Search

Trace organic contaminants (TrOCs), including pharmaceutically active compounds (PhACs), present significant challenges for conventional water treatment processes and pose potential risks to environmental and human health. To address these issues, nanofiltration (NF) and reverse osmosis (RO) membrane technologies have gained attention. This study aims to evaluate the performance of NF and RO membranes in removing TrOCs from wastewater and develop a predictive model using the Solution Diffusion Model. Experiments were conducted using a stirred cell setup at various target concentrations, stirring speeds, and operating pressures, with acetaminophen and caffeine selected as representative pharmaceutical compounds. The results demonstrated that most of the pharmaceutical compounds were effectively removed, showing excellent performance. NF membranes exhibited high permeate flux with somewhat lower removal efficiency (average 84.17%), while RO membranes demonstrated high removal efficiency (average 99.21%), highlighting their importance in trace pharmaceutical treatment. The predictive model based on the solution diffusion model correlated well with the experimental data, suggesting its potential utility for large-scale system applications. This study confirms that NF and RO membranes are effective technologies for the removal of TrOCs from wastewater, offering a promising solution to the challenges posed by trace pharmaceutical contaminants.

Pharmaceuticals and personal care products (PPCPs) discharged into environment has several adverse impacts. PPCPs are widely utilised for veterinary as well as cosmetic and personal health reasons. These are members of the expanding class of substances known as Contaminants of Emerging Concern (CECs). Antibiotic resistance in the environment and garbage generated by PPCP endanger life. The World Health Organisation (WHO) now recognises antibiotic resistance as a significant global health problem due to the expected increase in mortality caused by it. In the past ten years, mounting data has led experts to believe that the environment has a significant impact on the development of resistance. For human diseases, the external environment serves as a source of resistance genes. It also serves as a major pathway for the spread of resistant bacteria among various habitats and human populations. Large-scale DNA sequencing methods are employed in this thesis to better comprehend the dangers posed by environmental antibiotic resistance. The quantification of the number is an important step in this process. Metagenomic measurement of the number of antibiotic resistance genes in various contexts is a crucial step in this process. However, it's also crucial to put this data into a broader context by integrating things like taxonomic information, antibiotic concentrations, and the genomic locations of found resistance genes. [ABSTRACT FROM AUTHOR]

Water pollution is the most serious problem threatening global water resources. The release of both natural and anthropogenic factors in the aquatic environment is affecting the quality of water bodies, with Contaminants of Emerging Concern (CECs) being one of the major issues. In recent years, the availability of robust and sensitive analytical methods has allowed the detection and identification of a wide variety of pollutants. Pharmaceutically Active Compounds (PhACs) represent one large category of CECs detected in the aquatic environment, posing serious threats to human health and ecosystems. Hence, there is an urgent need for a better understanding of their environmental occurrence, fate, exposure-associated risks, and degradation in order to regulate exposure to pharmaceuticals in the environment. This review covers the current trends, newly developed state-of-the-art analytical methods, their challenges for PhACs detection in different water matrices, and the occurrence patterns in the aquatic environment. We also make a compressive assessment of the ineffective classic drinking water treatment plants (DWTPs) and the novel technologies such as membrane filtration and advanced oxidation processes that have been implemented to upgrade DWTPs. Their efficiency in removing PhACs is here discussed, as well as other embryonic technologies as promising solutions. The aim of this review article is to provide a comprehensive summary of the pathways and fate of PhACs in the environment, solutions for improving their monitoring assessments and the best methods for their removal in drinking water treatment plants.

Pharmaceutically active compounds (PhACs), in particular, nonsteroidal antiinflammatory drugs (NSAIDs) are in increasingly wider usage, and as such are more and more frequently part of the organic matter of recipient rivers, especially in their lower courses. To indicate their significance as pollutants, as well as the significant role that the presence of autochthonous microflora plays in solving this issue, we undertook to perform this experiment. The experiment, titled “Application of the model of cylindrical reactor in self-purification by indigenous microorganisms”, was conducted during a one-year period at the location of Vukovci, in the lower course of the Morača river. Assuming that the concentration of NSAIDs and PhACs in water can be reduced through selfpurification, it has been proven that such processes result in a modification of phenotype in the indigenous microbiological population. Having the abovementioned premise in mind, we constructed the experiment model, which entails kineticism of water, whereas the defined volume flow rate per unit time was 0.005 m/s, through the known distance of 432 m. Over one year of application of the model of the cylindrical reactor for enhancing self-purification capacity by indigenous microorganisms, auto-purification increased by 28.05%, the phenotype of the indigenous microorganisms changed by 24.62%, whereas the total concentration of particular PhACs, micropollutants, and NSAIDs decreased by 4.19%.

In recent years, the occurrence, fate, and adverse effects of pharmaceutically active compounds (PhACs) in aquatic organisms have become a noteworthy issue. In the present study, a rapid and sensitive multiresidue analytical method was developed for the determination of 18 parent PhACs and 5 metabolites in sea bream (Sparus aurata), by combining a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure with ultra-high performance liquid chromatography-Orbitrap-mass spectrometry (UHPLC-Orbitrap-MS). The method development involved optimization of extraction solvent, extraction salts, clean-up sorbents, and amount of sample evaluation, while identification on Orbitrap MS was based on accurate mass and further confirmation with MS/MS fragmentation. The developed method was validated, and linearity was higher than 0.99. Recoveries in all cases ranged between 62 and 107% (at 10, 50, and 100 ng g−1), while intra-day and inter-day precision, expressed as relative standard deviation, RSD, was lower than 4% and 7%, respectively. In addition, limits of quantification (LOQs) ranged between 0.5 and 19 ng g−1. The compounds presented a low matrix effect, between − 13 and 4%, while the expanded uncertainty U% estimated at the three spiking levels 10, 50, and 100 ng g−1 was found below 49% in all cases. Finally, the validated method was applied to sea bream samples from an aquaculture farm located in the Mediterranean Sea, with one positive finding for the antibiotic trimethoprim at a concentration of 26 ng g−1, presenting negligible human health risk. [ABSTRACT FROM AUTHOR]

In the present research study, an electrochemical process (EC) equipped with a porous cathode was combined with ultrasound (US) to efficiently degrade acetaminophen (ACE) as the target pollutant. The carbonaceous porous cathode was used for in situ generation of hydrogen peroxide. The generation of hydrogen through the cathodic reduction was current-dependent. As a result, the combination of US with EC resulted in the highest degradation efficiency (%) of 74.6 %. Increasing the concentration of Na2SO4 (as supporting electrolyte) from 0.01 to 0.1 M led to enhanced ACE degradation efficiency (%) from 50.6 to 75.7 %, respectively, while a significant drop in ACE removal efficiency from 93.0 to 22.0 % occurred when the initial concentration of ACE increased from 1 to 10 mg L–1, respectively. The operation of US/EC with pulse mode of US irradiation led to a slight increase in ACE degradation efficiency (%) (79.0 %). The presence of halide compounds (chloride ions) significantly enhanced the removal of ACE (96.1 %), while alcoholic compounds, especially methanol, produced a substantial suppressive effect on the treatment of ACE.

