The soybean processing wastewater (SPW) supplementation to facilitate the simultaneously treatment (SPW and mesosulfuron-methyl) of wastewater and production of biological substances by Rhodopseudomonas sphaeroides (R. sphaeroides) was discussed. Compared with the control group, with the addition of SPW, mesosulfuron-methyl was removed, and the yields of single-cell proteins, carotenoids, and bacteriochlorophyll were increased. In the 3 mg/L dose group, the mesosulfuron-methyl removal rate reached 97% after 5 days. Molecular analysis revealed that mesosulfuron-methyl exhibited induction effects on expression of the cpm gene and regulation effects on the synthesis of cytochrome P450 monooxygenases (P450) by activating HKs gene in TCS signal transduction pathway. For R. sphaeroides, this induction process required 1 day. The synthesis of P450 occurred 1 day after inoculation. Prior to expressing cpm gene and synthesizing P450, R. sphaeroides need a period of time to adapt to external mesosulfuron-methyl stimulation. However, the R. sphaeroides growth could not be maintained for more than 1 day due to the lack of organic matter in the raw wastewater. The SPW supplementation provided a sufficient carbon source in four groups with added SPW. After 5 days, R. sphaeroides became the dominant microflora in the wastewater. This new method could complete the treatment of mixed wastewater, the increased of biological substances output and the reuse of wastewater and R. sphaeroides cells as resources at the same time.

Increasing interest of seeking substitutable water resources accrues from shortage of freshwater. One of the options considered is reclaimed water (also designated as recycled water) that has been widely used in daily life. Although reclaimed water can serve as a feasible reliever of water pressure, attention about its technologies and potential risks is growing in the meantime. Most established wastewater treatment plants (WWTPs) predate many new contaminants, which means treatment processes cannot ensure to dislodge certain contaminants completely from origin water. Furthermore, a wide range of factors, such as seasons and influent variations, affect occurrence and concentration of reclaimed water-borne contaminants, making research about quality of reclaimed water especially significant. Many reclaimed water-borne contaminants, including biological and chemical contaminants, are toxic to human health, and complex wastewater matrix may aggravate water quality of concern. The widespread use of reclaimed water continues to be a concern on agriculture, ecological environment and human health. This study aims to: 1) provide a critical review about occurrence and profiles of diverse contaminants in the treated reclaimed water, 2) discuss the possibility to avoid the secondary pollution in reuse of reclaimed water, and 3) reveal the prospective consequences of using reclaimed water on agriculture, ecological environment and human health.

Acid mine drainage (AMD) is a global environmental issue. Conventionally, a number of active and passive remediation approaches are applied to treat and manage AMD. Case studies on remediation approaches applied in actual mining sites such as lime neutralization, bioremediation, wetlands and permeable reactive barriers provide an outlook on actual long-term implications of AMD remediation. Hence, in spite of available remediation approaches, AMD treatment remains a challenge. The need for sustainable AMD treatment approaches has led to much focus on water reuse and resource recovery. This review underscores (i) characteristics and implication of AMD, (ii) remediation approaches in mining sites, (iii) alternative treatment technologies for water reuse, and (iv) resource recovery. Specifically, the role of membrane processes and alternative treatment technologies to produce water for reuse from AMD is highlighted. Although membrane processes are favorable for water reuse, they cannot achieve resource recovery, specifically selective valuable metal recovery. The approach of integrated membrane and conventional treatment processes are especially promising for attaining both water reuse and recovery of resources such as sulfuric acid, metals and rare earth elements. Overall, this review provides insights in establishing reuse and resource recovery as the holistic approach towards sustainable AMD treatment. Finally, integrated technologies that deserve in depth future exploration is highlighted.

