A Review of Processes for Removing Antibiotics from Breeding Wastewater

In silico degradation of fluoroquinolones by a microalgae-based constructed wetland system

Fluoroquinolone antibiotics (FQs) have been used worldwide due to their extended antimicrobial spectrum. However, the overuse of FQs leads to frequent detection in the environment and cannot be efficiently removed. Microalgae-based constructed wetland systems have been proven to be a relatively proper method to treat FQs, mainly by microalgae, plants, microorganisms, and sediments. To improve the removal efficiency of microalgae-constructed wetland, a systematic molecular design, screening, functional, and risk evaluation method was developed using three-dimensional quantitative structure-activity relationship models, molecular dynamics simulation, molecular docking, and TOPKAT approaches. Five designed ciprofloxacin alternatives with improved bactericidal effects and lower human health risks were found to be more easily degraded by microalgae (16.11-167.88 %), plants (6.72-58.86 %), microorganisms (9.10-15.02 %), and sediments (435.83 %-1763.51 %) compared with ciprofloxacin. According to the mechanism analysis, the removal effect of the FQs can be affected via changes in the number, bond energy, and molecular descriptors of favorable and unfavorable amino acids. To the best of our knowledge, this is the first comprehensive study of improving the microalgae, plants, microorganisms, and sediment removal efficiency of FQs in constructed wetlands, which provides theoretical support for the treatment of FQ pollution.

Utilizing Morphological and Physiological Parameters of Lemna minor for Assessing Tetracyclines' Removal

Antibiotics with significant environmental toxicity, e.g., tetracyclines (TCs), are often used in large quantities worldwide, with 50-80% of the applied dose ending up in the environment. This study aimed to investigate the effects of exposure to tetracycline hydrochloride (TC) and minocycline hydrochloride (MIN) on L. minor. Our research evaluated the phytotoxicity of the TCs by analyzing plant growth and biomass and evaluating assimilation pigment levels and fluorescence. The research was extended with the ability potential of duckweed as a tool for removing TCs from water/wastewater. The results demonstrated that both TCs influenced Ir, Iy, biomass, and photosynthetic efficiency. The uptake of TC and MIN by duckweed was proportional to the concentration in the growth medium. The TC was absorbed more readily, reaching up to 8.09 mg × g-1 of dry weight (DW) at the highest concentration (19.2 mg × L-1), while MIN reached 6.01 mg × g-1 of DW. As indicated, the consequences of the influence of TC on plants were slightly smaller, in comparison to MIN, while the plants could biosorb this drug, even at the lowest tested concentration. This study has shown that using plants for drug biosorption can be an effective standalone or complementary method for water and wastewater treatment.

Reduction of organic matter containing benzimidazole and toxicity in real livestock wastewater through advanced oxidation processes

Livestock wastewater (LWW) has a complex characteristic of high organic matter content, metals, nutrients, and pharmaceutical compounds. Advanced oxidation processes (AOP) are a potential option for treating this wastewater. This study evaluated real LWW and the performance of UV/H2O2 and UV/peroxymonosulfate (UV/PMS) for its treatment. The experiments were conducted in a UV photoreactor (16 mW/m2, λ = 254 nm). The oxidant agents (Ox) tested were H2O2 and PMS, each at low, medium, and high TOC/Ox molar ratios. A pretreatment based on chemical precipitation was implemented. Annually, the LWW showed total organic carbon (TOC) values of 859 ± 13.37 mg/L, 168.85 ± 1.62 mg/L of total Kjeldahl nitrogen (TKN), and toxicity of 96% v/v. In the dry season, albendazole (ABZ) (95.3 ± 35.16 mg/L), Cu (4.3 ± 0.23 mg/L), Fe (3.8 ± 0.38 mg/L), and suspended solids (SS) (1015 ± 586.9 mg/L) were identified, so pretreatment was implemented. The UV/PMS process with the lowest molar ratio [TOC/Ox 1:0.75] removed significantly lower TOC concentrations (p < 0.05), but toxicity decreased entirely. The study of mineralization and toxicity provided insight into the changes in LWW during treatment with AOP. Furthermore, it contributed to establishing the technical basis for implementing efficient treatment processes.

Treatment of agricultural wastewater using microalgae: A review

The rapid development of agriculture has led to a large amount of wastewater, which poses a great threat to environmental safety. Microalgae, with diverse species, nutritional modes and cellular status, can adapt well in agricultural wastewater and absorb nutrients and remove pollutants effectively. Besides, after treatment of agricultural wastewater, the accumulated biomass of microalgae has broad applications, such as fertilizer and animal feed. This paper reviewed the current progresses and further perspectives of microalgae-based agricultural wastewater treatment. The characteristics of agricultural wastewater have been firstly introduced; Then the microalgal strains, cultivation modes, cellular status, contaminant metabolism, cultivation systems and biomass applications of microalgae for wastewater treatment have been summarized; At last, the bottlenecks in the development of the microalgae treatment methods, as well as recommendations for optimizing the adaptability of microalgae to wastewater in terms of wastewater pretreatment, microalgae breeding, and microalgae-bacterial symbiosis systems were discussed. This review would provide references for the future developments of microalgae-based agricultural wastewater treatment.