Despite the fact that there are tens of thousands of thermal baths in existence, knowledge about the occurrence of pharmaceutically active compounds (PhACs) in untreated thermal wastewater is very limited. Because used thermal water is typically legally discharged into surface waters without any treatment, the effluent poses environmental risks for the receiving water bodies. The aim of this study was to show the occurrence patterns and spatiotemporal characteristics of 111 PhACs in thermal wastewater. Six thermal water outflows of different thermal baths were tested in different seasons in the Budapest metropolitan region (Hungary), and diurnal analysis was performed. After solid-phase extraction, the samples were analysed and quantified by coupling supercritical fluid chromatography and mass spectrometry to perform simultaneous multi-residue drug analysis. The results confirm that water discharge pipes directly transport pharmaceuticals into surface water bodies; 34 PhACs were measured to be over the limit of quantification at least once, and 21 of them were found in more than one water sample. The local anaesthetic drug lidocaine, antiepileptic carbamazepine, analgesic derivative tramadol and illicit drug cocaine were detected in more than half of the samples. Caffeine, metoprolol and bisoprolol (cardiovascular drugs), benzoylecgonine (cocaine metabolite), diclofenac (NSAID), citalopram (antidepressant) and certain types of hormones also have a significant frequency of 30-50%. However, the occurrence and concentrations of PhACs vary according to the season and number/types of visitors. As demonstrated by the diurnal fluctuation, drug contamination of thermal waters can significantly vary, even for similar types of baths; furthermore, the quantity and types of some pollutants rapidly change in the discharged thermal wastewater. [ABSTRACT FROM AUTHOR]

In the present research study, an electrochemical process (EC) equipped with a porous cathode was combined with ultrasound (US) to efficiently degrade acetaminophen (ACE) as the target pollutant. The carbonaceous porous cathode was used for in situ generation of hydrogen peroxide. The generation of hydrogen through the cathodic reduction was current-dependent. As a result, the combination of US with EC resulted in the highest degradation efficiency (%) of 74.6%. Increasing the concentration of Na2SO4 (as supporting electrolyte) from 0.01 to 0.1 M led to enhanced ACE degradation efficiency (%) from 50.6 to 75.7%, respectively, while a significant drop in ACE removal efficiency from 93.0 to 22.0% occurred when the initial concentration of ACE increased from 1 to 10 mg L-1, respectively. The operation of US/EC with pulse mode of US irradiation led to a slight increase in ACE degradation efficiency (%) (79.0%). The presence of halide compounds (chloride ions) significantly enhanced the removal of ACE (96.1%), while alcoholic compounds, especially methanol, produced a substantial suppressive effect on the treatment of ACE. [ABSTRACT FROM AUTHOR]

The concentration profile, distribution and risk assessment of pharmaceutically active compounds (PhACs) in the coastal surface water from the Klang River estuary were measured. Surface coastal water samples were extracted using offline solid phase, applying polymeric C18 cartridges as extraction sorbent and measuring with liquid chromatography mass spectrometry-mass spectrometry (LC MS-MS) technique. Extraction method was optimized for its recovery, sensitivity and linearity. Excellent recoveries were obtained from the optimized method with percentage of recoveries ranging from 73 to 126%. The optimized analytical method achieved good sensitivity with limit of detection ranging from 0.05 to 0.15 ng L−1, while linearity of targeted compounds in the LC MS-MS system was more than 0.990. The results showed that amoxicillin has the highest concentration (102.31 ng L−1) followed by diclofenac (10.80 ng L−1) and primidone (7.74 ng L−1). The percentage of contribution (% of total concentration) for the targeted PhACs is in the following order; amoxicillin (92.90%) > diclofenac (3.95%) > primidone (1.23%) > dexamethasone (0.75%) > testosterone (0.70%) > sulfamethoxazole (0.33%) > progesterone (0.14%). Environmental risk assessment calculated based on deterministic approach (the RQ method), showed no present risk from the presence of PhACs in the coastal water of Klang River estuary. Nonetheless, this baseline assessment can be used for better understanding on PhACs pollution profile and distribution in the tropical coastal and estuarine ecosystem as well as for future comparative studies. [ABSTRACT FROM AUTHOR]

Abstract The by-products produced by pharmaceutically active compounds (PhACs) during chlorination are attracting wide concern. Thus, the transformation and toxicity of naproxen (NAP) during the chlorination process were assessed in this study. The transformation of NAP was found to follow pseudo-first-order kinetics, and the first-order rate constant was improved by increasing the NaOCl dose. High-resolution mass spectrometry (HRMS) was successfully applied to identify 14 chlorination products. This study represents the first elucidation and report of the exact structure of the primary chlorine substitution product ((2S)-2-(5-chloro-6-methoxy-2-naphthyl)propionic acid) based on HRMS and 1H NMR. Chlorine will primarily substitute the hydrogen atom on the C7 position of the naphthalene ring to form the mono-chlorine substitution product, as further validated at the theoretical level by quantum chemical calculations. A series of HOCl-induced reactions, including substitution, demethylation, and dehydrogenation, led to the transformation of NAP during the chlorination process. ECOSAR program revealed that the potential aquatic toxicity of the transformation products is significantly higher than that of the parent NAP. Their introduction into the environment may still pose potential risks. Graphical abstract Image 1 Highlights • Transformation of naproxen during the chlorination process was assessed. • First elucidation of exact structure of primary chlorine substitution product. • Primary product was further validated by quantum chemical calculation. • These products pose greater environmental concern. [ABSTRACT FROM AUTHOR]

