Antibiotic-resistant Escherichia coli and Klebsiella spp. in greywater reuse systems and pond water used for agricultural irrigation in the West Bank, Palestinian Territories

Hidden ecotoxicological dangers: Investigating pathogen circulation and non-toxic risks hazards in a crucial brazilian watershed

Numerous studies evaluate chemical contaminants released by human activities and their effects on biota and aquatic ecosystems. However, few of these studies address non-toxic agents and their potentially harmful effects, which, in a concealed manner, culminate in an increased ecotoxicological risk for aquatic life and public health. This study investigated the presence of toxic and non-toxic pollutants in one of the main watersheds in Northeast Brazil (Rio São Francisco) and proposed a model of dispersion and transfer of resistance among the analyzed bacteria, also assessing the health risks of individuals and aquatic organisms present there. The results are worrying because although most toxic parameters, including physical-chemical and chromatographic aspects, comply with Brazilian environmental standards, non-toxic (microbiological) parameters do not. This research reveals the circulation of pathogens in several points of this hydrographic basin, highlighting the hidden ecotoxicological potential of an aquatic environment considered unaffected by the usual patterns of toxic parameters.

LED-driven photo-Fenton process for micropollutant removal by nanostructured magnetite anchored in mesoporous silica

The presence of organic micropollutants in water bodies represents a threat to living organisms and ecosystems due to their toxicological effects and recalcitrance in conventional wastewater treatments. In this context, the application of heterogeneous photo-Fenton based on magnetite nanoparticles supported on mesoporous silica (SBA15) is proposed to carry out the non-specific degradation of the model compounds ibuprofen, carbamazepine, hormones, bisphenol A and the dye ProcionRed®. The operating conditions (i.e., pH, catalyst load and hydrogen peroxide concentration) were optimized by Response Surface Methodology (RSM). The paramagnetic properties of the nanocatalysts allowed their repeated use in sequential batch operations with catalyst losses below 1%. The feasibility of the process was demonstrated as removal rates above 90% after twelve accomplished after twelve consecutive cycles. In addition, the contributions of different reactive oxygen species, mainly •OH, were analyzed together with the formation of by-products, achieving total mineralization values of 15% on average.

Mitigating risks and maximizing sustainability of treated wastewater reuse for irrigation

Scarcity of freshwater for agriculture has led to increased utilization of treated wastewater (TWW), establishing it as a significant and reliable source of irrigation water. However, years of research indicate that if not managed adequately, TWW may deleteriously affect soil functioning and plant productivity, and pose a hazard to human and environmental health. This review leverages the experience of researchers, stakeholders, and policymakers from Israel, the United-States, and Europe to present a holistic, multidisciplinary perspective on maximizing the benefits from municipal TWW use for irrigation. We specifically draw on the extensive knowledge gained in Israel, a world leader in agricultural TWW implementation. The first two sections of the work set the foundation for understanding current challenges involved with the use of TWW, detailing known and emerging agronomic and environmental issues (such as salinity and phytotoxicity) and public health risks (such as contaminants of emerging concern and pathogens). The work then presents solutions to address these challenges, including technological and agronomic management-based solutions as well as source control policies. The concluding section presents suggestions for the path forward, emphasizing the importance of improving links between research and policy, and better outreach to the public and agricultural practitioners. We use this platform as a call for action, to form a global harmonized data system that will centralize scientific findings on agronomic, environmental and public health effects of TWW irrigation. Insights from such global collaboration will help to mitigate risks, and facilitate more sustainable use of TWW for food production in the future.

Organic Compounds and Antibiotic-Resistant Bacteria Behavior in Greywater Treated by a Constructed Wetland

Laundry greywater is considered as an alternative source of non-potable water, as it is discharged in approximately 70% of homes. Because this water contains compounds such as biodegradable and recalcitrant organic matter, surfactants, and microbiological compounds, it must be treated prior to reuse. Therefore, the objective of this study was to assess the behavior of organic matter and antibiotic-resistant bacteria (ARB) in greywater treated by a constructed wetland (CW). The results show that the organic matter removal efficiencies were 67.19%, 50.15%, and 63.57% for biological oxygen demand (BOD₅), chemical oxygen demand (COD) and total organic carbon (TOC), respectively; these efficiencies were not significant (p > 0.05). In addition, the CW allows the distribution of TOC and ionic compounds in the fractions below 1000 Da to increase by 5.03% and 13.05%, respectively. Meanwhile, the treatment of microbiological compounds generated non-significant removals (p > 0.05), along with increases in bacteria resistant to the antibiotics ciprofloxacin (CIP) and ceftriaxone (CTX) of 36.34%, and 40.79%, respectively. In addition, a strong association between ARB to CIP, CTX, cationic and non-ionic surfactants was determined, indicating the role of surfactants in ARB selection. It is suggested that disinfection systems should be employed prior to the reuse of the treated water.

