Impacts of typical pharmaceuticals and personal care products on the performance and microbial community of a sponge-based moving bed biofilm reactor

Performance evaluation of a new sponge-based moving bed biofilm reactor for the removal of pharmaceutical pollutants from real wastewater

Pharmaceutical pollutants, a group of emerging contaminants, have attracted outstanding attention in recent years, and their removal from aquatic environments has been addressed. In the current study, a new sponge-based moving bed biofilm reactor (MBBR) was developed to remove chemical oxygen demand (COD) and the pharmaceutical compound Ibuprofen (IBU). A 30-L pilot scale MBBR was constructed, which was continuously fed from the effluent of the first clarifier of the Southern Tehran wastewater treatment plant. The controlled operational parameters were pH in the natural range, Dissolved Oxygen of 1.5-2 mg/L, average suspended mixed liquor suspended solids (MLSS), and mixed liquor volatile suspended solids (MLVSS) of 1.68 ± 0.1 g/L and 1.48 ± 0.1 g/L, respectively. The effect of hydraulic retention time (HRT) (5 h, 10 h, 15 h), filling ratio (10%, 20%, 30%), and initial IBU concentration (2 mg/L, 5 mg/L, 10 mg/L) on removal efficiencies was assessed. The findings of this study revealed a COD removal efficiency ranging from 48.9 to 96.7%, with the best removal efficiency observed at an HRT of 10 h, a filling ratio of 20%, and an initial IBU concentration of 2 mg/L. Simultaneously, the IBU removal rate ranged from 25 to 92.7%, with the highest removal efficiency observed under the same HRT and filling ratio, albeit with an initial IBU concentration of 5 mg/L. An extension of HRT from 5 to 10 h significantly improved both COD and IBU removal. However, further extension from 10 to 15 h slightly enhanced the removal efficiency of COD and IBU, and even in some cases, removal efficiency decreased. Based on the obtained results, 20% of the filling ratio was chosen as the optimum state. Increasing the initial concentration of IBU from 2 to 5 mg/L generally improved COD and IBU removal, whereas an increase from 5 to 10 mg/L caused a decline in COD and IBU removal. This study also optimized the reactor's efficiency for COD and IBU removal by using response surface methodology (RSM) with independent variables of HRT, filling ratio, and initial IBU concentration. In this regard, the quadratic model was found to be significant. Utilizing the central composite design (CCD), the optimal operating parameters at an HRT of 10 h, a filling ratio of 21%, and an initial IBU concentration of 3 mg/L were pinpointed, achieving the highest COD and IBU removal efficiencies. The present study demonstrated that sponge-based MBBR stands out as a promising technology for COD and IBU removal.

Sulfamethoxazole removal from wastewater via anoxic/oxic moving bed biofilm reactor: Degradation pathways and toxicity assessment

The effects of sulfamethoxazole (SMZ), an antibiotic commonly detected in the water environment, on the performance of a single staged anoxic/oxic moving bed biofilm reactor (A/O MBBR), was investigated. The anoxic zone played a key role in the removal of SMZ with a percentage of contribution accounting for around 85% in the overall removal. Denitrifying heterotrophic microbes present in the anoxic zone showed relatively more resistance to higher SMZ loads. It was found that in extracellular polymeric substances, protein content was increased consistently with the increase in SMZ concentration. Based on the detected biotransformation products, four degradation pathways were proposed and the toxicity was evaluated. Metagenomic analysis revealed that at higher SMZ load the activity of genera, such as Proteobacteria and Actinobacteria was significantly affected. In summary, proper design and operation of staged A/O MBBR can offer a resilient and robust treatment towards SMZ removal from wastewater.

Effects of High Pharmaceutical Concentrations in Domestic Wastewater on Membrane Bioreactor Treatment Systems: Performance and Microbial Community