We analyzed the conjoint effects of sewage inputs and hydrological alteration on the occurrence of teratological forms and on the assemblage composition of stream benthic diatoms. The study was performed in 11 Mediterranean streams which received treated or untreated urban sewage (Impact sites, I), whose composition and morphological anomalies were compared to upstream unaffected (Control, C) sites. The impact sites had high concentrations of ammonium, phosphorus, and pharmaceutical compounds (antibiotics, analgesics, and anti-inflammatories), particularly in those receiving untreated sewage. Impact sites had a higher proportion of teratological forms as well as a prevalence of diatom taxa tolerant to pollution. The differences in the diatom assemblage composition between the paired C and I sites were the largest in the impacted sites that received untreated sewage inputs as well as in the systems with lower dilution capacity. In these sites, the diatom assemblage was composed by a few pollution-tolerant species. Mediterranean river systems facing hydrological stress are highly sensitive to chemical contamination, leading to the homogenization of their diatom assemblages. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Novel fouling control with quorum quenching bacteria (QQ) entrapped PAC-beads. • QQ affected microbial communities in both bulk sludge and biocake. • QQ largely reduced AHL levels in bulk sludge and fully depleted AHLs in biocake. • QQ-PAC-beads greatly increased floc size, hence enhancing sludge dewaterability. • PAC facilitated high removal efficiencies of trace amounts of pharmaceuticals. Abstract This study aimed to integrate the quorum quenching (QQ) strategy with powdered activated carbon (PAC) adsorption for fouling control and simultaneous removal of trace amounts of selected pharmaceutically active compounds (PhACs) in laboratory membrane bioreactors (MBRs). With the addition of QQ strains immobilized in PAC-alginate beads, a 4.6-folds delay in fouling was achieved. The QQ strains not only altered the sludge properties, but also influenced the microbial communities in the MBRs, thus leading to distinct quorum sensing signal molecule (acyl-homoserine lactones, AHLs) profiles. Despite the difference in AHL profiles, the total AHL concentrations were greatly reduced in bulk sludge, and completely quenched in biocake with QQ supplementation. PAC addition enabled high removals of all PhACs, and also resulted in a prominent increase in sludge floc size, which further enhanced sludge filterability. These QQ-entrapped PAC-alginate beads provide a novel MBR setting with less biofouling and high removal efficiency of PhACs. [ABSTRACT FROM AUTHOR]

Antibiotics are emergent contaminants that can induce adverse effects in terrestrial and aquatic organisms. The surface water compartment is of particular concern as it receives direct waste water discharge. Modeling is highlighted as an essential tool to understand the fate and behavior of these compounds and to assess their ecotoxicological risk. This study aims at testing the ability of the GREAT-ER model in simulating sulfamethoxazole (SMX) concentrations in the surface waters of the arid high-altitude Katari catchment (Bolivian Altiplano), assessing the sensitivity of the parameters considered, and evaluating the ecotoxicological risk posed. The model predicted the general spatial pattern of SMX concentrations. No contaminant abatement was observed during the wet season, supporting the idea that non-point sources, such as runoff and remobilization processes, play an important role during that season. During the dry season, the abatement capacity was 91%, suggesting that natural attenuation, particularly photodegradation, is high during low flow. Pharmaceutical consumption was the parameter that influenced the environmental concentrations the most. The ratio of Predicted Environmental Concentrations to predicted no-effect concentrations varied between 0.14 and 26.6 for the wet season and between 0.14 and 7.6 for the dry season depending on the river stretch. [ABSTRACT FROM AUTHOR]

The main aim of the present investigation was the treatment of ibuprofen (IBP)-polluted aquatic phase using a novel oxygen-permeable cathode (OPC)-equipped electrochemical process (ECP) integrated with ultrasound (US). According to kinetic modeling, the decomposition rate of IBP by the integrated process was 3.2 × 10 −2 min −1 which was significant in comparison with the OPC-equipped ECP (1.4 × 10 −2 min −1 ) and US alone (2.4 × 10 −3 min −1 ). Increasing the current resulted in the enhanced generation of H 2 O 2 and consequently, improved the degradation of IBP in the solution. Excessive concentrations of Na 2 SO 4 as supporting electrolyte led to no significant enhancement in the reactor efficiency. At initial IBP concentration of 1 mg L −1 , complete removal of IBP with reaction rate of 1.7 × 10 −1 min −1 was happened within a short reaction time of 30 min. The pulse mode of US led to more than 10% increase in the removal efficiency compared with the normal mode. The presence of scavenging compound of methanol caused the highest drop in the efficiency of the integrated treatment process, indicating the substantial role of free hydroxyl radicals in the degradation of IBP. Intermediate byproducts generated in the solution during the decomposition were also identified and interpreted. [ABSTRACT FROM AUTHOR]

The presence of pharmaceutically active compounds (PhACs) in wastewater treatment plant effluent poses a potential risk to aquatic ecosystems. Constructed wetlands have recently been used to control PhACs. However, the microbial communities that are involved in these processes have not been comprehensively investigated. This study aimed to evaluate the removal of PhACs and microbial response in constructed wetlands during the treatment of PhACs. The effects of PhACs on bacterial communities in constructed wetland mesocosms were analyzed by Illumina MiSeq sequencing technology. Results indicated that removal efficiencies of PhACs were enhanced over time, and constructed wetlands offer higher removal efficiencies for the PhACs studied compared to conventional wastewater treatment plants. Plants improved microbial richness and diversity while both indices were negatively correlated with PhAC concentrations ranging from 30 to 500 μg/L in constructed wetland mesocosms. The microbial communities of the constructed wetland mesocosms were dominated by Proteobacteria, Acidobacteria, and Bacteroidetes under PhAC exposure, while Desulfobulbus and Treponema were the dominant genera. In particular, Proteobacteria were correlated with PhAC concentrations. Overall, this study provides valuable microbial community ecology data to understand how microbial populations respond to PhAC stress in constructed wetlands. [ABSTRACT FROM AUTHOR]