Occurrence and removal of 81 representative Pharmaceutical Active Compounds (PhACs) were assessed in a municipal WWTP located in a highly industrialized area, with partial water reuse after UV tertiary treatment and discharge to a Mediterranean river. Water monitoring was performed in an integrated way at different points in the WWTP and river along three seasons.Consistent differences between therapeutic classes were observed in terms of influent concentration, removal efficiencies and seasonal variation. Conventional (primary and secondary) treatment was unable to completely remove numerous compounds and UV-based tertiary treatment played a complementary role for some of them. Industrial activity influence was highlighted in terms of PhACs presence and seasonal distribution.Even if global WWTP effluent impact on the studied river appeared to be minor, PhACs resulted widespread pollutants in river waters. Contamination can be particularly critical in summer in water scarcity areas, when water flow decreases considerably.

The long-term ecological risk of micropollutants, especially endocrine disrupting chemicals (EDCs) has threatened reclaimed water quality. In this study, estrogenic activity and ecological risk of eight typical estrogenic EDCs in effluents from sewage plants were evaluated. The estrogenic activity analysis showed that steroidal estrogens had the highest estrogenic activity (ranged from 10−1 to 103 ng-E2/L), phenolic compounds showed weaker estrogenic activity (mainly ranged from 10−3 to 10 ng-E2/L), and phthalate esters were negligible. The ecological risk of the estrogenic EDCs which was characterized by risk quotient ranged from 10−4 to 103, with an order in descending: steroids estrogens, phenolic compounds and phthalate esters. The eight estrogenic EDCs were scored and sorted based on the comparison of the estrogenic activity and the ecological risk, suggesting that 17α-ethynylestradiol (EE2), estrone (E1) and estradiol (E2) should be the priority EDCs to control in municipal sewage plants.

Water shortages are an issue of growing worldwide concern. Irrigated agriculture accounts for about 70% of total freshwater withdrawals globally, therefore alternatives to use of conventional sources need to be investigated. This paper critically reviews the application of treated wastewater for agricultural fertigation (i.e., water and nutrient recovery) considering different perspectives: legislation, agronomic characteristics, social acceptability, sustainability of treatment technologies. Critical issues that still need further investigation for a wider application of fertigation practices include accumulation of emerging contaminants in soils, microbiological and public health implications, and stakeholders' acceptance. A techno-economic methodological approach for assessing the sustainability of treated wastewater reuse in agriculture is subsequently proposed herein, which considers different possible local conditions (cultivated crops and effluent characteristics). The results showed that tailoring effluent characteristics to the desired nutrient composition could enhance the process economic sustainability; however, water savings have a major economic impact than fertilizers’ savings, partly due to limited P reuse efficiency. The developed methodology is based on a practical approach and may be generalized to most agricultural conditions, to evaluate and encourage safe and efficient agricultural wastewater reuse practices.

The increasing demand for fresh water coupled with the need to recycle water and nutrients has witnessed a global increase in wastewater irrigation. However, the development of antibiotic resistance hotspots in different environmental compartments, as a result of wastewater reuse is becoming a global health concern. The effect of irrigation water sources (wastewater, surface water, fresh water) on the presence and abundance of antibiotic resistance genes (ARGs) (blaCTX₋ₘ₋₃₂, tet-W, sul1, cml-A, and erm-B) and class 1 integrons (intI1) were investigated in the irrigation water-soil-crop continuum using quantitative real-time PCR (qPCR). Sul1 and blaCTX₋ₘ₋₃₂ were the most and least abundant ARGs in three environments, respectively. The abundance of ARGs and intI1 significantly decreased from wastewater to surface water and then fresh water. However, irrigation water sources had no significant effect on the abundance of ARGs and intI1 in soil and crop samples. Principal component analysis (PCA) showed that UV index and air temperature attenuate the abundance of ARGs and intI1 in crop samples whereas the air humidity and soil electrical conductivity (EC) promotes the ARGs and intI1. So that the climate condition of semi-arid regions significantly affects the abundance of ARGs and intI1 in crop samples. The results suggest that treated wastewater might be safely reused in agricultural practice in semi-arid regions without a significant increase of potential health risks associated with ARGs transfer to the food chain. However, further research is needed for understanding and managing ARGs transfer from the agricultural ecosystem to humans through the food chain.

