Membrane processes for removal of pharmaceutically active compounds (PhACs) from water and wastewaters

Removal of extracellular free DNA and antibiotic resistance genes from water and wastewater by membranes ranging from microfiltration to reverse osmosis

Free DNA in the effluent from wastewater treatment plants has recently been observed to contain antibiotic resistance genes (ARGs), which may contribute to the spread of antibiotic resistance via horizontal gene transfer in the receiving environment. Technical membrane systems applied in wastewater and drinking water treatment are situated at central nodes between the environmental and human related aspects of the "One Health" approach and are considered as effective barriers for antibiotic resistant bacteria. However, they are not evaluated for their permeability for ARGs encoded in free DNA, which may result, for example, from the release of free DNA after bacterial die-off during particular treatment processes. This study examined the potential and principle mechanisms for the removal of free DNA containing ARGs by technical membrane filtration. Ten different membranes, varied by the charge (neutral and negative) and the molecular weight cut off (in a range from microfiltration to reverse osmosis), were tested for the removal of free DNA (pure supercoiled and linearized plasmids encoding for ARGs and free linear chromosomal DNA with a broader fragment size spectrum) in different water matrices (distilled water and wastewater treatment plant effluent). Our results showed that membranes with a molecular weight cut off smaller than 5000 Da (ultrafiltration, nanofiltration and reverse osmosis) could retain ≥99.80% of free DNA, both pure plasmid and linear fragments of different sizes, whereas microfiltration commonly applied in wastewater treatment showed no retention. Size exclusion was identified as the main retention mechanism. Additionally, surface charging of the membrane and adsorption of free DNA on the membrane surface played a key role in prevention of free DNA permeation. Currently, majority of the applied membranes is negatively charged to prevent adsorption of natural organic matter. In our study, negatively charged membranes showed lower retention of free DNA compared to neutral ones due to repulsion of free DNA molecules, reduced adsorption and decreased blockage of the membrane surface. Therefore, the applied membrane may not be as an effective barrier for ARGs encoded in free DNA, as it would be predicted based only on the molecular weight cut off. Thus, careful considerations of membrane's specifications (molecular weight cut-off and charge) are required during design of a filtration system for retention of free DNA.

Development and application of relevance and reliability criteria for water treatment removal efficiencies of chemicals of emerging concern

With the growth in production and use of chemicals and the fact that many end up in the aquatic environment, there is an increasing need for advanced water treatment technologies that can remove chemicals of emerging concern (CECs) from water. The current lack of a homogenous approach for testing advanced water treatment technologies hampers the interpretation and evaluation of CEC removal efficiency data, and hinders informed decision making by stakeholders with regard to which treatment technology could satisfy their specific needs. Here a data evaluation framework is proposed to improve the use of current knowledge in the field of advanced water treatment technologies for drinking water and wastewater, consisting of a set of 9 relevance criteria and 51 reliability criteria. The two criteria sets underpin a thorough, unbiased and standardised method to select studies to evaluate and compare CEC removal efficiency of advanced water treatment technologies in a scientifically sound way. The relevance criteria set was applied to 244 papers on removal efficiency, of which only 20% fulfilled the criteria. The reliability criteria were applied to the remaining papers. In general these criteria were fulfilled with regards to information on the target compound, the water matrix and the treatment process conditions. However, there was a lack of information on data interpretation and statistics. In conclusion, a minority of the evaluated papers are suited for comparison across techniques, compounds and water matrixes. There is a clear need for more uniform reporting of water treatment studies for CEC removal. In the future this will benefit the selection of appropriate technologies.

Heterotrophic Kinetic Study and Nitrogen Removal of a Membrane Bioreactor System Treating Real Urban Wastewater under a Pharmaceutical Compounds Shock: Effect of the Operative Variables

Numerous studies have analyzed the viability of the biodegradation and removal of different compounds of emerging concern in biological systems for wastewater treatment. However, the effect on the heterotrophic biomass of organic matter removal is sometimes missed. The aim of the present research was to study the effect of the addition of a mix of three pharmaceuticals (carbamazepine, ciprofloxacin, and ibuprofen) on the behavior of the biomass in two different membrane-based biological systems treating urban wastewater. The present research studied a membrane bioreactor (MBR) pilot plant operating at a similar mixed liquor suspended solids (MLSS) concentration (about 5.5 g/L). This system works as an MBR and is combined with a moving bed biofilm reactor (MBBR-MBR) to treat real urban wastewater at 6 and 10 h of hydraulic retention time (HRT) under three different shocks of pharmaceuticals with increasing concentrations. In all cases, the organic matter removal was, in average terms, higher than about 92% of biochemical oxygen demand on the fifth day (BOD5), 79% of chemical oxygen demand (COD), and 85% of total organic carbon (TOC). Nevertheless, the removal is higher in the MBBR-MBR technology under the same HRT and the MLSS is similar. Moreover, the removal increased during the shock of pharmaceutical compounds, especially in the MBR technology. From a kinetic perspective, MBBR-MBR is more suitable for low HRT (6 h) and MBR is more effective for high HRT (10 h). This could be due to the fact that biofilm systems are less sensitive to hostile environments than the MBR systems. The removal of N-NH4+ decreased considerably when the pharmaceutical compounds mix was introduced into the system until no removal was detected in cycle 1, even when biofilm was present.

