Glutamicibacter nicotianae AT6: A new strain for the efficient biodegradation of tilmicosin

The degradation of tilmicosin (TLM), a semi-synthetic 16-membered macrolide antibiotic, has been receiving increasing attention. Conventionally, there are three tilmicosin degradation methods, and among them microbial degradation is considered the best due to its high efficiency, eco-friendliness, and low cost. Coincidently, we found a new strain, Glutamicibacter nicotianae sp. AT6, capable of degrading high-concentration TLM at 100 mg/L with a 97% removal efficiency. The role of tryptone was as well investigated, and the results revealed that the loading of tryptone had a significant influence on TLM removals. The toxicity assessment indicated that strain AT6 could efficiently convert TLM into less-toxic substances. Based on the identified intermediates, the degradation of TLM by AT6 processing through two distinct pathways was then proposed.

Deciphering the core bacterial community structure and function and their response to environmental factors in activated sludge from pharmaceutical wastewater treatment plants

Pharmaceutical wastewater is recognized for its heightened concentrations of organic pollutants, and biological treatment stands out as an effective technology to remove these organic pollution. Therefore, a comprehensive exploration of core bacterial community compositions, functions, and their responses to environmental factors in pharmaceutical wastewater treatment plants (PWWTPs) is important for understanding the removal mechanism of these organic pollutants. This study comprehensively investigated 36 activated sludge (AS) samples from 15 PWWTPs in China. The results revealed that Proteobacteria (45.41%) was the dominant phylum in AS samples, followed by Bacteroidetes (19.54%) and Chloroflexi (4.13%). While the dominant genera were similar in both aerobic and anaerobic treatment processes, their relative abundances exhibited significant variations. Genera like HA73, Kosmotoga, and Desulfovibrio were more abundant during anaerobic treatment, while Rhodoplanes, Bdellovibrio, and Hyphomicrobium dominated during aerobic treatment. 13 and 10 core operational taxonomic units (OTUs) were identified in aerobic and anaerobic sludge, respectively. Further analysis revealed that core OTUs belonging to genera Kosmotoga, Desulfovibrio, Thauera, Hyphomicrobium, and Chelativorans, were associated with key functions, including sulfur metabolism, methane metabolism, amino acid metabolism, carbohydrate metabolism, toluene degradation, and nitrogen metabolism. Furthermore, this study highlighted the crucial roles of environmental factors, such as COD, NH4+-N, SO42-, and TP, in shaping both the structure and core functions of bacterial communities within AS of PWWTPs. Notably, these factors indirectly affect functional attributes by modulating the bacterial community composition and structure in pharmaceutical wastewater. These findings provide valuable insights for optimizing the efficiency of biochemical treatment processes in PWWTPs.

Adsorption of an antiseptic in a functionalized fixed-bed: Analysis of breakthrough scenarios and validation of simplistic models defending a novel proposition

BACKGROUND

Chlorhexidine gluconate (CHG) and cetrimide, which are widely used in various pharmaceutical compositions, are considered potentially hazardous compounds. This combination was largely used during and after Covid 19 pandemic for sanitization. Removal of these two compounds from pharmaceutical waste-water with commercial and functionalized activated carbon in a packed bed column is reported.

METHODS

Effects of changes in bed height, flow rate, and initial concentration on the performance of the packed bed are analyzed using Yoon-Nelson, BDST and Thomas models for commercial scale-up operation. The effects of primary design parameters like bed depth and operating parameters like inflow rate and inlet concentration of influent wastewater are studied on the extent of removal of cetrimide and chlorhexidine gluconate. Granular activated carbon (GAC) is functionalized using HF and NH4OH. The extent of enhanced adsorption using the functionalized GAC is demonstrated using breakthrough curves.

SIGNIFICANT FINDINGS

K. H. Chu's iconic proposition is validated. Breakthrough time (BT) increases with bed heights and it is less in the case of cetrimide as compared to chlorhexidine gluconate. This shows that cetrimide wins in the competition and occupies the pores much faster than CHG. Mostly, BT-CHG (GAC) < BT-CHG (FAC-HF) < BT-CHG (FAC-NH3) and BT-cetrimide (GAC) < BT-cetrimide (FAC-NH3) < BT-cetrimide (FAC-HF) for a particular bed height. BT-CHG(FAC-HF)BT-cetrimide(FAC-HF) Collapse

Key Words

• Adsorption
• Breakthrough
• Covid-19
• Packed bed column
• Pharmaceutical wastewater
• Semi-empirical models

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MESH Headings

• Charcoal
• Water Purification
• Anti-Infective Agents, Local
• Adsorption
• Water Pollutants, Chemical/analysis
• Wastewater
• Cetrimonium
• Pharmaceutical Preparations
• Chlorhexidine/analogs & derivatives

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Grants Collapse

Affiliation(s)

Debamita Pal Department of Chemical Engineering, Jadavpur University, Kolkata, 700032, West Bengal, India
Debasree Banerjee Department of Chemical Engineering, Jadavpur University, Kolkata, 700032, West Bengal, India
Ujjaini Sarkar Department of Chemical Engineering, Jadavpur University, Kolkata, 700032, West Bengal, India.

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Photocatalytic decomposition of metronidazole by zinc hexaferrite coated with bismuth oxyiodide magnetic nanocomposite: Advanced modelling and optimization with artificial neural network

The objective of the present study was to employ a green synthesis method to produce a sustainable ZnFe12O19/BiOI nanocomposite and evaluate its efficacy in the photocatalytic degradation of metronidazole (MNZ) from aqueous media. An artificial neural network (ANN) model was developed to predict the performance of the photocatalytic degradation process using experimental data. More importantly, sensitivity analysis was conducted to explore the relationship between MNZ degradation and various experimental parameters. The elimination of MNZ was assessed under different operational parameters, including pH, contaminant concentration, nanocomposite dosage, and retention time. The outcomes exhibited high a desirability performance of the ANN model with a coefficient correlation (R2) of 0.99. Under optimized circumstances, the MNZ elimination efficiency, as well as the reduction in chemical oxygen demand (COD) and total organic carbon (TOC), reached 92.71%, 70.23%, and 55.08%, respectively. The catalyst showed the ability to be regenerated 8 times with only a slight decrease in its photocatalytic activity. Furthermore, the experimental data obtained demonstrated a good agreement with the predictions of the ANN model. As a result, this study fabricated the ZnFe12O19/BiOI nanocomposite, which gave potential implication value in the effective decontamination of pharmaceutical compounds.

In situ generated iron oxide nanosheet on iron foam electrode for enhanced electro-Fenton performance toward pharmaceutical wastewater treatment

Electro-Fenton (EF) is considered to be an effective technology for the purification of organic wastewater containing antibiotics, but the construction of accessible and efficient heterogeneous EF catalytic materials still faces challenges. In this study, an iron foam-derived electrode (FeOx/if-400) was prepared by a simple method (chemical oxidation combined heat treatment). The fabricated electrode presented great EF degradation efficiency under wide pH range (almost completely removing 50 mg L-1 TNZ within 60 min) and maintained great stability after consecutive operation (>95% removal after six cycles). Also, the FeOx/if-400 electrode showed good purification ability for pharmaceutical wastewater as evaluated by the quadrupole time-of-flight mass spectrometry and the three-dimensional excitation-emission matrix fluorescence spectroscopy. Based on experimental results, characterization analysis, and density functional theory (DFT) calculations, the EF reaction mechanism of FeOx/if-400 electrode and the organics degradation pathways in simulated and real matrices were proposed. Significantly, the biotoxicity assessment of the degradation intermediate products was revealed by ECOSAR software and relative inhibition of E. coli, which fully proved the environmental friendliness of the EF process by the FeOx/if-400 cathode. This work provides a green and effective EF system, showing a promising application potential in the field of organic wastewater treatment containing antibiotic contaminants.

Efficient treatment of veterinary pharmaceutical industrial wastewater by catalytic ozonation process: degradation of enrofloxacin via molecular ozone reactions

The study focused on the efficacious performance of bimetallic Fe-Zn loaded 3A zeolite in catalytic ozonation for the degradation of highly toxic veterinary antibiotic enrofloxacin in wastewater of the pharmaceutical industry. Batch experiments were conducted in a glass reactor containing a submerged pump holding catalyst pellets at suction. The submerged pump provided the agitation and recirculation across the solution for effective contact with the catalyst. The effect of ozone flow (0.8-1.55 mg/min) and catalyst dose (5-15 g/L) on the enrofloxacin degradation and removal of other conventional pollutants COD, BOD5, turbidity was studied. In batch experiments, 10 g of Fe-Zn 3A zeolite efficiently removed 92% of enrofloxacin, 77% of COD, 69% BOD5, and 61% turbidity in 1 L sample of pharmaceutical wastewater in 30 min at 1.1 mg/min of O3 flow. The catalytic performance of Fe-Zn 3A zeolite notably exceeded the removal efficiencies of 52%, 51%, 52%, and 59% for enrofloxacin, COD, BOD5, and turbidity, respectively, achieved with single ozonation process. Furthermore, an increase in the biodegradability of treated pharmaceutical industrial wastewater was observed and made biodegradable easily for subsequent treatment.