Robust CA-GO-TiO2/PTFE Photocatalytic Membranes for the Degradation of the Azithromycin Formulation from Wastewaters

We have developed an innovative thin-film nanocomposite membrane that contains cellulose acetate (CA) with small amounts of TiO2-decorated graphene oxide (GO) (ranging from 0.5 wt.% to 2 wt.%) sandwiched between two polytetrafluoroethylene (PTFE)-like thin films. The PTFE-like films succeeded in maintaining the bulk porosity of the support while increasing the thermal and chemical robustness of the membrane and boosting the catalytic activity of TiO2 nanoparticles. The membranes exhibited a specific chemical composition and bonding, with predominant carbon-oxygen bonds from CA and GO in the bulk, and carbon-fluorine bonds on their PTFE-like coated sides. We have also tested the membranes' photocatalytic activities on azithromycin-containing wastewaters, demonstrating excellent efficiency with more than 80% degradation for 2 wt.% TiO2-decorated GO in the CA-GO-TiO2/PTFE-like membranes. The degradation of the azithromycin formulation occurs in two steps, with reaction rates being correlated to the amount of GO-TiO2 in the membranes.

A comprehensive review on the fate and impact of antibiotic residues in the environment and public health: A special focus on the developing countries

The widespread application of antibiotics in human and veterinary medicine has led to the pervasive presence of antibiotic residues in the environment, posing a potential hazard to public health. This comprehensive review aims to scrutinize the fate and impact of antibiotic residues, with a particular focus on the context of developing nations. The investigation delves into the diverse pathways facilitating the entry of antibiotics into the environment and meticulously examines their effects on human health. The review delineates the current state of antibiotic residues, evaluates their exposure in developing nations, and elucidates existing removal methodologies. Additionally, it probes into the factors contributing to the endurance and ecotoxicity of antibiotic residues, correlating these aspects with usage rates and associated mortalities in these nations. The study also investigates removal techniques for antibiotic residues, assessing their efficiency in environmental compartments. The concurrent emergence of antibiotic-resistant bacteria, engendered by antibiotic residues, and their adverse ecological threats underscore the necessity for enhanced regulations, vigilant surveillance programs, and the adoption of sustainable alternatives. The review underlines the pivotal role of public education and awareness campaigns in promoting responsible antibiotic use. The synthesis concludes with strategic recommendations, strengthening the imperative for further research encompassing comprehensive monitoring, ecotoxicological effects, alternative strategies, socio-economic considerations, and international collaborations, all aimed at mitigating the detrimental effects of antibiotic residues on human health and the environment. PRACTITIONER POINTS: Antibiotic residues are widely distributed in different environmental compartments. Developing countries use more antibiotics than developed countries. Human and veterinary wastes are one of the most responsible sources of antibiotic pollution. Antibiotics interact with biological systems and trigger pharmacological reactions at low doses. Antibiotics can be removed using modern biological, chemical, and physical-chemical techniques.

Insights on the Synthesis of Al-MCM-41 with Optimized Si/Al Ratio for High-Performance Antibiotic Adsorption

Studies indicate that approximately two-thirds of the rivers of the world are contaminated by pharmaceutical compounds, especially antibiotics and hormones. Data reported by the World Health Organization (WHO, 2015) revealed an increase of 65% in antibiotic consumption between 2000 and 2015, with a worldwide increase of 200% expected up to 2030. Environmental contamination by antibiotics and their metabolites can cause the alteration of bacterial genes, leading to the generation of superbacteria. In this work, adsorption was explored as a strategy to mitigate antibiotic contamination, proposing the use of the Al-MCM-41 mesoporous material as an efficient and high-capacity adsorbent. Evaluation of the influence of the synthesis parameters enabled understanding of the main variables affecting the adsorption capacity of Al-MCM-41 for the removal of a typical antibiotic, amoxicillin (AMX). It was found that the adsorbent composition and specific surface area were the main factors that should be optimized in order to obtain the highest AMX removal capacity. Using statistical tools, the best Si/Al ratio in Al-MCM-41 was found to be 10.5, providing an excellent AMX uptake of 132.2 mg per gram of adsorbent. The Si/Al ratio was the most significant factor affecting the adsorption. The cation-π interactions increased with an increase of the Al content, while the interactions involving silanols (Yoshida H-bonding and dipole-dipole hydrogen bridges) decreased.

Occurrence and removal of antibiotics from aquaculture wastewater by solar-driven Fe(VI)/oxone process

In this study, the occurrence and removal of ten selected antibiotics from aquaculture wastewater by the process solar + Fe(VI)+oxone were investigated. The detection levels of the antibiotics in the aquaculture wastewater samples were at ng/L. The degradation of the selected antibiotics under the process solar + Fe(VI)+oxone followed pseudo-first-order kinetics. As the most abundant antibiotic in the studied aquaculture wastewater, norfloxacin (NFX) was used as the model compound to study the reaction mechanism and detoxification ability of the treatment system, as well as the effects of reaction parameters and environmental factors. The active species including O2•-, O21, and Fe(V)/Fe(IV) contributed to NFX degradation in the process solar + Fe(VI)+oxone. Decarboxylation, the piprazine ring opening, defluorination of the benzene ring, oxygen addition and the cleavage of the quinolone/benzene ring were main degradation pathways of NFX. Around 20% mineralization was reached and the inhibition rate of the bacteria (Escherichia Coli) growth was reduced from 95.5% to 47.1% after the NFX degradation for 60 min. Despite the suppression of NFX degradation by NO2-, PO43- and humic acid, the NFX degradation in three aquaculture wastewater samples was faster than that in ultrapure water due to the positive effect of Br-and other factors. The above results demonstrate the treatment process solar-driven Fe(VI)/oxone has a good potential in antibiotics removal from the aquaculture wastewater.