Removal and fate of emerging organic micropollutants (EOMs) in municipal wastewater by a pilot-scale membrane bioreactor (MBR) treatment under varying solid retention times

This study investigates the removal and fate of 23 emerging organic micropollutants (EOMs) including a wide range of pharmaceuticals (antibiotics, β-blockers, analgesics, diuretics, psychostimulants, antiepileptics, immunosuppressives, anticoagulants), and steroid hormones detected in municipal wastewater by a pilot-scale membrane bioreactor (MBR) plant at two different solid retention times (SRTs) of 60 and 21 days. Different removal efficiencies of the selected EOMs were observed and explained based on their physicochemical properties (such as distribution coefficient, log D; dissociation constant, pK_a; solid-water distribution coefficients, and K_d) along with process operating parameters. The dominant removal mechanisms of EOMs were biotransformation and sorption onto the sludge, which were confirmed by the mass balance study. Moreover, changes in the sludge properties, as a consequence of different SRTs, were evaluated based on variations in soluble microbial products (SMP), extracellular polymeric substances (EPS), and capillary suction time (CST). Finally, the quality of the MBR effluent was compared with some established guidelines, which confirmed the fulfilment of water quality requirements for reuse purposes.

Roles of ammonia-oxidizing bacteria in improving metabolism and cometabolism of trace organic chemicals in biological wastewater treatment processes: A review

While there has been a significant recent improvement in the removal of pollutants in natural and engineered systems, trace organic chemicals (TrOCs) are posing a major threat to aquatic environments and human health. There is a critical need for developing potential strategies that aim at enhancing metabolism and/or cometabolism of these compounds. Recently, knowledge regarding biodegradation of TrOCs by ammonia-oxidizing bacteria (AOB) has been widely developed. This review aims to delineate an up-to-date version of the ecophysiology of AOB and outline current knowledge related to biodegradation efficiencies of the frequently reported TrOCs by AOB. The paper also provides an insight into biodegradation pathways by AOB and transformation products of these compounds and makes recommendations for future research of AOB. In brief, nitrifying WWTFs (wastewater treatment facilities) were superior in degrading most TrOCs than non-nitrifying WWTFs due to cometabolic biodegradation by the AOB. To fully understand and/or enhance the cometabolic biodegradation of TrOCs by AOB, recent molecular research has focused on numerous crucial factors including availability of the compounds to AOB, presence of growth substrate (NH₄-N), redox potentials, microorganism diversity (AOB and heterotrophs), physicochemical properties and operational parameters of the WWTFs, molecular structure of target TrOCs and membrane-based technologies, may all significantly impact the cometabolic biodegradation of TrOCs. Still, further exploration is required to elucidate the mechanisms involved in biodegradation of TrOCs by AOB and the toxicity levels of formed products.

Impact of Advanced Oxidation Products on Nanofiltration Efficiency

The aim of the work was to determine the influence of salicylic acid (SA) oxidation products on the effectiveness of their further removal in the membrane filtration process. Two commercial polyamide-based polymer membranes, HL (GE Osmonics) and TS80 (TriSepTM), were used and characterized by SEM microscopic analysis, contact angles, and free surface energy. The products of salicylic acid oxidation, 2,3- and 2,5-dihydroxybenzoic acid and catechol, were determined and their impact on the removal of unreacted salicylic acid in the nanofiltration process was investigated. It was also checked to what extent and why they were retained or not by the membranes. The results of the research have shown that the main product of salicylic acid oxidation, 2,3-dihydroxybenzoic acid, has a negative impact on the retention of salicylic acid in the nanofiltration stage, while the other product, catechol, improves SA retention. The determined values of contact angles correlate well with solubility (S) of the tested compounds, which increases in the following order SSA < S2,3-DHBA < SCAT, while the contact angle of the membrane decreases. Nevertheless, it has been shown that some oxidation products can penetrate the environment due to poorer membrane separation properties of these products.

Efficient removal of zinc from water and wastewater effluents by hydroxylated and carboxylated carbon nanotube membranes: Behaviors and mechanisms of dynamic filtration

In this work, a bench scale study was designed to investigate the removal of zinc (Zn²⁺) and regeneration efficiencies of functionalized-MWCNT (f-MWCNT) membranes. The f-MWCNTs were incorporated into polyvinylchloride (PVC) hollow fiber membranes (HFMs), which acted as a substrate and a barrier for MWCNTs leaching to water. The results revealed that the removal capacity of Zn²⁺ through f-CNT membranes were above 98% for the synthetic water and over 70% for real wastewater effluents; predominantly involved surface complexation reaction. The acquired removal efficiency of CNT membrane is attributed to high absolute zeta potential followed by the hydrophilicity of the nanotubes coated the inside surface of HFMs and high concentration of oxygen functional groups on CNT surfaces. Later on, different regenerating solutions were used to desorb Zn²⁺ ions repeatedly from the inner surface of membranes and to recycle the CNT membranes for continuous removal of Zn²⁺ from water. The XPS analysis revealed that, Zn²⁺ ions were completely recovered owing to the ion exchange interactions. The results further confirmed that f-CNT membranes retained their original removal capacity after several successive cycles. Therefore, we recommend that, f-CNTs-based membranes have the potential to be used for large-scale removal and recovery of heavy metal ions from water or wastewater.