Enhanced tetracycline degradation with TiO2/natural pyrite S-scheme photocatalyst

In this study, TiO2 nanoparticles were employed as a photocatalyst for the degradation of tetracycline (TC) under visible light irradiation. The TiO2 nanoparticles were decorated on natural pyrite (TiO2/NP) and characterized using XRD, FTIR, and SEM-EDX methods. This study evaluated the impacts of various operational parameters such as pH, catalyst dosage, initial TC concentration, and light intensity on TC removal. The findings revealed that under optimal conditions (pH 7, catalyst: 2 g/L, TC: 30 mg/L, and light intensity: 60 mW/cm2), 100% of TC and 84% of TOC were removed within 180 min. The kinetics of TC elimination followed a first-order model. The dominant oxidation species involved in the photocatalytic elimination of TC was found to be ·OH radicals in the TiO2/NP system. The reuse experiments showed the high capability of the catalyst after four consecutive cycles. This study confirmed that the TiO2/NP system has high performance in photocatalytic TC removal under optimized experimental conditions.

Pretreatment of 3-hydroxyacetophenone in pharmaceutical wastewater using combined salting-out crystallization+ Fenton system and subsequent impact analysis of effluent water

Selecting a suitable pretreatment process for pharmaceutical wastewater that is difficult to treat biochemically so that it can enter the subsequent biochemical treatment. In this study, pharmaceutical wastewater consisting of 45 g/L sodium bisulfate, 9 g/L 3-hydroxyacetophenone (3-HAP), and 36.75 g/L sulfuric acids,which is a kind of typical pharmaceutical wastewater, was used for the pretreatment case study, and the process was screened by technology. A salting-out crystallization+Fenton system(SC-F) was developed for the treatment of this wastewater. The salting-out agent is formed by the pH adjustment process without additional additions and the salting-out crystallization effect is significant for the precipitation of 3-HAP from the wastewater. Subsequently, the optimal operating conditions for SC-F were derived from experiments as H2O2 of 0.4692 mol/L, n(H2O2):n(Fe2+)=30:1, pH=3. Under optimal conditions, the reaction time of 2 h achieved a COD removal rate of 90% and a BOD/COD value of 0.56, confirming the effectiveness of the technology in treating this wastewater. Additionally, it was discovered that the Fenton treatment was not significantly impacted by the inorganic components of the effluent. Analysis of effluent properties and possible effects on subsequent treatment by LC-MS and toxicity analysis. The results show that the biodegradability are enhanced by the pretreatment technology. However, the effluent still suffers from high acidity and high salt content, and this study proposes a solution to this problem. Furthermore, research on the treatment of 3-HAP wastewater has not been reported and this study provides a new case study in the field of wastewater treatment.

Single-atom Zr embedded Ti4O7 anode coupling with hierarchical CuFe2O4 particle electrodes toward efficient electrooxidation of actual pharmaceutical wastewater

Electrocatalytic oxidation is commonly restricted by low degradation efficiency, slow mass transfer, and high energy consumption. Herein, a synergetic electrocatalysis system was developed for removal of various drugs, i.e., atenolol, florfenicol, and diclofenac sodium, as well as actual pharmaceutical wastewater, where the newly-designed single-atom Zr embedded Ti4O7 (Zr/Ti4O7) and hierarchical CuFe2O4 (CFO) microspheres were used as anode and microelectrodes, respectively. In the optimal reaction system, the degradation efficiencies of 40 mg L-1 atenolol, florfenicol, and diclofenac sodium could achieve up to 98.8%, 93.4%, and 85.5% in 120 min with 0.1 g L-1 CFO at current density of 25 mA cm-2. More importantly, in the flow-through reactor, the electrooxidation lasting for 150 min could reduce the COD of actual pharmaceutical wastewater from 432 to 88.6 mg L-1, with a lower energy consumption (25.67 kWh/m3). Meanwhile, the electrooxidation system maintained superior stability and environmental adaptability. DFT theory calculations revealed that the excellent performance of this electrooxidation system could be ascribed to the striking features of the reduced reaction energy barrier by single-atom Zr loading and abundant oxygen vacancies on the Zr/Ti4O7 surface. Moreover, the characterization and experimental results demonstrated that the CFO unique hierarchical structure and synergistic effect between electrodes were also the important factors that could improve the system performance. The findings shed light on the single-atom material design for boosting electrochemical oxidation performance.

TiO2/graphene composite nanofibers for efficient photocatalytic degradation of pharmaceutical compounds: Rifampin, Phenazopyridine, Azathioprine

Pharmaceutical wastewater treatment is an essential component of environmental protection and sustainable development. In this study, our aim was to investigate the morphology, characterization, and effectiveness of TiO2/graphene composite nanofiber photocatalysts in the treatment of pharmaceutical wastewater containing three different pharmaceutical groups, such as an antibiotic (rifampin), painkiller (phenazopyridine), and immunosuppressant (azathioprine). Various parameters such as pH, salt concentration, and initial pharmaceutical compound concentration were optimized to achieve maximum degradation kinetics and efficiency. The optimum conditions were determined to be 1.5% graphene content, 30 ppm initial concentration of pharmaceutical compound, pH=5, and a 0.5 g/L photocatalyst dose. The presence of salt slightly decreased the degradation kinetics, but it did not significantly affect the performance of the TiO2/graphene composite nanofibers photocatalyst. At optimum condition, TiO2/1.5% graphene composite nanofibers degraded 50% of phenazopyridine, 86.89% of rifampin, and completely azathioprine. Comparing with phenazopyridine, N heteroatom-rich molecule of azathioprine and hydroxyl-rich molecule of rifampin lead to being susceptible to photocatalytic degradation. The reuse of the photocatalyst in multiple cycles showed consistent performance, indicating its potential for practical and economic applications.

Implementation of water hyacinth (Eichhornia crassipes) and water lettuce (Pistia stratiotes) in the re-treatment of conventionally treated pharmaceutical wastewater: a case study of Radiant Pharmaceuticals Limited, Dhaka, Bangladesh

Since Bangladesh already has robust pharmaceutical industries, nearly all companies owned effluent treatment plant (ETP) facilities to improve the quality of wastewater. Water retreatment utilizing affordable, accessible, and environmentally sustainable techniques have not yet been thoroughly investigated. In this study, the potential of water hyacinth and water lettuce was investigated at three different concentrations: 50% of total volume coverages (1000 g macrophytes/2000 ml water), 75% of total volume coverages (1500 g macrophytes/2000 ml water), and 100% of total volume coverages (2000 g macrophytes/2000 ml water) on the post-treated ETP's wastewater for 3 weeks in a mesocosm environment. Heavy metals, such as chromium (Cr) and nickel (Ni) along with physicochemical parameters (pH, EC, TDS, DO, and BOD5) were measured after 7 days intervals. Results indicated that water hyacinth was considerably more efficient than water lettuce at removing many factors, including metals. Water hyacinth was able to remove 79.15% of nickel and 92.97% of chromium while also increasing DO and EC by 36.72% and 14.59%, respectively, at 100% of total volume coverages. On the other hand, 100% of the total volume coverage of water lettuce decreased the pH, TDS, and BOD5 readings by 6.70%, 31.62%, and 87.61%, respectively. With each treatment, the water quality significantly improved over the control. The findings suggest that the pharmaceutical industries may improve the quality of their treated wastewater even more by integrating phytoremediation technology with traditional ETP facilities.

Synthesis and characterization of rGO/Fe0/Fe3O4/TiO2 nanocomposite and application of photocatalytic process in the decomposition of penicillin G from aqueous

In this study, we synthesized rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite according to Hummer's, and straightforward sol-gel method. The FESEM, EDX, TEM, FT-IR, XRD, BET, UV spectra, and VSM analysis were applied to determine the catalyst properties. Optimization of influence parameters on photocatalytic process performance to penicillin G degradation in aqueous media. pH (4-8), nanocomposite dose (10-20 mg/L), reaction time (30-60 min), and penicillin G concentration (50-100 mg/L) were optimized via central composite design. In the optimum condition of PCP, supplementary studies were done. As a result of the analysis, the nanocomposite was well synthesized and displayed superior photocatalytic properties for degrading organic pollutants. In addition to being magnetically separable, the synthesized rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite exhibits high recyclability up to 5 times. The quadratic model of optimization is based on the adjusted R²(0.99), and predicated R²(0.97) suggested. According to the analysis of variance test, the model was significant (F-Value = 162.95, P-Value = 0.0001). Photocatalytic process is most efficiently decomposed at pH = 6.5, catalyst dose = 18.5 mg/L, reaction time = 59.1 min, and penicillin G concentration = 52 mg/L (efficiency = 96%). The chemical oxygen demand and total organic carbon decrease were 78, and 65%. The photolysis and adsorption mechanism as a single mechanism had lower performance in penicillin G degradation. Benzocaine had the greatest effect on reducing the efficiency of the process as a radical scavenger. The °OH, h^+, and O₂^●- were the main reactive oxidant species in penicillin G removal. Phenoxyacetaldehyde, Acetanilide, Diacetamate, Phenylalanylglycine, N-Acetyl-l-phenylalanine, Diformyldapsone, and Succisulfone were the main intermediates in penicillin G degradation. The results indicated the photocatalytic process with rGO/Fe⁰/Fe₃O₄/TiO₂ nanocomposite on a laboratory scale has good efficiency in removing penicillin G antibiotic. The application of real media requires further studies.