Keystone microalgae species determine the removal efficiency of sulfamethoxazole: a case study of Chlorella pyrenoidosa and microalgae consortia

In recent years, antibiotics pollution has caused serious harm to the aquatic environment, and microalgae mediated degradation of antibiotics has attracted increasing attention. However, the potential toxicity of antibiotics to keystone microalgae species or their microalgae consortia, and the impact of microalgal diversity on antibiotic removal need to be further studied. In this study, we investigated the removal efficiency and tolerance of five freshwater microalgae (Chlorella pyrenoidosa, Scenedesmus quadricauda, Dictyosphaerium sp., Haematoccocus pluvialis, and Botryococcus braunii) and their microalgae consortia to sulfamethoxazole (SMX). We found that the removal efficiency of SMX by C. pyrenoidosa reached 49%, while the other four microalgae ranged between 9% and 16%. In addition, C. pyrenoidosa, S. quadricauda, and Dictyosphaerium sp. had better tolerance to SMX than H. pluvialis, and their growth and photosynthesis were less affected. At 10 and 50 mg/L SMX, the removal capacity of SMX by mixed microalgae consortia was lower than that of C. pyrenoidos except for the consortium with C. pyrenoidos and S. quadricauda. The consortia generally showed higher sensitivity towards SMX than the individual species, and the biochemical characteristics (photosynthetic pigment, chlorophyll fluorescence parameters, superoxide anion (O₂ ^-), superoxide dismutase activity (SOD), malondialdehyde (MDA) and extracellular enzymes) were significantly influenced by SMX stress. Therefore, the removal of antibiotics by microalgae consortia did not increase with the number of microalgae species. Our study provides a new perspective for the selection of microalgal consortia to degrade antibiotics.

Preparation and characterization of activated carbons from Lemon Pulp for oxytetracycline removal

This study aims to remove oxytetracycline (OTC) that harms the ecosystem, with activated carbon (LPAC) obtained from Lemon Pulp (LP). Characterization and properties of LPAC were analyzed by Brunauer-Emmett-Teller (BET), Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM), X-ray diffraction (XRD) and point of zero charge (pH_PZC) analyses. BET surface area, pore volume and pH_PZC of LPAC produced by carbonization at 400 °C and activation with KOH at 800 °C were obtained as 1333.01 m²/g, 0.391 cm³/g, and 6.81, respectively. pH, reaction time, initial OTC concentration, and adsorbent amounts were optimized in the adsorption study performed with LPAC with high porosity and micropores. Kinetic evaluation was made with pseudo-first-order, pseudo-second-order, and intra-particle diffusion models and Freundlich, Langmuir, and Temkin equations are used to investigate their isotherms under reaction equilibrium conditions, and also the results were analyzed by statistical method (ANOVA). In pseudo-second-order kinetic and Freundlich isotherm models, where the best results were obtained, R² values were calculated as 0.999 and 0.995, respectively. Maximum OTC removal efficiency was found as 104.22 mg/g. Overall, this research indicates that LPAC for the treatment of water contaminated with antibiotics is environmentally friendly green material.

Occurrence of antibiotics in wastewater: Potential ecological risk and removal through anaerobic-aerobic systems

Antibiotics are intensively used to improve public health, prevent diseases and enhance productivity in animal farms. Contrarily, when released, the antibiotics laden wastewater produced from pharmaceutical industries and their application sources poses a potential ecological risk to the environment. This study provides a discussion on the occurrence of various antibiotics in wastewater and their potential ecological risk in the environment. Further, a critical review of anaerobic-aerobic processes based on three major systems (such as constructed wetland, high-rate bioreactor, and integrated treatment technologies) applied for antibiotics removal from wastewater is performed. The review also explores microbial dynamics responsible for antibiotic biodegradation in anaerobic-aerobic systems and its economic feasibility at wider-scale applications. The operational problems and prospective modifications are discussed to define key future research directions. The appropriate selection of treatment processes, sources control, understanding of antibiotic fate, and adopting precise monitoring strategies could eliminate the potential ecological risks of antibiotics. Integrated bio-electrochemical systems exhibit antibiotics removal ≥95% by dominant Geobacter sp. at short HRT ∼4-10 h. Major process factors like organic loading rate, hydraulic loading rate (HRT), and solid retention time significantly affect the system performance. This review will be beneficial to the researchers by providing in-depth understanding of antibiotic pollution and its abatement via anaerobic-aerobic processes to develop sustainable wastewater treatment technology in the future.

Role of bio-electrochemical technology for enzyme activity stimulation in high-consumption pharmaceuticals biodegradation

Active pharmaceutical ingredients (APIs) and their intermediate residues have recently been considered a serious concern. Among technologies, bio-electrochemical technologies (BETs) have stimulated the production of bio-electrical energy. This review aims to examine the benefit and mechanism of BETs on the degradation of high-consumption pharmaceutical compounds, including antibiotic, anti-inflammatory, and analgesic drugs, and the stimulation of enzymes induced in a bioreactor. Moreover, intermediates and the proposed pathways of pharmaceutical compound biodegradation in BETs are to be explained in this review. According to studies performed exclusively, the benefit of BETs is using bio-electroactive microbes to mineralize recalcitrant pharmaceutical contaminants by promoting enzyme activity and energy. Since BETs use the electron transfer chain between bio-anode/-cathode and pharmaceuticals, the enzyme activity is essential in the oxidation and reduction of phenolic rings of drugs and the ineffective detoxification of effluent from the treatment plant. This study is suggested a vital and influential role of BETs in mineralizing and enzyme induction in bioreactors. Eventually, a content of future developments or outlooks of BETs are propounded to improve the pharmaceutical industries' wastewater problems.

