Micropollutants removal and health risk reduction in a water reclamation and ecological reuse system

Global insight into the occurrence, treatment technologies and ecological risk of emerging contaminants in sanitary sewers: Effects of the SARS-CoV-2 coronavirus pandemic

The SARS-CoV-2 pandemic caused changes in the consumption of prescribed/non-prescribed drugs and the population's habits, influencing the detection and concentration of emerging contaminants (ECs) in sanitary sewage and harming environmental and health risks. Therefore, the present work sought to discuss current literature data on the effects of the "COVID-19 pandemic factor" on the quality of raw sewage produced over a five-year period (2018-2019: pre-pandemic; 2020-2022: during the pandemic) and biological, physical, chemical and hybrid treatment technologies, influencing factors in the removal of ECs and potential ecological risks (RQs). Seven hundred thirty-one publications correlating sewage and COVID-19 were identified: 184 pre-pandemic and 547 during the pandemic. Eight classes and 37 ECs were detected in sewage between 2018 and 2022, with the "COVID-19 pandemic factor" promoting an increase in estrogens (+31,775 %), antibiotics (+19,544 %), antiepileptics and antipsychotics (+722 %), pesticides (+200 %), analgesics, anti-inflammatories and anticoagulants (+173 %), and stimulant medications (+157 %) in sanitary sewage. Among the treatment systems, aerated reactors integrated into biomembranes removed >90 % of cephalexin, clarithromycin, ibuprofen, estrone, and 17β-estradiol. The absorption, adsorption, and biodegradation mechanisms of planted wetland systems contributed to better cost-benefit in reducing the polluting load of sewage ECs in the COVID-19 pandemic, individually or integrated into the WWTP. The COVID-19 pandemic factor increased the potential ecological risks (RQs) for aquatic organisms by 40 %, with emphasis on clarithromycin and sulfamethoxazole, which changed from negligible risk and low risk to (very) high risk and caffeine with RQ > 2500. Therefore, it is possible to suggest that the COVID-19 pandemic intensified physiological, metabolic, and physical changes to different organisms in aquatic biota by ECs during 2020 and 2022.

Quantitative structure-biotransformation relationships of organic micropollutants in aerobic and anaerobic wastewater treatments

Biotransformation is one of the dominant processes to remove organic micropollutants (OMPs) in wastewater treatment. However, studies on the role of molecular structure in determining the biotransformation rates of OMPs are limited. We evaluated the biotransformation of 14 OMPs belonging to different chemical classes under aerobic and anaerobic conditions, and then explored the quantitative structure-biotransformation relationships (QSBRs) of the OMPs based on biotransformation rates using valid molecular structure descriptors (electrical and physicochemical parameters). Pseudo-first-order kinetic modeling was used to fit the biotransformation rate, and only 2 of the 14 OMPs showed that the biotransformation rate constant (kbio) values were higher under anaerobic conditions than aerobic conditions, indicating that aerobic conditions were more favorable for biotransformation of most OMPs. QSBRs infer that the electrophilicity index (ω) is a reliable predictor for OMPs biotransformation under aerobic conditions. ω corresponds to the interaction between OMPs and microbial enzyme active sites, this process is the rate-limiting step of biotransformation. However, under anaerobic conditions the QSBR based on ω was not significant, indicating that specific functional groups may be more critical than electrophilicity. In conclusion, QSBRs can serve as alternative tools for the prediction of the biotransformation of OMPs and provide further insights into the factors that influence biotransformation.

Occurrence and Health Risks of Organic Micropollutants in Tap Water in Dalian

Organic micropollutants (OMPs) in tap water may pose risks to human health. Previous studies on the potential health risks of OMPs in tap water may have underestimated the potential health risks of OMPs due to their limited coverage in target pollutants and incomplete toxicity data. In this study, tap water samples were collected in 37 sampling sites in Dalian, China. More than 1,200 target pollutants were screened by combining screening analysis and target analysis. A total of 93 OMPs were detected, with concentration summation ranging from 157 to 1.7 × 104 ng/L among different sampling sites. A total of 17 OMPs (12 agrochemicals, 3 pharmaceuticals and personal care products, and 2 other compounds) were detected in over 80% of the sampling sites. Especially, imidacloprid, tebuconazole, and atrazine-desethyl were found in all the sampling sites. Computational toxicology models were adopted to predict the missing toxicity threshold values of the identified chemicals. Noncarcinogenic risks were estimated to be negligible among all the sampling sites, while carcinogenic risks at six sites were above 10-6 but below 10-4, indicating non-negligible risks. Griseofulvin contributed the most to the carcinogenic risk. This study offers valuable insights that can guide future initiatives to safeguard tap water safety.

Occurrence of antibiotics in reclaimed water, and their uptake dynamics, phytotoxicity, and metabolic fate in Lolium perenne L

Reclaimed water (RW) has been extensively used for irrigation in agriculture, yet the occurrence of antibiotics in real RW, and their toxicity, uptake dynamics and metabolic fate still needs comprehensive exploration. In this study, we investigated the residual concentrations of nineteen antibiotics in the RW from four wastewater treatment plants, and determined their toxicity on plant at environment-relevant concentration. Total found concentrations of these antibiotics ranged from 623.66 ng L-1 to 1536.96 ng L-1, which decreased 10.3 and 19.4 % of roots' length and weight. Uptake dynamics analysis of the most hazardous antibiotic, norfloxacin (NFX) showed increasing amounts in the roots and leaves up to 3087.71 μg g-1. Ryegrass also can remove >80 % of 100 μg L-1 NFX being achieved by biodegradation through ring cleavage, decarboxylation, defluorination, hydrogenation, methylation and oxidation. Toxicity assessment of the identified byproducts showed their more toxic effect on fish, daphnia and algae. This study extended our understanding of the fate of antibiotics in plants during irrigation with reclaimed water, and emphasized its safety and pollutants' biomagnification concerns.

Investigation of water quality and aquatic ecological succession of a newly constructed river replenished by reclaimed water in Beijing

The potential to create new ecosystems in rivers is possible through the use of reclaimed water as a replenishment source, although the long-term effects of this method are unknown. In this study, the water quality and aquatic ecological evolution of a newly constructed river replenished by reclaimed water in Beijing (the Jing River) were investigated, and the conventional water quality, phytoplankton indicators, and submerged plant growth conditions from October 2018 to December 2020 were analyzed. Spearman's correlation and redundancy analysis between possible influential environmental factors and algal indicators were conducted. The results show that the major water quality indicators could meet the water quality standards for landscape water. There were seven phyla present, including 322 species of phytoplankton. The phytoplankton density increased, followed by a decreasing trend. Phytoplankton densities at each monitoring site reached 10 × 10⁶ to 25 × 10⁶ cells/L in 2019 before decreasing in 2020, then ranging from 8 × 10⁶ to 20 × 10⁶ cells/L. Phytoplankton growth was influenced by changing water quality and ecosystems. Consequently, the submerged plant coverage rate gradually increased from 2018 (0%) to 2020 (26.27%-37.06%), as did biodiversity. Through the implementation of ecological restoration measures in the Jing River, the reclaimed water environment evolved into a more natural water environment, which could provide some reference for similar areas to use reclaimed water as a water replenishment source.

