lactam resistant gene (bla_NPS) were only detected in wet weather samples. Frequency of integron genes Intl2 and Intl3 detection increased by 42% in wet weather samples. Culturable E. coli and Enterococcus spp. significantly correlated with 19 of 47 (40%) ARG tested. Sewage-associated markers crAssphage and HF183 significantly correlated (p < 0.05) with the following ARGs: intl1, sul1, tet(M), ampC, mexB, and tet(W). The presence of sewage-associated marker genes along with ARGs associated with sewage suggested that aging sewage infrastructure contributed to contaminant loading in the Bay. Further research should focus on collecting spatial and temporal data on the microbiological contaminants especially viruses in SDOs.

Formation and speciation of haloacetamides and haloacetonitriles for chlorination, chloramination, and chlorination followed by chloramination

The formation of haloacetamides (HAcAms) and haloacetonitriles (HANs) from a solution containing natural organic matter and a secondary effluent sample was evaluated for disinfection by chlorination, chloramination, and chlorination followed by chloramination (Cl₂NH₂Cl process). The use of preformed monochloramine (NH₂Cl) produced higher concentrations of HAcAms and lower concentrations of HANs than chlorination, while the Cl₂NH₂Cl process produced the highest concentrations of HAcAms and HANs. These results indicate that the Cl₂NH₂Cl process, which inhibited the formation of regulated trihalomethanes compared with chlorination, enhanced the formation of HAcAms and HANs. For disinfection in the presence of bromide, brominated dihaloacetamides and dihaloacetonitriles were formed, and the trends were similar to those observed for chlorinated species in the absence of bromide. The degrees of bromine substitution of dihaloacetamides and dihaloacetonitriles were highest for chlorination, followed by the Cl₂NH₂Cl process and then by the NH₂Cl process. For the Cl₂NH₂Cl process, HAN formation kept gradually increasing with prechlorination time increasing from 0 to 120 min, while HAcAm formation increased only until it reached a maximum at around 10-30 min. These results suggest that the prechlorination time could be reduced to control the formation of HAcAms and HANs. During chloramination, the formation of HAcAms and HANs was lower when using preformed NH₂Cl than when chloramines were formed in situ, with higher formation of HAcAms and HANs when chlorine was added before ammonia than vice versa for the secondary effluent; this finding suggests that preformed NH₂Cl could be used to inhibit the formation of HAcAms and HANs during chloramination.

Water conservation quantities vs customer opinion and satisfaction with water efficient appliances in Miami, Florida

During 2006-2007, Miami-Dade County, Florida, USA, provided incentives for low income and senior residents in single family homes for retrofitting with high efficiency fixtures. The participating residences were retrofitted with high-efficiency toilets, showerheads, and aerators. In 2012, a telephone survey was conducted to evaluate the satisfaction of the participants and the associated effects on water conservation practices. This study evaluates the attitudes and opinions of the participants relative to water use efficiency measures and the actual reduction in water consumption characteristics of the participating households. The participant characteristics were analyzed to identify correlations between the socio-demographic factors, program satisfaction and actual water savings. Approximately 65.5% of the survey respondents reported changes in their water use habits and 76.6% reported noticeable reduction in their water bills. The analyses showed that the satisfaction levels of the participants were closely correlated with the actual water savings. The results also showed that satisfaction level along with water saving potential (i.e., implementation of water efficiency devices) or change of water use habits has provided positive synergistic effect on actual water savings. The majority of the participants surveyed (81.3-89.1%) reported positive attitudes for water conservation incentive program and the benefits of the high efficiency fixtures.