Despite pharmaceuticals being widely detected in water-bodies worldwide, what remain unclear are the effects of high pharmaceutical concentrations on the treatment efficiency of biological wastewater treatment processes, such as membrane bioreactor (MBR) systems. This study investigated the efficiency of MBR technology in the treatment of synthetic wastewater containing a mixture of five typical pharmaceuticals (ofloxacin, sulfamethoxazole, sulfamethylthiadiazole, carbamazepine and naproxen) with a total concentration of 500 µg/L. Both the control MBR (MBRc) without pharmaceutical dosing and the MBR operated with high influent pharmaceutical concentrations (MBRe) were operated under room temperature with the same hydraulic retention time of 11 h and the same sludge retention time of 30 d. The removal efficiency rates of total nitrogen and total phosphorus were 83.2% vs. 90.1% and 72.6% vs. 57.8% in the MBRc vs. MBRe systems, and both MBRs achieved >98% removal of organics for a 180-day period. The floc size decreased, and membrane fouling became more severe in the MBRe system. Microbial diversity increased in the MBRe system and the relative abundances of functional microbe differed between the two MBRs. Furthermore, the total relative abundances of genes involved in glycolysis, assimilating nitrate reduction and nitrification processes increased in the MBRe system, which could account for the higher organics and nitrogen removal performance. This work provides insights for MBR operation in wastewater treatment with high pharmaceutical concentrations.

Triclocarban-contaminated wastewater treatment by innovative hybrid moving entrapped bead activated sludge reactor (HyMER): Continuous performance and computational dynamic simulation analysis

Triclocarban (TCC) has been used in consumer products and is a widespread contaminant in municipal wastewater treatment systems that ultimately accumulates in natural receiving water and soil. This work aims to apply an innovative hybrid moving entrapped bead activated sludge reactor (named "HyMER") that integrates entrapped TCC-degrading microbes and freely suspended activated sludge to treat TCC-contaminated wastewater. A previously isolated TCC-degrading bacterium (Pseudomonas fluorescens strain MC46, called MC46) and barium alginate entrapment were applied. The synthetic TCC-contaminated wastewater treatment (with TCC concentration of 10 mg/L) was performed using 20-cycle fed-batch reactor operation with feeding times of 12 and 24 h and cycle times of 13 and 25 h. The results indicated that the HyMER effectively reduced chemical oxygen demand by up to 80 and 95 % and TCC by up to 53 and 83 %, respectively, with feeding times of 12 and 24 h. Three TCC degradation intermediate products were found-3,4-dichloroaniline, 4-chloroaniline, and aniline. Scanning electron microscopic analysis revealed shorter cells and bacterial appendage development as cell adaptations against TCC and its intermediates. The live/dead assay indicated high survival of entrapped MC46 in toxic conditions, with up to 84 % viable cells. Based on computational fluid dynamic analysis, no entrapped cell agglomeration showed in the reactor, indicating the potential application of HyMER for real wastewater treatment. These results exhibit the feasibility of HyMER and its applicability for future toxic wastewater treatment.

The effect of biocarriers on the nitrification and microbial community in moving bed biofilm reactor for anaerobic digestion effluent treatment

The performance of a moving bed biofilm reactor (MBBR) depends largely on the type of biofilm carrier used. However, how different carriers affect the nitrification process, particularly when treating anaerobic digestion effluents, is not completely understood. This study aimed to evaluate the nitrification performance of two distinct biocarriers in MBBRs over a 140-d operation period, with a gradually decreasing hydraulic retention time (HRT) from 20 to 10 d. Reactor 1 (R1) was filled with fiber balls, whereas a Mutag Biochip was used for reactor 2 (R2). At an HRT of 20 d, the ammonia removal efficiency of both reactors was >95%. However, as the HRT was reduced, the ammonia removal efficiency of R1 gradually declined, ultimately dropping to 65% at a 10-d HRT. In contrast, the ammonia removal efficiency of R2 consistently exceeding 99% throughout the long-term operation. R1 exhibited partial nitrification, whereas R2 exhibited complete nitrification. Analysis of microbial communities showed that the abundance and diversity of bacterial communities, particularly nitrifying bacteria such as Hyphomicrobium sp. And Nitrosomonas sp., in R2 was higher than that in R1. In conclusion, the choice of biocarrier significantly impact the abundance and diversity of microbial communities in MBBR systems. Therefore, these factors should be closely monitored to ensure the efficient treatment of high-strength ammonia wastewater.