There is growing concern worldwide about the exposure of groundwater resources to pharmaceutically active compounds (PhACs) and agricultural contaminants, such as pesticides, nitrate, and Escherichia coli . For regions with a low population density and an abundance of water, regional contamination assessments are not carried out systematically due to the typically low concentrations and high costs of analyses. The objectives of this study were to evaluate regional-scale contaminant distributions in untreated groundwater in a rural region of Quebec (Canada). The geological and hydrogeological settings of this region are typical of post-glacial regions around the world, where groundwater flow can be complex due to heterogeneous geological conditions. A new spatially distributed Anthropogenic Footprint Index (AFI), based on land use data, was developed to assess surface pollution risks. The Hydrogeochemical Vulnerability Index (HVI) was computed to estimate aquifer vulnerability. Nine wells had detectable concentrations of one to four of the 13 tested PhACs, with a maximum concentration of 116 ng·L − 1 for benzafibrate. A total of 34 of the 47 tested pesticides were detected in concentrations equal to or greater than the detection limit, with a maximum total pesticide concentration of 692 ng·L − 1 . Nitrate concentrations exceeded 1 mg·L − 1 N-NO 3 in 15.3% of the wells, and the Canadian drinking water standard was exceeded in one well. Overall, 13.5% of the samples had detectable E. coli . Including regional-scale sources of pollutants to the assessment of aquifer vulnerability with the AFI did not lead to the identification of contaminated wells, due to the short groundwater flow paths between recharge and the sampled wells. Given the occurrence of contaminants, the public health concerns stemming from these new data on regional-scale PhAC and pesticide concentrations, and the local flow conditions observed in post-glacial terrains, there is a clear need to investigate the sources and behaviours of local-scale pollutants. [ABSTRACT FROM AUTHOR]

In this study, the employment of purpose-made dual-channel compact capillary electrophoresis (CE) instrument with capacitively coupled contactless conductivity detection (C 4 D) as a simple and inexpensive solution for screening determination of various pharmaceutical pollutants frequently occurring in surface water and hospital wastewater in Hanoi, Vietnam is reported. Five negatively charged pharmaceutically active compounds, namely ibuprofen, diclofenac, bezafibrate, ketoprofen and mefenamic acid were determined using the first channel whereas three positively charged ones, namely diphenhydramine, metoprolol and atenolol were determined with the second channel of the CE-C 4 D instrument. Two different background electrolytes (BGEs) were used in these two CE channels independently. The best detection limits achieved were in the range of 0.2–0.8 mg/L without sample pre-concentration. Enrichment factors up to 200 were obtainable with the inclusion of a solid phase extraction step. Good agreement between results obtained from CE-C 4 D and those with the standard confirmation method (HPLC-DAD) was achieved, with correlation coefficients higher than 0.98. [ABSTRACT FROM AUTHOR]

Pharmaceutically active compounds (PhACs), which find their way easily into the water sources, are emerging as a major concern for drinking water quality and aquatic species. Therefore, their removal from water sources is a priority from environmental point of view. During the past decade, different methods including membrane separation, adsorption systems and chemical transformation have been evaluated for removal of these compounds. This paper reviews different aspects of PhAC removal by using membrane separation processes, as they have been conventionally known to show high potential in the production of superior quality drinking and industrial water. In brief, osmosis membranes can efficiently remove almost all PhACs though its operational cost is relatively high and nanofiltration (NF) membranes are highly influenced by electrostatic and hydrophobic interaction. Moreover, the efficiency of membrane bioreactors (MBRs) is difficult to predict due to the complex interaction of compounds with microorganisms. To improve the performance and robustness of membrane technology, it is suggested to combine membranes with other systems, such as activated carbon and enzymatic degradation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tunable GO in Ce-MOFs promoted the photocatalytic performance. • The composite facilitates the charge transfer in photocatalysis. • •O 2 – has been identified as the major reactive oxygen species. • Steady-state concentrations of ROS have been calculated. • This composite shows better water stability than the pristine Ce-MOFs. Pharmaceutically active compounds (PhACs) are ubiquitously detected in water matrices, arousing growing concern. Effective abatement of these toxic environmental contaminants is challenging but of great importance. Ce-based MOFs have been considered novel metal–organic framework (MOFs)-based photocatalysts in water treatment. However, limited light absorption ability, fast recombination of photogenerated carriers, and water stability limited the further application. Here, the UiO-66 (Ce) was successfully constructed onto the surface of a series of graphene oxide (GO) (1 mg ∼ 7.5 mg) in situ. GO with oxygen-containing functional groups (OCFGs) increased the adsorption (∼45 %) of the trace amount of sulfamethoxazole (SMX) (200 μg/L) over the interfaces and enhanced the degradation efficiency of SMX. The composite with the optimal ratio (GO@ UiO-66 (Ce)-5) significantly increased the charge separation ability and produced a large number of reactive oxygen species (ROS). •O 2 – was proved to be the major driving reactive substance for SMX degradation with the calculated steady-state concentration of 2.5 × 10-9 M (∼1.37 times higher with bubbled oxygen), which is much higher than that of detected •OH (1.62 × 10-14). Major operational parameters including dissolved oxygen, initial solution pH, and catalyst dosages were investigated systematically. Several intermediates were identified by high-performance liquid chromatography coupled with triple quadrupole mass spectrometry (HPLC-MS/MS). By choosing the strategy, MOFs were closely bonded to the surface of the GO matrix, making the leakage of Ce ions inhibited obviously (∼3 times) in the water treatment process. This study offers useful guidance for improving the performance of existing photocatalytic materials for PhACs removal. [ABSTRACT FROM AUTHOR]

Water polluted by pharmaceutically active compounds (PhACs) and water-borne pathogens urgently need to develop eco-friendly and advanced water treatment techniques. This paper evaluates the potential of using calcium peroxide (CaO 2), a safe and biocompatible oxidant both PhACs (thiamphenicol, florfenicol, carbamazepine, phenobarbital, and primidone) and pathogens (Escherichia coli, Staphylococcus aureus) in water. This paper evaluates the potential of using calcium peroxide (CaO 2) as a safe and biocompatible oxidant to remove both PhACs (thiamphenicol, florfenicol, carbamazepine, phenobarbital, and primidone) and pathogens (Escherichia coli , Staphylococcus aureus) in water. The increased CaO 2 dosage increased efficiencies of PhACs attenuation and pathogens inactivation, and both exhibited pseudo-first-order degradation kinetics (R2 > 0.90). PhACs attenuation were mainly via oxidization (H 2 O 2 , •OH/O•−, and O 2 •−) and alkaline hydrolysis (OH−) from CaO 2. Moreover, concentrations of these reactive species and their contributions to PhACs attenuation were quantified, and mechanistic model was established and validated. Besides, possible transformation pathways of target PhACs except primidone were proposed. As for pathogen indicators, the suitable inactivation dosage of CaO 2 was 0.1 g L−1. The oxidability (18–64%) and alkalinity (82–36%) generated from CaO 2 played vital roles in pathogen inactivation. In addition, CaO 2 at 0.01–0.1 g L−1 can be applied in remediation of SW contaminated by PhACs and pathogenic bacteria, which can degrade target PhACs with efficiencies of 21–100% under 0.01 g L−1 CaO 2 , and inactivate 100% of test bacteria under 0.1 g L−1 CaO 2. In short, capability of CaO 2 to remove target PhACs and microbial pathogens reveals its potential to be used as a representative technology for the advanced treatment of waters contaminated by organic compounds and microbial pathogens. • CaO2 in-situ remediated surface water contaminated by PhACs and bacteria. • HRS (H2O2, OH –̇OH, and O2 –) from CaO2 hydrolysis played main roles • Determine [HRS] and its second-order reaction rate constant with PhAC (k HRS,C). • Mechanistic modeling can predict PhACs attenuation within 25% deviation. • Degradation pathways of target PhACs were proposed. [ABSTRACT FROM AUTHOR]