Decoration of polylactic acid on graphene oxide for efficient adsorption of methylene blue and tetracycline

Decorating nanomaterials on graphene oxide (GO) can enhance its adsorption capacity and removal efficiency of water pollutants. In this study, for the first time, nano-sized polylactic acid (PLA) has been successfully decorated on the surface of GO through a facile synthesis approach. The adsorptive efficiency of GO-PLA for removing methylene blue (MB) and tetracycline (TC) from an aqueous solution was examined. The characterization confirmed the successful decoration of PLA on GO nanosheets with the nano size of PLA. It was hypothesized that the PLA was decorated on the surface of GO through covalent bonding between oxygen-containing functional groups and lactide molecules. The optimum adsorption parameters determined were at the adsorbent dose of 0.5 g L^-1, pH 4, contact time of 120 min, and temperature of 318 K. The pseudo-second-order kinetic model described the contaminants' adsorption behaviour, and the intraparticle diffusion model revealed that both surface adsorption and intraparticle diffusion controlled the adsorption process. Langmuir isotherm model best described the adsorption behaviour of the pollutants on GO-PLA and demonstrated the maximum monolayer uptake capacities of MB (332.5 mg g^-1) and TC (223.7 mg g^-1). The adsorption results indicated that the uptake capacities of GO-PLA in comparison to GO have increased by approximately 70% and 110% for MB and TC, respectively. These observations reflect the remarkable role of nano-sized PLA that enhanced the adsorption capacity due to its additional functional group and larger surface area.

Global trends in the research and development of medical/pharmaceutical wastewater treatment over the half-century

The COVID-19 pandemic has severely impacted public health and the worldwide economy. The overstretched operation of health systems around the world is accompanied by potential and ongoing environmental threats. At present, comprehensive scientific assessments of research on temporal changes in medical/pharmaceutical wastewater (MPWW), as well as estimations of researcher networks and scientific productivity are lacking. Therefore, we conducted a thorough literature study, using bibliometrics to reproduce research on medical wastewater over nearly half a century. Our primary goal is systematically to map the evolution of keyword clusters over time, and to obtain the structure and credibility of clusters. Our secondary objective was to measure research network performance (country, institution, and author) using CiteSpace and VOSviewer. We extracted 2306 papers published between 1981 and 2022. The co-cited reference network identified 16 clusters with well-structured networks (Q = 0.7716, S = 0.896). The main trends were as follows: 1) Early MPWW research prioritized sources of wastewater, and this cluster was considered to be the mainstream research frontier and direction, representing an important source and priority research area. 2) Mid-term research focused on characteristic contaminants and detection technologies. Particularly during 2000-2010, a period of rapid developments in global medical systems, pharmaceutical compounds (PhCs) in MPWW were recognized as a major threat to human health and the environment. 3) Recent research has focused on novel degradation technologies for PhC-containing MPWW, with high scores for research on biological methods. Wastewater-based epidemiology has emerged as being consistent with or predictive of the number of confirmed COVID-19 cases. Therefore, the application of MPWW in COVID-19 tracing will be of great interest to environmentalists. These results could guide the future direction of funding agencies and research groups.

Preparation of sludge-based micro-electrolysis filler and its application in pharmaceutical wastewater treatment by an up-flow aerated filter

Sewage sludge (SS) and raw pharmaceutical wastewater (RPW) are both toxic and harmful wastes, which are a menace to human and animal health and the ecosystem. A sludge-base micro-electrolysis filler (SMEF) was gained by SS and Fe powder as the primary raw materials. The preparation process of the SMEF was achieved based on the tetracycline hydrochloride (TCH) removal efficiency. The physicochemical characteristics (e.g., surface area, morphology features, function groups, and valence state of Fe) of the obtained SMEF were decided. With an Fe/SS ratio of 1/2, a sintering temperature of 1050 °C, a sintering time of 30 min, an initial pH of 3, and a filler dosage of 100 g/L, the SMEF demonstrated a high degradation ability for TCH with a removal rate reached 95.62% in 24 h. Kinetic analysis showed that the adsorption process of TCH was consistent with the pseudo-first-order Lagergren kinetic model. Moreover, degradation mechanism analysis showed that TCH was gradually degraded through dehydroxylation, demethylation, ring opening, oxidation, and reduction in solution. The SMEF had a good continuous removal performance for contaminants in RPW in an up-flow aerated filter. The removal efficiency of TOC and TN reached 46.60 and 42.27% within 24 h, respectively. The treated pharmaceutical wastewater was considered non-biotoxic after 24-h treatment with the SMEF. This study presents a innovative Fe-C micro-electrolysis filler based on SS and is important to the environmental-friendly recycling of SS and sustainable treatment of RPW, achieving the purpose of waste disposal.

Efficient photocatalysis of tetracycline hydrochloride (TC-HCl) from pharmaceutical wastewater using AgCl/ZnO/g-C3N4 composite under visible light: Process and mechanisms

AgCl/ZnO/g-C₃N₄, a visible light activated ternary composite catalyst, was prepared by combining calcination, hydrothermal reaction and in-situ deposition processes to treat/photocatalyse tetracycline hydrochloride (TC-HCl) from pharmaceutical wastewater under visible light. The morphological, structural, electrical, and optical features of the novel photocatalyst were characterized using scanning electron microscopy (SEM), UV-visible light absorption spectrum (UV-Vis DRS), X-ray diffractometer (XRD), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS), and transient photocurrent techniques. All analyses confirmed that the formation of heterojunctions between AgCl/ZnO and g-C₃N₄ significantly increase electron-hole transfer and separation compared to pure ZnO and g-C₃N₄. Thus, AgCl/ZnO/g-C₃N₄ could exhibit superior photocatalytic activity during TC-HCl assays (over 90% removal) under visible light irradiation. The composite could maintain its photocatalytic stability even after four consecutive reaction cycles. Hydrogen peroxide (H₂O₂) and superoxide radical (^·O₂) contributed more than holes (h⁺) and hydroxyl radicals (^·OH) to the degradation process as showed by trapping experiments. Liquid chromatograph-mass spectrometer (LC-MS) was used for the representation of the TC-HCl potential degradation pathway. The applicability and the treatment potential of AgCl/ZnO/g-C₃N₄ against actual pharmaceutical wastewater showed that the composite can achieve removal efficiencies of 81.7%, 71.4% and 69.0% for TC-HCl, chemical oxygen demand (COD) and total organic carbon (TOC) respectively. AgCl/ZnO/g-C₃N₄ can be a prospective key photocatalyst in the field of degradation of persistent, hardly-degradable pollutants, from industrial wastewater and not only.

Removal of ceftriaxone sodium antibiotic from pharmaceutical wastewater using an activated carbon based TiO2 composite: Adsorption and photocatalytic degradation evaluation

The water pollution becomes a serious concern for the sustainability of ecosystems due to the existence of pharmaceutical products (ceftriaxone (CEF) antibiotic). Even in low concentration of CEF has lethal effects on ecosystem and human health. To remove CEF, TiO₂ is considered as an effective and efficient nanoparticles, however its performance is reduced due to wider energy gap and rapid recombination of charge carriers. In this study, activated carbon based TiO₂ (ACT-X) heterogeneous nanocomposites were synthesized to improve the intrinsic properties of TiO₂ and their adsorption-photocatalytic performance for the removal of CEF. The characterization results revealed that ACT-X composites have slower recombination of charge carriers, lower energy band gap (3.05 eV), and better light absorption under visible region of light. From ACT-X composites, the ACT-4 photocatalyst has achieved highest photocatalytic degradation (99.6%) and COD removal up (99.2%). The results of radical scavengers showed that photocatalytic degradation of CEF is mainly occurred due to superoxide and hydroxyl radicals. Meanwhile, the reusability of ACT-4 up to five cycles shows more than 80% photocatalytic degradation, which make the process more economical. The highest experimental adsorption capacity is achieved up to 844.8 mg g^-1 using ACT-4. The favorable and multilayer heterogeneous adsorption is carried out according to the well-fitted data with pseudo-second-order and Freundlich models, respectively. These results indicate that the carbon-based TiO₂ composites can be used as a green, stable, efficient, effective, reusable, renewable, and sustainable photocatalyst to eliminate the pharmaceutical pollutants (antibiotics) via adsorption and photocatalytic degradation processes.

Construction of bacterial consortium for efficient degradation of mixed pharmaceutical dyes

Synthetic dyes are established colorants in the pharmaceutical industries for the coating and coloration of tablets, capsules, etc. to mark the specific formulation and dosage, improve the stability, and esthetic value. The pharmaceuticals manufacturing process releases large volumes of dye-containing wastewaters, contributing to eco-toxic concerns related to different health risks. In this study, biodegradation of amaranth, sunset yellow, tartrazine, indigo carmine, and quinoline yellow dyes was investigated in the mixed environment. Initially, 24 tolerant bacterial strains were isolated from pharmaceutical wastewater samples, among which 19 strains were found to be non-virulent. Five different consortia were constructed by considering the 19 strains among which C1 consisting of strains DY7, 10, 11, and 18 was found to be the most potential consortium with an overall efficiency of 96.65% dye degradation in the presence of glucose after 15 days. The strains DY7, 10, 11, and 18 were identified as members of the Klebsiella genus by 16S rRNA partial sequencing. The cell wall structure, carbohydrate utilization profile, and metabolic characterization were conducted on the selected strains of C1. Among the 25 different antibiotics, DY7 and DY11 exhibited the highest zone of growth inhibition in the presence of cefixime, and DY10 was restricted by chloramphenicol whereas DY18 was found sensitive to ceftazidime/tazobactam.