Vision and perception of community on the use of recycled water for household laundry: a case study in Australia

This study investigates the community perception of household laundry as a new end use of recycled water in three different locations of Australia through a face to face questionnaire survey (n=478). The study areas were selected based on three categories of (1) non-user, (2) perspective user and (3) current user of recycled water. The survey results indicate that significantly higher number (70%) of the respondents supported the use of recycled water for washing machines (χ(2)=527.40, df=3; p=0.000). Significant positive correlation between the overall support for the new end use and the willingness of the respondents to use recycled water for washing machine was observed among all users groups (r=0.43, p=0.000). However, they had major concerns regarding the effects of recycled water on the aesthetic appearance of cloth, cloth durability, machine durability, odour of the recycled water and cost along with the health issues. The perspective user group had comparatively more reservations and concerns about the effects of recycled water on washing machines than the non-users and the current users (χ(2)=52.73, df=6; p=0.000). Overall, community from all three study areas are willing to welcome this new end use as long as all their major concerns are addressed and safety is assured.

Expert stakeholder attitudes and support for alternative water sources in a groundwater depleted region

The main objectives of this research were to quantify the risks/benefits and impacts of alternative water sources (AWSs) as perceived by expert stakeholders and to evaluate the overall support for multiple AWSs by expert stakeholders. The St. Johns River (SJR) basin, FL, USA was chosen as a case study for AWSs because it is a fresh groundwater depleted region and there are ongoing activities related to water supply planning. Expert stakeholders included federal, state, and local governments, public utilities, consulting engineering and industry, and environmental and social non-governmental organizations. AWSs under consideration in the SJR basin include surface water, desalination, water reclamation, and water conservation. A two-phase research approach was followed that focused on expert stakeholders. First, an elicitation study was used to identify salient beliefs about AWSs. Open-ended questions were asked about the risks/benefits of AWSs in terms of the three pillars of sustainability: ecological, economic, and human health impacts. Second, an online survey was constructed using beliefs identified during the elicitation study. The online survey was used to quantify attitudes toward and overall support for AWSs. The salient beliefs of expert stakeholders were dominated by the ecological pillar of sustainability. The support of expert stakeholders for AWSs, from least favorable to most favorable, was surface water withdrawals<desalination<water reclamation<water conservation, and was shaped by attitudes. The results of this research provide an improved understanding of the beliefs and attitudes that influence decision-makers involved in water supply planning.

Management experiences and trends for water reuse implementation in Northern California

In 2010, California fell nearly 300,000 acre-ft per year (AFY) short of its goal to recycle 1,000,000 AFY of municipal wastewater. Growth of recycled water in the 48 Northern California counties represented only 20% of the statewide increase in reuse between 2001 and 2009. To evaluate these trends and experiences, major drivers and challenges that influenced the implementation of recycled water programs in Northern California are presented based on a survey of 71 program managers conducted in 2010. Regulatory requirements limiting discharge, cited by 65% of respondents as a driver for program implementation, historically played an important role in motivating many water reuse programs in the region. More recently, pressures from limited water supplies and needs for system reliability are prevalent drivers. Almost half of respondents (49%) cited ecological protection or enhancement goals as drivers for implementation. However, water reuse for direct benefit of natural systems and wildlife habitat represents just 6-7% of total recycling in Northern California and few financial incentives exist for such projects. Economic challenges are the greatest barrier to successful project implementation. In particular, high costs of distribution systems (pipelines) are especially challenging, with $1 to 3 million/mile costs experienced. Negative perceptions of water reuse were cited by only 26% of respondents as major hindrances to implementation of surveyed programs.

Effect of chlorination on endotoxin activities in secondary sewage effluent and typical Gram-negative bacteria

Wastewater reuse is a viable and attractive method to address water shortage problems. However, wastewater can have high endotoxin activity. Endotoxins are toxic inflammatory agents and are considered a risk factor for wastewater reuse. In this study, the effect of chlorination on endotoxin activity in secondary sewage effluent was evaluated by Limulus (Tachypleus tridentatus) Amebocyte Lysate assay. It was found that chlorination could not decrease endotoxin activity of secondary effluent effectively under the conditions employed in this study. Chlorination of a pure cultured Gram-negative bacterium (Escherichia coli), and a Gram-negative bacterium isolated from secondary sewage effluent, resulted in a significant increase in endotoxin activity, suggesting that the presence of Gram-negative bacteria contributed substantially to endotoxin activity, masking any potential reduction that may be attributable to chlorination. Furthermore, the activities of both free and cell-bound endotoxins in pure culture increased significantly during chlorination due to cell wall damage induced by chlorination.