Abstract: Pharmaceutically active compounds (PhACs) are considered as emerging environmental problem due to their continuous input and persistence to the aquatic ecosystem even at low concentrations. Among them, carbamazepine (CBZ) has been detected at the highest frequency, which ends up in aquatic systems via wastewater treatment plants (WWTPs) among other sources. The identification and quantification of CBZ in wastewater (WW) and wastewater sludge (WWS) is of major interest to assess the toxicity of treated effluent discharged into the environment. Furthermore, WWS has been subjected for re-use either in agricultural application or for the production of value-added products through the route of bioconversion. However, this field application is disputable due to the presence of these organic compounds and in order to protect the ecosystem or end users, data concerning the concentration, fate, behavior as well as the perspective of simultaneous degradation of these compounds is urgently necessary. Many treatment technologies, including advanced oxidation processes (AOPs) have been developed in order to degrade CBZ in WW and WWS. AOPs are technologies based on the intermediacy of hydroxyl and other radicals to oxidize recalcitrant, toxic and non-biodegradable compounds to various by-products and eventually to inert end products. The purpose of this review is to provide information on persistent pharmaceutical compound, carbamazepine, its ecological effects and removal during various AOPs of WW and WWS. This review also reports the different analytical methods available for quantification of CBZ in different contaminated media including WW and WWS. [Copyright &y& Elsevier]

Despite the availability of analytic data, little is known about the toxicity of salicylic acid (SA) on aquatic non-target organisms. The present study aimed at evaluating the impact of SA through a short-term exposure of the Mediterranean mussel Mytilus galloprovincialis to five environmentally relevant concentrations of SA. A set of suitable biomarkers was applied at selected time-points on mussel digestive glands, including histological observations and expression of oxidative stress related genes. The obtained results showed a conspicuous hemocytic infiltration among mussel digestive tubules, as confirmed also by a flow cytometric approach that revealed an increase of halinocytes and granulocytes. Interestingly, a significant dose and time dependent decrease in the expression levels of oxidative stress related genes was found in mussels exposed to SA except for the glutathione S-transferase gene that was significantly up-regulated in a time-dependent manner confirming its important role against oxidant species and in the metabolism of pharmaceuticals. [Display omitted] • Mussels M. galloprovincialis were exposed to realistic doses of salicylic acid (SA). • SA exposure induced massive hemocyte infiltration in mussel digestive gland (DG). • Halinocytes and granulocytes increased as cell defence strategy against SA exposure. • SA exposure caused unbalance in the expression of oxidative stress related genes. • GST confirmed its role against oxidant species and in metabolism of pharmaceuticals. [ABSTRACT FROM AUTHOR]

Highlights: [•] Fungal enzyme could degrade TrOC that are resistant to bacterial degradation. [•] Some TrOC well removed by bacteria were poorly removed by fungal enzyme. [•] Bacterial complemented well the degradation of TrOC by fungal MBR. [•] Biodegradation was a major TrOC removal mechanism by fungi-bacteria (F-B) MBR. [•] Redox-mediator dosing improved removal of resistant TrOC diclofenac by F-B MBR. [Copyright &y& Elsevier]

Abstract: A wide range of Pharmaceuticals and Personal Care Products (PPCPs) are present in the environment, and many of their adverse effects are unknown. The emergence of new compounds or changes in regulations have led to dynamical studies of occurrence, impact and treatment, which consider geographical areas and trends in consumption and innovation in the pharmaceutical industry. A Quantitative study of Structure–Activity Relationship ((Q)SAR) was performed to assess the possible adverse effects of ninety six PPCPs and metabolites with negligible experimental data and establish a ranking of concern, which was supported by the EPA EPI Suite™ interface. The environmental and toxicological indexes, the persistence (P), the bioaccumulation (B), the toxicity (T) (extensive) and the occurrence in Spanish aquatic environments (O) (intensive) were evaluated. The most hazardous characteristics in the largest number of compounds were generated by the P index, followed by the T and B indexes. A high number of metabolites has a concern score equal to or greater than their parent compounds. Three PBT and OPBT rankings of concern were proposed using the total and partial ranking method (supported by a Hasse diagram) by the Decision Analysis by Ranking Techniques (DART) tool, which was recently recommended by the European Commission. An analysis of the sensibility of the relative weights of these indexes has been conducted. Hormones, antidepressants (and their metabolites), blood lipid regulators and all of the personal care products considered in this study were at the highest levels of risk according to the PBT and OPBT total rankings. Furthermore, when the OPBT partial ranking was performed, X-ray contrast media, H2 blockers and some antibiotics were included at the highest level of concern. It is important to improve and incorporate useful indexes for the predicted environmental impact of PPCPs and metabolites and thus focus experimental analysis on the compounds that require urgent attention. [Copyright &y& Elsevier]

Abstract: The impact of humic acid fouling on the membrane transport of two pharmaceutically active compounds (PhACs) – namely carbamazepine and sulfamethoxazole – in forward osmosis (FO) was investigated. Deposition of humic acid onto the membrane surface was promoted by the complexation with calcium ions in the feed solution and the increase in ionic strength at the membrane surface due to the reverse transport of NaCl draw solute. The increase in the humic acid deposition on the membrane surface led to a substantial decrease in the membrane salt (NaCl) permeability coefficient but did not result in a significant decrease in the membrane pure water permeability coefficient. As the deposition of humic acid increased, the permeation of carbamazepine and sulfamethoxazole decreased, which correlated well with the decrease in the membrane salt (NaCl) permeability coefficient. It is hypothesized that the hydrated humic acid fouling layer hindered solute diffusion through the membrane pore and enhanced solute rejection by steric hindrance, but not the permeation of water molecules. The membrane water and salt (NaCl) permeability coefficients were fully restored by physical cleaning of the membrane, suggesting that humic acid did not penetrate into the membrane pores. [Copyright &y& Elsevier]