Pre-treatment of real pharmaceutical wastewater by heterogeneous Fenton and persulfate oxidation processes

This study compares the pre-oxidation of pharmaceutical wastewater by hydroxyl radical based advanced oxidation (HR-AOP) and a sulfate radical based advanced oxidation process (SR-AOP). The heterogeneous Fenton process is chosen as a model HR-AOP and persulfate (PS) activation as a model SR-AOP. The pre-treatment efficacy of both processes in terms of TOC, and COD removals using Fe₃O₄-rGO catalyst were considered. Under the investigated experimental conditions, both processes yielded fluctuating COD values with time. The heterogeneous Fenton process discovered to be the most efficient to remove 68.7% TOC in 180 min of treatment, when Fe₃O₄-rGO: H₂O₂ = 300 mg L^-1:150 mM H₂O₂ was used at pH 3. Notably, the heterogeneous Fenton system was not considerably inhibited at the natural pH of pharmaceutical wastewater (6.75), as the process successfully removed 64.6% TOC. On the other hand, in persulfate activation studies, Fe₃O₄-rGO: PS = 400 mg L^-1: 5 mM was the ideal condition for removing 59.5% TOC in 180 min at pH 3. Whereas the natural pH condition significantly inhibited the TOC removal, as only 20.8% TOC removal was feasible. The wastewater characterisation before and after Fenton treatment reveals that Fenton oxidation leads to an increase in inorganics (chlorides: 160 ± 15 mg L^-1, nitrates: 63.14 ± 3.08 mg L^-1, sulfates: 266.31 ± 31.39 mg L^-1) necessitating an additional treatment step to reduce COD and inorganics further.

Fabrication and characterization of pectin-graphene oxide-magnesium ferrite-zinc oxide nanocomposite for photocatalytic degradation of diclofenac in an aqueous solution under visible light irradiation

Wastewater containing pharmaceutical contaminants has become a critical environmental concern due to rising population and drug consumption caused by increased life expectancy. Diclofenac (DCF) is one of the most applicable drugs for veterinary and human health purposes, polluting surface waters in different ways. This work aims to synthesize a novel pectin-graphene oxide (GO)-magnesium ferrite (MgFe₂O₄)-zinc oxide (ZnO) nanocomposite (PGMZ) for photocatalytic degradation of DCF in an aquatic environment under visible light irradiation. The single and synthesized nanocomposites were characterized by several analyses, confirming the successful synthesis of the nanocomposite. Effects of four operation conditions, including nanocomposite dosage (1-1.25 g/L), nanocomposite type, initial contaminant concentration (35-55 mg/L), and solution pH (3-11), were investigated on the degradation performance. From the kinetic study, the effect of mixing two composites, i.e., synergy percentage, was 38.7% when ZnO-MgFe₂O₄ particles were added to the GO-pectin structure. By examining the effect of different free radical enhancers and scavenging compounds on the DCF photodegradation, the most influential scavenging components were in the following order; NaCl > Na₂CO₃ > Na₂SO₄, while K₂S₂O₈ was a better enhancer than H₂O₂ at their optimal concentration. Finally, the PGMZ photocatalyst was reused six times with a reduction of about 20% in its removal efficiency, indicating excellent reusability and stability.

Design of TiO2/Ag3BiO3 n-n heterojunction for enhanced degradation of tetracycline hydrochloride under visible-light irradiation

Pharmaceutical residual contaminants in aquatic ecosystems have caused severe risks to human health. Affordable, eco-friendly and effective photocatalysts to deal with these pollutants has become a hot topic in the scientific community. In this research, Ag₃BiO₃ nanoparticles were embedded on TiO₂ to form n-n heterojunction through a facile hydrothermal method. According to scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FT-IR), brunauer emmett teller (BET), electrochemical impedance spectroscopy (EIS), X-ray photoelectron spectroscopy (XPS), energy-dispersive X-ray spectroscopy (EDS), photoluminescence (PL), X-ray diffraction (XRD), transmission electron microscopy (TEM), and UV-vis diffuse reflectance spectroscopy (UV-vis DRS) tests, the successful construction of TiO₂/Ag₃BiO₃ heterojunction is proved. TiO₂/Ag₃BiO₃ heterojunctions were employed as photocatalysts to remove tetracycline hydrochloride (TCH) under visible light irradiation in aqueous solution. Optimum TCH photodegradation efficiency was observed for TiO₂/Ag₃BiO₃ (10%), 15.4 times superior to that of TiO₂. The enhanced TCH photodegradation efficiency of TiO₂/Ag₃BiO₃ results from improved light absorption capacity and the reduction of recombination of photogenerated charge carriers via generation of n-n heterojunctions. The mechanism of increasing the photodegradation efficiency of TCH was determined by employing reactive species quenching experiments. TiO₂/Ag₃BiO₃ (10%) also exhibited an acceptable stability.

Design and preliminary techno-economic assessment of a pilot scale pharmaceutical wastewater treatment system for ammonia removal and recovery of fertilizer

Recovery of nutrients from wastewater has a paramount importance for a sustainable and safe environment. In this study removal of ammonia and recovery of resources in the form of struvite from a complex pharmaceutical acidic wastewater having high concentration of ammoniacal nitrogen (NH₄-N > 40 g/L) and other co-existing contaminants (magnesium, phosphorous, phenol etc.) was explored. Response Surface Methodology (RSM) was employed for design of experiments and process optimization. RSM results revealed that removal of ammoniacal nitrogen, i.e., struvite precipitation was found to be maximum in alkaline pH (10.5-11.0) at a N:Mg molar ratio (1:0.030 to 1:0.035) and N:P molar ratio (1:0.025 to 1:0.030). X-Ray diffraction, thermo-gravimetric analysis and Fourier transform-infrared spectroscopy confirmed the presence of struvite crystals in the obtained precipitate. Techno-economic assessment (TEA) based on mass energy balance principle and market equipment specifications revealed that a pilot-scale plant set up would have a break-even period of 1.06 years with a return on investment as 94.28%. This clearly elucidated the economic viability of the developed process for industrial applications for management of high ammonia laden pharmaceutical wastewater. While further specific technological improvements are needed for reduction of cost, this study will guide researchers and industries for careful selection of target markets to reduce the cost for successful implementation.

Self-cleaning MnZn ferrite/biochar adsorbents for effective removal of tetracycline

A renewable tri-metallic spinel decorated biochar adsorbent (MZF-BC) was fabricated by a facile hydrothermal method and to remove tetracycline. The physicochemical properties of MZF-BC were well studied. MZF-BC with a hybrid pore structure of mesopores (~7.6 nm) and macropores (~50 nm) has the maximum tetracycline adsorption capacity reaching 142.4 mg g^-1. Through the study of adsorption kinetics, isotherms and key influencing factors, it was found that MZF-BC adsorption on tetracycline was primarily multi-layer effect with the initial adsorption behavior of pore filling associated with hydrogen bonding and π-π stacking. Furthermore, the MZF-BC performs excellent regeneration ability by driving Fenton-like catalysis as the self-cleaning process in the liquid phase. This study contributes to a new insight into the in-situ regeneration of biochar-based adsorbents after adsorbing organic pollutants in pharmaceutical wastewater treatment.

Facile synthesis of electrocatalytically active bismuth oxide nanosheets for detection of palladium traces in pharmaceutical wastewater

Current synthesis routes of bismuth oxide nanosheets (BiONS) are relatively complicated, requiring the use of halogens or metalloids. Herein, a facile method to synthesize BiONS without the addition of halogens or other metalloids was developed. The synthesized BiONS were identified to have flake-shaped structures (300-1000 nm in width) with the thickness of 6-10 nm, which were predominantly made of β-Bi₂O₃. Such BiONS were applied to modify the surface of screen-printed carbon electrodes (BiONS-SPCEs) for the development of a robust palladium (Pd²⁺) sensor. After optimizing the electrochemical parameters of the sensor, it was found that the linear sensor response range and limit of detection for Pd²⁺ were 40-400 and 1.4 ppb, respectively. The electrocatalytic activity of the Pd²⁺-sensor was validated in the competing environment of other metal and metalloid ions. Real samples collected during a Pd recovery process from pharmaceutical wastewater were used to verify the application of BiONS-SPCEs in control of palladium recovery process. The quantitative results of post recovery palladium concentrations obtained using BiONS-SPCEs in treated pharmaceutical wastewater samples were in good agreement with those obtained by inductively coupled plasma-optical emission spectrometry (ICP-OES). Thus, such Pd²⁺-sensor provided the possibility of on-site process control of complex industrial samples for obtaining near-instant information that would lead to better management of resources used in the process, and same time assure environmental standards for both recovered products and processed discharge.

Synthesis of new hybrid composite based on TiO2 for photo-catalytic degradation of sulfamethoxazole and pharmaceutical wastewater, optimization, performance, and reaction mechanism studies

In this study photo-catalytic degradation of sulfamethoxazole (SMX) from aqueous solutions using carbon quantum dot (CQD)-decorated Cu-TiO₂ was investigated. The as-prepared photo-catalyst samples were characterized by various FTIR, XRD, FE-SEM, TEM, EDX, BET, and DRS techniques. The investigation of effective photo-catalytic operational parameters confirmed that the complete removal of SMX (20 mg/L) can be accomplished at pH: 6.0 and light intensity: 75 mW/cm² over a 30-min reaction time. DRS analysis demonstrated adding CQD to the Cu-TiO₂ reduced its bandgap energy from 2.97 to 2.90 eV. The photo-catalytic degradation kinetics of SMX fit well with the pseudo-first-order model. The radical trapping experiment indicates that HO^• and O₂^•- active species were more effective species for SMX degradation, and the higher inhibition effect on the SMX degradation efficiency was assigned to O₂^•- ions. The water matrix species-inhibited effect in SMX removal was as follows: SO₄^2- > Cl^- > NO₃^- > CO₃^- > no ions. The synthesized photo-catalyst could be recycled after six consecutive cycles of SMX degradation with an insignificant decrease in performance. The total organic carbon (TOC) analysis suggested the mineralization of SMZ by composite photo-catalysts. The minimum inhibitory concentration (MIC) for Escherichia coli remained at 12.5 mg L^-1 SMX. A possible mechanism and pathway of SMX degradation in the photo-catalytic system was presented.