Responses of biofilm communities in a hybrid moving bed biofilm reactor-membrane bioreactor system to sulfadiazine antibiotic exposure

Antibiotics in wastewater can affect the structures and functions of bacterial communities, subsequently influencing how well a biological process performs. Therefore, the characteristics of bacterial community were investigated in a hybrid moving bed biofilm reactor-membrane bioreactor system when treating domestic wastewater containing sulfadiazine (SDZ). Results indicated total nitrogen removal reduced by 10.2%, 9.1%, 2.7% and 2.9%, respectively, with increasing carbon to nitrogen (C/N) ratios (2.5, 4, 6 and 9) when SDZ was present (0.5 mg/L). The microbial communities' analysis revealed that the abundance of nitrogen removal-related bacteria increased with C/N. Specifically, the abundance of ammonia-oxidizing bacteria (0.46%-0.90%) was low, and the nitrite-oxidizing bacteria (2.16%-7.13%) and denitrifying bacteria showed a significant increase (Hyphomicrobium: 0.57%-3.54%) when C/N ratio increased. The abundance of denitrifying bacterial declined by 4.82-8.56% at different C/N ratios, while nitrifying bacterial rose by 0.70-5.67%. Interestingly, the denitrifying bacteria Enterobacter, Sphingomonas and Gemmatimonas acted as mutualistic bacteria that stabilized denitrification.

Critical review of biochemical pathways to transformation of waste and biomass into bioenergy

In recent years, biofuel or biogas have become the primary source of bio-energy, providing an alternative to conventionally used energy that can meet the growing energy demand for people all over the world while reducing greenhouse gas emissions. Enzyme hydrolysis in bioethanol production is a critical step in obtaining sugars fermented during the final fermentation process. More efficient enzymes are being researched to provide a more cost-effective technique during enzymatic hydrolysis. The exploitation of microbial catabolic biochemical reactions to produce electric energy can be used for complex renewable biomasses and organic wastes in microbial fuel cells. In hydrolysis methods, a variety of diverse enzyme strategies are used to promote efficient bioethanol production from various lignocellulosic biomasses like agricultural wastes, wood feedstocks, and sea algae. This paper investigates the most recent enzyme hydrolysis pathways, microbial fermentation, microbial fuel cells, and anaerobic digestion in the manufacture of bioethanol/bioenergy from lignocellulose biomass.

Effect of allelochemicals sustained-release microspheres on the ingestion, incorporation, and digestion abilities of Daphnia magna Straus

Allelochemicals sustained-release microspheres (ACs-SMs) exhibited great inhibition effect on algae, however, few studies have focused on ACs-SMs toxicity on invertebrate. In this study, the effects of single high-concentration ACs (15 mg/L, SH-ACs), repeated low-concentration ACs (3 × 5 mg/L, RL-ACs) and ACs-SMs containing 15 mg/L ACs exposure on the ingestion, incorporation, and digestion of Daphnia magna Straus (DS) were investigated by stable isotope ¹⁵N labeling method. Meanwhile, the diversity and abundance of microflora in DS guts were determined by 16S rRNA genes and cloning methods. The results showed that SH-ACs exposure caused 50% and 33.3% death rates for newborn and adult DS, while RL-ACs exposure caused 10% death rate for newborn DS and no obvious effect on the activity of adult DS. And ACs-SMs exposure did not diminish the motility of both newborn and adult DS, indicating the lower acute toxicity of ACs-SMs. Furthermore, SH-ACs inhibited the ingestion (-6.45%), incorporation (-47.1%) and digestion (-53.8%) abilities of DS and reduced the microbial abundance (-27.7%) in DS guts. Compared with SH-ACs, RL-ACs showed relatively low impact on the ingestion (-3.23%), incorporation (-5.89%) and digestion (-23.9%) abilities of DS. Interestingly, ACs-SMs enhanced the ingestion (+9.68%), incorporation (+52.9%) and digestion (+51.3%) abilities of DS and increased the microbial abundance (+10.7%) in DS guts. Overall ACs and ACs-SMs reduced the diversity of microflora in DS guts. In conclusion, ACs-SMs can release ACs sustainably and prolong the sustained release time, which not only effectively reduce the toxicity of ACs, but also had positive effects on DS.