Abstract: This study investigated the impact of chemical cleaning on the physicochemical properties of a nanofiltration membrane and its subsequent separation efficiency of inorganic salts and two pharmaceutically active compounds (PhACs), sulfamethoxazole and carbamazepine. Chemical cleaning was simulated by immersing virgin membrane samples in aqueous citric acid, sodium hydroxide (NaOH), ethylenediaminetetraacetic-acid (EDTA) and sodium dodecyl sulphate (SDS) at various temperatures for 18h. The cleaning temperature did not exert any discernible impact on the surface charge of the NF270 membrane selected in this study. However, high cleaning temperatures were shown to either amplify or reduce the impact of chemical cleaning on several other membrane properties (including hydrophobicity, surface roughness and permeability) as well as the rejection of both inorganic salts and PhACs. The influence of chemical cleaning on the membrane surface roughness was enhanced at elevated cleaning temperatures. Similarly, at a high cleaning temperature, caustic and acidic cleaning caused a more significant increase in the membrane surface hydrophobicity than that at an ambient temperature. An increase in the cleaning temperature could also slightly amplify the decrease in the membrane permeability due to acidic cleaning. When a caustic cleaning solution (pH 11.5) was used, the membrane permeability only varied slightly with the temperature. Results obtained from Fourier transform infrared spectroscopy (FTIR) analysis suggest that chemical cleaning even at a high temperature did not permanently alter the chemical composition of the membrane active or support layer. Indeed, the effects of chemical cleaning at a high temperature on the physicochemical properties of the membrane could be attributed to the conformational changes of the membrane polymeric matrix. Chemical cleaning using citric acid, SDS or EDTA at a high temperature resulted in a considerable increase in the rejection of salts and PhACs in their neutral form. On the other hand, caustic cleaning at an elevated temperature had no discernible impact on the rejection of inorganic salts and neutral PhACs. This is because caustic cleaning and an elevated cleaning temperature cause opposing effects on the rejection of these solutes. Chemical cleaning at all temperatures investigated in this study did not affect the removal of negatively charged sulfamethoxazole. [Copyright &y& Elsevier]

Highlights: [•] Membrane fouling and cleaning could alter the membrane surface properties. [•] Membrane fouling and cleaning affected the separation performance of the NF270. [•] Caustic cleaning could recover the permeate flux to slightly above 100%. [•] Caustic cleaning resulted in a decrease in the rejection of salts and neutral PhAC. [•] However, the impact on negatively charged PhAC rejection was less significant. [Copyright &y& Elsevier]

Abstract: The effect of chemical cleaning on the nanofiltration of two pharmaceutically active compounds (PhACs), namely sulfamethoxazole and carbamazepine, was investigated. Membrane cleaning was simulated by exposing the virgin membrane samples to cleaning reagents including acidic, caustic, sodium dodecyl sulphate (SDS), and ethylenediaminetetraacetic-acid (EDTA) under controlled conditions. Prolonged exposure to acid and SDS rendered the membrane slightly less negatively charged. Caustic and acidic cleaning, however, resulted in a marked increase in the membrane surface hydrophobicity. In addition, it is hypothesised that chemical cleaning may alter the porosity of the polymeric matrix and even the hydrophilicity within the membrane active layer. Indeed, caustic cleaning led to an increase in the membrane permeability while acidic cleaning produced the opposite effect. An increase in the membrane permeability was also observed as a result of SDS and EDTA cleaning. This hypothesis is also supported by the rejection data. Among the four reagents investigated, strong caustic cleaning (pH 11.5 and 12) resulted in a significant decrease in both conductivity and carbamazepine rejection. Chemical cleaning did not affect the rejection of the negatively charged sulfamethoxazole (pH 8–10). However, below pH 8, there was considerable effect of caustic cleaning on the rejection of sulfamethoxazole. A small reduction in salt rejection was also found after strong acidic cleaning (pH 1.5). Both acidic and SDS cleaning resulted in a small increase in the rejection of carbamazepine, however there was no effect on sulfamethoxazole rejection. The effect of EDTA cleaning on the separation performance of the NF270 membrane was the smallest amongst the four reagents investigated. [Copyright &y& Elsevier]

The effect of five process variables—pH, dissolved organic matter (DOM), ozone concentration, contact time, and temperature— on the removal efficiency of 14 selected pharmaceutically active compounds and bisphenol A was studied through fractional factorial- designed experiments. Results showed that DOM content and ozone dose had the most significant effect, accounting for 60-99% of the observed variability in oxidation efficiencies for compounds with both fast and slower reaction rates with ozone. Oxidation efficiency of > 90% is expected for the fast-reacting compounds at ozone exposures > 1.3 mg/L × min, over the wide range of operating conditions used in the study. For compounds with a slower reaction rate with ozone, the oxidation efficiency is expected to be variable and strongly dependent on the characteristics of the raw water, particularly the concentration and nature of the DOM. [ABSTRACT FROM AUTHOR]

Abstract: The impact of four pharmaceutically active compounds (PhACs) introduced both individually and in mixtures was ascertained on the performance of laboratory-scale wastewater treatment sequencing batch reactors (SBRs). When introduced individually at concentrations of 0.1, 1 and 10 μM, no significant differences were observed with respect to chemical oxygen demand (COD) and ammonia removal. Microbial community analyses reveal that although similarity index values generally decreased over time with an increase in PhAC concentrations as compared to the controls, no major microbial community shifts were observed for total bacteria and ammonia-oxidizing bacteria (AOB) communities. However, when some PhACs were introduced in mixtures, they were found to both inhibit nitrification and alter AOB community structure. Ammonia removal decreased by up to 45% in the presence of 0.25 μM gemfibrozil and 0.75 μM naproxen. PhAC mixtures did not however affect COD removal performance suggesting that heterotrophic bacteria are more robust to PhACs than AOB. These results highlight that the joint action of PhACs in mixtures may have significantly different effects on nitrification than the individual PhACs. This phenomenon should be further investigated with a wider range of PhACs so that toxicity effects can more accurately be predicted. [Copyright &y& Elsevier]