Highly efficient amino-functionalized aluminum-based metal organic frameworks mesoporous nanorods for selective extraction of hydrocortisone in pharmaceutical wastewater

Hydrocortisone (HC), as a common steroid hormone drug, is also one of the key intermediates involved in the synthesis of multiple steroid hormone drugs. Residual HC in pharmaceutical wastewater frequently pollutes environmental water as steroid hormone contaminant and possesses great threat to human health as well as sustainable development of the ecosystem. Herein, in order to develop a highly efficient adsorbent system for selective enrichment and detection of HC in pharmaceutical wastewater, a novel amino-functionalized aluminum-based metal organic frameworks (Al-MOFs@NH₂) mesoporous nanorod is fabricated, in which 2-aminoterephthalic acid plays a dual role as organic linker and functional modification unit. The resultant Al-MOFs@NH₂ not only exhibits stable mesoporous structure but also has large specific surface area (849.76 m² g^-1) and plentiful binding sites, which significantly increases the adsorption capacity for HC. Under the promotion of hydrogen bonding and hydrophobic interaction together, Al-MOFs@NH₂ possesses high adsorption capacity (218.53 mg g^-1) for HC, as well as shows satisfactory selectivity for HC and other steroid hormones. Moreover, a method using Al-MOFs@NH₂ as solid phase extraction adsorbents combined with high performance liquid chromatography (HPLC) has been developed to specifically enrich and detect trace amount of HC in pharmaceutical wastewater. The developed method has a low limit of detection (LOD) (0.5×10^-3 μg mL^-1) and shows satisfactory recoveries for HC (75.9%-102.5%) with an acceptable relative standard deviation (RSD). These results demonstrate that the facile one-step preparation and excellent adsorption capacity makes Al-MOFs@NH₂ attractive to capture and remove environmental steroid hormone pollutants. More importantly, the method proposed in this work is expected to provide a prospective solution for analysis of strong bioactive contaminants in pharmaceutical wastewater.

Recent development on core-shell photo(electro)catalysts for elimination of organic compounds from pharmaceutical wastewater

Pharmaceutical organics are a vital milestone in contemporary human research since they treat various diseases and improve the quality of human life. However, these organic compounds are considered one of the major environmental hazards after the conception, along with the massive rise in antimicrobial resistance (AMR) in an ecosystem. There are various biological and catalytic technologies existed to eliminate these organics in aqueous system with their limitation. Advanced Oxidation processes (AOPs) are used to decompose these pharmaceutical organic compounds in the wastewater by generating reactive species with high oxidation potential. This review focused various photocatalysts, and photocatalytic oxidation processes, especially core-shell materials for photo (electro)catalytic application in pharmaceutical wastewater decomposition. Moreover, we discussed in details about the design and recent developments of core shell catalysts and comparison for photocatalytic, electrocatalytic and photo electrocatalytic applications in pharmaceutical wastewater treatment. In addition, the mixture of inorganic and organic core-shell materials, and metal-organic framework-based core-shell catalysts discussed in detail for antibiotic degradation.

Towards practical integration of MBR with electrochemical AOP: Improved biodegradability of real pharmaceutical wastewater and fouling mitigation

In the current study, we report enhanced treatment of real pharmaceutical wastewater by integration of Electrooxidation (EO) with Membrane Bio-Reactor (MBR) for the first time. Integrated pre-pilot EO-MBR plant consisted of a 3D printed electrochemical flowcell equipped with graphite electrodes installed in the effluent recirculation line of an MBR equipped with a hollow fiber membrane module. Results demonstrated that 5 V was the optimum voltage level for an isolated EO system. Isolated EO system led to 40% COD removal and 2.5 fold biodegradability index (BOD₅/COD) improvement after 24 hr treatment at the optimum voltage of 5 V and 160 mL.min^-1 flowrate. Almost complete removal of COD and BOD₅ was observed for the EO-MBR system with 160 mL.min^-1 recirculation rate and 24 hr HRT, while respective values were 60 and 87% for the MBR system at same operational conditions. Oxidation of pharmaceutical compounds identified in real wastewater and the fate of main oxidation-recalcitrant by-products were confirmed using liquid chromatography techniques. In addition, the integrated EO-MBR system led to significant membrane fouling mitigation with a 28 day extended operational time before reaching the Trans Membrane Pressure (TMP) limit value of 30 kPa. Measurements revealed reduced Extracellular Polymeric Substances (EPS) Concentration of membrane sludge cake layer of EO-MBR along with significant reduction of proteinaceous compounds in the LB-EPS fraction of cake layer in comparison with isolated MBR system. Fouling behavior improvement of the EO-MBR system was attributed to the electrophilic attack of electrochemically generated hydroxyl radicals to the electron-rich moieties of EPS organic foulants. Reduced proteinaceous/humic-like substances of LB-EPS from the cake layer were further confirmed by Emission Excitation matrix (EEM) and Fourier Transform InfraRed (FTIR) spectroscopic methods. The results of current research provide a helpful basis for future studies by elucidating the complex operating/fouling mechanism of integrated Advanced Oxidation Processes (AOPs) with MBR systems for enhanced treatment of organics polluted wastewaters with low biodegradability.

Advanced electro-Fenton degradation of a mixture of pharmaceutical and steel industrial wastewater by pallet-activated-carbon using three-dimensional electrode reactor

In the present work, a three-dimensional electrode reactor (3Der) using pallet activated carbon (PAC), as particle electrodes, was investigated to degrade non-biodegradable organic pollutants in pharmaceutical wastewater and steel industry wastewater. The effect of operating parameters, such as pH, electrode distance, O₂ flow rate, and current density was investigated. The TOC removal efficiency in 3Der was achieved at the highest mineralization yield of 94.1% after 180 min electrolysis, which was 10-19% higher than the two-dimensional electrode reactor (2Der). The higher performance of the 3Der can be attributed to the indirect and direct oxidation mechanisms. The impact of supporting electrolytes was decreased in order as chloride > nitrate > sulfate. The morphology of sludge and the presence of Fe(OH)₃ after Fenton-oxidation were investigated. 3Der system improved biodegradability of pharmaceutical wastewater after electro-Fenton treatment at a PW/SIW ratio of 3:1 (BOD₅/COD = 0.6). Hence, the mechanism of 3Der/PAC, as particle electrodes was also proposed. 3Der with PAC particle electrodes using steel industry wastewater as a catalyst is an exciting technique for remediation of organic contaminated pharmaceutical wastewater.

Removal of denatured protein particles enhanced UASB treatment of oxytetracycline production wastewater

Enhanced hydrolysis, which can selectively destroy antibiotic potency, has been previously demonstrated to be an effective pretreatment technology for the biological treatment of antibiotic production wastewater. However, full-scale application of enhanced hydrolysis to the treatment of real oxytetracycline production wastewater showed that the up-flow anaerobic sludge blanket (UASB) reactors treating the pretreated wastewater could only be stable under a low organic loading rate (OLR) of 1.8 ± 0.4 g·COD/L/d. Deterioration of UASB was also confirmed in treating the same wastewater using a bench-scale reactor (R1) at an OLR of 4.4 ± 0.3 g·COD/L/d. Assuming that the particles formed due to the denaturation of soluble proteins under the hydrolysis temperature (110 °C), resulting in the significant increase of suspended solids (SS) in oxytetracycline production wastewater from less than 200 mg/L to 1200 ± 500 mg/L, were responsible for the deterioration of UASB, the pretreated wastewater was filtered using polypropylene cotton fiber and ultrafiltration membrane, and then fed into two parallel bench-scale UASB reactors (R2 and R3). Both reactors maintained a stable COD removal (53.2% ~ 61.1%) even at an OLR as high as 8.0 g·COD/L/d. When the feed of R3 was switched to unfiltered wastewater, however, deterioration of the reactor occurred again. Microscopic observation showed that the granules in R3 were fully covered by protein particles after the switch of the feed. It was possible that the tight layer of the denatured protein particles blocked the inner pores of the granules, resulting in the obstruction of substrate transfer and biogas emission, while removing the protein particles could abate such blockage problem. This study provides a scientific basis for the efficient treatment of antibiotic production wastewater.

Treatment of fluorine-containing pharmaceutical wastewater by VUV/UV process

As an advanced oxidation process, vacuum ultraviolet/ultraviolet (VUV/UV) has been intensively studied for drinking water treatment, but assessment of its feasibility for wastewater treatment has rarely been conducted. This study investigated the treatment of fluorine-containing pharmaceutical wastewater by VUV/UV process and examined the defluorination and therefore the improvement of biodegradability of the wastewater after the process. The results indicated that the degradation of a model fluorine-containing organic compound (namely, 4-fluorophenol) was mainly achieved via the attack of the fluorine atom linking directly to the aromatic ring by the HO^• generated from VUV photolysis of water. As the solution pH increased from 4.0 to 10.0, the COD removal efficiency of the real pharmaceutical wastewater decreased slightly from 18.1 to 15.9%, while the release ratio of F^- increased from 50.8 to 75.5%. As the dissolved oxygen increased from 0.15 to 12 mg L^-1, the removal efficiency of COD and the release ratio of F^- increased from 9.2 to 17.1% and from 48.2 to 75.5%, respectively. The biodegradability index (BOD/COD) increased significantly from 0.24 to 0.47 after the VUV/UV irradiation, which confirmed the feasibility of applying the VUV/UV process for improving biodegradability of the pharmaceutical wastewater.