Review of socio-economic drivers of community acceptance and adoption of decentralised water systems

The aim of this paper is to highlight key social and economic drivers crucial to understanding community acceptance and adoption of decentralised water systems. The review focused on social science literature pertaining to alternative forms of household water, with an emphasis on research examining decentralised water acceptance. Researchers consistently reported that most communities were open to alternative water sources for domestic applications; however, this was highly dependent upon the level of personal contact with the water. Acceptance and adoption of alternative water technology, such as decentralised systems, was influenced by risk perception, water culture, and threat perception. Motivational drivers were also identified as potentially influencing adoption of decentralised systems. A clear limitation of the literature was found to be an over-reliance on measuring people's intentions to adopt alternative water systems and building a conceptual understanding of acceptance solely on hypothetical water supply scenarios. Further, within the social science literature there appears to be a skewing towards focusing on acceptance of centralised alternative water, such as recycled and desalinated water systems. Although there are some research outcomes that are generalizable to the decentralised water context, it is clear that there is a significant gap in the knowledge base of social drivers specific to the acceptance of decentralised water systems and the factors contributing to its widespread use. It is recommended that future research focus on examining public attitudes relevant to decentralised water systems, as well as adoption behaviours among current users of these systems. This will assist in developing policies specific to domestic decentralised water use.

What affects public acceptance of recycled and desalinated water?

This paper identifies factors that are associated with higher levels of public acceptance for recycled and desalinated water. For the first time, a wide range of hypothesized factors, both of socio-demographic and psychographic nature, are included simultaneously. The key results, based on a survey study of about 3000 respondents are that: (1) drivers of the stated likelihood of using desalinated water differ somewhat from drivers of the stated likelihood of using recycled water; (2) positive perceptions of, and knowledge about, the respective water source are key drivers for the stated likelihood of usage; and (3) awareness of water scarcity, as well as prior experience with using water from alternative sources, increases the stated likelihood of use. Practical recommendations for public policy makers, such as key messages to be communicated to the public, are derived.

Desalinated versus recycled water: public perceptions and profiles of the accepters

Many countries' water resources are limited in both quantity and quality. While engineering solutions can now safely produce recycled and desalinated water from non-potable sources at a relatively low cost, the general public is sceptical about adopting these alternative water sources. Social scientists, policy makers and technical experts need to better understand what is causing this lack of acceptance by the general population and how acceptance levels for recycled and desalinated water can be increased. This study is the first to conduct a comparative analysis of knowledge, perceptions, and acceptability, and determine segments of residents who are more open-minded than the general population toward the use of recycled and desalinated water. The Australian population once perceived desalinated water as environmentally unfriendly, and recycled water as a public health hazard. The general level of knowledge about these two concepts as potential water sources has historically been low. After nearly five years of serious drought, accompanied by severe water restrictions across most of the country, and subsequent media attention on solutions to water scarcity, Australians now show more acceptance of desalinated water for close-to-body uses, and less resistance to recycled water for garden watering and cleaning uses. The types of people likely to be strong accepters of the two alternative water sources are distinctly different groups, and can be reached through different media mixes. This finding has significant implications for policy makers and water practitioners.