Abstract: Pharmaceutically active compounds (PhACs) are commonly found in wastewater influent. However, little research has focused on determining their impact on fundamental processes in wastewater treatment such as nitrogen removal. In this study, focus was placed on 4 commonly occurring PhACs (ketoprofen, naproxen, carbamazepine and gemfibrozil). Their effect was ascertained in the ammonia oxidizing bacterium (AOB), Nitrosomonas europaea in terms of membrane integrity and nitrite production. These PhACs were shown to inhibit nitrite production at concentrations of 1 and 10μM while no effect was observed at 0.1μM. The maximum observed nitrification inhibition was 25%, 29%, 22% and 26% for ketoprofen, naproxen, carbamazepine and gemfibrozil, respectively. A decrease in the live/dead ratio ranging from 10% to 16% suggests that these PhACs affect membrane integrity in N. europaea. The difference in nitrite production between PhACs treated cells and non PhAC treated controls was still significant following washing suggesting that inhibition is irreversible. Finally, nitrite production when adjusted to the live fraction of cells was also found to decrease suggesting that PhACs inhibited the activity of surviving cells. These results suggest that the presence of PhACs may affect AOB activity and may impact nitrogen removal, a key function in wastewater treatment. Follow up studies with additional AOB and in mixed culture are needed to further confirm these results. [ABSTRACT FROM AUTHOR]

The retention of sulfamethoxazole (SMZ) by nanofiltration (NF) membranes is strongly influenced by the pH value of the solution. The retention of SMZ reaches its peak value when the solution pH rises above its p K value as the compound transforms into a negatively charged species. Charge repulsion is the main mechanism involved in SMZ removal by NF membranes. In this study, the removal of SMZ by NF membranes, as a function of solution chemistry, was examined at pH 8.9 to investigate the effect of solution conditions on charge repulsion. The results show that the retention of negatively charged SMZ is relatively independent of SMZ concentration, and an increase in the ionic strength of the solution causes a relatively small reduction in retention. A small effect of humic acid (HA) on SMZ retention was noticed at pH 8.9, which can be explained by a small but insignificant improvement in the zeta potential of the membrane caused by HA at high pH values. However, it was found that SMZ concentration in the feed decreased significantly in solutions containing tannic acid (TA). The Adams-Bohart model was applied to our experimental data and was found to be suitable for describing the initial part of the breakthrough curves. The adsorptive parameters of the membrane were determined. [ABSTRACT FROM AUTHOR]

Abstract: A progressive freeze concentration process, unidirectional downward freezing (UDF), was investigated for removal of five commonly used pharmaceuticals (ibuprofen, gemfibrozil, acetylsalicylic acid, metoprolol and sulfamethoxazole) in water. The feed water with the pharmaceutically active compounds (PhACs) at concentrations from ng/L to mg/L range was frozen at −7 and −15°C. The separation efficiency of PhACs in the single stage and two-stage UDF was examined. By freezing only 80% (volume) of the feed water and without washing of the ice, about 84–92% reduction of the drug content in ice was achieved in the single stage UDF and about 99% reduction in the two-stage UDF. The partitioning behavior of the PhACs in the ice and liquid phases seems different from the solutes in glucose solutions or liquid foods reported in the literature. A strong linear relationship between the PhACs concentration and their TOC concentration was established, suggesting that TOC, a parameter commonly used to measure WWTP effluent quality might be used to monitor the level of PhACs in WWTP effluent. [Copyright &y& Elsevier]

Abstract: Adsorption is one of the main mechanisms contributing to compound removal by membrane filtration, in addition to size exclusion and charge repulsion. In this study, the adsorption of 22 endocrine disrupting compounds and pharmaceutically active compounds by ultrafiltration (UF), nanofiltration (NF) and reverse osmosis (RO) membranes was investigated using 24-h bottle tests at 21 and 4°C. Two natural waters (Lake Ontario and effluent from a membrane bioreactor (MBR)) and one laboratory-grade water were examined. Adsorption was strongly correlated with compound log K ow and membrane pure water permeability, and moderately correlated with compound water solubility. Adsorption was observed to be highest by the UF membrane followed by the NF and RO membranes. The influence of temperature on adsorption in the range examined was found to be insignificant. Three compounds for which deuterium-labelled surrogates were available (acetaminophen, carbamazepine, gemfibrozil) were examined to determine the influence of water matrix on adsorption. Adsorption of gemfibrozil may have been hindered due to competition for adsorption sites from the organic matter present in the lake water and MBR effluent. [Copyright &y& Elsevier]

The occurrence of bioactive pharmaceutical compounds in the aquatic environment is an emerging concern. Liquid chromatography, coupled with mass spectrometry (LC–MS) or tandem mass spectrometry (LC–MS–MS) using an electrospray ionization interface, is a crucial tool for addressing this issue. We review in this manuscript LC–MS and LC–MS–MS studies on waterborne PhACs in the last decade, including research activity in different geographical areas and the current status of the technology used for sample preparation, chromatographic separation, and mass spectrometric detection. A detailed overview on quality-control and quality-assurance (QC/QA) procedures is also presented, with emphasis on the need for a concerted approach to determine the numerical values associated with detection limits, and the use of low-level data qualifiers. [ABSTRACT FROM AUTHOR]

Urban pollution and hydrological stress are common stressors of stream ecosystems, but their combined effects on ecosystem functioning are still unclear. We measured a set of functional processes and accompanying environmental variables in locations upstream and downstream of urban sewage inputs in 13 streams covering a wide range of water pollution levels and hydrological variability. Sewage inputs seriously impaired stream chemical characteristics and led to complex effects on ecosystem functioning. Biofilm biomass accrual, whole-reach nutrient uptake and metabolism (ecosystem respiration) were generally subsidized, whereas organic matter decomposition and biofilm phosphorus uptake capacity decreased with increasing pollutant concentrations. Hydrological stress affected stream ecosystem functioning but its effect was minor compared to the effects of urban pollution, due to the large inter-site variability of the streams. Changes appeared mainly linked to the concentration of pharmaceutically active compounds, followed by other chemical characteristics and by hydrology. The results point to the need to further improve sewage treatment, especially as climate change will stress riverine organisms and reduce the dilution capacity of the receiving streams. Unlabelled Image • Sewage led to complex effects on stream ecosystem functioning. • The contribution of hydrological stress was minor. • Water quality (specifically pharmaceuticals) was related to stream functioning changes. • Biofilm-level processes showed more consistent patterns than ecosystem-level ones. • These effects will become more frequent in following years, due to global change. [ABSTRACT FROM AUTHOR]