Enhancing anaerobic digestion of pharmaceutical industries wastewater with the composite addition of zero valent iron (ZVI) and granular activated carbon (GAC)

Anaerobic digestion of pharmaceutical wastewater is challenged by its contained toxic compounds which limits the stability and efficiency of methane production and organic degradation. In this study, zero valent iron (ZVI) and granular activated carbon (GAC) were added with different strategies to improve anaerobic digestion of pharmaceutical wastewater. The results confirmed synergy effects of ZVI + GAC for both COD removal (increased by 13.4%) and methane production (increased by 11.0%). Furthermore, ZVI + GAC improved the removal of pharmaceutical intermediates, in particular, the residues (%) of dehydroepiandrosterone (DHEA) and 2,2'-methylenebis(6-tert-butyl-4-methylphenol) were only 30.48 ± 6.53 and 39.92 ± 4.50, and effectively reduced biotoxicity. The promoted results were attributed to the establishment of direct interspecies electron transfer (DIET). Microbial community analysis revealed that ZVI + GAC decreased species evenness and richness in bacterial whereas increased in archaeal. The relative abundance of acetotrophic methanogens decreased but hydrogenotrophic and methylotrophic methanogens increased, which broadening the pathway of methane production.

Bioaugmentation of electrogenic halophiles in the treatment of pharmaceutical industrial wastewater and energy production in microbial fuel cell under saline condition

Pharmaceutical wastewater with different toxic recalcitrant materials and high salinity requires a novel treatment technology before released into the environment. The present research details the treatment of pharmaceutical wastewater along with energy production using bioaugmentation of halophilic consortium in air cathode microbial fuel cell (ACMFC) under saline condition (4%). Organic load (OL) varied from 1.04 to 3.51 gCOD/L was studied in ACMFC. TCOD (Total Chemical Oxygen Demand) removal exhibited 65%, 72%, 84% and 89% at 1.04, 1.52, 2.01 and 2.52 gCOD/L OL respectively. SCOD (Soluble Chemical Oxygen Demand) removal of 60%, 66%, 76% and 82% was recorded during the operation of identical OL (1.04-2.52 gCOD/L). Prominent TCOD (92%), SCOD (90%), TSS (Total Suspended Solids) removal of 73% was attained at 3.02 gCOD/L OL with corresponding energy production of 896 mV (Current density (CD) - 554 mA/m², Power density (PD)-505 mW/m²). CE (Columbic Efficiency) was 43%, 38%, 33%, 30%, 28% and 22% at different OL ranged between 1.04 and 3.51 gCOD/L. Increase in OL to 3.51 gCOD/L revealed decrement in TCOD (68%), SCOD (62%), TSS (52%) removal and energy production (CD-234 mA/m², PD-165 mW/m²). Complete removal of phenol was accomplished at different OL in 6 (1.04, 1.52 gCOD/L) and 8 (2.01, 2.52 and 3.02 gCOD/L) days respectively. Ochrobactrum, Marinobacter, Bacillus and Rhodococcus were the dominant halophilic electrogenic strain in ACMFC at different OL.

Feasibility of partial-denitrification/ anammox for pharmaceutical wastewater treatment in a hybrid biofilm reactor

Biological nitrogen removal from pharmaceutical wastewater has drawn increasing attention due to biotoxicity and inhibition. In this study, for the first time, a novel approach integrating partial-denitrification with anaerobic ammonia oxidation (PD/A) in a sequencing biofilm batch reactor (SBBR) was proposed and demonstrated to be efficient to treat the bismuth nitrate and bismuth potassium citrate manufacturing wastewater, containing ammonia (NH₄⁺-N) and nitrate (NO₃^--N) of 6300±50 mg L ^- 1 and 15,300±50 mg L ^- 1. The maximum anammox activity was found at the shock effect of influent total nitrogen (TN) of 100 mg L ^- 1 with NO₃^--N/NH₄⁺-N of 1.0. Long-term operation demonstrated that the PD/A biofilm was developed rapidly after 30 days using synthetic influent, with TN removal efficiency increasing from 40.9% to 80.8%. Significantly, the key bacteria for PD/A had high tolerance and adapted rapidly to pharmaceutical wastewater, achieving a relatively stable TN removal efficiency of 81.2% with influent NH₄⁺-N and NO₃^--N was 77.9 ± 2.6 and 104.1 ± 4.4 mg L ^- 1 at a relatively low COD/NO₃^--N of 2.6. Anammox pathway contributed to TN removal reached 83.6%. Significant increase of loosely-bound extracellular polymeric substances was obtained with increasing protein of 3-turn helices structure as response to the inhibitory condition. High-throughput sequencing analysis revealed that the functional genus Thauera was highly enriched in both biofilms (9.5%→43.6%) and suspended biomass (15.5%→57.5%), which played a key role in high NO₂^--N accumulation. While the anammox bacteria decreasing from 7.8% to 1.6% in biofilm, and from 1.8% decreased to 0.1% in the suspended sludge. Overall, this study provides a new method of high-strength pharmaceutical wastewater treatment with low energy consumption and operation cost, as well as a satisfactory efficiency.

Antibiotic residues in wastewaters from sewage treatment plants and pharmaceutical industries: Occurrence, removal and environmental impacts

Sewage treatment plants (STPs) and pharmaceutical manufactories (PMFs) are recognized as important reservoirs for aquatic pollution with antibiotics. Although the occurrence of multiple classes of antibiotics has been mostly reported for STPs and PMFs, knowledge on the effects of wastewater treatment processes on the removal of antibiotics is not well documented. In this study, wastewaters were collected from different treatment points of two STPs and two PMFs in eastern China. Thirty-seven antibiotics within the four classes of fluoroquinolones (FQs), macrolides (MACs), sulfonamides (SAs) and tetracyclines (TCs) were analyzed. Among the investigated antibiotics, 19-33 out of 37 target compounds were detected at least once in the STPs wastewaters ranging from low ng/L to approximately 12.7 μ/L. In the wastewater samples collected from PMFs, up to 34 antibiotics were present with detection frequencies up to 100%, showing generally higher concentrations (up to 19.0 μ/L) than those at the STPs. FQs and SAs were the dominant antibiotic families, which accounted for more than 90% of the total antibiotic concentration in the wastewaters. Moreover, the removal of antibiotics by anaerobic-anoxic-oxic (A²O), membrane bioreactor (MBR) and conventional activated sludge (CAS) systems was evaluated. The MBR system exhibited the best performance, mainly due to the processes of biodegradation and sorption during biological treatments. Notably, several SAs (SMP, SMZ) and FQs (CIN, ENO) antibiotics were consistently detected at concentration levels of μ/L in the effluent samples. The culturable antibiotic-resistance tests and risk assessment indicated that the antibiotic-contaminated effluents would facilitate the development of resistant bacteria and pose high toxicity to non-target organisms in the aquatic environment. Overall, the findings suggested an urgent need for improving the wastewater treatment technologies for simultaneous removal of different classes of antibiotics.

Fe2+/H2O2-Strengite method with the enhanced settlement for phosphorus removal and recovery from pharmaceutical effluents

Phosphorus excessively discharged into the water body is a primary cause of eutrophication, but phosphorus resource is limited and non-renewable. If phosphorus could be recovered from wastewaters, it can not only prevent phosphorus pollution but also achieve the recycling of phosphorus resources. This work proposed a novel strategy, Fe²⁺/H₂O₂-strengite method with the enhanced settlement, for phosphorus removal and recovery from pharmaceutical wastewater containing organic phosphorus (OP). In this scheme, OP could be converted into inorganic phosphorus (IP) in the Fe²⁺/H₂O₂ oxidation system, and then IP was recovered in the strengite system. This approach possessed the advantages of simple operation, high efficiency and valuable recovery products, besides, reducing the consumption of reagents, and hardly resulting in secondary pollution. Sixty cycles of phosphorus removal and recovery experiments were conducted, in which pH value was 4 and the initial molar ratio of Fe/P was 1.5. This process achieved a satisfactory and steady phosphorus removal performance, with soluble phosphate and total phosphorus removal efficiencies of 95.3% ± 1.7% and 91.4% ± 2.5%, respectively, and phosphorus was recovered. Possible mechanisms involved: the formation of amorphous strengite (FePO₄·2H₂O) analogue, the adsorption of hydrous ferric oxide (HFO) to phosphorus, and the flocculation of ferric salts. Besides, the presence of quartz as carriers could enhance the settling efficiency of products. Also, via various characterizations, products included amorphous strengite analogue and goethite mixed with phosphorus. This work provided an effective method to reduce OP pollution and recover phosphorus, and supplied thoughts for the treatment of refractory pollutants and the recycling of limited resources.

Compositional characteristics of dissolved organic matter in pharmaceutical wastewater effluent during ozonation

The compositional characteristics of dissolved organic matter (DOM) in pharmaceutical wastewater effluent can affect the further improvement and application of the ozone treatment process. The present study investigated the changes of chemical structures, molecular weight (MW) distribution, hydrophobicity/hydrophilicity distribution, fluorescence properties and the molecular composition of DOM in pharmaceutical wastewater effluent during ozonation. Besides, the toxicity change of pharmaceutical wastewater effluent during ozonation was estimated. The results show that ozone is prone to attack high MW fractions, which contributes the most to the UV₂₅₄ value and could improve the biodegradability of refractory DOM in pharmaceutical wastewater effluent. Hydrophobic acid contained the most aromatic and unsaturated bonded organic matter, and was more readily oxidized under ozonation. In fluorescent components, ozonation significantly decreased humic-like acid compounds, and hydrophobic humic-like compounds exhibited the highest removal through parallel factor analysis. At the molecular level, the main organics removed by ozone were compounds with high H/C and low O/C, especially compounds where H/C >1.5. The CHO, CHON and CHOS compounds exhibited high removal under ozonation in formula classes. Lignin compounds, condensed aromatics compounds, and unsaturated hydrocarbons were effectively removed by ozone in compound classes. After ozonation, the number of lipid and sugar compounds increased. In addition, O/Cwa (the intensity-weighted average parameters of O/C) and NOSCwa (nominal oxidation state of carbon) were significantly positively correlated with acute toxicity on the luminescence. With the increase of ozone dose, the acute toxicity of pharmaceutical wastewater effluent after ozonation first decreased and then increased.