Effect of organophosphate esters on microbial community and proteomics in constructed wetlands and its removal mechanism

Organophosphorus esters (OPEs) may cause potential risks to human health and ecological environment safety when they enter water. In this study, A lab-scale vertical flow constructed wetlands (VFCWs) exposed to dichlorvos (DDVP) was carried out to reveal removal effect and mechanism of DDVP in VFCWs. The findings indicated CWs can remove DDVP with 94%-95% average removal efficiency in long-term operation. Besides, soluble phosphate (SRP) and total phosphorus (TP) were removed by VFCWs with 48.60%-64.10% average removal efficiency, and the addition of DDVP enhanced the effect of CWs on nitrogen removal. High-throughput sequencing demonstrated that Massiilia (2.67%-18.06%), Denitratisoma (2.07%-3.80%) and SM1A02 (2.85%-4.67%) played an important role in the removal process of DDVP in VFCWs. Proteomics of plant root showed that A0A3B6ARQ4 (increased 29.53 times) and LOC_Os11g38050.1 protein (decreased 0.001 times) responsed more sensitive to OPEs which suggested DDVP enhancesenhancing plants energy production and hydrolyase synthesis, thereby promoting it hydrolysis. Therefore, the use of VFCWs to treat organic phosphate wastewater has future prospects.

Distribution, source, risk and phytoremediation of polycyclic aromatic hydrocarbons (PAHs) in typical urban landscape waters recharged by reclaimed water

A park that had used reclaimed water as the sole water supply for fourteen years, was selected to analyze the distribution, sources and risks of 16 priority polycyclic aromatic hydrocarbons (PAHs) in waters and sediments. The effects of phytoremediation were investigated in waterbodies classified as phytoremediation, transitional and non-phytoremediation areas. Diagnostic ratio (DR) and principal component analysis (PCA) were used to analyze the sources of PAHs, while risk quotient (RQ) was used as risk assessment tool. Results showed that ∑PAH concentrations in sediments ranged from 29.4 to 1245.6 ng‧g^-1, with average of 354.3 ng‧g^-1, corresponding to a moderate pollution level. The concentration of PAHs in water ranged from 10.6 to 326.3 ng‧L^-1, with average of 147.2 ng‧L^-1, corresponding to a low pollution level. The ∑PAHs in sediments showed a downward trend from northwest to southeast along with the water flow direction, with average values of 459.5, 362.9 and 246.1 ng‧L^-1 in the upstream, midstream and downstream, respectively. In contrast, PAH concentrations in water were consistent with recreational activities in the urban park area. There were 95% of water samples and 72% of sediment samples obtaining the Ant/(Ant + Phe) > 0.1 and Flu/(Flu + Pyr) > 0.5, indicating that coal combustion was the major source of PAHs in both the water and sediment. The RQ_∑PAH(NCs) values in water and sediment were all between 1 and 800, while RQ_∑PAH(MPCs) reached equal to 0, suggesting that ∑PAHs presented a low ecological risk. Acenaphthene accounted for 28.4% of RQ_(NCs), and became the most risk PAH in water column. Aquatic plants effectively removed high-ring PAHs from water and middle-ring PAHs from sediments, reducing the overall risks posed by PAHs.

Simulation Study on the Optimisation of Replenishment of Landscape Water with Reclaimed Water Based on Transparency

Water-scarce cities have fewer surface water (SW) resources available for ecological use, causing landscape water to deteriorate due to water shortage and fail to perform their intended landscape functions. As a result, many cities use reclaimed water (RW) to replenish them. However, this could cause concern among the people, as RW usually has higher nutrient concentrations, which may stimulate algae growth and deteriorate the aesthetic senses of the receiving water bodies. In order to assess the feasibility of using RW for this purpose, this study used Xingqing Lake in Northwest China as insight into the effect of RW replenishment on the visual landscape quality of urban landscape water. Water transparency (measured by SD) is used as an intuitive indicator to reflect the comprehensive influence of suspended solids and algae growth on the water's aesthetic quality. Scenario analyses were carried out after calibrating and validating one-year data in MIKE 3 software with both SD and algae growth calculations, and the results showed that the low concentration of suspended matter in RW could compensate for the decrease in SD due to algal blooms caused by high concentrations of nitrogen and phosphorus, and the effect on SD is especially pronounced under conditions that are not conducive to algal growth, such as good flow conditions and low temperature. In addition, to meet a SD ≥ 70 mm, the total water inflow required can be significantly reduced with the optimal application of RW. It is also indicated that partial or complete utilization of RW to replace SW for replenishing the landscape water could be feasible from the viewpoint of landscape quality, at least for the landscape water investigated in this study. This can provide a method for the improvement to urban water management practices by using RW for replenishment in water-scarce cities.

Unraveling the key driving factors involved in cometabolism enhanced aerobic degradation of tetracycline in wastewater

Cometabolism has shown great potential in increasing the engineering feasibility of microalgae-based biotechnologies for the aerobic treatment of antibiotics-polluted wastewaters. Yet, the underlying mechanisms involved in improved microalgal performance remain unknown. In this study, we incorporated transcriptomics, gene network analysis, and enzymatic activities with cometabolic pathways of tetracycline (TC) by Chlorella pyrenoidosa to identify the key driving factors. The results demonstrated that cometabolism constructed a metabolic enzymes-photosynthetic machinery to improve the electron transport chain and activities of catalytic enzymes, which resulted in subsequent 100% removal of TC. Coupling formation dynamics of the intermediates with roles of identified metabolic enzymes, degradation of TC can be induced by de/hydroxylation, de/hydrogenation, bond-cleavage, decarboxylation, and deamination. Evaluation of 18 antibiotics' removal in reclaimed water showed cometabolism decreased the total concentrations of these antibiotics from 495.54 ng L^-1 to 221.80 ng L^-1. Our findings not only highlight the application potential of cometabolism in increasing engineering feasibility of microalgal degradation of antibiotics from wastewaters, but also provide the unique insights into unraveling the "black-box" of cometabolisms in aerobic biodegradation.