Enhanced hydrolytic removal of tylosin in wastewater using polymer-based solid acid catalysts converted from polystyrene

Antibiotic production wastewater usually contains high concentrations of antibiotic residues, which can cause instability and deterioration of biological wastewater treatment units and also domestication and proliferation of antibiotic-resistance bacteria. An effective pretreatment on antibiotics production wastewater is expected to selectively reduce the concentration of antibiotics and decrease the toxicity, rather than mitigate organic and other contaminants before further treatments. In this work, two polymer-based solid acids, PS-S and CPS-S bearing high concentrations of -SOH₃ groups (up to 4.57 mmol/g), were prepared and successfully used for hydrolytic mitigation of 100 mg/L tylosin within 20 min. The co-existence of high concentrations of COD and humic substances did not affect the mitigation of tylosin obviously, while more than 500 mg/L of nitrogenous compounds suppressed the hydrolytic efficiency. Recycle and reuse experiments showed that the solid acids performed well in five cycles after regeneration. Three transformation products (P1, P2 and P3) were identified using UPLC-QTOF-MS/MS. Sugar moieties including mycarse, mycaminose, and mycinose detached and released simultaneously or in order from the 16-member lactone ring through desugarization, which led to a dramatic decrease in antibacterial activity as revealed by cytotoxicity evaluations using S. aureus. Ecotoxicity estimation indicated the acute toxicities of the hydrolyzed products to model species (e.g., fish, daphnid and green algae) were classified as "not harmful". This work suggested an effective and selective method to pretreat tylosin-contained production wastewater by using polymer-based solid acids. These results will shed light on effective elimination of antibiotics pollution from pharmaceutical industries through strengthening the pretreatments.

The Effect of Quinolones on Common Duckweed Lemna minor L., a Hydrophyte Bioindicator of Environmental Pollution

Plant growth and the development of morphological traits in plants are inhibited under exposure to pharmaceuticals that are present in soil and water. The present study revealed that moxifloxacin (MOXI), nalidixic acid (NAL), levofloxacin (LVF) and pefloxacin (PEF) at concentrations of >0.29, >0.48, >0.62 and >1.45 mg × L^-1, respectively, inhibited the growth (Ir) of duckweed plants and decreased their yield (Iy). In the current study, none of the tested quinolones (QNs) at any of the examined concentrations were lethal for common duckweed plants. However, at the highest concentration (12.8 mg × L^-1), LVF increased Ir and Iy values by 82% on average and increased the values of NAL, PEF and MOXI by 62% on average. All tested QNs led to the loss of assimilation pigments. In consequence, all QNs, except for LVF, induced changes in chlorophyll fluorescence (Fv/Fm), without any effect on phaeophytinization quotient (PQ) values. The uptake of NAL, MOXI, LVF by Lemna minor during the 7-day chronic toxicity test was directly proportional to drug concentrations in the growth medium. Nalidixic acid was absorbed in the largest quantities, whereas in the group of fluoroquinolones (FQNs), MOXI, LVF and PEF were less effectively absorbed by common duckweed. This study demonstrated that biosorption by L. minor occurs regardless of the plants' condition. These findings indicate that L. minor can be used as an effective biological method to remove QNs from wastewater and water and that biosorption should be a mandatory process in conventional water and wastewater treatment.

Roles of substrates in removing antibiotics and antibiotic resistance genes in constructed wetlands: A review

Antibiotics and corresponding antibiotic resistance genes (ARGs) are emerging pollutants in wastewater that pose a significant threat to the environment and human health. Constructed wetlands (CWs) are a cost-effective technology for eliminating these pollutants through substrates, plants, and microorganisms. Detailed reviews of the roles of CW substrates on antibiotic and ARG removal and recent progress in the field are lacking. This paper reviews the mechanisms influencing antibiotic and ARG (intracellular and extracellular) removal in CWs, and natural, biomass, chemical, modified, industrial, novel, and combined substrates on their removal efficiencies. Generally, substrates remove antibiotics and ARGs mainly through adsorption, biodegradation, chemical oxidation, and filtration. Other mechanisms, such as photolysis, may also contribute to removal. Natural substrates (e.g., gravel, zeolite) are more frequently employed than other types of substrates. The removal performance of antibiotics and intracellular ARGs by zeolite was better than that of gravel through enhanced substrate adsorption, filtration, and biodegradation processes. Moreover, Mn ore showed promising high capability to remove high concentration of antibiotics through various removal pathways. In addition, combined substrates of soil/sand/gravel and other substrates further facilitate antibiotic removal. Future research is suggested to explore the mechanisms of competitive adsorption and redox-controlled biodegradation, investigate the effect of Fe/Mn oxides on the removal of antibiotics and ARGs via chemical oxidation, evaluate the removal of extracellular ARGs by CWs with different substrates, and investigate the effect of substrates on removal of antibiotics and ARGs in full-scale CWs.

Analytical key issues and challenges in the LC-MS/MS determination of antibiotics in wastewater

The research on antibiotics occurrence in the aquatic environment has become a hot topic in the last years due to their potential negative effects, associated to possible bacterial antibiotic-resistance, after continuous exposure to these compounds. Most of antibiotic residues are not completely removed in the wastewater treatment plants (WWTPs) and end up in the aquatic environment through treated wastewater (WW). The development of reliable analytical methodologies for the determination of antibiotics in influent (IWW) and effluent wastewater (EWW) is needed with different purposes, among others: monitoring their occurrence in the aquatic environment, performing environmental risk assessment, estimating removal efficiencies of WWTPs, or estimating the consumption of these compounds. In this paper, we perform an in-depth investigation on analytical key issues that pose difficulties in the determination of antibiotics in complex matrices, such as WW, and we identify challenges to be properly addressed for successful analysis. The analytical technique selected was liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), as it is the most powerful and widely applied at present for antibiotic residues determination. The mass spectrometric behavior of 18 selected antibiotics, the chromatographic performance, ion ratio variations associated to the sample matrix when using different precursor ions or protomers, and the macrolides adsorption to glass vial, were some of the issues studied in this work. On the basis of the detailed study performed, an analytical LC-MS/MS method based on sample direct injection has been developed for quantification of 18 antibiotics in IWW and EWW, allowing their determination at low ng L^-1 levels.