A step forward on site-specific environmental risk assessment and insight into the main influencing factors of CECs removal from wastewater

The presence of Contaminants of Emerging Concern (CECs) in water systems has been recognized as a potential source of risk for human health and the ecosystem. The present paper aims at evaluating the effects of different characteristics of full-scale Wastewater Treatment Plants (WWTPs) on the removal of 14 selected CECs belonging to the classes of caffeine, illicit drugs and pharmaceuticals. Particularly, the investigated plants differed because of the treatment lay-out, the type of biological process, the value of the operating parameters, the fate of the treated effluent (i.e. release into surface water or reuse), and the treatment capacity. The activity consisted of measuring concentrations of the selected CECs and also traditional water quality parameters (i.e. COD, phosphorous, nitrogen species and TSS) in the influent and effluent of 8 plants. The study highlights that biodegradable CECs (cocaine, methamphetamine, amphetamine, benzoylecgonine, 11-nor-9carboxy-Δ9-THC, lincomycin, trimethoprim, sulfamethoxazole, sulfadiazine, sulfadimethoxine, carbamazepine, ketoprofen, warfarin and caffeine) were well removed by all the WWTPs, with the best performance achieved by the MBR for antibiotics. Carbamazepine was removed at the lowest extent by all the WWTPs. The environmental risk assessed by using the site-specific value of the dilution factor resulted to be high in 3 out of 8 WWTPs for carbamazepine and less frequently for caffeine. However, the risk was reduced when the dilution factor was assumed equal to the default value of 10 as proposed by EU guidelines. Therefore, a specific determination of this factor is needed taking into account the hydraulic characteristics of the receiving water body.

Removal of pharmaceuticals by vertical flow constructed wetland with different configurations: Effect of inlet load and biochar addition in the substrate

Pharmaceuticals (PCs) residues are considered an emerging threat to the environment due to their persistency, ecotoxicity and bioaccumulative nature. To study the PC (amoxicillin, AMX; caffeine, CF; ibuprofen, IBU) removal efficiency of vertical flow constructed wetland (VFCW), three setups of VFCWs were configured: SB (substrate matrix + biochar (BC)); SBP (substrate matrix + BC + plant); SP (substrate matrix + plant) and changes in effluent PC load was estimated at 24, 48, 72, 96, 120, 144 and 168 h intervals. SBP with an influent load of 1,000 μg L^-1 showed the maximum removals of 75.51% (AMX), 87.53% (CF), and 79.93% (IBU) significantly higher than that of SB and SP (p < 0.00). Results showed an inverse relationship between removal efficacy and influent PCs loading. The average removal (%) by VFCWS (of all studied setups) was in the order: 66.20 > 47.88 > 39.0 (IBU), 56.56 > 42.12 > 34.36 (AMX), and 74.13 > 64.0 > 52.07 (CF) with 1,000, 5,000 > 10,000 μg L^-1 influent load, respectively. The maximum removal of COD, NH₄⁺-N, and NO₃-N was recorded at 88.8%, 83.1%, and 64.9%, respectively in SBP, and their removal was hardly affected by influent PC concentration. In summary, planted VFCW spiked with BC could be a viable approach for the removal of PCs in wastewater. The impact of PC load on plant toxicity in VFCWs can be taken as a research problem for future work in this series.

Advances in bioremediation of emerging contaminants from industrial wastewater by oxidoreductase enzymes

The bioremediation of emerging recalcitrant pollutants in wastewater via enzyme biotechnology has been evolving as cost-effective with an input of low-energy technological approach. However, the enzyme based bioremediation technology is still not fully developed at a commercial level. The oxidoreductases being the domineering biocatalysts are promising candidates for wastewater treatments. Henceforth, comprehending their global market and biotransformation efficacy is mandatory for establishing these techno-economic bio-enzymes in commercial scale. The biocatalytic strategy can be established as a combinatorial approach with existing treatment technology to achieve towering bioremediation and effective removal of emerging pollutants from wastewater. This review provides a novel insight on the toxicological xenobiotics released from industries such as paper and pulps, soap and detergents, pharmaceuticals, textiles, pesticides, explosives and aptitude of peroxidases, nitroreductase and cellobiose dehydrogenase in their bio-based treatment. Moreover, the review comprehensively covers environmental relevance of wastewater pollution and the critical challenges based on remediation achieved through biocatalysts for future prospectives.

