Carbamazepine removal from wastewater and the degradation mechanism in a submerged forward osmotic membrane bioreactor

Elucidating the dynamics of carbamazepine uptake using date pit-derived activated carbon: A comprehensive kinetic and thermodynamic analysis

Water contamination with pharmaceuticals such as Carbamazepine (CBZ) presents a significant environmental challenge. This study investigates the use of activated carbon derived from waste date pits (DPAC) for the removal of CBZ from water. The impact of several parameters such as pH, temperature, CBZ concentration, and flow rate on the adsorption were assessed. The generated DPAC demonstrated a specific surface area of 309 m2/g, a pore volume of 0.264 cm³/g, and the pores are mainly distributed at 1.86, 2.73, and 3.43 nm. The Langmuir, Freundlich, Sips, and Toth isotherms were used to fit the experimental data, and the results indicate the occurrence of monolayer adsorption and heterogeneous surface conditions. The Linear Driving Force model was used for kinetic analysis, showing improved fit at higher concentrations. Thermodynamic analyses revealed the process to be endothermic, spontaneous, and entropically driven. The DPAC achieved an adsorption capacity of 14.89 mg/g and maintained 94 % effectiveness after the first regeneration cycle and 70 % after four cycles. This study highlights the potential of DPAC as a sustainable adsorbent for advanced water purification.

CuFeS2/GAC particle combined with electrochemical activation of persulfates for efficient degradation of carbamazepine

Electrochemically activated persulfate is a potential advanced oxidation process due to its advantages of environmental friendliness, high efficiency, and convenient operation. An Fe-Cu-S granular activated carbon (CuFeS2/GAC, abbreviated as FCSG) particles electrode was developed and applied to degrade carbamazepine (CBZ) combined with electrochemical activation of persulfate (E-PDS-FCSG) in this work. Compared to two-dimensional electrochemical process (E-PDS), the three-dimensional (3D) E-PDS-FCSG process exhibited higher removal efficiency of CBZ and lower energy consumption. The removal efficiency of CBZ and power consumption increased by 96% and reduced by 67%, respectively. Over 98% of CBZ removal rate was reached within 25 min. Apart from the same free radicals in two-dimensional electrochemical process, both Fe2+ and Cu+ on the surface of three-dimensional particle electrodes can directly activate PDS to produce SO4•-, and the existence of S2- strengthens the circulation of Fe3+/Fe2+ and Cu2+/Cu+. Furthermore, FCSG particle electrode can not only directly enhance the activation of PDS, but also accelerate the electron transfer, and then effectively promoting reactive species generation. LC-MS analysis showed that the main degradation pathways of CBZ involved decarbonylation, deamination, dealkylation, ring opening and mineralization. Moreover, after five cycle experiments, over 80% of CBZ removal rate could be achieved, demonstrating that the E-PDS-FCSG system had excellent electrocatalytic performance and good stability. These findings indicate that FCSG is a promising material and could be used as a particle electrode for removing organic pollutants from water.

Valorization and Upcycling of Acid Mine Drainage and Plastic Waste via the Preparation of Magnetic Sorbents for Adsorption of Emerging Contaminants

Plastic waste poses a serious environmental risk, but it can be recycled to produce a variety of nanomaterials for water treatment. In this study, poly(ethylene terephthalate) (PET) waste and acid mine drainage were used in the preparation of magnetic mesoporous carbon (MMC) nanocomposites for the adsorptive removal of pharmaceuticals and personal care products (PPCPs) from water samples. The latter were then characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), transmission electron microscopy (TEM), Brunauer-Emmett-Teller (BET), and ζ potential. The results of Brunauer-Emmett-Teller isotherms revealed high specific surface areas of 404, 664, and 936 m2/g with corresponding pore sizes 2.51, 2.28, and 2.26 nm for MMC, MMAC-25%, and MMAC-50% adsorbents, respectively. Under optimized conditions, the equilibrium studies were best described by the Langmuir and Freundlich models and kinetics by the pseudo-second-order model. The maximum adsorption capacity for monolayer adsorption from the Langmuir model was 112, 102, and 106 mg/g for acetaminophen, caffeine, and carbamazepine, respectively. The composites could be reused for up to six cycles without losing their adsorption efficiency. Furthermore, prepared adsorbents were used to remove acetaminophen, caffeine, and carbamazepine from wastewater samples, and up to a 95% removal efficiency was attained.

Elucidating distinct roles of chemical reduction and autotrophic denitrification driven by three iron-based materials in nitrate removal from low carbon-to-nitrogen ratio wastewater