Emerging technologies for enhanced removal of residual antibiotics from source-separated urine and wastewaters: A review

Antibiotic residues are of significant concern in the ecosystem because of their capacity to mediate antibiotic resistance development among environmental microbes. This paper reviews recent technologies for the abatement of antibiotics from human urine and wastewaters. Antibiotics are widely distributed in the aquatic environment as a result of the discharge of municipal sewage. Their existence is a cause for worry due to the potential ecological impact (for instance, antibiotic resistance) on bacteria in the background. Numerous contaminants that enter wastewater treatment facilities and the aquatic environment, as a result, go undetected. Sludge can act as a medium for some chemicals to concentrate while being treated as wastewater. The most sewage sludge that has undergone treatment is spread on agricultural land without being properly checked for pollutants. The fate of antibiotic residues in soils is hence poorly understood. The idea of the Separation of urine at the source has recently been propagated as a measure to control the flow of pharmaceutical residues into centralized wastewater treatment plants (WWTPs). With the ever increasing acceptance of urine source separation practices, visibility and awareness on dedicated treatement technologies is needed. Human urine, as well as conventional WWTPs, are point sources of pharmaceutical micropollutants contributing to the ubiquitous detection of pharmaceutical residues in the receiving water bodies. Focused post-treatment of source-separated urine includes distillation and nitrification, ammonia stripping, and adsorption processes. Other reviewed methods include physical and biological treatment methods, advanced oxidation processes, and a host of combination treatment methods. All these are aimed at ensuring minimized risk products are returned to the environment.

Advanced insights on removal of antibiotics by microalgae-bacteria consortia: A state-of-the-art review and emerging prospects

Antibiotics abuse has triggered a growing environmental problem, posing a major threat to both ecosystem and human health. Unfortunately, there are still several shortcomings to current antibiotics removal technologies. Microalgae-bacteria consortia have been shown to be a promising antibiotics treatment technology owing to advantages of high antibiotics removal efficiency, low operational cost, and carbon emission reduction. This review aims to introduce the removal mechanisms, influencing factors, and future research perspectives for using microalgae-bacteria consortia to remove antibiotics. The interaction mechanisms between microalgae and bacteria are comprehensively revealed, and their exclusive advantages have been summarized in a "Trilogy" strategy, including "reinforced physical contact", "upgraded substance utilization along with antibiotics degradation", and "robust biological regulation". What's more, the relationship between different interaction mechanisms is emphatically analyzed. The important influencing factors, including concentration and classes of antibiotics, environmental conditions, and operational parameters, of antibiotics removal were also assessed. Three innovative treatment systems (microalgae-bacteria fuel cells (MBFCs), microalgae-bacteria membrane photobioreactors (MB-MPBRs), and microalgae-bacteria granular sludge (MBGS)) along with three advanced techniques (metabolic engineering, machine learning, and molecular docking and dynamics) are then introduced. In addition, concrete implementing schemes of the above advanced techniques are also provided. Finally, the current challenges and future research directions in using microalgae-bacteria consortia to remove antibiotics have been summarized. Overall, this review addresses the current state of microalgae-bacteria consortia for antibiotics treatment and provides corresponding recommendations for enhancing antibiotics removal efficiency.

Enhanced Adsorption of Tetracycline by Thermal Modification of Coconut Shell-Based Activated Carbon

Tetracycline (TC) is one of the most frequently detected antibiotics in various water matrices, posing adverse effects on aquatic ecosystems. In this study, coconut shell-based powdered activated carbon (PAC) was thermally modified under various temperatures to enhance TC adsorption. The PAC subjected to 800 °C (PAC800) showed the best TC adsorption. PAC and PAC800 were characterized using N₂ adsorption/desorption isotherm, X-ray photoelectron spectroscopy, Raman spectroscopy, XRD, Boehm titration, and zeta potential analyses. Increases in the specific surface area, C/O ratio, C=O, surface charge, basic groups, and the number of stacked graphene layers along with a decrease in structural defects were observed for PAC800 compared to PAC. The TC adsorption was significantly improved for PAC800 compared to that of PAC, which is attributable to the enhanced electrostatic attraction and π-π EDA interactions induced by the changes in the properties. The Freundlich isotherm was the best fit indicating the heterogeneous nature, and the Freundlich constant of PAC and PAC800 increased from 85.8 to 119.5 and 132.1 to 178.6 (mg/g)‧(L/mg)^1/n, respectively, when the temperature was increased from 296.15 to 318.15 K. The kinetics were well described by the pseudo-second-order adsorption model and the rate constant of PAC and PAC800 increased from 0.80 to 1.59 and from 0.72 to 1.29 × 10^-3 g/mg‧min, respectively, as the temperature was increased. The activation energy of PAC and PAC800 was 23.7 and 19.6 J/mol, respectively, while the adsorption enthalpy was 196.7 and 98.5 kJ/mol, respectively, indicating endothermic nature. However, it was suggested that TC adsorption onto PAC800 was more favorable and was more contributed to by physisorption than that onto PAC. These results strongly suggest that the properties, adsorption capacity, and adsorption mechanisms of carbonaceous adsorbents can be significantly changed by simple thermal treatment. More, the results provide valuable information about the design of carbonaceous adsorbents with better performance where the structures and functional groups, which positively affect the adsorption, must be improved.