Covalent-anion-driven self-assembled cadmium/ molybdenum sulfide hybrids for efficient nitenpyram degradation

Photocatalytic technology is an attractive and promising approach for nitenpyram degradation; however, how to ensure the carrier separation efficiency and catalytic sites exposure is still great challenges. In this study, we construct CdS@MoS₂ (CM) nanohybrids with a 3D hierarchical configuration to enhance the separation and transfer efficiency of the photo-induced electron by a covalent-anion-driven self-assembly method. The vertical orientation of MoS₂ ultrathin nanosheets not only provides a large specific surface area for the oxidation and reduction reactions but also enables the active edge sites of MoS₂ to be maximally exposed. As a result, this structure drastically facilitates the exposure of the catalytic active region and the performance of the carrier transfer and injection into photocatalytic degradation for nitenpyram (NTP). The optimal CdS-MoS₂ has an impressive and stable NTP removal efficiency with a high reaction rate constant up to 0.078 min^-1, which is 3.25 times higher than that of pure cadmium sulfide. The photocatalytic degradation mechanism and degradation pathway of NTP were presented by synthesizing the results of experimental analysis and density flooding theory (DFT) calculations. In further, for the first time, the cytotoxicity and genotoxicity of NTP on moving bed biofilm reactors (MBBRs) was disclosed and a continuous photocatalytic wastewater pretreatment device based on the CM is proposed for the stable biological nitrogen removal activity of MBBRs, which can degrade more than 80% NTP per hour.

Electrocatalytic degradation of sulfamethylthiadiazole by GAC@Ni/Fe three-dimensional particle electrode

In this work, GAC@Ni/Fe particle electrodes were prepared and employed for the degradation of sulfamethylthiadiazole (SMT) by three-dimensional electrocatalytic technology. The effects of particle electrode bi-metal loading ratio, cell voltage, particle electrode dosage, electrode plate spacing, and SMT initial concentration on SMT removal were studied. In addition, GAC@Ni/Fe particle electrode was analyzed by the scanning electron microscope (SEM), transmission electron microscope (TEM), X-ray diffractometer (XRD), X-ray photoelectron spectrometer (XPS), and Fourier transform infrared spectrometer (FTIR) to characterize which indicated that a significant amount of iron-nickel oxide was formed on the surface of GAC@Ni/Fe particle electrode. The results indicated that when the nickel-iron loading ratio is 1:1, the SMT removal effect is the best, and the removal rate can reach 90.89% within 30 min. Compared with the granular activated carbon without bimetal, the removal efficiency is increased by 37.58%. The degradation of SMT in the GAC@Ni/Fe particle three-dimensional electrode reactor is the joint result of both direct oxidation and indirect oxidation. The contribution rates of direct oxidation of anode and particle electrode and indirect oxidation of ·OH in the degradation are 32%, 27%, and 41%, respectively. Based on the intermediate detected by ultra-high liquid chromatography and the calculation of bond energy of SMT molecule by Gauss software, the degradation pathway of SMT in the GAC@Ni/Fe three-dimensional electrode reactor is proposed. This research provides a green, healthy, and effective method for removing sulfonamide micro-polluted wastewater.

The environmental distribution and removal of emerging pollutants, highlighting the importance of using microbes as a potential degrader: A review

Emerging pollutants (EPs) create a worldwide concern owing to their low concentration and severe toxicity to the receptors. The prominent emerging pollutants categories as pharmaceutical and personal care product, plasticizer, surfactants, and persistent organic pollutants. Typically, EPs are widely disseminated in the aquatic ecosystem and capable of perturbing the physiology of water bodies as well as humans. The primary sources of EPs in the environment include anthropogenic release, atmospheric deposition, untreated or substandard treated wastewater, and extreme weather events. Intensive research has been done covering the environmental distribution, ecological disturbance, fate, and removal of EPs in the past decades. However, a systematic review on the distribution of EPs in the engineered and natural aquatic environment and the degradation of different EPs by using anaerobic sludge, aerobic bacteria, and isolated strains are limited. This review article aims to highlight the importance, application, and future perceptions of using different microbes to degrade EPs. Overall, this review article illustrates the superiority of using non-cultivable and cultivable microbes to degrade the EPs as an eco-friendly approach. Practically, the outcomes of this review paper will build up the knowledge base solutions to remove EPs from the wastewater.