Modeling micropollutant removal by nanofiltration and reverse osmosis membranes: considerations and challenges

Organic micropollutants (OMPs) in drinking water constitute a potential risk to human health; therefore, effective removal of these pollutants is required. Nanofiltration (NF) and reverse osmosis (RO) are promising membrane-based technologies to remove OMPs. In NF and RO, the rejection of OMPs depends on the properties and characteristics of the membrane, the solute, and the solution. In this review, we discuss how these properties can be included in models to study and predict the rejection of OMPs. Initially, an OMP classification is proposed to capture the relevant properties of 58 OMPs. Following the methodology described in this study, more and new OMPs can be easily included in this classification. The classification aims to increase the comprehension and mechanistic understanding of OMP removal. Based on the physicochemical principles used to classify the 58 OMPs, it is expected that other OMPs in the same groups will be similarly rejected. From this classification, we present an overview of the rejection mechanisms involved in the removal of specific OMP groups. For instance, we discuss the removal of OMPs classified as perfluoroalkyl substances (e.g., perfluorooctanoic acid, PFOA). These substances are highly relevant due to their human toxicity at extremely low concentration as well as their persistence and omnipresence in the environment. Finally, we discuss how the rejection of OMPs can be predicted by describing both the membrane-solution interface and calculating the transport of solutes inside the membrane. We illustrate the importance and impact of different rejection mechanisms and interfacial phenomena on OMP removal and propose an extended Nernst-Plank equation to calculate the transport of solutes across the membrane due to convection, diffusion, and electromigration. Finally, we show how the theory discussed in this review leads to improved predictions of OMP rejection by the membranes.

State-of-the-Art Review on the Application of Membrane Bioreactors for Molecular Micro-Contaminant Removal from Aquatic Environment

In recent years, the emergence of disparate micro-contaminants in aquatic environments such as water/wastewater sources has eventuated in serious concerns about humans’ health all over the world. Membrane bioreactor (MBR) is considered a noteworthy membrane-based technology, and has been recently of great interest for the removal micro-contaminants. The prominent objective of this review paper is to provide a state-of-the-art review on the potential utilization of MBRs in the field of wastewater treatment and micro-contaminant removal from aquatic/non-aquatic environments. Moreover, the operational advantages of MBRs compared to other traditional technologies in removing disparate sorts of micro-contaminants are discussed to study the ways to increase the sustainability of a clean water supplement. Additionally, common types of micro-contaminants in water/wastewater sources are introduced and their potential detriments on humans’ well-being are presented to inform expert readers about the necessity of micro-contaminant removal. Eventually, operational challenges towards the industrial application of MBRs are presented and the authors discuss feasible future perspectives and suitable solutions to overcome these challenges.

Hydrolyzed urine for enhanced valorization and toxicant degradation of wet coffee processing wastes: Implications for soil contamination and health risk reductions

Coffee pulp (CP) and wastewater, from wet coffee processing plants, pollute water and soil ecosystems unless a greener management system is employed. The aim was to evaluate the effect of hydrolyzed human urine (HU) on the dynamics of total phenol, caffeine, and heavy metals during CP and coffee processing wastewater (CPWW) co-composting. The associated health risks reduction after application for cabbage production was also estimated. For the purpose, five treatments were prepared as C₀ (CP, control), C₁ (CP + CPWW), C₂ (CP + 1:1 CPWW:HU), C₃ (CP + 1:2 CPWW:HU) and C₄ (CP + 1:3 CPWW:HU). The optimum compost was applied for cabbage cultivation in comparison with mineral fertilizer and without fertilization in a greenhouse. The total phenol reduction was in the order of C₁ (77.71%) < C₀ (78.66%) < C₄ (79.89%) < C₃ (91.20%) < C₂ (91.48%), and maximum significant reduction of caffeine was also observed in C₃ (81.34%) and C₂ (82.66%). Pb and Cd were significantly reduced in C₂, and Cr in C₃ with a reduction of 4.38-15.13%, 12.50-33.00%, and 2.94-19.57%, respectively. The bio-concentration factor decreased in the order of Cd > Cr > Ni > Pb with concentrations, hazard quotient, hazard index (along with phenol) < 1, and cancer risk values below 1.00E-04, indicating very little risk. Thus, supplementing HU enhanced degradation of the anti-nutrient factors, and provide compost that enrich soil nutrients with little health risks of application.

Contaminants of emerging concern (CECs) in aquaculture effluent: Insight into breeding and rearing activities, alarming impacts, regulations, performance of wastewater treatment unit and future approaches

The contamination of aquaculture products and effluents by contaminants of emerging concern (CECs) from the direct chemical use in aquaculture activities or surrounding industries is currently an issue of increasing concern as these CECs exert acute and chronic effects on living organisms. CECs have been detected in aquaculture water, sediment, and culture species, and antibiotics, antifoulants, and disinfectants are the commonly detected groups. Through accumulation, CECs can reside in the tissue of aquaculture products and eventually consumed by humans. Currently, effluents containing CECs are discharged to the surrounding environment while producing sediments that eventually contaminate rivers as receiving bodies. The rearing (grow-out) stages of aquaculture activities are issues regarding CECs-contamination in aquaculture covering water, sediment, and aquaculture products. Proper regulations should be imposed on all aquaculturists to control chemical usage and ensure compliance to guidelines for appropriate effluent treatment. Several techniques for treating aquaculture effluents contaminated by CECs have been explored, including adsorption, wetland construction, photocatalysis, filtration, sludge activation, and sedimentation. The challenges imposed by CECs on aquaculture activities are discussed for the purpose of obtaining insights into current issues and providing future approaches for resolving associated problems. Stakeholders, such as researchers focusing on environment and aquaculture, are expected to benefit from the presented results in this article. In addition, the results may be useful in establishing aquaculture-related CECs regulations, assessing toxicity to living biota, and preventing pollution.

A synthetical methodology for identifying priority pollutants in reclaimed water based on meta-analysis

Wastewater reclamation and reuse is an increasing global project, while the reclamation treatment on wastewater does not completely remove all pollutants in water. The residual pollutants in reclaimed water would cause potential risk on human health and ecosystem safety during the long-term use. It is impossible to analyze and control all pollutants one by one in practice, therefore, identification and control of priority pollutants will be efficient strategy to ensure the safe use of reclaimed water. An integrated three-step methodology for identifying priority pollutants in reclaimed water was proposed in this study. First, a comprehensive literature survey on the occurrence of pollutants in reclaimed water was conducted, and a dataset D_PR for pollutants occurrence in reclaimed water was established, containing 1,113 pollutants. Second, 611 chemicals that had been recommended as hazardous pollutants for various water bodies in previous literatures were summarized, and a dataset D_HP for hazardous pollutants in water was obtained. Third, meta-analysis on these two datasets (D_PR and D_HP) was performed, a new dataset D_HPR for hazardous pollutants in reclaimed water was established, including 265 candidates. Finally, 59 substances out of dataset D_HPR were identified as priority pollutants for reclaimed water based on their recommendation frequency. It is expected that this synthetical methodology will provide powerful support for scientific evaluating and managing water pollution and ensuring safe use of reclaimed water.