Hierarchically Annular Mesoporous Carbon Derived from Phenolic Resin for Efficient Removal of Antibiotics in Wastewater

Antibiotics have become a new type of environmental pollutant due to their extensive use. High-performance adsorbents are of paramount significance for a cost-effective and environmentally friendly strategy to remove antibiotics from water environments. Herein, we report a novel annular mesoporous carbon (MCN), prepared by phenolic resin and triblock copolymer F127, as a high-performance adsorbent to remove penicillin, streptomycin, and tetracycline hydrochloride from wastewater. The MCNs have high purity, rich annular mesoporosity, a high surface area (605.53 m²/g), and large pore volume (0.58 cm³/g), improving the adsorption capacity and facilitating the efficient removal of penicillin, streptomycin, and tetracycline hydrochloride from water. In the application of MCNs to treat these three kinds of residual antibiotics, the adsorption amounts of tetracycline hydrochloride were higher than penicillin and streptomycin, and the adsorption capacity was up to 880.6 mg/g. Moreover, high removal efficiency (99.6%) and excellent recyclability were achieved. The results demonstrate that MCN adsorbents have significant potential in the treatment of water contaminated with antibiotics.

ZnCo2O4/g-C3N4/Cu nanocomposite as a new efficient and recyclable heterogeneous photocatalyst with enhanced photocatalytic activity towards the metronidazole degradation under the solar light irradiation

In this study, ZnCo₂O₄/g-C₃N₄/Cu is synthesized as a new and highly effectual solar light-driven heterogeneous photocatalyst. The prepared photocatalyst is characterized using FT-IR, XRD, XPS, DRS, FESEM, TEM, EDS, and elemental mapping techniques. The performance of ZnCo₂O₄/g-C₃N₄/Cu is studied towards the metronidazole (MNZ) degradation under solar light irradiation. The kinetics of MNZ degradation and efficacy of the operational parameters comprising the initial MNZ amount (10-30 mg L^-1), photocatalyst dosage (0.005-0.05 g L^-1), pH (3-11), and contact time (5-30 min) on the MNZ degradation process are investigated. Surprisingly, the ZnCo₂O₄/g-C₃N₄/Cu nanocomposite presents a privileged photocatalytic performance towards the MNZ degradation under solar light irradiation. The enhanced photocatalytic activity of this photocatalyst can be ascribed to the synergistic optical effects of ZnCo₂O₄, g-C₃N₄, and Cu. The value of band gap energy for ZnCo₂O₄/g-C₃N₄/Cu is estimated to be 2.3 eV based on the Tauc plot of (αhν)² vs. hν. The radical quenching experiments confirm that the superoxide radicals and holes are the principal active species in the photocatalytic degradation of MNZ, whereas the hydroxyl radicals have no major role in such degradation. The as-prepared photocatalyst is simply isolated and recycled for at least eight runs without noticeable loss of the efficiency. Using the natural sunlight source, applying a very low amount of the photocatalyst, neutrality of the reaction medium, short reaction time, high efficiency of the degradation procedure, utilizing air as the oxidant, low operational costs, and easy to recover and reuse of the photocatalyst are the significant highlights of the present method. It is supposed that the current investigation can be a step forward in the representation of an efficacious photocatalytic system in the treatment of a wide range of contaminated aquatic environments.

Hydrogen Peroxide Activated by Biochar-Supported Sulfidated Nano Zerovalent Iron for Removal of Sulfamethazine: Response Surface Method Approach

Biochar (BC)-supported sulfide-modified nanoscale zerovalent iron (S-nZVI/BC) was prepared using the liquid-phase reduction method for the application of the removal of sulfamethazine (SMZ) from water. The reaction conditions were optimized by the Box−Behnken response surface method (RSM). A model was constructed based on the influence factors of the removal rate, i.e., the carbon-to-iron ratio (C/Fe), iron-sulfur ratio (Fe/S), pH, and hydrogen peroxide (H2O2) concentration, and the influence of each factor on the removal efficiency was investigated. The optimal removal process parameters were determined based on theoretical and experimental results. The results showed that the removal efficiency was significantly affected by the C/Fe ratio and pH (p < 0.0001) but relatively weakly affected by the Fe/S ratio (p = 0.0973) and H2O2 concentration (p = 0.022). The optimal removal process parameters were as follows: 0.1 mol/L H2O2, a pH of 3.18, a C/Fe ratio of 0.411, and a Fe/S ratio of 59.75. The removal rate of SMZ by S-nZVI/BC was 100% under these conditions. Therefore, it is feasible to use the Box−Behnken RSM to optimize the removal of emerging pollutants in water bodies by S-nZVI/BC.

A Review of Methods for Removal of Ceftriaxone from Wastewater

The presence of pharmaceuticals in surface water and wastewater poses a threat to public health and has significant effects on the ecosystem. Since most wastewater treatment plants are ineffective at removing molecules efficiently, some pharmaceuticals enter aquatic ecosystems, thus creating issues such as antibiotic resistance and toxicity. This review summarizes the methods used for the removal of ceftriaxone antibiotics from aquatic environments. Ceftriaxone is one of the most commonly prescribed antibiotics in many countries, including Tanzania. Ceftriaxone has been reported to be less or not degraded in traditional wastewater treatment of domestic sewage. This has piqued the interest of researchers in the monitoring and removal of ceftriaxone from wastewater. Its removal from aqueous systems has been studied using a variety of methods which include physical, biological, and chemical processes. As a result, information about ceftriaxone has been gathered from many sources with the searched themes being ceftriaxone in wastewater, ceftriaxone analysis, and ceftriaxone removal or degradation. The methods studied have been highlighted and the opportunities for future research have been described.