Bamboo charcoal powder-based polyurethane as packing material in biotrickling filter for simultaneous removal of n-hexane and dichloromethane

Bamboo charcoal powder-based polyurethane (BC-PU) was firstly applied in biotrickling filter to treat n-hexane and dichloromethane (DCM) simultaneously. Maximum elimination capacity of 12.68 g m^-3h^-1 n-hexane was achieved and exceed 30.28 g m^-3h^-1 DCM could be degraded. BTF respond quickly to the mixed shock loadings, and recovered to 76% and 100% respectively in less than 1 h. By increasing inlet loading (IL) of DCM from 6.20 g m^-3h^-1 to 28.36 g m^-3h^-1, the removal efficiency of n-hexane decreased from 73.4% to 55.9% corresponding to the IL of 19.96 g m^-3h^-1. N-hexane degradation was inhibited by high IL of DCM due to enzymes competition for active sites. The growth of key microorganisms Mycobacterium sp., Hyphomicrobium sp. was stimulated and colonized. BC-PU is an innovative and applicable bio-based material in the process of biological purification, which could be widely applied to treat hydrophobic pollutants in the pharmaceutical industry.

Innovative Perspectives on Biofilm Interactions in Poultry Drinking Water Systems and Veterinary Antibiotics Used Worldwide

Prudent use of antibiotics in livestock is widely considered to be important to prevent antibiotic resistance. This study aimed to evaluate the interactions between biofilms and veterinary antibiotics in therapeutic concentrations administrated via drinking water through a standardized experimental setup. In this context, two biofilms formed by pseudomonads (Pseudomonas (P.) aeruginosa or P. fluorescens) and a susceptible Escherichia (E.) coli strain were developed in a nutrient-poor medium on the inner surface of polyvinyl chloride pipe pieces. Subsequently, developing biofilms were exposed to sulfadiazine/trimethoprim (SDZ/TMP) or tylosin A (TYL A) in dosages recommended for application in drinking water for 5 or 7 days, respectively. Various interactions were detected between biofilms and antibiotics. Microbiological examinations revealed that only TYL A reduced the number of bacteria on the surface of the pipes. Additionally, susceptible E. coli survived both antibiotic treatments without observable changes in the minimum inhibitory concentration to 13 relevant antibiotics. Furthermore, as demonstrated by HPLC-UV, the dynamics of SDZ/TMP and TYL A in liquid media differed between the biofilms of both pseudomonads over the exposure period. We conclude that this approach represents an innovative step toward the effective evaluation of safe veterinary antibiotic use.

Facial fabricated biocompatible homogeneous biocarriers involving biochar to enhance denitrification performance in an anoxic moving bed biofilm reactor

Biochar prepared from pineapple peel was facially combined with polyurethane sponges for the first time to form homogeneous biocompatible biocarriers, which can enhance denitrification performance in an anoxic MBBR. The experiments showed that a higher NO₃^--N removal efficiency (96.24 ± 1.3%) and kinetic constant (0.26 h^-1) were obtained in the MBBR employing these new biocarriers (B-MBBR), compared with a control MBBR with polyurethane sponges (C-MBBR). The attached and suspended biomass of the B-MBBR was increased by 47% and 26%, respectively. Biochar significantly enhanced the abundance of functional bacteria in terms of promoting biofilm (i.e., Leptonema), denitrifying bacteria (i.e., Thauera, Enterobacter and Pseudomonas) and electroactive bacteria (i.e., Geobacter) in the B-MBBR. Meanwhile, based on the content of coenzyme I (NADH) and denitrifying enzymes, biochar would also enhance electron transport activity for denitrification. Consequently, these facial prepared biocarriers are effective to enhance denitrification performance in MBBR with application significance.

Responses of microbial communities and their interactions to ibuprofen in a bio-electrochemical system

Ibuprofen has caused great concerns due to their potential environmental risks. However, their removal efficiency and their effects on microbial interactions in bio-electrochemical system remain unclear. To address these issues, a lab-scale bio-electrochemical reactor integrated with sulfur/iron-mediated autotrophic denitrification (BER-S/IAD) system exposing to 1000 μg L^-1 ibuprofen was operated for about two months. Results revealed that the BER-S/IAD system obtained efficient simultaneous denitrification (98.93%) and phosphorus (82.67%) removal, as well as an excellent ibuprofen removal performance (96.98%). Ibuprofen had no significant impacts on the nitrate (NO₃^--N) removal and the ammonia (NH₄⁺-N) accumulation, but decreased the total nitrogen (TN) and total phosphorus (TP) removal efficiencies. MiSeq sequencing analysis revealed that ibuprofen significantly (P < 0.05) decreased the microbial community diversity and changed their overall structure. Some bacteria related to denitrification and phosphorus removal, such as Pseudomonas and Thiobacillus, decreased significantly (P < 0.05). Moreover, molecular ecological network (MEN) analysis revealed that ibuprofen decreased the network's size and complexity, and enhanced the negative correlations of Proteobacteria and Firmicutes. Besides, ibuprofen decreased the links of some keystone bacteria related to denitrification and phosphorus removal. This research could provide a new dimension for our comprehending of the responses of microbial communities and their interactions to ibuprofen in bio-electrochemical system.