Regenerable temperature-responsive biocatalytic nanofiltration membrane for organic micropollutants removal

Biocatalytic nanofiltration membranes (BNMs) exhibit great potentials in organic micropollutants removal attributed to its synergistic effect between enzyme catalysis and membrane separation. However, the difficulties in regeneration of the BNMs halted their economic practicality. Inspired by cell membranes with stimuli-responsive channels, we have developed the temperature-responsive BNMs with nanogating function by poly(N-isopropyl acrylamide) (PNIPAM) modification. PNIPAM modification increases the geometric confinement of the support layer to enzymes, thus improving enzyme loading, inhibiting enzyme leakage, and preventing membrane permeability decline caused by enzyme excess migration and aggregation. By optimizing the concentration of reaction monomers, modification time, and strategies, the PNIPAM-based BNMs show high bisphenol A (BPA) removal efficiency and long-term stability. Furthermore, the PNIPAM-polyethyleneimine-based BNMs can be easily regenerated at 38°C, and the laccase activity and BPA removal efficiency are fully recovered. This work would promote the real application of BNMs in bioconversion, drug delivery, and biosensors.

Ecological insights into the disturbances in bacterioplankton communities due to emerging organic pollutants from different anthropogenic activities along an urban river

Emerging organic pollutants (EOPs) in urban rivers have raised concerns regarding their eco-toxicological effects. However, the bacterioplankton community disturbances caused by EOPs in urban rivers and the associated ecological mechanisms remain unclear. This study provided profiles of the spatial distribution of a bacterioplankton community disturbed by human activity along an urban river. The results showed that EOP concentration and composition were differently distributed in residential and industrial areas, which significantly influenced bacterioplankton community structure. Based on redundancy analysis, parabens (methylparaben and propylparaben) were the major factors driving bacterioplankton community changes. Parabens inhibited gram-positive bacteria and promoted oxidative stress-tolerant bacteria in the river ecosystem. Parabens also disturbed ecological processes of bacterioplankton community assembly, shifting from a homogeneous selection (consistent selection pressure under similar environmental condition) to stochastic processes (random changes due to birth, death, immigration, and emigration) with changing in paraben concentrations. Heterogeneous selection was predicted to dominate microbial community assembly with paraben concentration changes exceeding 61.6 ng/L, which could deteriorate the river ecosystem. Furthermore, specific bacterial genera were identified as potential bioindicators to assess the condition of EOP contaminants in the river. Overall, this study highlights significant disturbances in bacterioplankton communities by EOPs at environmental concentrations, and our results could facilitate generation of appropriate management strategies aimed at EOPs in urban rivers.

Water intake meets the Water from inside the human body – physiological, cultural, and health perspectives - Synthetic and Systematic literature review

Background. The average adult human body of 70 kilograms consists in about 67.85% water distributed evenly to an average of 70 % in all major organs of the body: skin, muscles, brain, spinal cord, liver, heart, lungs, spleen, kidneys, pancreas and gastro-intestinal tract. A smaller percentage is found in the bones (30%), teeth (5%) and fat tissue (50%). Objective. This review article attempts to present different perspectives on the physiological properties of water in the human body. We describe from the ancient Chinese medicine theory about water being one of the 5 elements of nature and its harmonious interrelation with the other elements in order to balance the human body, to the successful experiments of researchers which demonstrated waters’ capability to change its molecular structure based on feelings, intentions and energy it was exposed to. We briefly describe the role of water for the human body and what effects can the lack of it have, especially dehydration with all the phases of severity. Also, we present the health benefits of drinking water and which type of water is best to consume. We shorty review the different types of natural mineral waters in Romania and the importance of the Romanian researches for balneology and how the waters cand be administrated in crenotherapy for different types of pathologies. Methods. To elaborate our systematic review, we have searched for relevant open access articles and review articles in ISI Web of Science, published from January 2017 until August 2021. The terms used were water AND health in the title. Articles were excluded in the second phase if they did not reach the relevance citation criterion. The eligible articles were analyzed in detail regarding water importance for human health. Results. Our search identified, first, 548 articles. After applying a PEDro like selection filter and, we selected 93 articles with a minimum of 8 points on our PEDro like filtering scale (good, very good, and excellent articles with a minimum of 5 citations per year). Detailed analysis of the 93 selected articles has conducted us to the elimination of 33 of them as being on a different subject than that of our article. To the 60 full articles retained for this systematic and synthetic article, we have added 10 articles found through a separate Google search, as being considered of high relevance for our subject and necessary to be included. Conclusions. Water is essential for the entire planet and also indispensable for the survival of the human body. Keywords: water intake, water balance, body water, water molecular structure, dehydration, crenotherapy

Mitigation of emerging pollutants and pathogens in decentralized wastewater treatment processes: A review

Emerging pollutants (such as micropollutants, microplastics) and pathogens present in wastewater are of rising concern because their release can affect the natural environment and drinking water resources. In this decade, with increasing numbers of small-scale decentralized wastewater systems globally, the status of emerging pollutant and pathogen mitigation in the decentralized wastewater treatment processes has received more attention. This state-of-the-art review aims to discuss the mitigation efficiencies and mechanisms of micropollutants, microplastics, and pathogens in single-stage and hybrid decentralized wastewater treatment processes. The reviewed results revealed that hybrid wastewater treatment facilities could display better performance compared to stand-alone facilities. This is because the multiple treatment steps could offer various microenvironments, allowing incorporating several mitigation mechanisms (such as sorption, degradation, filtration, etc.) to remove complicated emerging pollutants and pathogens. The factors (such as system operation conditions, environmental conditions, wastewater matrix) influencing the removals of emerging pollutants from wastewater in these systems have been further identified. Nevertheless, it was found that very limited research work focused on synergised or conflicted effects of operation conditions on various emerging pollutants naturally present in the wastewater. Meanwhile, effective, reliable, and rapid analysis of the emerging pollutants and pathogens in the complicated wastewater matrix is still a major challenge.