Fungal biodegradation of the N-nitrosodimethylamine precursors venlafaxine and O-desmethylvenlafaxine in water

Antidepressant drugs such as Venlafaxine (VFX) and O-desmethylvenlafaxine (ODMVFX) are emerging contaminants that are commonly detected in aquatic environments, since conventional wastewater treatment plants are unable to completely remove them. They can be precursors of hazardous by-products, such as the carcinogenic N-nitrosodimethylamine (NDMA), generated upon water chlorination, as they contain the dimethylamino moiety, necessary for the formation of NDMA. In this study, the capability of three white rot fungi (Trametes versicolor, Ganoderma lucidum and Pleurotus ostreatus) to remove both antidepressants from water and to decrease NDMA formation potential was investigated. Furthermore, transformation by-products (TPs) generated along the treatment process were elucidated and also correlated with their NDMA formation potential. Very promising results were obtained for T. versicolor and G. lucidum, both being able to remove up to 100% of ODMVFX. In the case of VFX, which is very recalcitrant to conventional wastewater treatment, a 70% of removal was achieved by T. versicolor, along with a reduction in NDMA formation potential, thus decreasing the associated problems for human health and the environment. However, the NDMA formation potential remained practically constant during treatment with G. lucidum despite of the equally high VFX removal (70%). This difference was attributed to the generation of different TPs during both fungal treatments. For example, G. lucidum generated more ODMVFX, which actually has a higher NDMA formation potential than the parent compound itself.

Performance of secondary wastewater treatment methods for the removal of contaminants of emerging concern implicated in crop uptake and antibiotic resistance spread: A review

Contaminants of emerging concern (CEC) discharged in effluents of wastewater treatment plants (WWTPs), not specifically designed for their removal, pose serious hazards to human health and ecosystems. Their impact is of particular relevance to wastewater disposal and re-use in agricultural settings due to CEC uptake and accumulation in food crops and consequent diffusion into the food-chain. This is the reason why the chemical CEC discussed in this review have been selected considering, besides recalcitrance, frequency of detection and entity of potential hazards, their relevance for crop uptake. Antibiotic-resistant bacteria (ARB) and antibiotic resistance genes (ARGs) have been included as microbial CEC because of the potential of secondary wastewater treatment to offer conditions favourable to the survival and proliferation of ARB, and dissemination of ARGs. Given the adverse effects of chemical and microbial CEC, their removal is being considered as an additional design criterion, which highlights the necessity of upgrading conventional WWTPs with more effective technologies. In this review, the performance of currently applied biological treatment methods for secondary treatment is analysed. To this end, technological solutions including conventional activated sludge (CAS), membrane bioreactors (MBRs), moving bed biofilm reactors (MBBRs), and nature-based solutions such as constructed wetlands (CWs) are compared for the achievable removal efficiencies of the selected CEC and their potential of acting as reservoirs of ARB&ARGs. With the aim of giving a picture of real systems, this review focuses on data from full-scale and pilot-scale plants treating real urban wastewater. To achieve an integrated assessment, technologies are compared considering also other relevant evaluation parameters such as investment and management costs, complexity of layout and management, present scale of application and need of a post-treatment. Comparison results allow the definition of design and operation strategies for the implementation of CEC removal in WWTPs, when agricultural reuse of effluents is planned.

Bioaugmentation of membrane bioreactor with Achromobacter denitrificans strain PR1 for enhanced sulfamethoxazole removal in wastewater

Achromobacter denitrificans strain PR1, previously found to harbour specific degradation pathways with high sulfamethoxazole (SMX) degradation rates, was bioaugmented into laboratory-scale membrane bioreactors (MBRs) operated under aerobic conditions to treat SMX-containing real domestic wastewater. Different hydraulic retention times (HRTs), which is related to reaction time and loading rates, were considered and found to affect the SMX removal efficiency. The availability of primary substrates was important in both bioaugmented and non-bioaugmented activated sludge (AS) for cometabolism of SMX. High HRT (24 h) resulted in low food to microorganism ratio (F/M) and low SMX removal, due to substrate limitation. Decrease in HRT from 24 h to 12 h, 6 h and finally 4 h led to gradual increases in primary substrates availability, e.g. organic compounds and ammonia, resulted in increased SMX removal efficiency and degradation rate, and is more favorable for high-rate wastewater treatment processes. After inoculation into the MBRs, the bioaugmentation strain was sustained in the reactor for a maximum of 31 days even though a significant decrease in abundance was observed. The bioaugmented MBRs showed enhanced SMX removal, especially under SMX shock loads compared to the control MBRs. The results of this study indicate that re-inoculation is required regularly after a period of time to maintain the removal efficiency of the target compound.

Kinetic and mechanistic investigations of the degradation of propranolol in heat activated persulfate process

This study investigated the heat activated persulfate (heat/PS) process in the degradation of propranolol from water. Various factors (e.g., temperature, persulfate dose, initial pH and natural water constituent) on PRO degradation kinetics have been investigated. The results showed that the PRO degradation followed a pseudo-first-order kinetics pattern. As temperature rises, the pseudo-first-order rate constant (k obs) was improved significantly, and the k obs determined at 40-70 °C satisfied the Arrhenius equation, yielding an activation energy of 99.0 kJ mol-1. The radical scavenging experiments and the EPR tests revealed that both SO4˙- and ·OH participated in degrading PRO, with SO4˙- playing a dominant role. Higher PS concentration and neutral pH favored PRO degradation. The impact of Cl- and HCO3 - were concentration-dependent. A lower concentration of Cl- and HCO3 - could accelerate PRO degradation, while the presence of HA showed inhibitory effects. Seven degradation products were recognized through LC/MS/MS analysis. Cleavage of ether bond, hydroxylation, and ring-opening of naphthol moiety are involved in the PRO's degradation pathway. Finally, the formation of disinfection byproducts (DBPs) before and after pre-treated by heat/PS was also evaluated. Compared with direct chlorination of PRO, the heat/PS pre-oxidation greatly impacted the DBPs formation. The higher PRO removal efficiency in natural water indicated the heat/PS process might be capable of treating PRO-containing water samples, however, its impacts on the downstream effect on DBPs formation should be also considered.