Synthetic organic antibiotics residues as emerging contaminants waste-to-resources processing for a circular economy in China: Challenges and perspective

Synthetic antibiotics have been known for years to combat bacterial antibiotics. But their overuse and resistance have become a concern recently. The antibiotics reach the environment, including soil from the manufacturing process and undigested excretion by cattle and humans. It leads to overburden and contamination of the environment. These organic antibiotics remain in the environment for a very long period. During this period, antibiotics come in contact with various flora and fauna. The ill manufacturing practices and inadequate wastewater treatment cause a severe problem to the water bodies. After pretreatment from pharmaceutical industries, the effluents are released to the water bodies such as rivers. Even after pretreatment, effluents contain a significant number of antibiotic residues, which affect the living organisms living in the water bodies. Ultimately, river contaminated water reaches the ocean, spreading the contamination to a vast environment. This review paper discusses the impact of synthetic organic contamination on the environment and its hazardous effect on health. In addition, it analyzes and suggests the biotechnological strategies to tackle organic antibiotic residue proliferation. Moreover, the degradation of organic antibiotic residues by biocatalyst and biochar is analyzed. The circular economy approach for waste-to-resource technology for organic antibiotic residue in China is analyzed for a sustainable solution. Overall, the significant challenges related to synthetic antibiotic residues and future aspects are analyzed in this review paper.

Removal of METH through Tertiary or Advanced Treatment in a WWTP

METHs are drugs that enter wastewater through the feces and urine of users. Conventional wastewater treatment plants are not capable of removing this type of emerging contaminant, but, in recent years, techniques have been developed to abate drugs of abuse. The present investigation focused on obtaining the technique that keeps the best balance between the comparison criteria considered: efficiency; costs; development stage; and waste generation. That is why a bibliographic review was carried out in the scientific databases of the last eight years, concluding that the six most popular techniques are: SBR, Fenton reaction, mixed-flow bioreactor, ozonation, photocatalysis, and UV disinfection. Subsequently, the Saaty and Modified Saaty methods were applied, obtaining a polynomial equation containing the four comparison criteria for the evaluation of the techniques. It is concluded that the UV disinfection method is the one with the best relationship between the analyzed criteria, reaching a score of 0.8591/1, followed by the Fenton method with a score of 0.6925/1. This research work constitutes a practical and easy-to-use tool for decision-makers, since it allows finding an optimal treatment for the abatement of METHs.

Antibiotics in Wastewater: Baseline of the Influent and Effluent Streams in Kuwait

This study provides baseline information on the concentrations of antibiotics in influent and effluent from two wastewater treatment plants in regular operation in the State of Kuwait. Wastewater samples were collected from the influent and effluent streams of two WWTPs, over four sampling campaigns and analyzed for a broad range of antibiotics. The mean influent concentrations of sulfamethoxazole, ciprofloxacin, clarithromycin, and cefalexin were 852 ng/L, 672 ng/L, 592 ng/L), and 491 ng/L, respectively, at Umm Al Hayman WWTP. At the Kabd WWTP, the influent concentration of clarithromycin was highest with a mean of 949 ng/L, followed by ciprofloxacin (mean, 865 ng/L), cefalexin (mean, 598 ng/L), and sulfamethoxazole (mean, 520 ng/L). The dominant compounds in the effluent from Umm Al Hayman were sulfamethoxazole (mean, 212 ng/L), ciprofloxacin (mean, 153 ng/L), ofloxacin (mean, 120 ng/L), dimetridazole (mean, 96 ng/L), and metronidazole (mean, 93 ng/L). Whereas, at the Kabd WWTP, the dominant compounds were sulfamethoxazole (mean, 338 ng/L), dimetridazole (mean, 274 ng/L), cefalexin (mean, 213 ng/L), ciprofloxacin (mean, 192 ng/L), and clarithromycin (189 ng/L). The mean influent concentrations of all compounds were higher than those measured in the effluents. The concentrations of antibiotic compounds were not significantly different between the two WWTPs (p > 0.05). The removal efficiencies of the various antibiotics over the four sampling campaigns for the Kabd and Umm Hayman WWTPs ranged between 10.87 and 99.75% and also showed that they were variable and were compound dependent. The data clearly show that the concentrations of antibiotics measured in the influents of both WWTPs were highest in samples collected during the winter-summer (September samples) transition followed by the concentrations measured during the winter-summer (March samples) transition period. This is possibly linked to the increased prescription of these medications to treat infectious diseases and flu prevalent in Kuwait during these periods. This study provides the first reported concentrations of antibiotics in the dissolved aqueous influents and effluents of WWTPs in Kuwait. Additional studies are required to evaluate the environmental impact that antibiotic residues may cause since treated wastewater is used in irrigation, and often there are instances when untreated wastewater is discharged directly into the marine environment.

UV/TiO2 Photocatalysis as an Efficient Livestock Wastewater Quaternary Treatment for Antibiotics Removal

Antibiotics are among the most common pharmaceutical compounds, and they have been extensively used for the prevention and treatment of bacterial diseases for more than 50 years. However, merely a small fraction of antibiotics is metabolized in the body, while the rest is discharged into the environment through excretion, which can cause potential ecological problems and human health risks. In this study, the elimination of seventeen antibiotics from real livestock wastewater effluents was investigated by UV/TiO2 advanced oxidation process. The effect of process parameters, such as TiO2 loadings, solution pHs, and antibiotic concentrations, on the efficiency of the UV/TiO2 process was assessed. The degradation efficiency was affected by the solution pH, and higher removal efficiency was observed at pH 5.8 and 9.9, while the catalyst loading had no significant effect on the degradation efficiency. UV photolysis showed a good removal efficiency of the antibiotics. However, the highest removal efficiency was shown by the UV/photocatalyst system due to their synergistic effects. The results showed that more than 90% of antibiotics were removed by UV/TiO2 system during the 60 min illumination, while the corresponding TOC and COD removal was only 10 and 13%, respectively. The results of the current study indicated that UV/TiO2 advanced oxidation processes is a promising method for the elimination of various types of antibiotics from real livestock wastewater effluents.