Effective nitrate removal is a key challenge when treating low carbon-to-nitrogen ratio wastewater. How to select an effective inorganic electron donor to improve the autotrophic denitrification of nitrate nitrogen has become an area of intense research. In this study, the nitrate removal mechanism of three iron-based materials in the presence and absence of microorganisms was investigated with Fe2+/Fe0 as an electron donor and nitrate as an electron acceptor, and the relationship between the iron materials and denitrifying microorganisms was explored. The results indicated that the nitrogen removal efficiency of each iron-based material coupled sludge systems was higher than that of iron-based material. Furthermore, compared with the sponge iron coupled sludge system (60.6%-70.4%) and magnetite coupled sludge (56.1%-65.3%), the pyrite coupled sludge system had the highest removal efficiency of TN, and the removal efficiency increased from 62.5% to 82.1% with time. The test results of scanning electron microscope, X-ray photoelectron spectroscopy and X-ray diffraction indicated that iron-based materials promoted the attachment of microorganisms and the chemical reduction of nitrate in three iron-based material coupled sludge systems. Furthermore, the pyrite coupled sludge system had the highest nitrite reductase activity and can induce microorganisms to secrete more extracellular polymer substances. Combined with high-throughput sequencing and PICRUSt2 functional predictive analysis software, the total relative abundance of the dominant bacterial in pyrite coupled sludge system was the highest (72.06%) compared with the other iron-based material systems, and the abundance of Blastocatellaceae was relatively high. Overall, these results suggest that the pyrite coupled sludge system was more conducive to long-term stable nitrate removal.

Effect of zeolites on the reduction of the ecotoxicity of carbamazepine in the environment

In this study, the impact of calcination of zeolites on the ecotoxicity of carbamazepine solutions in two matrices, water and synthetic sewage, was assessed. Two types of zeolites were tested: natural zeolite, in the form of a zeolite rock consisting mainly of clinoptilolite, and a synthetic zeolite type 5 A. Additionally, zeolites were calcined at a temperature of 200 °C. The kinetics of carbamazepine adsorption in aqueous solutions and in synthetic sewage matrix was determined. Higher adsorption capacity was obtained for carbamazepine aqueous solutions as well as zeolites after the calcination process. Considering type of zeolite, the highest and fastest uptake of carbamazepine was observed for natural zeolite after calcination. In the case of ecotoxicity, carbamazepine solutions before adsorption was the most toxic towards Raphidocelis subcapitata, next Aliivibrio fischeri and Daphnia magna, regardless to the matrix type. The differentiation in toxicity regarding the type of matrix was observed, in the case of algae and bacteria, higher toxicity was demonstrated by carbamazepine solutions in the water matrix, while in the case of crustaceans-the sewage matrix. After the adsorption process, the toxicity of carbamazepine solutions on zeolites decreased by 34.5-60.9 % for R. subcapitata, 33-39 % for A. fischeri and 55-60 % for D. magna, thus confirming the effectiveness of the proposed method of carbamazepine immobilization.

Degradation of carbamazepine from wastewater by ultrasound-enhanced zero-valent iron -activated persulfate system (US/Fe0/PS): kinetics, intermediates and pathways

Carbamazepine (CBZ) is a common antiepileptic drug. CBZ enters the environment through unreasonable and standardized ways such as human and animal metabolites, discarded drugs, and more than half of its metabolites are released into the environment. Since CBZ is not easy to be degraded, continuous input of CBZ into the water environment will cause long-term impact on the water ecological environment and seriously endanger human health. Aiming at how to degrade wastewater containing carbamazepine, studies were conducted on the degradation of carbamazepine by ultrasound/zero-valent iron/persulfate system (US/F e 0 /PS). Firstly, the removal effects of carbamazepine by different systems, such as ultrasound/sodium persulfate (US/PS), zero-valent iron/persulfate system (F e 0 /PS) and US/F e 0 /PS, were compared; Secondly, the influence of factors, such as ultrasonic power, sodium persulfate dosage, zero-valent iron dosage, reaction temperature, pH, etc., on the reaction was investigated by the control variables method. Results show that ultrasound power, PS concentration, pH and temperature have a great influence on the removal of carbamazepine in US/Fe0/PS reaction system. Besides, the optimum parameters for degradation of carbamazepine with US/F e 0 /PS reaction system were determined ([CBZ]0 = 0.025 mM; [PS]0 = 0.4 mM; Fe0 = 4.0 mg/L; ultrasonic power = 40 W; T = 30 ℃; initial pH = 5.0). Finally, the intermediates and degradation pathways of carbamazepine by US/F e 0 /PS system were analyzed and speculated. It was inferred that two intermediates were generated during the degradation of carbamazepine, mainly through the ring opening and decyclization of piperazine rings. It was proved that process US/F e 0 /PS has a very important application value in the degradation of antibiotic-containing wastewater.

Hydroxylated transformation products of pharmaceutical active compounds: Generation from processes used in wastewater treatment plants and its environmental monitoring

Pharmaceutical active compounds (PhACs) are organic pollutants detected in wastewater and aquatic environments worldwide in concentrations ranging from ng L-1 to μg L-1. Wastewater effluents containing PhACs residues is discharged in municipal sewage and, subsequently collected in municipal wastewater treatment plants (WWTPs) where are not entirely removed. Thus, PhACs and its transformation products (TPs) are discharged into water bodies. In the current work, the transformation of PhACs under treatments used in municipal WWTPs such as biological, photolysis, chlorination, and ozonation processes was reviewed. Data set of the major transformation pathways were obtained of studies that performed the PhACs removal and TPs monitoring during batch-scale experiments using gas and liquid chromatography coupled with tandem mass spectrometry (GC/LC-MS/MS). Several transformation pathways as dealkylation, hydroxylation, oxidation, acetylation, aromatic ring opening, chlorination, dehalogenation, photo-substitution, and ozone attack reactions were identified during the transformation of PhACs. Especially, hydroxylation reaction was identified as transformation pathway in all the processes. During the elucidation of hydroxylated TPs several isobaric compounds as monohydroxylated and dihydroxylated were identified. However, hydroxylated TPs monitoring in wastewater and aquatic environments is a topic scarcely studied due to that has no environmental significance, lack of available analytic standars of hydroxylated TPs and lack of analytic methods for their identification. Thus, screening strategy for environmental monitoring of hydroxylated TPs was proposed through target and suspect screening using GC/LC-MS/MS systems. In the next years, more studies on the hydroxylated TPs monitoring are necessary for its detection in WWTPs effluents as well as studies on their environmental effects in aquatic environments.