Micropollutants removal in tertiary moving bed biofilm reactors (MBBRs): Contribution of the biofilm and suspended biomass

The performance of tertiary moving bed biofilm reactors (MBBRs) was evaluated in terms of micropollutants (MPs) removal from secondary-treated municipal wastewater. After stepwise establishment of a mature biofilm, monitored by scanning electron and confocal microscopies, abiotic and biotic removals of MPs were deeply studied. Since no MPs reduction was observed by the both photodegradation and volatilization, abiotic removal of MPs was ascribed to the sorption onto the biomass. Target MPs i.e. Naproxen, Diclofenac, 17β-Estradiol and 4n-Nonylphenol, arranged in the ascending order of hydrophobicity, abiotically declined up to 2.8%, 4%, 9.5% and 15%, respectively. MPs sorption onto the suspended biomass was found around two times more than the biofilm, in line with MPs' higher sorption kinetic constants (k_sor) found for the suspended biomass. When comparing abiotic and biotic aspects, we found that biotic removal outperformed its counterpart for all compounds as Diclofenac, Naproxen, 17β-Estradiol and 4n-Nonylphenol were biodegraded by 72.8, 80.6, 84.7 and 84.4%, respectively. The effect of the changes in organic loading rates (OLRs) was investigated on the pseudo-first order degradation constants (k_biol), revealing the dominant biodegradation mechanism of co-metabolism for the removal of Diclofenac, Naproxen, and 4n-Nonylphenol, while 17β-Estradiol obeyed the biodegradation mechanism of competitive inhibition. Biotic removals and k_biol values of all MPs were also seen higher in the biofilm as compared to the suspended biomass. To draw a conclusion, a quite high removal of recalcitrant MPs is achievable in tertiary MBBRs, making them a promising technology that supports both pathways of co-metabolism and competitive inhibition, next to the abiotic attenuation of MPs.

Fenton oxidation of municipal secondary effluent: comparison of Fe/Ce-RGO (reduced graphene oxide) and Fe2+ as catalysts

The advanced treatment of municipal secondary effluent by heterogeneous and homogeneous Fenton processes using Fe/Ce-RGO (reduced graphene oxide) and Fe²⁺ as catalysts was studied and compared. Sulfamethazine (SMT) was spiked in the effluent to examine the effectiveness of the emerging contaminant removal. The Fe/Ce-RGO catalyst was characterized using a scanning electron microscope (SEM) and cycle voltammetry curves. The removal of dissolved organic carbon (DOC), soluble chemical oxygen demand (SCOD), SMT, and ultraviolet-visible spectroscopy in 254 nm (UV₂₅₄) of municipal secondary effluents was examined. The DOC removal efficiency of secondary effluent (without addition of SMT) was 36.30% and 11.74% using Fe/Ce-RGO and Fe²⁺ as catalysts, respectively. The removal efficiency of DOC, SCOD, and SMT in heterogeneous Fenton process was higher than that in homogeneous Fenton process. The changes of three-dimensional excitation-emission matrix (3DEEM) fluorescence, soluble microbial products (SMPs), humic acids, and UV₂₅₄ were determined, and the results indicated that UV_254, aromatic proteins, and humic acids decreased rapidly in both processes; however, polysaccharides and protein-like substances were difficult to degrade. Although some toxic substances produced after Fenton-like treatment, the biodegradability of the treated effluent was enhanced.

Organic micropollutants removal in sequential batch reactor followed by nanofiltration from municipal wastewater treatment

The removal of 26 organic micropollutants (OMPs) in synthetic municipal wastewater was investigated via the process of aerobic sequential batch reactor (SBR) alone and SBR followed by nanofiltration (NF). SBR-NF performed better than SBR alone, ascribed to the contribution of NF: 1) complete biomass rejection resulted in diverse microbial community and much less fluctuated performance than SBR alone, and 2) direct OMPs rejection (74-98%) increased their retention time in SBR and thus overall removal via biodegradation/transformation and accumulation in SBR. Nine OMPs showed high biological removal (over 60%), 6 OMPs showed moderate biological removal (30-70%) and 10 OMPs showed low biological removal (below 40%). Most readily and moderately biodegradable OMPs contained strong electron donating group. Most refractory OMPs contained strong electron withdrawing group and/or halogen substitute. The batch addition of powdered activated carbon (100 mg/L) into SBR showed short term sorption performance for both OMPs and bulk organics.

Impact of simultaneous retention of micropollutants and laccase on micropollutant degradation in enzymatic membrane bioreactor

This study systematically compares the performance of ultrafiltration (UF) and nanofiltration (NF) based enzymatic membrane bioreactors (EMBRs) for the degradation of five micropollutants, namely atrazine, carbamazepine, sulfamethoxazole, diclofenac and oxybenzone to elucidate the impact of effective membrane retention of micropollutants on their degradation. Based on the permeate quality, NF-EMBR achieved 92-99.9% micropollutant removal (i.e., biodegradation + membrane retention), while the removal of these micropollutants by UF-EMBR varied from 20 to 85%. Mass balance analysis revealed that micropollutant degradation was improved by 15-30% in NF-EMBR as compared to UF-EMBR, which could be attributed to the prolonged contact time between laccase and micropollutants following their effective retention by the NF membrane. A small decline in permeate flux was observed during EMBR operation. However, the flux could be recovered by flushing the membrane with permeate.