Occurrence of pharmaceutically active and non-steroidal estrogenic compounds in three different wastewater recycling schemes in Australia

The discovery that natural and synthetic chemicals, in the form of excreted hormones and pharmaceuticals, as well as a vast array of compounds with domestic and industrial applications, can enter the environment via wastewater treatment plants and cause a wide variety of environmental and health problems even at very low concentrations, suggests the need for improvement of water recycling. Three Australian wastewater recycling schemes, two of which employ reverse osmosis (RO) technology, the other applying ozonation and biological activated carbon filtration, have been studied for their ability to remove trace organic contaminants including 11 pharmaceutically active compounds and two non-steroidal estrogenic compounds. Contaminant concentrations were determined using a sensitive analytical method comprising solid phase extraction, derivatization and GC with MS using selected ion monitoring. In raw wastewater, concentrations of analgesics and non-steroidal anti-inflammatory medications were comparable to those found in wastewaters around the world. Remarkably, removal efficiencies for the three schemes were superior to literature values and RO was responsible for the greatest proportion of contaminant removal. The ability of RO membranes to concentrate many of the compounds was demonstrated and highlights the need for continued research into monitoring wastewater treatment, concentrate disposal, improved water recycling schemes and ultimately, safer water and a cleaner environment.

Qualitative monitoring of tertiary treated wastewater reuse extensive distribution system: total coliforms number and residual chlorine concentration

During a 5-month summer period, samples of tertiary treated wastewater flowing in an extensive distribution system composed of storage tanks and pipes were collected at 2-week intervals, from 21 different sampling points, including the exit from the wastewater treatment plant (WWTP). The WWTP producing this effluent treated one of the most popular European tourist resorts on the north coast of the island of Crete, at the southernmost point of Greece. The average summer equivalent population treated by the plant exceeded 50,000, falling to under 5,000 in the winter. The samples were analyzed for total coliforms number (TC in cfu / 100 mL) and residual chlorine concentration (RCHL in mg/L). In almost 60% of the samples the TC number was so large that it could be safe to suggest that the WWTP and distribution system failed to reach the EPA standards for wastewater reuse for tree irrigation (faecal coliforms < or = 200 cfu/100 mL and RCHL < 1 mg/L) due mainly to inflow and septage handling, above designed limits. The licensing operational and reuse standards were set in TC < or = 500 cfu/100 mL, where 76% of the analyzed samples recorded larger values. It was also estimated that in 14% of the samples the wastewater quality failed to reach even the less strict WHO standards of FC < or = 1.000 cfu/100 mL. When chlorination was properly adjusted the effluent quality was improved (last three sets of samplings for each collection point), helped by the WWTP inflow decrease. As a result the values recorded in all tanks and collectors were also improved. However, even then, the required licensing standards were randomly and barely achieved. This suggests that specific wastewater quality standard at the exit of a WWTP do not guarantee that the wastewater will still retain these characteristics at its final application point.

Removal of natural hormones by nanofiltration membranes: measurement, modeling, and mechanisms

The removal mechanisms of four natural steroid hormones-estradiol, estrone, testosterone, and progesterone-by nanofiltration (NF) membranes were investigated. Two nanofiltration membranes with quite different permeabilities and salt retention characteristics were utilized. To better understand hormone removal mechanisms, the membrane average pore size was determined from retention data of inert organic solutes of various molecular weights and a pore transport model that incorporates steric (size) exclusion and hindered convection and diffusion. Results indicate that, at the early stages of filtration, adsorption (or partitioning) of hormones to the membrane polymer is the dominant removal mechanism. Because the adsorptive capacity of the membrane is limited, the final retention stabilizes when the adsorption of hormones into the membrane polymer has reached equilibrium. At this later filtration stage, the overall hormone retention is lower than that expected based solely on the size exclusion mechanism. This behavior is attributed to partitioning and subsequent diffusion of hormone molecules in the membrane polymeric phase, which ultimately results in a lower retention. Hormone diffusion in the membrane polymeric matrix most likely depends on the size of the hormone molecule, hydrogen bonding of hormones to membrane functional groups, and hydrophobic interactions of the hormone with the membrane polymeric matrix.