Anthropogenic disturbances on distribution and sources of pharmaceuticals and personal care products throughout the Jinsha River Basin, China

Pharmaceuticals and personal care products (PPCPs) are recognized as a group of emerging contaminants closely related to anthropogenic activities, which capture increasing attention worldwide. To evaluate the anthropogenic disturbances on PPCP distribution and sources, this study investigated the distribution and sources of 50 PPCPs along the 2300 km long Jinsha River and revealed different anthropogenic disturbances on PPCPs. Results showed that 40 out of the 50 PPCPs were ubiquitously detected among these river water samples, with the concentrations varied from less than 1 ng/L to more than 500 ng/L. Although most PPCPs concentrations were much lower in the Jinsha River than in highly developed rivers, the prevalence of PPCPs suggested the widespread use and improper disposal of PPCPs in the Jinsha River. The risk assessment also revealed that some PPCPs posed risks to aquatic organisms in the Jinsha River. Anthropogenic activities including human habitation and dam construction had different influence on PPCPs. PPCP distribution varied significantly across the "Hu Huanyong line", indicating human habitation significantly influenced PPCP distribution. Dam construction was insignificant in altering PPCP distribution throughout the Jinsha River. Moreover, the land use index indicated degradation level of multiple lands related to anthropogenic activities and represented the major sources of PPCPs in the Jinsha River. Most PPCPs were correlated with anthropogenic lands, for example, antibiotics, analgesics, and endocrine disrupting chemicals mainly originated from artificial surfaces, whereas other PPCPs mainly originated from cultivated lands. Together, this study indicates the disturbances of multiple anthropogenic activities on PPCP distribution and sources along the Jinsha River, which contributes to PPCP management in rural areas.

Fate and biodegradation characteristics of triclocarban in wastewater treatment plants and sewage sludge composting processes and risk assessment after entering the ecological environment

Triclocarban (TCC) has a high detection frequency in soil, rivers, sediments, and organisms, and its ecological risks have attracted substantial attention. In this study, we analyzed the fate of TCC in four wastewater treatment plants (WWTPs) in Zhengzhou, China, the biodegradation characteristics during the composting process, and the ecological risks of TCC when entering different environmental compartments. The concentration of TCC in the influent was 731.1-812.4 ng/L. More than 53.4% of TCC was biodegraded during the wastewater treatment process, and less than 2.5% was retained in the effluent. TCC was effectively removed through microbial degradation and sewage sludge absorption, and there were only minor differences in the different wastewater treatment processes. It is worth noting that more than 38% of TCC was enriched in sewage sludge (1430.1-1663.8 ng/g). The corresponding biodegradation rates of TCC were 65.7% and 82.8% in sewage sludge after 17 days of composting treatment with sawdust and straw as bulking agents, respectively. The estimated results showed that effluent discharge into the city rivers was safe. Composting could effectively degrade TCC and decrease the ecological risk of TCC when applied to sewage sludge.

Advances in laccase-triggered anabolism for biotechnology applications

This is the first comprehensive overview of laccase-triggered anabolism from fundamental theory to biotechnology applications. Laccase is a typical biological oxidordeuctase that induces the one-electronic transfer of diverse substrates for engendering four phenoxy radicals with concomitant reduction of O₂ into 2H₂O. In vivo, laccase can participate in anabolic processes to create multifarious functional biopolymers such as fungal pigments, plant lignins, and insect cuticles, using mono/polyphenols and their derivatives as enzymatic substrates, and is thus conducive to biological tissue morphogenesis and global carbon storage. Exhilaratingly, fungal laccase has high redox potential (E° = 500-800 mV) and thermodynamic efficiency, making it a remarkable candidate for utilization as a versatile catalyst in the green and circular economy. This review elaborates the anabolic mechanisms of laccase in initiating the polymerization of natural phenolic compounds and their derivatives in vivo via radical-based self/cross-coupling. Information is also presented on laccase immobilization engineering that expands the practical application ranges of laccase in biotechnology by improving the enzymatic catalytic activity, stability, and reuse rate. Particularly, advances in biotechnology applications in vitro through fungal laccase-triggered macromolecular biosynthesis may provide a key research direction beneficial to the rational design of green chemistry.

Sunlight-induced changes in naturally stored reclaimed water: Dissolved organic matter, micropollutant, and ecotoxicity

Natural sunlight is a vital environmental element and plays a significant role in the ecological storage of reclaimed water (RW), but its impacts on RW quality are poorly understood. In this study, sunlight-induced changes in RW with a focus on dissolved organic matter (rDOM) and 52 residual micropollutants were investigated in the field during the summer and winter seasons. The results indicated that sunlight exposure led to the dissipation of chromophoric DOM (CDOM) in the summer (55% loss) and winter (19% loss) after 14 consecutive sunny days. During open storage of RW, CDOM absorption in UVC regions was preferentially removed in the summer, while during the winter there was preferential removal of CDOM in UVA regions. The results also showed higher fluorescent DOM (FDOM) removal in summer than in winter (49% and 28%, respectively). Results in both seasons indicated that humic acid-like compounds were the most photolabile fractions and were preferentially removed under sunlight exposure. Sunlight also induced attenuation of micropollutants in the summer and winter at reductions of 66% and 24% from the initial values, respectively. Significant attenuation (>75%) was only observed for endocrine-disrupting chemicals, pharmaceuticals, and sunscreens in the summer, but they accounted for 76% of the total concentrations. Vibrio fischeri toxicity tests demonstrated that sunlight constantly decreased the luminescent bacteria acute toxicity of RW, which was estimated to be caused mainly by the sunlight-induced changes of FDOM and CDOM, while the detected micropollutants could only explain 0.02%-2% of acute toxicity. These findings have important implications regarding our understanding of the ecological storage of reclaimed water and the contribution of management strategies.

Occurrence and Fate of Emerging Pollutants in Water Environment and Options for Their Removal

Emerging pollutants (EPs) are chemicals known to cause major impacts on the terrestrial, aquatic life and human health as a result of their chronic and acute toxicity. Although lots of studies on EPs behavior in the aquatic environment are currently available in literature, an urgent requirement exists to complete toxicological studies and develop and implement efficient and ecological methods for their removal. This paper raises some relevant problems related to water environment pollution with EPs, the risks they can generate for aquatic life and humans and opportunities to reduce the effects of pollution by EPs removal. Categories of emerging chemicals of concern in the environment, their sources, fate and impacts, with some examples are discussed. Organic UV filters are shortly presented as a relative new EPs category, with a focus on the need to develop extensive experimental studies on their environmental occurrence, fate and removal. Furthermore, sources for the aquatic environment resulting from discharging EPs directly into rivers from wastewater treatment plants are examined. The incidence of environmental and human health risks related to EPs is also considered. The removal of EPs from the environment as a solution to risk mitigation is addressed, with emphasis on several non-conventional processes involving biological removal of EPs. The paper provides a critical look at the current challenges posed by the presence of emerging pollutants in the aquatic environment, with critical comments and recommendations for further research to reduce the impact of EPs on water and human health and improve the performance of developed methods for their removal.