Selection of performance reference compound (PRC) for passive sampling of pharmaceutical residues in an effluent dominated river

A passive sampling device, a polar organic chemical integrative sampler (POCIS), was used to monitor 13 pharmaceuticals and 8 transformation products in upstream and downstream wastewater treatment plant effluent. A POCIS laboratory calibration study was performed to determine uptake behavior and the effect of water flow on the sampling rate. Most compounds showed a linear accumulation, and the sampling rate values ranged from 0.031 to 0.559 L/day. The developed POCIS samplers were used in field experiments in a wastewater-impacted river. Using the calculated sampling rates, the time-weighted average concentration values were measured by three different approaches: (1) laboratory calibration sampling rates (2) performance reference compound (PRC) correction sampling rates and (3) field calibration sampling rates. Nine deuterated compounds (acetaminophen-d₃, antipyrine-d₃, sulfamethoxazole-d₄, carbamazepine-d₁₀, diclofenac acid-d₄, clofibric acid-d₄, bezafibrate-d₆, ibuprofen-d₃ and naproxen-d₃) were studied as PRCs. Antipyrine-d₃ was successfully tested as a PRC for sulfamethoxazole, ibuprofen, 2-hydroxy ibuprofen, diclofenac acid, 4-hydroxydiclofenac acid, carbamazepin, carbamazepin 10,11-epoxide, sulfadiazine, 1-naphthol, antipyrine, naproxen and 4-chlorobenzoic acid. Finally, the POCIS was used to monitor target compounds in river water and measure their attenuation. For most compounds, the POCIS attenuation results were not significantly different from those of the spot samples, which demonstrated that a POCIS with a PRC correction can determine the attenuation of organic micropollutants in rivers.

Distribution of Anticancer Drugs in River Waters and Sediments of the Yodo River Basin, Japan

This article reviews the pollution status of anticancer drugs present in the Yodo River basin located in the Kansai district of Japan, covering both the soluble and insoluble (adsorbed on the river sediments and suspended solids) levels. Procedures ranging from sampling in the field and instrumental analytical methods to the data processing for mass balance estimation of the target basin are also described. All anticancer drugs concerned with this article were detected in sewage and river waters, where the presence of bicalutamide (BLT) was identified at considerably high concentrations (maximum 254 ng/L in the main stream, 151 ng/L in tributaries, and 1032 ng/L in sewage treatment plant (STP) effluents). In addition, sorption distribution coefficient (logKd) values showed a tendency to become higher in the silty sediments at Suita Bridge than in the sandy sediments at Hirakata Bridge; these trends were supported by the results of the laboratory-scale sorption experiment. STPs were concluded to be the main sources of the anticancer drug load in the river, and a mass flux evaluation revealed that the effect of attenuation in the river environment was small. The effectiveness of ozonation in the sewage treatment process for removal of these anticancer drugs was further confirmed. The present article should be of value for facilitating the environmental risk assessment of a wide range of drugs in a broader geographical area.

Analysis of the biodegradation of synthetic testosterone and 17α-ethynylestradiol using the edible mushroom Lentinula edodes

The mycelium of Lentinula edodes produces enzymes which may degrade xenobiotics including steroid hormones. The aim of the study was to determine whether the mycelium from in vitro cultures of L. edodes are able to degrade endocrine disruptors such as testosterone and 17α-ethynylestradiol. To prove the possibility of xenobiotics degradation, cultures of L. edodes were cultivated in an Oddoux liquid medium with the addition of synthetic 17α-ethynylestradiol and synthetic testosterone. The endocrine disruptors were extracted from the mycelium and determined qualitatively by RP-HPLC. The degradation products of testosterone and 17α-ethynylestradiol were identified using a UPLC/MS/MS analysis. Undegraded testosterone was determined at the amount of 2.97 mg/g dry weight but only in one of the L. edodes extracts from in vitro cultures supplemented with 50 mg of this compound. In turn, 17α-ethynylestradiol was not determined in any samples. Additionally in all extracts, mushroom sterols (ergosterol peroxide and ergosterol) were determined. Their total amounts were significantly lower in samples containing the abovementioned steroids than in extracts from mycelium L. edodes without the addition of steroid hormones. The results demonstrated that the mycelium of L. edodes can be used in the biodegradation process of a water environment contaminated with endocrine disruptors.

Applying analytical decision methods for determination of the best treatment alternative to remove emerging micropollutants from drinking water and wastewater: triclosan example

Increasing human activities have not only substantially altered the natural material cycle but also created new synthetic chemicals flows. Some of these chemicals, which are described as micropollutants (MPs), may result in adverse effects on human health, aquatic organisms, and ecosystems. MPs can be transported to the environment and water resources in a variety ways including domestic and industrial wastewater. Unfortunately, most MPs are only partially removed in existing conventional treatment plants. Therefore, conventional treatment plants should be modernized by advanced treatment technologies to protect the environment and human health. However, there are various mysteries about best treatment techniques, evaluation criteria, and decision-making methods. In this study, it was aimed to determine the best treatment alternatives for triclosan (TCS) which is one of the priority MPs. A total of 18 evaluation criteria were identified and prioritized by employing analytical hierarchy process (AHP) and entropy methods. Treatment alternatives were identified and their performance was assessed through a comprehensive literature investigation. In decision-making processes of determining these alternatives, "technique for order preference by similarity to ideal solution (TOPSIS)," "preference ranking organization method for enrichment evaluation (PROMETHEE)," and "Višekriterijumsko kompromisno rangiranje (VIKOR)" analytical decision-making methods were employed, and priority rankings were determined according to each decision method. The final priority ranking was found as adsorption > membrane filtration > hybrid processes > advanced oxidation processes > constructed wetlands > conventional treatment processes > biological treatment > other treatment processes. Although the obtained results are specific to TCS, the employed analytical decision methods can be also used to decide the best treatment alternatives for other MPs.