• Biological & metabolic factors impacting PhAC biodegradation was reviewed. • Impact of transformation products & operational conditions discussed. • MBBR represent a promising technology for DCF and macrolides. • Constructed wetlands are interesting as an effluent polishing step. • Further toxicity assessment of metabolites and cost-benefit analyses needed. Wastewater effluent discharges have been considered as one of the main sources of synthetic chemicals entering into the aquatic environment. Even though they occur at low concentrations, pharmaceutically active compounds (PhACs) can have an impact on ecological toxicity that affects aquatic organisms. Moreover, new regulations in development toward preserving water quality reinforces the increasing need to monitor and abate some PhACs in wastewater treatment plants (WWTPs), where they are typically only partially eliminated. Unlike most previous reviews, we have focussed on how the main biological and chemical molecular factors impact the biotransformations of key PhACs in biological WWTP processes. Biotransformations have been found to be an important contributor towards the removal of PhACs from WWTP effluents. This review paper critically assesses these aspects and the recent advances that have been achieved in wastewater treatment processes for biodegradation of 7 PhACs; namely the non-steroidal anti-inflammatory drug (NSAID) diclofenac (DCF); the macrolide antibiotics azithromycin (AZM), erythromycin (ERY) and clarithromycin (CLR); the two natural estrogens estrone (E1) and 17β-estradiol (E2), and the synthetic estrogen 17α-ethinylesradiol (EE2). These represent the micropollutants of the EU Watch list in Decision 2015/495/EU that are most relevant to WWTPs due to their frequent detection. The metabolic pathways, transformation products and impact of relevant factors to biological WWTP processes is addressed in this review. The biokinetics of PhAC biodegradation in different engineered bioprocesses is also discussed. Promising technologies and operational strategies that are likely to have a high impact on controlling PhAC releases are highlighted and future research needs are also proposed. Image, graphical abstract [ABSTRACT FROM AUTHOR]

As freshwater sources continue to be influenced by wastewater effluents, there is a dire need to develop advanced water treatment processes capable of treating the wastewater-derived contaminants, especially for pharmaceutically active compounds (PhACs). Ultraviolet light (UV) combined with calcium peroxide (CaO 2) as an advanced oxidation process (AOP) to attenuate five widespread PhACs (carbamazepine (CBZ), primidone (PMD), phenobarbital (PBB), thiamphenicol (TAP) and florfenicol (FF)) was investigated in this paper. The degradation of these compounds followed pseudo-first-order kinetics (R 2 > 0.96). The optimum CaO 2 dosage was 0.1 g L−1 and lower initial contaminants concentration was beneficial to their degradation. The UV/CaO 2 treatment of test PhACs was attributed to the combination of UV/H 2 O 2 and UV-base-photolysis (UV/Ca(OH) 2), and the degradation mechanism was recognized as both UV direct photolysis and indirect photolysis caused by reactive radicals (•OH, triplet states of dissolved organic matter (3DOM*), and 1O 2). Furthermore, the tentative transformation pathways of the five PhACs were proposed based on the detected intermediates and the degradation mechanisms. The final products of inorganic carbon and nitrogen indicate UV/CaO 2 treatment can significantly mineralize test PhACs. Also, the CaO 2 addition significantly reduced the energy consumption of UV irradiation according to electrical energy per order. The effective removal of CBZ and PMD in a secondary wastewater effluent by UV/CaO 2 treatment demonstrates the potential use of this AOP technology in advanced treatment of wastewater-derived PhACs. Image 1 • UV/CaO 2 can effectively remove PhACs in aqueous phase. •.•OH, 1O 2 and 3DOM* were identified under UV/CaO 2 treatment • Ca(OH) 2 played an important role in the removal of PBB, TAP and FF. • The degradation pathways of test compounds were proposed. • UV/CaO 2 underwent a better removal of CBZ/PMD in WWE than UV/H 2 O 2. [ABSTRACT FROM AUTHOR]

Colloid media are not only an important "sink" for pollutants in the aquatic environment, but also a crucial regulating unit for the biogeochemical cycle of pollutants. In this study, the distribution and environmental risk levels of ten typical pharmaceutically active compounds (PhACs) in the water phase of effluent-receiving rivers were investigated using cross-flow ultrafiltration, solid-phase extraction, and liquid chromatography-tandem mass spectrometry as the pretreatment and analysis methods. The results showed that the total concentrations of the ten PhACs in the dissolved phase and colloidal phase ranged from 27.2 to 168.1 ng·L -1 and 164.5 to 751.1 ng·g -1 , respectively. Ibuprofen (IPF), roxithromycin (ROX), and erythromycin (ETM) are the dominating pollutants in the dissolved phase and colloidal phase, accounting for more than 80% of the total concentration. Strong adsorption properties for ROX, ketoconazole, ETM, and sertraline were found in the colloid phase, their colloid/water distribution coefficients (lg K col ) ranged from 3.2 to 4.0, and the percentage of PhACs absorbed to the colloidal phase reached 21.1%-34.5%. The risk assessment of acute and chronic toxicity to algae, daphnia, and fish showed that only IPF presented a high chronic risk to fish, while the risk levels of the other PhACs were at or below medium risk. It is worth noting that, in comparison with their acute risk, most PhACs have chronic negative effects on higher aquatic organisms.

Results reported here indicate that membrane fouling could influence the removal of two pharmaceutically active compounds (PhACs) namely sulfamethoxazole and carbamazepine, by a nanofiltration process. The effects of membrane fouling on solute rejection by the tight nanofiltration (NF)-90 membrane were quite negligible. In contrast, remarkable effects of membrane fouling on the rejection of both inorganic salts and PhACs were observed with the larger pore size NF-270 membrane. The effects of membrane fouling on solute rejection were strongly foulant-dependent. The three model foulants (sodium alginate, bovine serum albumin, and silica colloid) used in this study resulted in three distinctive modes of membrane fouling. Subsequently, these three modes of membrane fouling consistently showed different effects on the membrane separation efficiency. Inorganic colloidal fouling resulted in the most severe rejection decrease while causing the least permeate flux decline. This observed reduction in rejection could be attributed to the cake-enhanced concentration polarization phenomenon that was also thought to be the primary mechanism of flux decline in inorganic colloidal fouling. In contrast, organic fouling caused by the model foulant alginate led to a lesser decrease in the rejection of PhACs despite the fact that alginate caused the most severe flux decline. [ABSTRACT FROM AUTHOR]