Occurrence and risk assessment of emerging contaminants in a water reclamation and ecological reuse project

Water reclamation and ecological reuse is gradually becoming a popular solution to address the high pollutant loads and insufficient ecological flow of many urban rivers. However, emerging contaminants in water reuse system and associated human health and ecological risks need to be assessed. This study determined the occurrence and human health and ecological risk assessments of 35 emerging contaminants during one year, including 5 types of persistent organic pollutants (POPs), 5 pharmaceutical and personal care products (PPCPs), 7 endocrine disrupting chemicals (EDCs) and 18 disinfection by-products (DBPs), in a wastewater treatment plant (WWTP) and receiving rivers, as well as an unimpacted river for comparison. Results showed that most of PPCPs and EDCs, especially antibiotics, triclosan, estrogens and bisphenol A, occurred frequently at relatively high concentrations, and they were removed from 20.5% to 88.7% with a mean of 58.9% via WWTP. The highest potential noncarcinogenic and carcinogenic risks in different reuse scenarios were assessed using maximal detected concentrations, all below the acceptable risk limits, with the highest total combined risk value of 9.21 × 10^-9 and 9.98 × 10^-7, respectively. Ecological risk assessment was conducted using risk quotient (RQ) method and indicated that several PPCPs, EDCs and haloacetonitriles (HANs) pose high risk (RQ > 1) to aquatic ecology in the rivers, with the highest RQ up to 83.8. The study suggested that ecological risks need to be urgently addressed by updating and optimizing the process in WWTPs to strengthen the removal efficiencies of emerging contaminants. The study can serve as a reference for safer water reuse in the future, while further studies could be conducted on the health risk of specific groups of people, exposure parameters in water reuse, as well as more emerging contaminants.

Characterization of dissolved organic matter in reclaimed wastewater supplying urban rivers with a special focus on dissolved organic nitrogen: A seasonal study

This study investigated the seasonal characterization of dissolved organic matter (DOM) in reclaimed wastewater (RW) with a special focus on dissolved organic nitrogen (DON) from two full-scale municipal wastewater reclamation plants (WRPs) where the produced RW was used to augment urban rivers. Results showed that the concentrations of DON in RW ranged from 0.32 mg/L to 1.21 mg/L. A higher seasonal mean value of DON in RW from both of the WRPs was observed in winter (p < 0.05, ANOVA). DON chemical characteristics analysis, including ultrahigh-resolution mass spectrometry and ultrafiltration fractionation, showed that DON in RW exhibits more lability during winter than during the other three seasons. This finding was also supported by the results of an algal bioassay experiment, in which DON bioavailabilities were 63.7 ± 3.0%, 53.0 ± 5.3%, 49.5 ± 0.5%, and 49.8 ± 0.2% for WRP-A and were 60.8 ± 2.4%, 43.7 ± 2.2%, 41.2 ± 1.7%, and 43.1 ± 1.1% for WRP-B in winter, spring, summer, and autumn, respectively. Accordingly, DON in RW during winter is more prone to stimulate natural algae and microorganisms, which gives rise to eutrophication in urban rivers. At the molecular level, the seasonal changes in DON are not coupled with those of DOC, which highlights the necessity of DON measurement to obtain a comprehensive understanding of the seasonal characteristics of DOM in RW and its effect on wastewater reuse in urban rivers.

Municipal Solid Waste Landfills: An Underestimated Source of Pharmaceutical and Personal Care Products in the Water Environment

Pharmaceutical and personal care products (PPCPs) have been the focus of increasing concern in recent decades due to their ubiquity in the environment and potential risks. Out-of-date PPCPs are usually discharged into municipal solid wastes (MSWs), enter the leachates in MSW landfills, and have serious adverse effects on the surrounding water environment. However, the occurrence and removal of PPCPs from landfill leachates have rarely been examined to date. This lack of knowledge makes the landfill an underestimated source of PPCPs in the environment. In this review, we collected the relevant publications of PPCPs in landfill leachates, systematically summarized the occurrence of PPCPs in landfill leachates globally, evaluated the removal performances for various PPCPs by different types of on-site full-scale leachate treatment processes, and assessed the impacts of landfill leachates on PPCPs in the adjacent groundwater. In particular, influencing factors for PPCPs in landfill leachates, including the physicochemical properties of PPCPs, climate conditions, and characteristics of landfill sites (i.e., landfill ages) as well as sociological factors (i.e., economic development), were extensively discussed to understand their occurrence patterns. Future perspectives were also proposed in light of the identified knowledge gaps. To the best of our knowledge, this is the first review regarding the occurrence and removal of PPCPs from landfill leachates worldwide.

Investigation and assessment of micropollutants and associated biological effects in wastewater treatment processes

Currently, the wastewater treatment plants (WWTPs) attempt to achieve the shifting from general pollution parameters control to reduction of organic micropollutants discharge. However, they have not been able to satisfy the increasing ecological safety needs. In this study, the removal of micropollutants was investigated, and the ecological safety was assessed for a local WWTP. Although the total concentration of 31 micropollutants detected was reduced by 83% using the traditional biological treatment processes, the results did not reflect chemicals that had poor removal efficiencies and low concentrations. Of the five categories of micropollutants, herbicides, insecticides, and bactericides were difficult to remove, pharmaceuticals and UV filters were effectively eliminated. The specific photosynthesis inhibition effect and non-specific bioluminescence inhibition effect from wastewater were detected and evaluated using hazardous concentration where 5% of aquatic organisms are affected. The photosynthesis inhibition effect from wastewater in the WWTP was negligible, even the untreated raw wastewater. However, the bioluminescence inhibition effect from wastewater which was defined as the priority biological effect, posed potential ecological risk. To decrease non-specific biological effects, especially of macromolecular dissolved organic matter, overall pollutant reduction strategy is necessary. Meanwhile, the ozonation process was used to further decrease the bioluminescence inhibition effects from the secondary effluent; ≥ 0.34 g O₃/g DOC of ozone dose was recommended for micropollutants elimination control and ecological safety.

Removal of Organic Micro-Pollutants by Conventional Membrane Bioreactors and High-Retention Membrane Bioreactors

The ubiquitous presence of organic micropollutants (OMPs) in the environment as a result of continuous discharge from wastewater treatment plants (WWTPs) into water matrices—even at trace concentrations (ng/L)—is of great concern, both in the public and environmental health domains. This fact essentially warrants developing and implementing energy-efficient, economical, sustainable and easy to handle technologies to meet stringent legislative requirements. Membrane-based processes—both stand-alone or integration of membrane processes—are an attractive option for the removal of OMPs because of their high reliability compared with conventional process, least chemical consumption and smaller footprint. This review summarizes recent research (mainly 2015–present) on the application of conventional aerobic and anaerobic membrane bioreactors used for the removal of organic micropollutants (OMP) from wastewater. Integration and hybridization of membrane processes with other physicochemical processes are becoming promising options for OMP removal. Recent studies on high retention membrane bioreactors (HRMBRs) such as osmotic membrane bioreactor (OMBRs) and membrane distillation bioreactors (MDBRs) are discussed. Future prospects of membrane bioreactors (MBRs) and HRMBRs for improving OMP removal from wastewater are also proposed.