Transport of trace organic compounds through novel forward osmosis membranes: Role of membrane properties and the draw solution

Forward osmosis (FO) offers to be a very promising technology for the removal of trace organic compounds (TrOCs) from contaminated wastewater, and with the recent developments in FO membranes, the effect of both a higher water flux and reverse salt flux on the rejection of TrOCs needs to be explored. In this study two novel thin-film composite (TFC) membranes with greater water permeability and selectivity than the benchmark cellulose tri-acetate (CTA) membrane were compared at bench-scale in terms of TrOCs permeability. By probing the solute-membrane interactions that dictate the transport of TrOCs through the two membranes in the absence and presence of a draw solution, several conclusions were drawn. Firstly, steric hindrance is the main TrOCs transport -limiting mechanism through TFC membranes unless the negative membrane surface charge is significant, in which case, electrostatic interactions can dominate over steric hindrance. Secondly, the increase in ionic strength induced by the draw solution in the vicinity of and perhaps inside the membrane seems to favour the rejection of TrOCs by "shrinking" the membrane pores or by "shielding" the negative surface charge. Lastly, during FO operation, solute concentration polarisation becomes detrimental when working at high water fluxes, whereas the reverse solute flux has no direct impact on the transport of TrOCs through the membrane.

Removal of pharmaceutical compounds in water and wastewater using fungal oxidoreductase enzymes

Due to recalcitrance of some pharmaceutically active compounds (PhACs), conventional wastewater treatment is not able to remove them effectively. Therefore, their occurrence in surface water and potential environmental impact has raised serious global concern. Biological transformation of these contaminants using white-rot fungi (WRF) and their oxidoreductase enzymes has been proposed as a low cost and environmentally friendly solution for water treatment. The removal performance of PhACs by a fungal culture is dependent on several factors, such as fungal species, the secreted enzymes, molecular structure of target compounds, culture medium composition, etc. In recent 20 years, numerous researchers tried to elucidate the removal mechanisms and the effects of important operational parameters such as temperature and pH on the enzymatic treatment of PhACs. This review summarizes and analyzes the studies performed on PhACs removal from spiked pure water and real wastewaters using oxidoreductase enzymes and the data related to degradation efficiencies of the most studied compounds. The review also offers an insight into enzymes immobilization, fungal reactors, mediators, degradation mechanisms and transformation products (TPs) of PhACs. In brief, higher hydrophobicity and having electron-donating groups, such as amine and hydroxyl in molecular structure leads to more effective degradation of PhACs by fungal cultures. For recalcitrant compounds, using redox mediators, such as syringaldehyde increases the degradation efficiency, however they may cause toxicity in the effluent and deactivate the enzyme. Immobilization of enzymes on supports can enhance the performance of enzyme in terms of reusability and stability. However, the immobilization strategy should be carefully selected to reduce the cost and enable regeneration. Still, further studies are needed to elucidate the mechanisms involved in enzymatic degradation and the toxicity levels of TPs and also to optimize the whole treatment strategy to have economical and technical competitiveness.

Removal of emerging pharmaceutical contaminants by adsorption in a fixed-bed column: A review

Pharmaceutical pollutants substantially affect the environment; thus, their treatments have been the focus of many studies. In this article, the fixed-bed adsorption of pharmaceuticals on various adsorbents was reviewed. The experimental breakthrough curves of these pollutants under various flow rates, inlet concentrations, and bed heights were examined. Fixed-bed data in terms of saturation uptakes, breakthrough time, and the length of the mass transfer zone were included. The three most popular breakthrough models, namely, Adams-Bohart, Thomas, and Yoon-Nelson, were also reviewed for the correlation of breakthrough curve data along with the evaluation of model parameters. Compared with the Adams-Bohart model, the Thomas and Yoon-Nelson more effectively predicted the breakthrough data for the studied pollutants.

Decomposition of ibuprofen in water via an electrochemical process with nano-sized carbon black-coated carbon cloth as oxygen-permeable cathode integrated with ultrasound

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 H₂O₂ and consequently, improved the degradation of IBP in the solution. Excessive concentrations of Na₂SO₄ 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.

Stropharia rugosoannulata and Gymnopilus luteofolius: Promising fungal species for pharmaceutical biodegradation in contaminated water

Pharmaceuticals are environmental micropollutants that pose an emerging challenge because they are poorly eliminated in conventional wastewater treatment plants. Over the last decade, many attempts have been made to solve this problem, and wastewater fungal treatment is a promising alternative. In this study, six different ligninolytic fungi (Trametes versicolor, Ganoderma lucidum, Irpex lacteus, Stropharia rugosoannulata, Gymnopilus luteofolius and Agrocybe erebia) were studied as bioremediation candidates for the removal and degradation of six recalcitrant pharmaceutical micropollutants: Carbamazepine (CBZ), Venlafaxine (VFX), Iopromide (IPD), Diclofenac (DCF), Cyclophosphamide (CFD) and Ifosfamide (IFD). Self-immobilization in a pellet shape was achieved for all fungal mycelia (which was the first time that this was reported for S. rugosoannulata, G. luteofolius, and A. erebia). Biodegradation achievement was greater than 90% for IPD with G. luteofolius and greater than 70% for CBZ with S. rugosoannulata, which suggests a great potential for this alternative biological treatment. Besides, this was the first report where fungal treatment achieved CFD and IFD removals greater than 20% for the treatment with T. versicolor, G. lucidum and S. rugosoannulata.