A High Flux Electrochemical Filtration System Based on Electrospun Carbon Nanofiber Membrane for Efficient Tetracycline Degradation

In this work, an electrochemical filter using an electrospun carbon nanofiber membrane (ECNFM) anode fabricated by electrospinning, stabilization and carbonization was developed for the removal of antibiotic tetracycline (TC). ECNFM with 2.5 wt% terephthalic acid (PTA) carbonized at 1000 °C (ECNFM-2.5%-1000) exhibited higher tensile stress (0.75 MPa) and porosity (92.8%), more graphitic structures and lower electron transfer resistance (23.52 Ω). Under the optimal condition of applied voltage 2.0 V, pH 6.1, 0.1 mol L−1 Na2SO4, initial TC concentration 10 ppm and membrane flux 425 LMH, the TC removal efficiency of the electrochemical filter of ECNFM-2.5%-1000 reached 99.8%, and no obvious performance loss was observed after 8 h of continuous operation. The pseudo-first-order reaction rate constant in flow-through mode was 2.28 min−1, which was 10.53 times higher than that in batch mode. Meanwhile, the energy demand for 90% TC removal was only 0.017 kWh m−3. TC could be converted to intermediates with lower developmental toxicity and mutagenicity via the loss of functional groups (-CONH2, -CH3, -OH, -N(CH3)2) and ring opening reaction, which was mainly achieved by direct anodic oxidation. This study highlights the potential of ECNFM-based electrochemical filtration for efficient and economical drinking water purification.

Photocatalytic Degradation of Fluoroquinolone Antibiotics in Solution by Au@ZnO-rGO-gC3N4 Composites

The photocatalytic degradation of two quinolone-type antibiotics (ciprofloxacin and levofloxacin) in aqueous solution was studied, using catalysts based on ZnO nanoparticles, which were synthesized by a thermal procedure. The efficiency of ZnO was subsequently optimized by incorporating different co-catalysts of gC3N4, reduced graphene oxide, and nanoparticles of gold. The catalysts were fully characterized by electron microscopy (TEM and SEM), XPS, XRD, Raman, and BET surface area. The most efficient catalyst was 10%Au@ZnONPs-3%rGO-3%gC3N4, obtaining degradations of both pollutants above 96%. This catalyst has the largest specific area, and its activity was related to a synergistic effect, involving factors such as the surface of the material and the ability to absorb radiation in the visible region, mainly produced by the incorporation of rGO and gC3N4 in the semiconductor. The use of different scavengers during the catalytic process, was used to establish the possible photodegradation mechanism of both antibiotics.

Efficiency of an up-flow Anaerobic Sludge Blanket reactor coupled with an electrochemical system to remove chloramphenicol in swine wastewater

The application and design of treatment systems in wastewater are necessary due to antibiotics' potential toxicity and resistant genes on residual effluent. This work evaluated a coupled bio-electrochemical system to reduce chloramphenicol (CAP) and chemical oxygen demand (COD) on swine wastewater (SWW). SWW characterization found CAP of <10 μg/L and 17,434 mg/L of COD. The coupled system consisted of preliminary use of an Up-flow Anaerobic Sludge Blanket Reactor (UASB) followed by electrooxidation (EO). The UASB reactor (primary stage) was operated for three months at an organic load of 8.76 kg of COD/m³d and 50 mg CAP/L as initial concentration. In EO, we carried out a 2² (time operation and intensity) factorial design with a central composite design; we tried two Ti cathodes and one anode of Ti/PbO₂. Optimal conditions obtained in the EO process were 240 min of operation time and 1.51 A of current intensity. It was possible to eliminate 44% of COD and 64.2% of CAP in the preliminary stage. On bio-electrochemicals, total COD and CAP removal were 82.35 and >99.99%, respectively. This coupled system can be applied to eliminate antibiotics and other organic pollutants in agricultural, industrial, municipal, and other wastewaters.

Preparation of F-doped H2Ti3O7-{104} nanorods with oxygen vacancies using TiOF2 as precursor and its photocatalytic degradation activity

Photocatalytic degradation is an eco-friendly and sustainable method for the treatment of water pollutants especially tetracycline hydrochloride (TCH). Herein, we developed F-doped H2Ti3O7-{104} nanorods with oxygen vacancies using TiOF2 as a precursor by simple alkali hydrothermal and ion-exchange methods. The phase structure, surface composition, optical properties, specific surface areas and charge separation were analysed by a series of measurements. The effects of KOH concentration on the structure and properties of H2Ti3O7 were investigated. It is confirmed that the TiOF2/H2Ti3O7 composite can be formed in low concentration KOH solution (1 mol L-1), while the H2Ti3O7 single phase can be formed in high concentration KOH solution (>3 mol L-1). The prepared F-doped H2Ti3O7-{104} nanorods provide a high specific surface area of 457 m2 g-1 and a macroporous volume of 0.69 cm3 g-1. The appropriate mesoporous structure of the photocatalyst makes TCH have a stronger affinity on its surface, which is more conducive to the subsequent photodegradation. Moreover, a synergistic mechanism of photosensitization and ligand-metal charge transfer (LMCT) in the photocatalytic degradation of TCH was proposed. In addition, the prepared F-doped H2Ti3O7-{104} nanorods showed excellent cycle stability and resistance to light corrosion. After five cycles of photodegradation, the degradation rate of TCH was only reduced from 92% to 83%. This low-cost strategy could be used for the mass production of efficient photocatalysts, which can be used for TCH clean-up in wastewater treatment.