Impacts of sulfadiazine on the performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor system at different C/N ratios

The performance and membrane fouling of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system was evaluated when exposed to 0.5 mg/L of antibiotic sulfadiazine (SDZ). Results indicated that although SDZ reduced the removal efficiency of NH₄⁺-N and TN (up to 12%) and TOC (up to 6%) at low C/N (2.5 and 4), it had no significant effect at high C/N (6 and 9). It was found that SDZ was removed 75% and 58% at high C/N of 9 and low C/N of 2.5, respectively. SDZ decreased the ratio of volatile biomass/total biomass and sludge particle size and increased the concentrations of extracellular polymeric substance (EPS) and soluble microbial product (SMP) in MBR. Consequently, this accelerated the membrane fouling rates, with an average increase of 6.85 kPa/d at low C/N (2.5) and 0.513-0.701 kPa/d at medium and high C/N (4, 6 and 9).

Microbial communities responded to tetracyclines and Cu(II) in constructed wetlands microcosms with Myriophyllum aquaticum

Combined antibiotic and heavy metal pollution has generated considerable concern. Constructed wetlands (CWs) have been shown to efficiently remove pollutants; however, the microbial community responses to combined pollutants remain enigmatic. In this study, seven microcosm CWs were planted with Myriophyllum aquaticum, spiked with tetracyclines (TCs) (300-30,000 μg/L), alone or with Cu(II), to investigate the response of plant-associated microbial communities. TCs and the Cu/TC ratio greatly affected the performance of CWs. Tetracyclines led to higher microbial diversity, evenness and richness, while UniFrac distances and principal coordinate (PC_O) and redundancy analyses revealed that the co-presence of TCs and Cu(II) led to variations in bacterial communities. Proteobacteria, Cyanobacteria and Bacteroidetes were the dominant microbial phyla and Cloacibacterium, Hydrogenophaga, Rheinheimera and Denitratisoma accounted for 6.2-21.0% of all genera. Therefore, the co-occurrence of heavy metals should be considered when judging the removal potential of TCs in phytoremediation.

Performance of novel sponge biocarrier in MBBR treating recirculating aquaculture systems wastewater: Microbial community and kinetic study

In this study, a novel sponge biocarriers (SB) in moving bed bioreactor (MBBR) treating recirculating aquaculture systems wastewater was evaluated for the first time. Two lab-scale MBBRs were operated simultaneously for 116 days under various hydraulic retention times (HRTs). The reactors R1 and R2 were filled with K5 plastic carriers and SB, respectively. From the results, at an optimum HRT of 6 h, ammonia removal efficiency and nitrification rate were 86.67 ± 2.4% and 1.43 mg/L.h for the R1 and, 91.65 ± 1.3% and 1.52 mg/L.h for the R2, respectively. The microbial community analysis showed that the predominant genera in the nitrifying community were Nitrosomonas (AOB) and Nitrospira (NOB) in co-existence with heterotrophic genera Hyphomicrobium, Mesorhizobium, Zhizhongheella, and Klebsiella spp. Modified Stover-Kincannon model examined the ammonia removal kinetics, and the values of kinetic parameters obtained were U_max: 0.909 and 1.111 g/L.d and K_B: 0.929 and, 1.108 g/L.d for the R1 and R2, respectively. The correlation coefficients (R²) of the MBBRs were higher than 0.98, indicating that the model adequately described the experimental data. Overall, MBBR, filled with the proposed novel SB operated at 6 h HRT, can achieve the highest nitrification performance and increase the diversity of the functional microbial communities.