A Comprehensive Analysis of the Impact of Inorganic Matter on Membrane Organic Fouling: A Mini Review

Membrane fouling is a non-negligible issue affecting the performance of membrane systems. Particularly, organic fouling is the most persistent and severe form of fouling. The complexation between inorganic and organic matter may exacerbate membrane organic fouling. This mini review systematically analyzes the role of inorganic matter in membrane organic fouling. Inorganic substances, such as metal ions and silica, can interact with organic foulants like humic acids, polysaccharides, and proteins through ionic bonding, hydrogen bonding, coordination, and van der Waals interactions. These interactions facilitate the formation of larger aggregates that exacerbate fouling, especially for reverse osmosis membranes. Molecular simulations using molecular dynamics (MD) and density functional theory (DFT) provide valuable mechanistic insights complementing fouling experiments. Polysaccharide fouling is mainly governed by transparent exopolymer particle (TEP) formations induced by inorganic ion bridging. Inorganic coagulants like aluminum and iron salts mitigate fouling for ultrafiltration but not reverse osmosis membranes. This review summarizes the effects of critical inorganic constituents on fouling by major organic foulants, providing an important reference for membrane fouling modeling and fouling control strategies.

Smart utilisation of reverse solute diffusion in forward osmosis for water treatment: A mini review

Forward osmosis (FO) has been widely studied as a promising technology in wastewater treatment, but undesirable reverse solute diffusion (RSD) is inevitable in the FO process. The RSD is generally regarded as a negative factor for the FO process, resulting in the loss of draw solutes and reduced FO efficiency. Conventional strategies to address RSD focus on reducing the amount of reverse draw solutes by fabricating high selective FO membranes and/or selecting the draw solute with low diffusion. However, since RSD is inevitable, doubts have been raised about the strategies to cope with the already occurring reverse draw solutes in the feed solution, and the feasibility to positively utilise the RSD phenomenon to improve the FO process. Herein, we review the state-of-the-art applications of RSD and their benefits such as improving selectivity and maintaining the stability of the feed solution for both independent FO processes and FO integrated processes. We also provide an outlook and discuss important considerations, including membrane fouling, membrane development and draw/feed solution properties, in RSD utilisation for water and wastewater treatment.

Occurrence of emerging contaminants in biosolids in northern Queensland, Australia

This study aims to identify and quantify different classes of emerging contaminants (ECs), such as pharmaceutical and personal care products (PPCPs), per-and polyfluoroalkyl substances (PFAS), heavy metals (HMs), polycyclic musks (PMs) in biosolids from different sewage treatment plants (STPs) from regional councils across Northern Queensland, Australia. Biosolids samples were named BS1 to BS7 for each council. The results revealed significant variations in the concentrations of different ECs in biosolids which could be explained in some instances by the characteristics of the upstream sewage network. For instance, BS4-biosolids from a small agricultural shire (largely sugarcane) showed the highest concentration of zinc and copper, which were 2430 and 1050 mg/kg, respectively. Among PPCPs, the concentration of ciprofloxacin was found to be the highest in BS3 and BS5, two large regional council areas which are a mix of domestic and industrial (predominantly domestic) biosolids of 1010 and 1590 ng/g, respectively. In addition, the quantity of sertraline was consistently high in all biosolids except from BS7, one of the smaller regional councils, which is indicative of the domestic catchments attached. PFAS compounds were detected in all biosolids samples except in BS6, one of the small (agricultural and tourist) catchments. Two PFAS compounds emerged as the most common pollutants that were perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS). The largest industrial catchment biosolids, BS2 showed the highest concentration of PFOS at 253 ng/g, while the smallest regional council, BS7 showed the maximum concentration of 7.90 ng/g of PFOA. Overall, this study concludes that certain ECs such as HMs, antibiotics, PFOS and PFOA in biosolids may pose high environmental risks.

Fate and removal of iodinated X-ray contrast media in membrane bioreactor: Microbial dynamics and effects of different operational parameters