Water quality induced corrosion of stainless steel valves during long-term service in a reverse osmosis system

The current study analyzes the contribution of 10 water quality parameters (including pH, turbidity, conductivity, total dissolved solids (TDS), hardness, total organic carbon (TOC), alkalinity, calcium ions, chlorides and sulfates) to corrosion extent of stainless steel valves taken from different locations in a reverse osmosis system of a reclaimed water plant. The valves were in service for 5 years. Raman spectroscopy and X-ray photoelectron spectroscopy analyses are conducted to quantify corrosion products on different valves under various water quality conditions. On that basis, bivariate and multivariate regression analyses between the 10 water quality parameters and the corrosion extent of valve specimens (represented by metal loss percentage (MLP) values) are carried out to check the contribution of those water quality parameters to MLP. The results indicate that the proportions of metal oxides as corrosion products vary according to the corrosion extent of the valves. Although no linear correlation is found, all 10 water quality parameters except for pH show a significant positive correlation with the MLP values of the valve specimens. Moreover, results of multivariate regression suggest that the variation of MLP can be explained by turbidity, TDS, TOC and sulfates. A positive contribution of turbidity, TDS and TOC to MLP is observed, whereas the contribution of sulfates is negative. The results from the current work help to identify the reasons for water quality-induced failure of stainless steel equipment in RO systems.

Differential adsorption of zwitterionic PPCPs by multifunctional resins: The influence of the hydrophobicity and electrostatic potential of PPCPs

Zwitterionic pharmaceuticals and personal care products can interact with adsorbents in different ways due to their various properties. In this work, the effects of hydrophobicity and electrostatic potential were explored through the adsorption of ciprofloxacin (CPX) and tetracycline (TC) onto multifunctional resins. Nonionic surface interaction was dominant for the adsorption on high-surface-area resin GMA10. Thereinto, hydrophobic and π-π interaction dominant for hydrophobic CPX and hydrophilic TC, respectively. Electrostatic interaction played an important role for high-anion-exchange-capacity resin GMA90. Upon their adsorption onto GMA50 resin, the relatively separated positive and negative electrostatic potentials of CPX^+- due to the greater distance (∼12.33 Å) between the anionic and cationic groups led to electrostatic attraction and interaction (Ea = 8.64 ± 0.31 kJ/mol) and the vertical orientation of molecule on the surface. However, TC^+-0 displayed nonionic surface interaction (Ea = 7.96 ± 0.14 kJ/mol) due to its relatively neutral electrostatic potential arising from the adjacent functional groups. Hence, the surface of GMA50 was covered with TC^+-0 molecules adsorbed parallel to the surface, thereby restricting TC^+-0 adsorption. Coexisted with monovalent salts, CPX adsorption was facilitated due to the salting-out effect. By contrast, the salting-out effect for TC was extremely weak, and TC adsorption was restrained due to the competitive adsorption of salts.

Feasibility and safety of papermaking wastewater in using as ecological water supplement after advanced treatment by fluidized-bed Fenton coupled with large-scale constructed wetland

Reuse of pulp-and-paper industry wastewater as reclaimed water is an effective way to mitigate water resource shortage. In this study, the feasibility and safety of papermaking wastewater for the use as ecological water supplement after the treatment by fluidized-bed Fenton (FBF) coupled with constructed wetland (CW), were investigated from laboratory-scale to large-scale field. The optimum pH, H₂O₂, H₂O₂/Fe²⁺ ratio and hydraulic retention time (HRT) of FBF were 3.5, 0.93 mL/L, 4 and 60 min, respectively, based on reduction of both total organic carbon (TOC) and genotoxicity. Furthermore, the safety of effluent was evaluated using SOS/umu assay and 8-hydroxy-2-deoxyguanosine (8-OHdG) in zebrafish. Results showed FBF followed by CW improved the conventional water quality indicators and reduced the toxicity. Average removal rates of chemical oxygen demand (COD), ammonia nitrogen (NH₃-N), total nitrogen (TN), total phosphorus (TP) and colority were 87.3%, 93.59%, 51.73%, 84.75% and 95.86%, respectively. The equivalent concentration of 4-nitroquinoline 1-oxide (4-NQO-EQ) decreased from 30.6 ± 1.6 μg/L in influent to 12.4 ± 1.0 μg/L after treated by FBF, then decreased to 5.9 ± 0.4 μg/L after treated by CW and to 3.2 ± 0.3 μg/L after 12-km downstream self-purification. The chronic survival rates of 21-d zebrafish significantly increased from 0.0% in influent to 58.8 ± 4.0% in effluent of CW and gradually increased to 68.8 ± 2.6% after 12-km downstream self-purification. Similarly, 8-OHdG level in zebrafish decreased from 120.0 ± 19.3 ng/L in effluent of ecological oxidation pond to 94.0 ± 7.5 ng/L in effluent of CW and gradually decreased to 42.0 ± 3.0 ng/L after 12-km downstream self-purification. The study concluded that FBF-CW is an efficient detoxication and water quality improvement technology for papermaking wastewater to be used as an ecological water supplement.

Binary Dispersive Liquid-Liquid Microextraction Strategy for Accurate and Precise Determination of Micropollutants in Lake, Well and Wastewater Matrices

In this study, a binary mixture in dispersive liquid-liquid microextraction was used for the preconcentration and determination of selected pesticides, pharmaceutical and hormone by GC-MS. A Box-Behnken experimental design was used to optimize the amounts of binary mixture, dispersive solvent and salt. The optimum parameters obtained were dichloromethane/1,2-dichloroethane binary mixture (200 µL), ethanol (2.0 mL) and potassium nitrate (1.0 g). Analytical performance of each analyte was determined under the optimum conditions and the lowest and highest detection limits calculated were 0.43 and 5.9 ng/mL. Low relative standard deviations were obtained even in the lowest concentrations in linear calibration plots, signifying high precision for the sample preparation procedure and instrumental measurement. Accuracy of the developed method and applicability to real samples was tested on well, lake, hospital and municipal wastewater. The percent recoveries acquired at different spiked concentrations were satisfactory (89%-108%), validating the accuracy of the method for the quantification of the analytes in the selected matrices.

The utilization of reclaimed water: Possible risks arising from waterborne contaminants

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.

Health effects associated with wastewater treatment, reuse, and disposal

This paper highlights the review of scientific literature published in the year 2018 on issues related to health risks associated with human and the general environment on the reuse of wastewater, treatment as well as disposal. The literature review on the above issues divided into number of sections, and these sections include management of wastewater, wastewater reuse with focus on microbial hazards, and chemical hazards. Further, the review also provides some recent research related to wastewater treatment plants, disposal of wastewater, sludge, and biosolids management. PRACTITIONER POINTS: This paper highlights the review of scientific literature published in the year 2018. Review provide issues related to health risks associated with human and the general environment on the reuse of wastewater, treatment as well as disposal. Literature review covers selected papers relevant to the topic.