Wastewater reuse in food crop irrigation has led to agroecosystem pollution concerns and human health risks. However, there is limited attention on the relationship of sub-lethal antibiotic levels in vegetables and resistance selection. Most risk assessment studies show non-significant toxicity, but overlook the link between antibiotics in crops and propagation of gut microbiome resistance selection. The review highlights the risk of antibiotics in treated water used for irrigation, uptake, and accumulation in edible vegetable parts. Moreover, it elucidates the risks to the adaptive resistance selection of the gut microbiome from sub-lethal antibiotic levels, as a result of dietary contaminated vegetables. Experiments have reported that bacterial resistance selection is possible at concentrations that are several hundred-folds lower than lethal effect levels on susceptible cells. Consequently, mutants selected at low antibiotic levels, such as those from vegetables, are fitter and more resistant compared to those selected at high concentrations. Necessary standardization, such as the development of minimum acceptable antibiotic limits allowable in food crop irrigation water, with a focus on minimum selection concentration, and not only toxicity, has been proposed. Wastewater irrigation offers environmental benefits and can contribute to food security, but it has non-addressed risks. Research gaps, future perspectives, and frameworks of mitigating the potential risks are discussed.

The effects of Rhodopseudomonas capsulata (R. capsulata) in the treated effluent of soybean processing wastewater (SPW) on the remediation of imidacloprid in soil, soil fertility, and the microbial community structure in soil were studied. Compared with the control group, with the addition of effluent containing R. capsulata, imidacloprid was effectively removed, soil fertility was enhanced, and the microbial community structure was improved. Molecular analysis indicated that imidacloprid could exert induction effects on expression of cpm gene and regulation effects on the synthesis of cytochrome P450 monooxygenases (P450) by activating HKs gene in two-component system (TCS). For R. capsulata, this induction process required 1 day. The synthesis of P450 occurred 1 day after inoculation, because R. capsulata are a type of archaea and imidacloprid is an environmental stress. Before expression of the cpm gene and synthesis of P450, R. capsulata need a period of time to adapt to external imidacloprid stimulation. However, the lack of organic matter in the soil cannot sustain R. capsulata growth for more than 1 day. In four groups with added effluent, the remaining organic matter in the effluent provided a sufficient carbon source and energy for R. capsulata. Five days later, the microbial community structure was improved by R. capsulata in the soil. The new technique could be used to remediate imidacloprid, enhance soil fertility, treat SPW and realize the recycling and reuse of wastewater and R. capsulata cells.

With increasing demand for aquaculture products, water reuse is likely to increase for aquaculture operations around the world. Herein, wastewater stabilization ponds (WSP) represents low cost and sustainable treatment technologies to reduce nutrients and various contaminants of emerging concern from effluent. In the present study, we examined bioaccumulation of selected pharmaceuticals from several therapeutic classes by two important fish species in aquaculture with different feeding preferences (Cyprinus carpio and Sander lucioperca) and their common prey to test whether species specific accumulation occurs. Forty and nineteen from 66 selected pharmaceuticals and their metabolites were positively found in water and sediment samples, respectively from the representative WSP. After a six-month study, which corresponds to aquaculture operations, fourteen pharmaceuticals and their metabolites were detected (at a frequency of higher than 50% of samples) in at least one fish tissue collected from the WSP. We observed striking differences for species and organ specific BAFs among study compounds. Though muscle tissues consistently accumulated lower levels of the target analytes, several substances were elevated in brain, liver and kidney tissues (e.g., sertraline) of both species. Low residual concentrations of these target analytes in aquaculture products (fish fillets) suggest WSPs are promising to support the water-food nexus in aquaculture.