Prediction the performance of multistage moving bed biological process using artificial neural network (ANN)

Complexity, uncertainty, and high dynamic nature of nutrient removal through biological processes (BPs) makes it difficult to model and control these processes, forcing designers to rely on approximations, probabilities, and assumptions. To cope with this difficult task and perform an effective and well-controlled BP operation, an artificial neural network (ANN) algorithm was developed to simulate, model, and control a three-stage (anaerobic/anoxic and MBBR) enhanced nutrient removal biological process (ENR-BP) challenging real wastewater. The effect of surface area loading rate (SALR), organic matters (OMs), nutrients (N & P), feed flow rate (Q_feed), hydraulic retention time (HRT), and internal recycle flow (IRF) on the performance of the ENR-BP to fulfil rigorous discharge limitations were evaluated. Experimental data was used to develop the appropriate architecture for the AAN using iterative steps of training and testing. Significant removals of chemical oxygen demand (COD) (89.2 to 98.3%), NH₄⁺ (88.5 to 98.9%), and total phosphorus (TP) (77.9 to 99.9%) were achieved at a total HRT of 13.3 h (HRT_Z-1 = 3 h, HRT_Z-2 = 6 h and HRT_Z-3 = 5.3 h) and an IRF value of 1.75. The ENR-BP treatment mechanism relies on the use of OMs as a source of energy for phosphorus bio-uptake and the simultaneous nitrification and denitrification (SND) of nitrogen compounds. The removal efficiencies in the proposed ENR-BP were four fold higher than the suspended growth process and in the same order of magnitude of 5-stage Bardenpho-MBBR. The developed ANN-based model provides an efficient and robust tool for predicting and forecasting the performance of the ENR-BP.

Specific microbial diversity and functional gene (AOB amoA) analysis of a sponge-based aerobic nitrifying moving bed biofilm reactor exposed to typical pharmaceuticals

Four bench-scale sponge-based aerobic nitrifying moving bed biofilm reactors (MBBRs) were used to treat municipal wastewater containing typical pharmaceuticals (1 mg/L, 2 mg/L and 5 mg/L). This preliminary research aims to investigate the effects of sulfadiazine (SDZ), ibuprofen (IBU) and carbamazepine (CBZ) on nitrification performance and explore specific microbial diversity and functional gene (Ammonia-oxidizing bacteria (AOB), amoA) of MBBRs. After 90 days of operation, the MBBR without pharmaceuticals could remove up to 97.4 ± 1.5% of NH₄⁺-N while the removals of NH₄⁺-N by the MBBRs with SDZ, IBU and CBZ were all suppressed to varying degrees. Based on the Shannon and Chao 1 index, the specific microbial diversity and richness in biofilm samples increased at a range of 1 mg/L to 2 mg/L pharmaceuticals (SDZ, IBU or CBZ) and started decreasing after the pharmaceutical concentration was higher than 2 mg/L. The determination of functional gene (AOB amoA) showed that Proteobacteria was the most dominant bacteria within all biofilms with the relative abundance ranging from 24.81% to 55.32%. Furthermore, Nitrosomonas was the most numerous genus in AOB, followed by Campylobacter and Thauera, whose relative abundance shifted under the pressure of different pharmaceuticals.

Black liquor as biomass feedstock to prepare zero-valent iron embedded biochar with red mud for Cr(VI) removal: Mechanisms insights and engineering practicality

Black liquor (BL) is an agro-industrial residue with high number of lignocellulosic components which could be recognized as a biomass feedstock. In this work, BL coupled with red mud (RM), were applied to prepare cost-effective zero-valent iron (ZVI) embedded in biochar. The oligomers in BL acted as reductants for RM to generate ZVI, while the organic components could be converted into biochar during pyrolysis. The RM/BL demonstrated excellent performance in the removal of Cr(VI) (349.5 mg/g), as the mechanisms were reduction and adsorption. The fixed-bed column study was conducted and 1.7 L simulated wastewater could be treated by 1.0 g RM/BL. After reaction, 95.5% ± 0.8% and 82.5%±3.2% Cr-loaded adsorbents could be recovered by an external magnet for batch and fixed-bed experiments, respectively. All these results shed light on valorizing these two widespread agro-industrial byproducts, and bridged the knowledge gap between magnetic bio-adsorbent preparation and its industrial practicality on wastewater purification.