Water reclamation and reuse

Literature published in 2018 pertinent to water reclamation and reuse has been classified into five topics: safe reuse, treatment technologies, management, assessment, and case studies. Researches have been conducted to develop new technologies and improve conventional treatments for achieving sustainable wastewater reclamation, and increasing efforts have been made to facilitate safe water reuse. PRACTITIONER POINTS: The way of publicity greatly influences people's acceptance of water reuse and willingness to purchase produce irrigated with recycled water. Integrated process is the most commonly used treatment technology to reclaim water. There is a lack of local or regional regulatory and policy for sustainable water management.

Benzo(a)pyrene degradation by cytochrome P450 hydroxylase and the functional metabolism network of Bacillus thuringiensis

The relationship between benzo(a)pyrene biodegradation and certain target biomolecules has been investigated. To regulate the degradation process, the associated metabolism network must be clarified. To this end, benzo(a)pyrene degradation, carbon substrate metabolism and exometabolomic mechanism of Bacillus thuringiensis were analyzed. Benzo(a)pyrene was degraded through hydroxylation catalyzed by cytochrome P450 hydroxylase. After the treatment of 0.5 mg L^-1 of benzo(a)pyrene by 0.2 g L^-1 of cells for 9 d, biosorption and degradation efficiencies were measured at approximately 90% and 80%, respectively. During this process, phospholipid synthesis, glycogen, asparagine, arginine, itaconate and xylose metabolism were significantly downregulated, while glycolysis, pentose phosphate pathway, citrate cycle, amino sugar and nucleotide sugar metabolism were significantly upregulated. These findings offer insight into the biotransformation regulation of polycyclic aromatic hydrocarbons.

A review of selected microcontaminants and microorganisms in land runoff and tile drainage in treated sludge-amended soils

The objective of this study is to provide a snapshot of the quality of surface runoff and tile drainage in sludge-amended soil in terms of 57 microcontaminants, including pharmaceuticals, hormones and fragrances, and 5 different species of bacteria. It also discusses the main factors affecting their occurrence (soil characteristics, applied sludge load and rate, sludge application method, rain intensity and frequency). It is based on 38 investigations carried out by different research groups in Canada, Australia, the USA and Ireland. The most frequently investigated compounds were hormones, the antiseptics triclosan and triclocarban, the analgesics and anti-inflammatories acetaminophen, ibuprofen and naproxen, the antibiotic sulfamethoxazole, the lipid regulator gemfibrozil and the psychiatric drug carbamazepine. Of all the bacteria, E. coli was the most monitored species. It was found that concentrations of the studied pollutants in surface runoff and tile drainage may vary, depending on many factors. They are generally lower than those observed in the secondary municipal effluent and in surface water, but their contribution to the deterioration of surface water quality might be relevant, mainly in wide rural areas. In this context, the reported data or their ranges represent an attempt to provide reference thresholds and bands of observed concentrations for a rough estimation of the contribution made by the release of the selected pollutants into surface water bodies via surface runoff and tile drainage.

Degradation of cefradine in alga-containing water environment: a mechanism and kinetic study

Large quantities of antibiotics are manufactured, used, and eventually discharged into alga-containing water environment as prototypes, by-products, or transformation products. Different activities of Chlamydomonas reinhardtii toward cefradine (CFD) were studied, and the results indicated that CFD is resistant (removal rate of 5.45-14.72%) in simulated natural water environment. Cefradine was mainly removed by hydrolysis, adsorption, desorption, photodecarboxylation, and photoisomerization. The effects of C. reinhardtii density, initial solution pH, and different light sources on CFD removal efficiency were investigated. The optimum conditions occurred at a density of algae 10 × 10⁴ cells/mL, a solution pH of 9.0, and the ultraviolet (UV) light. Additionally, the removal kinetics under 16 different conditions was explored. The results showed that the removal of CFD fits well with a pseudo-first-order kinetic, and the half-life times are from 0.8 to 261.6 days. This study summarizes the CFD removal mechanisms in alga-containing water environment, highlights the important role played by light irradiation in eliminating CFD, and obtains the important kinetic data on CFD removal.

Performance and mechanism of a novel algal-bacterial symbiosis system based on sequencing batch suspended biofilm reactor treating domestic wastewater

A novel algal-bacterial symbiosis system based on sequencing batch suspended biofilm reactor (A-SBSBR) was developed for simultaneously enhanced nitrogen (N) and phosphorus (P) removal from domestic wastewater. Results showed that the total N (TN) and P (TP) removal efficiencies in A-SBSBR increased to 69.91% and 94.78%, respectively. The mechanism analysis indicated that TN removal mainly occurred at non-aeration stage, and TP removal happened during the whole cycle in A-SBSBR. Compared to control SBSBR, TN removal by denitrification and anabolism and TP removal by anabolism in A-SBSBR increased by 12.70%, 7.64% and 50.13%, respectively. The Chlorophyll a accumulation in biofilm increased to 4.80 ± 0.08 mg/g. Algae related to Chlorella and Scenedesmus and bacteria related to Flavobacterium, Micropruina and Comamonadaceae were enriched in A-SBSBR and responsible for the enhanced nutrients removal effect. This study may provide a new solution to achieve nutrients removal enhancement from wastewater.

Adsorption of Trace Estrogens in Ultrapure and Wastewater Treatment Plant Effluent by Magnetic Graphene Oxide

In the current study, graphene oxide, Fe3+, and Fe2+ were used for the synthesis of magnetic graphene oxide (MGO) by an in situ chemical coprecipitation method. Scanning electron microscopy, transmission electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction were used to characterize the well-prepared MGO. The prepared MGO was used as an adsorbent to remove five typical estrogens (estrone (E1), 17β-estradiol (E2), 17α-ethinylestradiol (17α-E2), estriol (E3), and synthetic estrogen (EE2)) at the ppb level from spiked ultrapure water and wastewater treatment plant effluent. The results indicated that the MGO can efficiently remove estrogens from both spiked ultrapure water and wastewater treatment plant effluent in 30 min at wide pH ranges from 3 to 11. The temperature could significantly affect removal performance. A removal efficiency of more than 90% was obtained at 35 °C in just 5 min, but at least 60 min was needed to get the same removal efficiency at 5 °C. In addition, an average of almost 80% of the estrogens can still be removed after 5 cycles of MGO regeneration but less than 40% can be reached after 10 cycles. These results indicate that MGO has potential for practical applications to remove lower levels of estrogens from real water matrixes and merits further evaluation.