Iodinated X-ray contrast media (ICM) are mainly used in medical sector, and their presence in environmental waters is a cause of concern as they are capable of forming highly toxic iodinated disinfection byproducts. In the present study, the removal mechanisms of the three ICM- iohexol, iopromide, and iopamidol were elucidated in a lab-scale aerobic membrane bioreactor (MBR). At steady-state operation (solids retention time (SRT)- 70 days, organic loading rate (OLR)- 0.80 KgCOD/m³-day, nitrogen loading rate (NLR)- 0.08 KgNH₄-N/m³-day, hydraulic retention time (HRT)- 12 h), the average removal of iohexol and iopromide was found to be 34.9 and 45.2 %, respectively, whereas iopamidol proved to be highly recalcitrant in aerobic conditions of the MBR (removal <10 % in all phases of the MBR operation). Further, through batch kinetic studies and mass balance analysis, it was observed that ICM were primarily biotransformed in the MBR system and biosorption (K_d < 10 L/Kg) was negligible. The biodegradation rate coefficient values (K_biol) of the ICM were found to be <0.65 L/g-d which indicate that biotransformation rate of ICM was slow. Increased OLR (1.60 KgCOD/m³-day) and reduced SRT (20 days) were found to negatively affect the removal of the ICM. Further, the removal of ICM was found to depend on its initial concentration, and the increment in the ammonium loading (0.16 KgNH₄-N/m³-day) did not favor its removal. The dosing of ICM altered the microbial dynamics of the mixed liquor and reduced the microbial diversity and richness. Bdellovibrio, Zoogloea, and bacteria belonging to TM7-3 class, Cryomorphaceae and Hyphomonadaceae families may contribute in ICM biotransformation.

Enhanced biodegradation of fluoroquinolones and the changes of bacterial communities and antibiotic-resistant genes under intermittent electrical stimulation

In this study, an anaerobic-aerobic coupling system under intermittent electrical stimulation was used to improve the biodegradation of synthetic wastewater containing fluoroquinolones (FQs). The effect of electrical stimulation on FQ removal performance is more pronounced with appropriate voltage and hydraulic retention time. In addition, the combination of anaerobic-anodic and aerobic-cathodic chambers is more conducive to improving the removal efficiency of FQs. Under 0.9 V, the removal efficiencies of ofloxacin, norfloxacin, ciprofloxacin, and enrofloxacin were significantly improved in the anaerobic-anodic and aerobic-cathodic system. The contribution of the anaerobic/aerobic anodic chambers to FQ removal was greater than that of the anaerobic/aerobic cathodic chambers. Electrical stimulation selectively enriched electroactive bacteria related to biodegradation (Desulfovibrio and Terrimonas), antibiotic-resistant bacteria (Atopobium and Neochlamydia), and nitrifying bacteria (SM1A02 and Reyranella). This study indicated the potential effectiveness of intermittent electrical stimulation in treating fluoroquinolone-containing wastewater in a biofilm reactor. However, electrical stimulation led to an increase in mobile genetic elements , induced horizontal gene transfer and enriched resistant bacteria, which accelerated the spread of antibiotic-resistant genes (ARGs) in the system, indicating that the diffusion of ARGs remains a challenge.

Treatment Trends and Combined Methods in Removing Pharmaceuticals and Personal Care Products from Wastewater-A Review

When discharged into wastewater, pharmaceuticals and personal care products (PPCPs) become microorganic contaminants and are among the largest groups of emerging pollutants. Human, animal, and aquatic organisms' exposures to PPCPs have linked them to an array of carcinogenic, mutagenic, and reproductive toxicity risks. For this reason, various methods are being implemented to remove them from water bodies. This report critically reviews these methods and suggests improvements to removal strategies. Biological, physical, and chemical methods such as biological degradation, adsorption, membrane filtration, and advanced electrical and chemical oxidation are the common methods used. However, these processes were not integrated into most studies to take advantage of the different mechanisms specific to each process and are synergistic in the removal of the PPCPs that differ in their physical and chemical characteristics (charge, molecular weight, hydrophobicity, hydrogen bonding, structure). In the review articles published to date, very little information is available on the use of such integrated methods for removing PPCPs. This report attempts to fill this gap with our knowledge.

Electrochemical-enhanced Fe3O4/biochar activates peroxymonosulfate (E/nano-Fe3O4/BC/PMS) for degradation of oxytetracycline

To find cost-effective and environmentally friendly free radical activators to stimulate peroxymonosulfate (PMS) oxidative degradation of organic pollutants, nano-Fe₃O₄/biochar (BC) composites were prepared and characterized in this work to examine their effectiveness in stimulating PMS oxidative degradation of Oxytetracycline (OTC) in water enhanced with electrochemical degradation. When the mass ratio of nano-Fe₃O₄ to BC is 1:1, the catalyst nano-Fe₃O₄/BC exhibits the most obvious degradation effect on OTC. After 4 h of degradation, the OTC concentrations were reduced from 20 to 2.65 mg L^-1, while treated with a single nano-Fe₃O₄ and a single BC are reduced by only 67.7% and 61.8%. Anions HCO₃^- and H₂PO₄^- significantly inhibit OTC degradation, and HCO₃^- has a stronger inhibitory effect than H₂PO₄^-, while Cl^- and NO₃^- can promote OTC degradation. Quenching test and electron spin paramagnetic resonance (EPR) detection showed that singlet oxygen (¹O₂) was the main active species in the degradation process, followed by hydroxyl radical (·OH). When reused for the third time, the removal rate of OTC by nano-Fe₃O₄/BC composites with mass ratios of 1:4, 1:2 and 1:1 was still more than 70%. Therefore, the nano-Fe₃O₄/BC composite is a promising PMS activator, which can realize the rapid oxidative degradation of OTC.