Perceptions on the use of recycled water for produce irrigation and household tasks: A comparison between Israeli and Palestinian consumers

Water scarcity has resulted in extensive wastewater recycling for agricultural irrigation in both Israel and the Palestinian Territories. However, minimal data have been collected regarding perceptions about wastewater recycling between the populations in these two areas. While geographically close and economically linked, these two populations differ in terms of governance, income, and access to technology for wastewater recycling. To address the data gap pertaining to perceptions of wastewater recycling, a survey was administered among a convenience sample of subjects (n = 236) recruited from Eilat, Israel and Bethlehem, West Bank, from May to November 2018. The survey included questions addressing knowledge of water sources, water scarcity, and recycled water; willingness to use recycled water for produce irrigation and household tasks; and demographics. Israeli willingness to use recycled water for various purposes ranged from 8.3% to 55.1%, and more than half of Israeli respondents were willing to serve both raw and cooked produce irrigated with recycled water. Willingness to use recycled water ranged from 28.9% to 41.7% among the Palestinian respondents, and Palestinian respondents were more willing to engage in high-contact uses (i.e. drinking and cooking) than Israeli respondents. Among the Israeli respondents, experience or familiarity with wastewater recycling and water contamination were frequently significantly associated with willingness to use recycled water. In contrast, among Palestinian respondents, personal water contamination experience, home water safety testing, and trust in authorities to monitor recycled wastewater reuse were frequently significantly associated with willingness to use recycled water. Given the likely increasing water stress in both Israel and the Palestinian Territories, as well as the continued evolution of wastewater treatment technologies and the substantial amount of agricultural trade ongoing between Israel and the Palestinian Territories, it is important to identify effective and appropriate outreach and communication strategies to enable successful and acceptable water recycling.

Chlorine disinfectants promote microbial resistance in Pseudomonas sp

The substantial use of disinfectants has increased antibiotic resistance, thereby mediating serious ecological safety issues worldwide. Accumulating studies have reported the role of chlorine disinfectants in promoting disinfectant resistance. The present study sought to investigate the role of chlorine disinfectants in developing multiple resistance in Pseudomonas sp. isolated from the river through antioxidant enzyme measurement, global transcriptional analyses, Gene Ontology (GO), and the Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis. The results demonstrated that 100 mg/L sodium hypochlorite could increase disinfectant resistance and antibiotic resistance. The SOS response (a conserved response to DNA damage) triggered by oxidative stress makes bacteria resistant to chlorine. An increase in antibiotic resistance could be attributed to a decreased membrane permeability, increased expression of MuxABC-OpmB efflux pump, beta-lactamase, and antioxidant enzymes. Additionally, KEGG enrichment analysis suggested that the differentially expressed genes were highly enriched in the metabolic pathways. In summary, the study results revealed the impact of chlorine disinfectants in promoting microbial disinfectant resistance and antibiotic resistance. This study will provide insight into disinfectant resistance mechanisms.

Greywater as a sustainable source for development of green roofs: Characteristics, treatment technologies, reuse, case studies and future developments

Municipal activities are one of the most important water users worldwide; thus, the treatment and reuse of greywater for non-potable purposes helps to reduce a remarkable amount of consumed water within urban communities. To achieve greywater reuse standards, and remove surfactants, micropollutants, organic matters, microorganisms and other pollutants various methods including physical, chemical and biological processes have been used. Treated greywater can be used on site for different purposes: carwash, toilet flushing, fire protection, green roofs, green walls, non-food irrigation etc. Among them, the use of greywater is very important in the expansion of the green roofs. Green roofs offer many benefits to urban areas such as decreasing air pollution, reducing building cooling needs, promoting mental health of habitants, noise reduction and aesthetics improvement. Therefore, this article provides an overview mainly from two aspects, the possibilities of greywater reuse by studying the characteristics and available options for greywater treatment and its benefits toward the developing green roofs.

Quantification and Characterization of Antimicrobial Resistance in Greywater Discharged to the Environment

In disenfranchised communities, untreated greywater (wastewater without sewage) is often environmentally discharged, resulting in potential human exposure to antimicrobial-resistant bacteria (ARB), including extended-spectrum beta-lactamase (ESBL) producers. We sought to examine the abundance of ARB, specifically ESBLs, and antimicrobial resistance genes (ARGs) in greywater from off-grid, pastoral Bedouin villages in Southern Israel. Greywater samples (n = 21) collected from five villages were analyzed to enumerate fecal coliforms and Escherichia coli. ESBL producers were recovered on CHROMagar ESBL and confirmed by VITEK®2 (bioMerieux, Marcy l’Etoile, France) for identification and antimicrobial susceptibility testing. Total genomic DNA was extracted from greywater samples and quantitative PCR (qPCR) was used to determine relative abundance (gene copies/16S rRNA gene) of class 1 integron-integrase intI1, blaTEM, blaCTX-M-32, sul1, and qnrS. The mean count of presumptive ESBL-producing isolates was 4.5 × 106 CFU/100 mL. Of 81 presumptive isolates, 15 ESBL producers were recovered. Phenotypically, 86.7% of ESBL producers were multi-drug resistant. Results from qPCR revealed a high abundance of intI1 (1.4 × 10−1 gene copies/16S rRNA), sul1 (5.2 × 10−2 gene copies/16S rRNA), and qnrS (1.7 × 10−2 gene copies/16S rRNA) followed by blaTEM (3.5 × 10−3 gene copies/16S rRNA) and blaCTX-M-32 (2.2 × 10−5 gene copies/16S rRNA). Results from our study indicate that greywater can be a source of ARB, including ESBL producers, in settings characterized by low sanitary conditions and inadequate wastewater management.