Aerobic granular sludge systems for treating hypersaline pharmaceutical wastewater: Start-up, long-term performances and metabolic function

The complex organics, residue pharmaceuticals and high salinity in pharmaceutical wastewater pose great challenges to biological wastewater treatment. In this study, granular sludge process was used for treating pharmaceutical wastewater because of its high pollutant removal efficiency. The results suggested that granules could not form within 90-d cultivation when directly fed with target hypersaline pharmaceutical wastewater (R_P) due to suppression of EPS secretion by high concentration of inhibitory organics, while granules were successfully developed with hypersaline synthetic wastewater (R_S) and diluted pharmaceutical wastewater (R_D), respectively. Further comparison of pollutant removal performance from target pharmaceutical wastewater showed that simultaneous removal of organics (effluent bCOD<1 mg L^-1) and nitrogen (average TN removal efficiency of 70.3%) could be achieved in R_D. Nevertheless, long acclimation period (i.e., 20 d) was needed for granules when carbon source was shifted from simple sodium acetate to complex organic pollutants in pharmaceutical wastewater, with nitrite significantly accumulated in R_S. Analysis of microbial community and nitrogen metabolism pathway indicated the higher abundance of nitrite oxidoreductase than that in the R_S to alleviate nitrite accumulation in the R_D, and functional strains such as Paracoccus and Mycobacterium played critical roles for high efficiency of organic degradation, nitrification and denitrification.

Continuous flow pulsed power plasma reactor for the treatment of aqueous solution containing volatile organic compounds and real pharmaceutical wastewater

The degradation of four recalcitrant and toxic VOCs (volatile organic compounds) present in pharmaceutical wastewater was studied using a continuous flow plasma reactor, along with evaluating its potential for real effluent treatment. The wastewater was sprayed into the plasma zone of the reactor, and it was re-circulated for better performance. The effect of different HRTs (hydraulic retention time) and initial concentrations of VOCs on the degradation efficiency were evaluated. In continuous reactor, complete removal of 200 mg/L of chloroform, chlorobenzene, and toluene was achieved at a HRT of 33.3 min, with an energy consumption of 22.4 kWh/m³. The study on the effect of different inlet loading rates of VOCs on elimination capacity showed that, the removal was limited initially by diffusion of reactive species and at higher loads, it was limited by insufficient amount of reactive species produced. During degradation of VOC mixture, more than 90% removal of chloroform, chlorobenzene and toluene was achieved at HRT of 33.3 min, and the TOC removal was 78.3%. The degradation efficiency of VOC mixture reduced slightly compared to that of individual compounds, due to insufficient amount of reactive species produced. The COD and BOD removal achieved after 140 min of direct plasma treatment of real pharmaceutical wastewater in batch reactor was 92.7% and 95.2%, respectively. Coagulation pre-treatment did not have a significant effect on the plasma treatment of real wastewater. When pharmaceutical effluent treatment was carried out in continuous flow reactor, 91.8% COD removal, 90.9% BOD removal and more than 90% degradation of all VOCs were achieved at a HRT of 150 min. Plasma treatment alone was capable of effectively treating the real pharmaceutical wastewater without any pre-treatment.

Optimization of growth conditions for enhancing the production of microbial laccase and its application in treating antibiotic contamination in wastewater

In this work, seven indigenous macrofungal isolates were selected to screen for their laccase production capability. Among them, isolates viz., Pleurotus eryngii, Pleurotus florida, Pleurotus sajor caju and Gandoderma lucidum were found to exhibit high laccase activity in the preliminary studies and were thus selected for the optimization studies with an aim to enhance laccase production. The pH optimization studies were carried out between pH range of 4-6. The laccase activity and biomass were found to be optimum at pH 4, 4.5, 4.5 and 5 for P. eryngii, P. florida, P. sajor caju and G. lucidum, respectively. Optimization studies with chemical inducers namely, tannic acid, 2,6 dimethoxyphenol and copper sulphate at three different concentration levels were conducted and tannic acid at 2 mM concentration was found to increase the laccase activity to about 45% followed by 2,6 dimethoxyphenol (2 mM) with an increase of about 43% and copper sulphate (0.1 mM) showing 21% increase in the yield. Biodegradation studies utilizing laccase isolated from P. eryngii, P. florida and P. sajor caju was carried out for a commonly detected fluoroquinolone antibiotic, levofloxacin, in water and pharmaceutical wastewater. The results indicated that the degradation efficiency of levofloxacin using laccase isolated from P. eryngii (88.9%) was comparable to commercial laccase (89%). When the cost economics of using crude laccase was evaluated against commercial laccase it was evident that the total cost of the treatment could be reduced by 71.7% if commercial grade laccase was replaced by crude enzyme extracted from indigenous macrofungi such Pleurotus eryngii, Pleurotus florida, and Pleurotus sajor caju indicating a promising and cost-effective alternative for wastewater treatment.

Mechanistic insights into ethidium bromide removal by palygorskite from contaminated water

Ethidium bromide (EtBr)-containing wastewater can be hazardous to biodiversity when released into the soil and water bodies without treatment. EtBr can mutate living microbial cells and pose toxicity to even higher organisms. This work investigated the removal of EtBr from aqueous solutions by a naturally occurring palygorskite (PFl-1) clay mineral via systematic batch adsorption experiments under different physicochemical conditions. EtBr existed in an undissociated form at pH ~7, and was adsorbed on PFl-1 obeying the Freundlich isotherm model. The maximum EtBr adsorption capacity was 285 mmol/kg. The best fitted kinetic model for EtBr adsorption was the pseudo-second order model. The amounts of exchangeable cations desorbed from PFl-1 during EtBr adsorption was linearly correlated to the amounts of EtBr adsorbed, with a slope of 0.97, implying that a cation exchange-based adsorption mechanism was dominating. Additionally, dimerization of EtBr molecules via bromide release assisted an increased EtBr removal by PFl-1 at high adsorbate concentrations. Detailed x-ray diffraction, Fourier transform infrared, scanning electron imaging and energy dispersive x-ray analyses confirmed that EtBr adsorption occurred dominantly on the surface of palygorskite which mineralogically constituted 80% of the bulk PFl-1 adsorbent. A small portion of EtBr was also adsorbed by PFl-1 through intercalation onto the smectite impurity (10%) in PFl-1. This study suggested that PFl-1 could be an excellent natural material for removing EtBr from pharmaceutical and laboratory wastewater.

Photocatalytic study of nanocomposite membrane modified by CeF3 catalyst for pharmaceutical wastewater treatment

Cerium fluoride (CeF₃) nanoparticles (NPs) were synthesized and applied in polysulfone (PS) membrane fabricated by phase inversion method. The produced nanocomposite membranes (PS/CeF₃) with different contents of CeF3 NPS (0.25%, 0.5%, 0.75% and 1% w/w) were used to treat pharmaceutical wastewaters. The membranes were characterized by FESEM, EDX, XRD, FTIR, porosity, and water contact angle analyses. Evaluation of the characteristics and performance of the nanocomposite membranes confirmed that utilizing photocatalytic CeF₃ NPs in membrane structure could effectively decompose organic contaminants in pharmaceutical wastewaters. It also improves the hydrophilicity and antifouling ability of membrane during filtration especially, in the presence of UV irradiation. The permeate flux of the PS membrane increased from 35.1 to 63.77 l/m²h by embedding 0.75% of CeF₃ NPs in membrane structure due to the porosity enhancement from 71.36-78.42% and the decrease in contact angle from 62.9º to 53.73º. Moreover, the flux decline of PS/CeF₃-0.75% membrane under UV irradiation was from 63.6 to 46.1 l/m²h that considerably lower than that of the neat PS membrane (from 34.7 to 4.9). On the other hand, the degradation efficiency of PS/CeF₃-0.75% membrane was more than 97%, and COD removed was more than 65% while they were 75% and 31%, respectively for the nascent PS membrane. Therefore, applying the appropriate amount of CeF₃ NPs in PS membranes not only greatly increased the permeate flux but also significantly enhanced the degradation efficiency and COD removal. This indicates that nanocomposite membranes can be confidently applied for pharmaceutical wastewater treatment UV irradiation.

Degradation of kanamycin from production wastewater with high-concentration organic matrices by hydrothermal treatment

It is known that many kinds of fermentative antibiotics can be removed by temperature-enhanced hydrolysis from production wastewater based on their easy-to-hydrolyze characteristics. However, a few aminoglycosides are hard to hydrolyze below 100°C because of their stability expressed by high molecular energy gap (ΔE). Herein, removal of hard-to-hydrolyze kanamycin residue from production wastewater by hydrothermal treatment at subcritical temperatures was investigated. The results showed the reaction temperature had a significant impact on kanamycin degradation. The degradation half-life (t_1/2) was shortened by 87.17-fold when the hydrothermal treatment temperature was increased from 100°C to 180°C. The t_1/2 of kanamycin in the N₂ process was extended by 1.08-1.34-fold compared to that of the corresponding air process at reaction temperatures of 140-180°C, indicating that the reactions during hydrothermal treatment process mainly include oxidation and hydrolysis. However, the contribution of hydrolysis was calculated as 75%-98%, which showed hydrolysis played a major role during the process, providing possibilities for the removal of kanamycin from production wastewaters with high-concentration organic matrices. Five transformation products with lower antibacterial activity than kanamycin were identified using UPLC-QTOF-MS analysis. More importantly, hydrothermal treatment could remove 97.9% of antibacterial activity (kanamycin EQ, 1,109 mg/L) from actual production wastewater with COD_Cr around 100,000 mg/L. Furthermore, the methane production yield in anaerobic inhibition tests could be increased about 2.3 times by adopting the hydrothermal pretreatment. Therefore, it is concluded that hydrothermal treatment as a pretreatment technology is an efficient method for removing high-concentration hard-to-hydrolyze antibiotic residues from wastewater with high-concentration organic matrices.