Degradation of chlortetracycline using immobilized laccase on Polyacrylonitrile-biochar composite nanofibrous membrane

The continuous release of antibiotic compounds through wastewater effluent into environment has raised concerns about their potential problems for different organisms. Enzymatic degradation with laccase is a green option for removal of pharmaceutical compounds from aqueous media. In this study, laccase was immobilized onto homemade Polyacrylonitrile-biochar composite nanofibrous membrane and the obtained biocatalyst was employed for removal of chlortetracycline, a widely used antibiotic, from aqueous media in continuous mode. The results showed that the immobilized laccase has improved storage, temperature and pH stability compared to free laccase. Also, it retained more than 50% of its initial activity after 7cycles of ABTS oxidation which indicated improved enzyme reusability. Finally, while using immobilized laccase for degradation of chlortetracycline in continuous mode exhibited 58.3%, 40.7% and 22.6% chlortetracycline removal efficiency at flux rates of 1, 2 and 3mL/h∙cm².

Bacterial diversity and population shifts driven by spotlight wastewater micropollutants in low-temperature highly nitrifying activated sludge

In this study the influence of low-temperature (8°C), sludge retention time (SRT) and loading of spotlight wastewater micropollutants (MPs) on bacterial community of activated sludge was investigated with a special focus on nitrification. Two Sequencing batch reactors (SBR) and two membrane bioreactors (MBR) were operated with synthetic municipal-like wastewater receiving and not receiving ibuprofen, diclofenac, estrone and 17α-ethynylestradiol (EE2). Bacterial population studies were related to removal efficiencies of studied MPs. The results showed that studied bacterial communities significantly differed from all previously published nitrifying activated sludge communities. Exceptionally low concentration of autotrophic nitrifying bacteria were found (<0.5%) as well as no common heterotrophic nitrifies were presenting in activated sludge and therefore could not be related to the MPs removal. Additionally SRT had a spacious effect on the diversity of bacteria and bacterial population shifts under pressure of MPs. Growth of Firmicutes was suppressed by presence of MPs in all the reactors. Increase of MPs concentrations in wastewater improved the removal of EE2. Abundance of Delta- and Gammaproteobacteria showed positive correlation with diclofenac removal.

Distribution of six anticancer drugs and a variety of other pharmaceuticals, and their sorption onto sediments, in an urban Japanese river

The distributions of 31 pharmaceuticals grouped into nine therapeutic classes, including six anticancer drugs, were investigated in the waters and sediments of an urban river in Japan. The coefficients of sorption (logK _d) to the river sediments were also determined from the results of a field survey and laboratory-scale experiment. Three anticancer drugs-bicalutamide, doxifluridine, and tamoxifen-were detected in the river sediments at maximum concentrations of 391, 392, and 250 ng/kg, respectively. In addition, the transformation products of psychotropic carbamazepine (2-hydroxy carbamazepine, acridine, and acridone) were detected in the range of 108 ng/kg (2-hydroxy carbamazepine) to 2365 ng/kg (acridine), and the phytoestrogen glycitein was detected in the range of N.D. to 821 ng/kg. The logK _d values of the targeted pharmaceuticals in river sediments in the field survey ranged from 0.5 (theophylline) to 3.3 (azithromycin). These results were in accord with those of the laboratory-scale sorption experiment. To the best of our knowledge, this is the first report of the detection of the anticancer drugs bicalutamide and tamoxifen, the transformation products of carbamazepine (2-hydroxy carbamazepine, acridine, and acridone), and the phytoestrogen genistein in river sediments.

Trend and current practices of palm oil mill effluent polishing: Application of advanced oxidation processes and their future perspectives

Palm oil processing is a multi-stage operation which generates large amount of effluent. On average, palm oil mill effluent (POME) may contain up to 51, 000 mg/L COD, 25,000 mg/L BOD, 40,000 TS and 6000 mg/L oil and grease. Due to its potential to cause environmental pollution, palm oil mills are required to treat the effluent prior to discharge. Biological treatments using open ponding system are widely used for POME treatment. Although these processes are capable of reducing the pollutant concentrations, they require long hydraulic retention time and large space, with the effluent frequently failing to satisfy the discharge regulation. Due to more stringent environmental regulations, research interest has recently shifted to the development of polishing technologies for the biologically-treated POME. Various technologies such as advanced oxidation processes, membrane technology, adsorption and coagulation have been investigated. Among these, advanced oxidation processes have shown potentials as polishing technologies for POME. This paper offers an overview on the POME polishing technologies, with particularly emphasis on advanced oxidation processes and their prospects for large scale applications. Although there are some challenges in large scale applications of these technologies, this review offers some perspectives that could help in overcoming these challenges.