Impact of Voltage Application on Degradation of Biorefractory Pharmaceuticals in an Anaerobic-Aerobic Coupled Upflow Bioelectrochemical Reactor

Diclofenac, ibuprofen, and carbamazepine are frequently detected in the environment, where they pose a threat to organisms and ecosystems. We developed anaerobic-aerobic coupled upflow bioelectrochemical reactors (AO-UBERs) with different voltages, hydraulic retention times (HRTs), and types of electrode conversion, and evaluated the ability of the AO-UBERs to remove the three pharmaceuticals. This study showed that when a voltage of 0.6 V was applied, the removal rate of ibuprofen was slightly higher in the system with aerobic cathodic and anaerobic anodic chambers (60.2 ± 11.0%) with HRT of 48 h than in the control systems, and the removal efficiency reached stability faster. Diclofenac removal was 100% in the 1.2 V system with aerobic anodic and anaerobic cathodic chambers, which was greater than in the control system (65.5 ± 2.0%). The contribution of the aerobic cathodic-anodic chambers to the removal of ibuprofen and diclofenac was higher than that of the anaerobic cathodic-anodic chambers. Electrical stimulation barely facilitated the attenuation of carbamazepine. Furthermore, biodegradation-related species (Methyloversatilis, SM1A02, Sporomusa, and Terrimicrobium) were enriched in the AO-UBERs, enhancing pharmaceutical removal. The current study sheds fresh light on the interactions of bacterial populations with the removal of pharmaceuticals in a coupled system.

Electron donor addition for stimulating the microbial degradation of 1,4 dioxane by sequential batch membrane bioreactor: A techno-economic approach

The presence of 1,4 dioxane in wastewater is associated with severe health and environmental issues. The removal of this toxic contaminant from the industrial effluents prior to final disposal is necessary. The study comprehensively evaluates the performance of sequential batch membrane bioreactor (MBR) for treating wastewater laden with 1,4 dioxane. Acetate was supplemented to the wastewater feed as an electron donor for enhancing and stimulating the microbial growing activities towards the degradation of 1,4 dioxane. The removal efficiency of 1,4 dioxane was maximized to 87.5 ± 6.8% using an acetate to dioxane (A/D) ratio of 4.0, which was substantially dropped to 31.06 ± 3.7% without acetate addition. Ethylene glycol, glyoxylic acid, glycolic acid, and oxalic acid were the main metabolites of 1,4 dioxane biodegradation using mixed culture bacteria. The 1,4 dioxane degrading bacteria, particularly the genus of Acinetobacter, were promoted to 92% at the A/D ratio of 4.0. This condition encouraged as well the increase of the main 1,4 dioxane degraders, i.e., Xanthomonadales (12.5%) and Pseudomonadales (9.1%). However, 50% of the Sphingobacteriales and 82.5% of Planctomycetes were reduced due to the inhibition effect of the 1,4 dioxane contaminate. Similarly, the relative abundance of Firmicutes, Verrucomicrobia, Chlamydiae, Actinobacteria, Chloroflexi, and Nitrospirae was reduced in the MBR at the A/D ratio of 4.0. The results derived from the microbial analysis and metabolites detection at different A/D ratios indicated that acetate supplementation (as an electron donor) maintained an essential role in encouraging the microorganisms to produce the monooxygenase enzymes responsible for the biodegradation process. Economic feasibility of such a MBR system showed that for a designed flow rate of 30 m³∙d^-1, the payback period from reusing the treated wastewater would reach 6.6 yr. The results strongly recommend the utilization of mixed culture bacteria growing on acetate for removing 1,4 dioxane from the wastewater industry, achieving dual environmental and economic benefits.

Enhancement of the immobilization on microalgae protective effects and carbamazepine removal by Chlorella vulgaris

Carbamazepine (CBZ) has drawn extensive attention due to their environmental threats. In this study, polyvinyl alcohol-sodium alginate polymers to immobilize Chlorella vulgaris (FACHB-8) were used to investigate whether immobilization can facilitate microalgae to alleviate the CBZ stress and enhance CBZ removal. The results showed that after immobilized treatment, the biomass of microalgae increased by approximately 20%, the maximum level of malondialdehyde content decreased from 28 to 13 μmol/g, and the photosynthetic capacity of F_V/F_M recovered to 90% of the control group. The CBZ removal rate increased from 67 to 84% by immobilization at a CBZ concentration of 80 mg·L^-1. The results indicated that immobilization technology can effectively protect microalgae from CBZ toxicity and improve the removal of CBZ, especially at high concentrations (> 50 mg/L). Biodegradation was the dominant pathway for microalgae to remove carbamazepine. This study added the understanding of the microalgae responses under immobilization and the interactions between immobilized microalgae and CBZ removal, thereby providing a novel insight into microalgae technology in high concentration wastewater treatments.