Cytotoxicity evaluation of ketoprofen found in pharmaceutical wastewater on HEK 293 cell growth and metabolism

Inefficient ketoprofen removal from pharmaceutical wastewater may negatively impact the ecosystem and cause detrimental risks to human health. This study was conducted to determine the cytotoxicity effects of ketoprofen on HEK 293 cell growth and metabolism, including cyclooxygenase-1 (COX-1) expression, at environmentally relevant concentrations. The cytotoxic effects were evaluated through the trypan blue test, DNS assay, MTT assay, and the expression ratio of the COX-1 gene. The results of this study show insignificant (p > 0.05) cytotoxic effects of ketoprofen on cell viability and cell metabolism. However, high glucose consumption rates among the treated cells cause an imitation of the Warburg effect, which is likely linked to the development of cancer cells. Apart from that, the upregulation of COX-1 expression among the treated cells indicates remote possibility of inflammation. Although no significant cytotoxic effects of ketoprofen were detected throughout this study, the effects of prolonged exposure of residual ketoprofen need to be evaluated in the future.

Study on optimization and performance of biological enhanced activated sludge process for pharmaceutical wastewater treatment

Simulated pharmaceutical wastewater was treated by moving bed biofilm reactor (MBBR) and total reflux sludge reactor process (STR) system. By cultivating specific bacterial groups, optimizing reactor process parameters, and comparatively analyzing the pollutant removal efficiency under stable operating conditions of the system, the treatment efficiency of the two systems under the combined impact load of organic pollutants on the target pollutants indole and naphthalene was studied. The optimal operation parameters of reactors: hydraulic retention time (HRT) was 8 h, aeration was 0.12 m³/h. The effect was better in 25 ± 1 °C than that in 20 ± 2 °C. During stable operation, the average removal rate of chemical oxygen demand (COD) and ammonia nitrogen (NH₄⁺-N) of the MBBR system was significantly higher than that of STR, and the two kinds of target pollutants concentration in water was lower than the detection limit. In the combined impact test of organic pollutants, the dominant bacterial group obtained by domestication had a high degradation ability, so the combined impact of indole and naphthalene had little effect on the two reactors. But in the fourth stage, the residual naphthalene concentration in the STR system effluent exceeded the target value. Therefore, the MBBR process has a stronger treatment effect on pharmaceutical wastewater than the STR system during the stable period and the impact load stage.

Sono-photocatalytic degradation of tetracycline and pharmaceutical wastewater using WO3/CNT heterojunction nanocomposite under US and visible light irradiations: A novel hybrid system

In this paper, in-situ fabrication of tungsten oxide (WO₃) on carbon nano-tube (CNT) was performed via sol-gel/hydrothermal method to prepare WO₃/CNT nanocomposites and then coupled with visible light and ultrasound (US) irradiations for sono-photocatalytic removal of tetracycline (TTC) and pharmaceutical wastewater treatment. The as-prepared catalysts were characterized by FT-IR, XRD, TEM, UV-VIS DRS, FESEM, EDS, TGA, BET, BJH, EIS, and EDX techniques. The characterization tests, indicated successful incorporation of CTNs into the WO₃ framework and efficient reduction of charge carries recombination rate after modifying with CNT. The investigation of experimental parameters verified that 60 mg/L TTC could be perfectly degraded at optimum operational parameters (WO₃/CNT: 0.7 g/L, pH: 9.0, US power: 250 W/m², and light intensity: 120 W/m² over 60 min treatment. Trapping experiments results verified that HO radicals and h⁺ were the main oxidative species in degradation of TTC. The as-prepared photocatalysts could be reused after six successive cycles with an approximately 8.8 % reduction in removal efficiency. Investigation of the effect of real pharmaceutical wastewater revealed that this system is able to eliminate 83.7 and 90.6 % of TOC and COD, respectively after 220 min of reaction time. Some compounds with lower toxic impact and molecular weight, compared to raw pharmaceutical wastewater, were detected after treatment by sono-photocatalysis process. The biodegradability of real pharmaceutical wastewater was improved significantly after treatment by WO₃/CNT sono-photocatalysis.

Decolorization and biodegradability of a real pharmaceutical wastewater treated by H2O2-assisted photoelectrocatalysis on TiO2 meshes

In recent years, photoelectrocatalysis (PEC) for the treatment of industrial wastewaters (IWWs) has been repeatedly proposed. However, despite the number of tests reported in literature, only a few of them were conducted on real IWWs. In this study, real pharmaceutical IWWs showing an intense recalcitrant color were treated by PEC and H₂O₂-assisted PEC (UV/TiO₂/Bias and UV/H₂O₂/TiO₂/Bias, respectively) on TiO₂ meshes having sub-micrometric features obtained by Plasma Electrolytic Oxidation. Photolysis (UV), chemical oxidation (H₂O₂) and H₂O₂-assisted photolysis (UV/H₂O₂) were tested in the same reactor for comparison. The configuration UV/H₂O₂/TiO₂/bias showed the best results in term of decolorization efficiency and rate, where decolorization was 55 % (single-step H₂O₂ dosing) and 44 % (three-step H₂O₂ dosing), after 2 h of contact time. In the same contact time, UV and UV/TiO₂/Bias processes did not give decolorization. A more effective COD removal was measured for the PEC processes, UV/H₂O₂/TiO₂/Bias (-24 %) and UV/TiO₂/Bias (-20 %), while COD removal by UV was almost 0 %. Correspondingly, the SOUR values showed that PEC combined with a single-step H₂O₂ dosage was the most effective configuration, leading to the highest biodegradability of the treated IWW with respect to the other processes. The energy consumption analysis demonstrated that PEC+H₂O₂ (single-step dosage) optimized energy costs.

Iron foam combined ozonation for enhanced treatment of pharmaceutical wastewater

In this study, iron foam combined ozonation was employed as an advanced oxidation process to treat the organic contaminants in real pharmaceutical wastewater. It was found that this procedure worked well in a wide range of pH, the existence of iron foam in ozonation system markedly elevated the mineralization level of organic contaminants. Within the reaction time of 120 min, iron foam combined ozonation achieved 53% of DOC removal percentage, which was 21% higher than that of ozone alone. Meanwhile, the biodegradability of the pharmaceutical wastewater was improved, a large part of the organic pollutants containing benzene rings and amino groups were effectively degraded, and a certain amount of phosphate and nitrogen also get removed. In iron foam combined ozonation, zero valent iron played the role as an activator. It was oxidized into iron oxides and oxyhydroxides, the electrons transferring among different valences of iron stimulated the decomposition of ozone and the generation of hydroxyl radicals, which accounted for most of the organic contaminants degradation.

Biotransformation of ibuprofen in biological sludge systems: Investigation of performance and mechanisms

Ibuprofen (IBU), a common non-steroidal anti-inflammatory drug (NSAID), is widely used by humans for controlling fever and pain, and is frequently detected in the influent of wastewater treatment plants and different aquatic environments. In this study, the biotransformation of IBU in activated sludge (AS), anaerobic methanogenic sludge (AnMS) and sulfate-reducing bacteria (SRB)-enriched sludge systems was investigated at three different concentrations of 100, 500 and 1000 μg/L via a series of batch and continuous studies. IBU at concentration of 100 μg/L was effectively biodegraded by AS whereas AnMS and SRB-enriched sludge were less effective in IBU biodegradation at all concentrations tested. However, at higher IBU concentrations of 500 and 1000 μg/L, AS showed poor IBU biodegradation and chemical oxygen demand (COD) removal due to inhibition of aerobic heterotrophic bacteria (i.e., Candidatus Competibacter) by IBU and/or IBU biotransformation products. The microbial analyses showed that IBU addition shifted the microbial community structure in AS, AnMS and SRB-enriched sludge systems, however, the removals of COD, nitrogen and sulfur in both anaerobic sludge systems were not affected significantly (p > 0.05). The findings of this study provided a new insight into biotransformation of IBU in three important biological sludge systems.

Ligand enhanced pharmaceutical wastewater treatment with Fenton process using pyrite as the catalyst: Column experiments

Advanced oxidation processes offer practical and cost effective solutions for the treatment of poorly biodegradable industrial wastewaters. Here, column experiments were performed to understand the role of a complexing agent, citrate, on Fenton-treatment of an actual pharmaceutical wastewater with pyrite as the catalyst under dynamic flow conditions. Our results suggest that the pharmaceutical wastewater treatment with Fenton reaction using pyrite as the catalyst was mainly regulated by the extent of Fe dissolution from pyrite, which, in turn, resulted in formation of hydroxyl radicals in solution. The Fenton treatment efficiency was much lower in the absence of citrate compared to citric acid containing systems due to clogging of column pores with oxidized Fe species. On the other hand, the addition of citrate to wastewater significantly improved Fenton process efficacy, and prolonged the lifecycle of pyrite-packed columns depending on solution pH. Low pH values were favorable for better Fenton efficiency in systems containing citrate due to combined effect of proton and ligand promoted dissolution and mobilization of oxidized Fe species.