Immobilized laccase on oxygen functionalized nanobiochars through mineral acids treatment for removal of carbamazepine

Biocatalytic treatment with oxidoreductase enzymes, especially laccases are an environmentally benign method for biodegradation of pharmaceutical compounds, such as carbamazepine to less harmful compounds. However, enzymes are required to be immobilized on supports to be reusable and maintain their activity. Functionalization of support prior to immobilization of enzyme is highly important because of biomolecule-support interface on enzyme activity and stability. In this work, the effect of oxidation of nanobiochar, a carbonaceous material produced by biomass pyrolysis, using HCl, H₂SO₄, HNO₃ and their mixtures on immobilization of laccase has been studied. Scanning electron microscopy indicated that the structure of nanobiochars remained intact after oxidation and Fourier transform infrared spectroscopy confirmed the formation of carboxylic groups because of acid treatment. Titration measurements showed that the sample treated with H₂SO₄/HNO₃ (50:50, v/v) had the highest number of carboxylic groups (4.7mmol/g) and consequently the highest efficiency for laccase immobilization. Additionally, it was observed that the storage, pH and thermal stability of immobilized laccase on functionalized nanobiochar was improved compared to free laccase showing its potential for continuous applications. The reusability tests towards oxidation of 2, 2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) showed that the immobilized laccase preserved 70% of the initial activity after 3cycles. Finally, using immobilized laccase for degradation of carbamazepine exhibited 83% and 86% removal in spiked water and secondary effluent, respectively.

Degradation of sulfamethazine using Fe3O4-Mn3O4/reduced graphene oxide hybrid as Fenton-like catalyst

In this paper, Fe₃O₄-Mn₃O₄/reduced graphene oxide (RGO) hybrid was synthesized through polyol process and impregnation method and used as heterogeneous Fenton-like catalyst for degradation of sulfamethazine (SMT) in aqueous solution. The hybrid catalyst had higher catalytic efficiency compared with Fe₃O₄-Mn₃O₄ and Mn₃O₄ as catalyst for degradation of SMT_. The effects of pH value, H₂O₂ concentration, catalyst dosage, initial SMT concentration and temperature on SMT degradation were investigated. The removal efficiency of SMT was about 98% at following optimal conditions: pH=3, T=35°C, Fe₃O₄/Mn₃O₄-RGO composites=0.5g/L, H₂O₂=6mM. The inhibitor experiments indicated that the main active species was hydroxyl radicals (·OH) on catalyst surface. At last, the possible catalytic mechanism was proposed.

Economic improvement of continuous pharmaceutical production via the optimal control of a multifeed bioreactor

Projections on the profitability of the pharmaceutical industry predict a large amount of growth in the coming years. Stagnation over the last 20 years in product development has led to the search for new processing methods to improve profitability by reducing operating costs or improving process productivity. This work proposes a novel multifeed bioreactor system composed of independently controlled feeds for substrate(s) and media used that allows for the free manipulation of the bioreactor supply rate and substrate concentrations to maximize bioreactor productivity and substrate utilization while reducing operating costs. The optimal operation of the multiple feeds is determined a priori as the solution of a dynamic optimization problem using the kinetic models describing the time-variant bioreactor concentrations as constraints. This new bioreactor paradigm is exemplified through the intracellular production of beta-carotene using a three feed bioreactor consisting of separate glucose, ethanol and media feeds. The performance of a traditional bioreator with a single substrate feed is compared to that of a bioreactor with multiple feeds using glucose and/or ethanol as substrate options. Results show up to a 30% reduction in the productivity with the addition of multiple feeds, though all three systems show an improvement in productivity when compared to batch production. Additionally, the breakeven selling price of beta-carotene is shown to decrease by at least 30% for the multifeed bioreactor when compared to the single feed counterpart, demonstrating the ability of the multifeed reactor to reduce operating costs in bioreactor systems. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:902-912, 2017.

Fenton-like degradation of sulfamethazine using Fe3O4/Mn3O4 nanocomposite catalyst: kinetics and catalytic mechanism

The kinetics and catalytic mechanism of sulfamethazine (SMT) degradation using Fe₃O₄/Mn₃O₄ nanocomposite as catalysts in heterogeneous Fenton-like process were investigated. The degradation process of SMT conformed to first-order kinetic model. The apparent activation energy (E _a ) of the process was calculated to be 40.5 kJ/mol. The reusability and stability of the catalysts were evaluated based on the results of the successive batch experiments. The intermediates were identified and quantified by ion chromatography (IC), high-performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC-MS). The results suggested that the bonds of S-C, N-C, and S-N were broken mainly by ·OH attack to form the organic compounds, which were gradually decomposed into small-molecule organic acids, such as oxalic acid, propionic acid, and formic acid. The possible catalytic mechanism for SMT degradation was tentatively proposed.

Incorporation of Graphene-Related Carbon Nanosheets in Membrane Fabrication for Water Treatment: A Review

The minimization of the trade-off between the flux and the selectivity of membranes is a key area that researchers are continually working to optimise, particularly in the area of fabrication of novel membranes. Flux versus selectivity issues apply in many industrial applications of membranes, for example the unwanted diffusion of methanol in fuel cells, retention of valuable proteins in downstream processing of biopharmaceuticals, rejection of organic matter and micro-organisms in water treatment, or salt permeation in desalination. The incorporation of nanosheets within membrane structures can potentially lead to enhancements in such properties as the antifouling ability, hydrophilicy and permeability of membranes, with concomitant improvements in the flux/selectivity balance. Graphene nanosheets and derivatives such as graphene oxide and reduced graphene oxide have been investigated for this purpose, for example inclusion of nanosheets within the active layer of Reverse Osmosis or Nanofiltration membranes or the blending of nanosheets as fillers within Ultrafiltration membranes. This review summarizes the incorporation of graphene derivatives into polymeric membranes for water treatment with a focus on a number of industrial applications, including desalination and pharmaceutical removal, where enhancement of productivity and reduction in fouling characteristics have been afforded by appropriate incorporation of graphene derived nanosheets during membrane fabrication.