Improving biological removal of pharmaceutical active compounds and estrogenic activity in a mesophilic anaerobic osmotic membrane bioreactor treating municipal sewage

The contamination of water sources by pharmaceutically active compounds (PhACs) and their effect on aquatic communities and human health have become an environmental concern worldwide. Membrane bioreactors (MBRs) are an alternative to improve biological removal of recalcitrant organic compounds from municipal sewage. Their efficiency can be increased by using high retention membranes such as forward osmosis (FO) and membrane distillation (MD). Thus, this research aimed to evaluate the performance of an anaerobic osmotic MBR coupled with MD (OMBR-MD) in the treatment of municipal sewage containing PhACs and estrogenic activity. A submerged hybrid FO-MD module was integrated into the bioreactor. PhACs removal was higher than 96% due to biological degradation, biosorption and membrane retention. Biological removal of the PhACs was affected by the salinity build-up in the bioreactor, with reduction in biodegradation after 32 d. However, salinity increment had little or no effect on biosorption removal. The anaerobic OMBR-MD removed >99.9% of estrogenic activity, resulting in a distillate with 0.14 ng L^-1 E2-eq, after 22 d, and 0.04 ng L^-1 E2-eq, after 32 d. OMBR-MD treatment promoted reduction in environmental and human health risks from high to low, except for ketoprofen, which led to medium acute environmental and human health risks. Carcinogenic risks were reduced from unacceptable to negligible, regarding estrogenic activity. Thus, the hybrid anaerobic OMBR-MD demonstrated strong performance in reducing risks, even when human health is considered.

Fate, elimination, and simulation of low-molecular-weight micropollutants in an integrated activated carbon-fertiliser drawn osmotic membrane bioreactor

This study investigated the behaviour and simulation of low-molecular-weight (low-MW) micropollutants (MPs) in a powdered activated carbon (PAC)-assisted fertiliser-drawn OMBR. 10% increase in water recovery and two times thinner fouling layer were observed in OMBR with addition of 100 mg-PAC/g-MLSS. This amount of PAC also boosted the richness and diversity in microbial community (Chao1 and Shannon index increased 1.5 times). Nearly 100% low-MW MPs were eliminated in PAC-OMBR, while 2-80% was achieved with traditional OMBR. This reduced the pathway of low-MW MPs into diluted fertiliser from 47% to < 1% of the total influent mass. Hydrophilicity played the crucial role in the removal of low-MW MPs, especially acetaminophen and nonylphenol. Neural network was suitable for the simulation of MP behaviour with high accuracy (R = 0.98, RMSE = 4.7%). The findings support safer and cleaner use of the diluted fertiliser and promote a cost-effective tool for real-time analysis of MP behaviour.

Individual and synergic effect of carbamazepine and diclofenac in the removal of organic matter from an expanded granular bed anaerobic reactor

Due to the negative effects caused to the natural environment by the presence of pharmaceutical-type traces and other pollutants in wastewater, it is necessary to develop and optimize efficient treatment systems. This study evaluated the effect of carbamazepine (CBZ) and diclofenac (DCF) on the behavior of seven EGSB (expanded granular sludge bed) anaerobic reactors at laboratory scale, using chromatographic and physicochemical analyses of the influent, effluent, and the biomass contained in the reactors. The results showed that CBZ had a greater effect on the removal and behavior of microorganisms than DCF, with average efficiencies of 34.04 ± 18.58%, 20.76 ± 8.51% and 16.29 ± 11.08% during stage II, III and IV, respectively, for CBZ, and 92.37 ± 12.74%, 26.77 ± 5.90% and 22.28 ± 9.60% during stage II, III and IV, respectively, for DCF. Additionally, it was found that the interaction of the co-substrate used (sodium acetate) in conjunction with the pharmaceutical compounds decreased the efficiency of the system in terms of the removal of analytes.

The effect of temperature and styrene concentration on biogas production and degradation characteristics during anaerobic removal of styrene from wastewater

In the current study, styrene was removed anaerobically from wastewaters at temperatures of 35 ℃, 25 ℃, and 15 ℃ and concentration range of 20-150 ppm in the presence of ethanol as a co-substrate and co-solvent. Maximum styrene removal of 93% was achieved at 35 ℃. The volatilization of styrene was negligible at about 2% at all experimented temperatures. The average special methane yield (SMY) at 35 ℃ was 4.14- and 225-times higher than that of at T = 25 ℃ and T = 15 ℃, respectively, but no methane was produced in the absence of ethanol. The proteins content of the soluble microbial product (SMP) and extracellular polymeric substance (EPS) was much higher than the carbohydrate content. At styrene concentration > 80 ppm, SMY, SMP, and EPS dropped sharply. The results confirmed the well performance of anaerobic microorganisms in removing styrene from wastewater and biogas production at mesophilic condition.

A breakthrough dynamic-osmotic membrane bioreactor/nanofiltration hybrid system for real municipal wastewater treatment and reuse

This study designed a Dynamic-Osmotic membrane bioreactor/nanofiltration (OsMBR/NF) system for municipal wastewater treatment and reuse. Results indicated that a continuously rotating FO module with 60 RPM in Dynamic-OsMBR system could enhance shear stress and reduce cake layer of foulants, leading to higher flux (50%) compared to Traditional-OsMBR during a 40-operation day. A negligible specific reverse salt flux (0.059 G/L) and a water flux of 2.86 LMH were recorded when a mixture of 0.1 M EDTA-2Na/0.1 M Na₂CO₃/0.9 mM Triton114 functioned as draw solution (DS). It was found that the Dynamic-OsMBR/NF hybrid system could effectively remove pollutants (∼98% COD, ∼99% PO₄^3-P, ∼93% NH₄⁺-N, > 99% suspended solids) from wastewater. In short, this developed system can be considered a breakthrough technology as it successfully minimizes membrane fouling by shear force, and achieves high water quality for reuse by two membrane- barriers.

A Review on the Removal of Carbamazepine from Aqueous Solution by Using Activated Carbon and Biochar

Carbamazepine (CBZ), one of the most used pharmaceuticals worldwide and a Contaminant of Emerging Concern, represents a potential risk for the environment and human health. Wastewater treatment plants (WWTPs) are a significant source of CBZ to the environment, polluting the whole water cycle. In this review, the CBZ presence and fate in the urban water cycle are addressed, with a focus on adsorption as a possible solution for its removal. Specifically, the scientific literature on CBZ removal by activated carbon and its possible substitute Biochar, is comprehensively scanned and summed up, in view of increasing the circularity in water treatments. CBZ adsorption onto activated carbon and biochar is analyzed considering several aspects, such as physicochemical characteristics of the adsorbents, operational conditions of the adsorption processes and adsorption kinetics and isotherms models. WWTPs usually show almost no removal of CBZ (even negative), whereas removal is witnessed in drinking water treatment plants through advanced treatments (even >90%). Among these, adsorption is considered one of the preferable methods, being economical and easier to operate. Adsorption capacity of CBZ is influenced by the characteristics of the adsorbent precursors, pyrolysis temperature and modification or activation processes. Among operational conditions, pH shows low influence on the process, as CBZ has no charge in most pH ranges. Differently, increasing temperature and rotational speed favor the adsorption of CBZ. The presence of other micro-contaminants and organic matter decreases the CBZ adsorption due to competition effects. These results, however, concern mainly laboratory-scale studies, hence, full-scale investigations are recommended to take into account the complexity of the real conditions.

Synergistic effect of sonication on photocatalytic oxidation of pharmaceutical drug carbamazepine

Photocatalytic, sono-photocatalytic oxidation of pharmaceutical drug of carbamazepine was successfully carried out using Ag/AgCl supported BiVO4 catalyst. For this purpose, firstly, photocatalytic oxidation was optimized by central composite design methodology and then synergistic effect of sonication was investigated. Low frequency (20 kHz) probe type and high frequency (850 kHz) plate type sonication at pulse and continuous mode were studied to degrade the carbamazepine (CBZ) containing wastewater. Pulse duties of 1:5 and 5:1 (on : off) were tested using the high frequency sonication system in the sono-photocatalytic oxidation of CBZ. The effects of frequency, power density measured from calorimetry by changing amplitudes were discussed in the sono-photocatalytic oxidation of CBZ. Complete carbamazepine removal was achieved at the optimum conditions of 5 ppm CBZ initial concentration with 1.5 g/L of catalysts loading and at an alkaline pH of 10 at the end of 4 h of photocatalytic reaction under visible LED light irradiation. Both low frequency and high frequency sonication systems caused an increase in photocatalytic efficiency in a shorter treatment time of 60 min. CBZ removal increased from 44% to 65.42% in low frequency sonication of 20 kHz at the amplitude of 20% (0.15 W/mL power density). In the case of high frequency ultrasonic system (850 kHz), CBZ removal increased significantly from 44% to 89.5 % at 75% amplitude (0.12 W/mL power density) within 60 min of reaction. Continuous mode sonication was observed to be more effective than that of pulse mode sonication not only for degradation efficiency and also for electrical energy consumption needed to degrade CBZ. Sono-catalytic oxidation was also conducted with simulated wastewater that contains SO42-, CO32-, NO3-, Cl- anions and natural organic component of fulvic acid. The CBZ degradation was inhibited slightly in the presence of NO3- and Cl-, and fulvic acid, however, the existence of SO42- and CO32- increased the degradation degree of CBZ. Toxicity tests were performed to determine the toxicity of untreated CBZ, and treated CBZ by photocatalytic, and sono-photocatalytic oxidations.

Progress in osmotic membrane bioreactors research: Contaminant removal, microbial community and bioenergy production in wastewater

Renewable energy, water conservation, and environmental protection are the most important challenges today. Osmotic membrane bioreactor (OMBR) is an innovative process showing superior performance in bioenergy production, eliminating contaminants, and low fouling tendency. However, salinity build-up is the main drawback of this process. Identifying the microbial community can improve the process in bioenergy production and contaminant treatment. This review aims to study the recent progress and challenges of OMBRs in contaminant removal, microbial communities and bioenergy production. OMBRs are widely reported to remove over 80% of total organic carbon, PO₄^3-, NH₄⁺ and emerging contaminants from wastewater. The most important microbial phyla for both hydrogen and methane production in OMBR are Firmicutes, Proteobacteria and Bacteroidetes. Firmicutes' dominance in anaerobic processes is considerably increased from usually 20% at the beginning to 80% under stable condition. Overall, OMBR process has great potential to be applied for simultaneous bioenergy production and wastewater treatment.

State-of-the-Art and Opportunities for Forward Osmosis in Sewage Concentration and Wastewater Treatment

The application of membrane technologies for wastewater treatment to recover water and nutrients from different types of wastewater can be an effective strategy to mitigate the water shortage and provide resource recovery for sustainable development of industrialisation and urbanisation. Forward osmosis (FO), driven by the osmotic pressure difference between solutions divided by a semi-permeable membrane, has been recognised as a potential energy-efficient filtration process with a low tendency for fouling and a strong ability to filtrate highly polluted wastewater. The application of FO for wastewater treatment has received significant attention in research and attracted technological effort in recent years. In this review, we review the state-of-the-art application of FO technology for sewage concentration and wastewater treatment both as an independent treatment process and in combination with other treatment processes. We also provide an outlook of the future prospects and recommendations for the improvement of membrane performance, fouling control and system optimisation from the perspectives of membrane materials, operating condition optimisation, draw solution selection, and multiple technologies combination.

Biodegradation of Emerging Pharmaceuticals from Domestic Wastewater by Membrane Bioreactor: The Effect of Solid Retention Time

Although conventional biological treatment plants can remove basic pollutants, they are ineffective at removing recalcitrant pollutants. Membrane bioreactors contain promising technology and have the advantages of better effluent quality and lower sludge production compared to those of conventional biological treatment processes. In this study, the removal of pharmaceutical compounds by membrane bioreactors under different solid retention times (SRTs) was investigated. To study the effect of SRT on the removal of emerging pharmaceuticals, the levels of pharmaceuticals were measured over 96 days for the following retention times: 20, 30, and 40-day SRT. It was found that the 40-day SRT had the optimum performance in terms of the pharmaceuticals’ elimination. The removal efficiencies of the chemical oxygen demand (COD) for each selected SRT were higher than 96% at steady-state conditions. The highest degradation efficiency was observed for paracetamol. Paracetamol was the most removed compound followed by ranitidine, atenolol, bezafibrate, diclofenac, and carbamazepine. The microbial community at the phylum level was also analyzed to understand the biodegradability of pharmaceuticals. It was noticed that the Proteobacteria phylum increased from 46.8% to 60.0% after 96 days with the pharmaceuticals. The Actinobacteria class, which can metabolize paracetamol, carbamazepine, and atenolol, was also increased from 9.1% to 17.9% after adding pharmaceuticals. The by-products of diclofenac, bezafibrate, and carbamazepine were observed in the effluent samples.

Degradation mechanism of Ibuprofen via a forward osmosis membrane bioreactor

Ibuprofen (IBU) is a non-steroidal drug that is classified as a trace organic compound (TrOC). A forward osmosis membrane bioreactor (FOMBR) has traditionally been a favored technology for wastewater treatment. In this study, the IBU degradation mechanism was clarified using an FOMBR. The results indicated that the average removal efficiencies of contaminants were greater than 96.32%. The ultra-performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOF-MS) results demonstrated that there were 10 intermediates and 5 possible pathways during the IBU degradation. Decarboxylation and hydroxylation may be the primary pathways of IBU degradation. The microbial results illustrated that Proteobacteria was dominant and of utmost importance in the degradation process. Thauera and Azoarcus were the dominant genera that participated in contaminant degradation.

A comprehensive review of nutrient-energy-water-solute recovery by hybrid osmotic membrane bioreactors

Hybrid osmotic membrane bioreactor (OMBR) takes advantage of the cooperation of varying biological or desalination processes and can achieve NEWS (nutrient-energy-water-solute) recovery from wastewater. However, a lack of universal parameters hinders our understanding. Herein, system configurations and new parameters are systematically investigated to help better evaluate recovery performance. High-quality water can be produced in reverse osmosis/membrane distillation-based OMBRs, but high operation cost limits their application. Although bioelectrochemical system (BES)/electrodialysis-based OMBRs can effectively achieve solute recovery, operation parameters should be optimized. Nutrients can be recovered from various wastewater by porous membrane-based OMBRs, but additional processes increase operation cost. Electricity recovery can be achieved in BES-based OMBRs, but energy balances are negative. Although anaerobic OMBRs are energy-efficient, salinity accumulation limits methane productions. Additional efforts must be made to alleviate membrane fouling, control salinity accumulation, optimize recovery efficiency, and reduce operation cost. This review will accelerate hybrid OMBR development for real-world applications.

Flocculation Efficiency and Mechanism of Carbamazepine by Microbial Flocculant Extracted from Klebsiella pneumoniae J1

The microbial flocculant (MFX) extracted from Klebsiella pneumoniae J1 was used to remove carbamazepine in prepared wastewater and domestic sewage. The influence factors and flocculation mechanism were studied. The optimal carbamazepine removal conditions for MFX were pH of 7-8, 7 mL of flocculant, 0.1 mL of coagulant, and 35°C, and the removal rate reached 81.75%. MFX was efficient in the removal of carbamazepine in both domestic sewage (75.03%) and secondary sedimentation tank effluent (69.76%). The pseudo-first-order kinetic equation fitted the adsorption process better than the pseudo-second-order kinetic equation, which suggested that the adsorption was not pure chemical adsorption. The analysis of floc size suggested that the repulsive force between carbamazepine and MFX was weakened under alkalescent conditions, which can help the growth and coherence of flocs and increase the carbamazepine removal efficiency. Enough dosage of MFX can generate larger flocs, but excessive dosage of MFX will decrease the carbamazepine removal rate because of increase in electrostatic repulsion. The analysis of 3D-EEM and FTIR suggested that hydroxyl, amino, and carboxyl in MFX played an important role in the removal of carbamazepine. As an eco-friendly and highly efficient microbial flocculant, MFX has potential for practical applications in carbamazepine removal.