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•The SPSMBR demonstrated its superior performance in removing SAs.•Biological degradation is the key mechanism for removal of SAs.•Tyrosine-like materials significantly affected SAs ...removal.•Sponge could promote the enrichment of bacteria associated with SAs removal.•More tyrosine-like materials in the SPSMBR enhanced the removal of SAs.
A novel laboratory-scale aerobic submerged membrane bioreactor integrating sponge-plastic biocarriers (SPSMBR) was conducted to study the removal and degradation mechanisms of sulfonamide antibiotics (SAs). Experimental results indicated that SPSMBR had a better removal of sulfadiazine (91% SDZ) and sulfamethoxazole (88% SMZ) than that of a conventional aerobic submerged membrane bioreactor (CSMBR) (76% SDZ and 71% SMZ, respectively). Material balance calculations suggested that biodegradation is the primary removal mechanism of SDZ and SMZ. Protein (tyrosine-like materials) significantly affected the removal of SAs. Moreover, the SPSMBR exhibited its better performance in removing SAs due to more abundance of tyrosine-like materials. The 16S rRNA sequencing showed that biocarriers could promote the enrichment of slow growing bacteria, especially Thermomonas, associated with the removal of SAs. Valuable insights into the removal and degradation mechanisms of SAs in the SPSMBR systems are documented here.
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•Research and application of the AnDMBRs are still in the nascent stage.•Various important factors affecting AnDMBRs performance are reviewed.•The formation and characterization of DM ...layer need further attention.•Optimizing AnDMBR configurations and operational conditions are important.•Advancement in biogas collection and modifying sludge properties is urgent.
Recently, an increasing level of attention has focused on the emerging technology of anaerobic dynamic membrane bioreactors (AnDMBRs), owing to its merits such as low membrane module cost, easy control of membrane fouling, low energy consumption and sludge production, as well as biogas production. As research on AnDMBRs is still in the nascent stage, an introduction of bioreactor configurations, dynamic membrane (DM) module, and DM layer formation and cleaning is firstly presented. The process performance of the AnDMBR for wastewater treatment is then reviewed with regard to pollutant removal, DM filterability, biogas production, and potential advantages over the conventional anaerobic membrane bioreactor (AnMBR). In addition, the important parameters affecting process performance are briefly discussed. Lastly, the challenges encountered and perspectives regarding the future development of the AnDMBR process to promote its practical applications are presented.
This article provides a comprehensive review on aerobic composting remediation of soil contaminated with total petroleum hydrocarbons (TPHs). The studies reviewed have demonstrated that composting ...technology can be applied to treat TPH contamination (as high as 380,000 mg kg−1) in clay, silt, and sandy soils successfully. Most of these studies reported more than 70% removal efficiency, with a maximum of 99%. During the composting process, the bacteria use TPHs as carbon and energy sources, whereas the fungi produce enzymes that can catalyze oxidation reactions of TPHs. The mutualistic and competitive interactions between the bacteria and fungi are believed to sustain a robust biodegradation system. The highest biodegradation rate is observed during the thermophilic phase. However, the presence of a diverse and dynamic microbial community ensures that TPH degradation occurs in the entire composting process. Initial concentration, soil type, soil/compost ratio, aeration rate, moisture content, C/N ratio, pH, and temperature affect the composting process and should be monitored and controlled to ensure successful degradation. Nevertheless, there is insufficient research on optimizing these operational parameters, especially for large-scale composting. Also, toxic and odorous gas emissions during degradation of TPHs, usually unaddressed, can be potential air pollution sources and need further insightful characterization and mitigation/control research.
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•Composting is technically robust and cost-effective for TPH degradation.•Microbial activity determines the success of composting.•Moisture content and aeration rate are decisive operational parameters.•Gas emissions from composting should be mitigated to avoid secondary pollution.
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•Technologies used for recovery of value-added products from industrial effluents have been narrated.•Microbial electrochemical technologies are one of the important technologies for ...remediation of pollutants.•Integration of technologies is necessary for better efficiencies to remediate pollutants.•In depth studies are necessary to close existing knowledge gaps in field of resource recovery.
Increased population and industrialization generate a large number of organic pollutants that create problems on the planet earth. The level of freshwater is reducing which has pushed the society to reuse/recycle wastewater. Eco-friendly and economically sound treatment of industrial wastewater has attracted global attention and hence is a thrust area of research. Organic compounds rich wastewater can be used to generate bioenergy and value-added products from the resource recovery point of view. Wastewater treatment(s) can be used to trap energy from industrial effluents in form of biofuel, bioenergy and biogas. Recovered products can be used in various ways such as recovered nutrients for (bio)fertilizer production and algal biomass for bioplastic production. Microbial electrochemical technology is a promising approach for resource recovery. This review article aims to present and discuss trends and scientific developments about recovery of value-added products from dye industry effluent. It also provides state-of-art technical information about technologies for remediation of pollutants from dye industry effluent with emphasis on nanotechnological approaches and microbial electrochemical technologies (METs). It narrates literature on classification and properties of dyes, effects of dye pollutants on environment and human health and factors affecting degradation of dyes. Generation of bioenergy and recovery of valuables from dye industrial wastewater along with challenges and perspectives of this research area have been covered.
Ammonium pollution in groundwater and surface water is of major concern in many parts of the world due to the danger it poses to the environment and people's health. This study focuses on the ...development of a low cost adsorbent, specifically a modified biochar prepared from corncob. Evaluated here is the efficiency of this new material for removing ammonium from synthetic water (ammonium concentration from 10 to 100mg/L). The characteristics of the modified biochar were determined by Brunauer-Emmett-Teller (BET) test, Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM). It was found that ammonium adsorption on modified biochar strongly depended on pH. Adsorption kinetics of NH4+-N using modified biochar followed the pseudo-second order kinetic model. Both Langmuir and Sips adsorption isotherm models could simulate well the adsorption behavior of ammonium on modificated biochar. The highest adsorption capacity of 22.6mg NH4+-N/g modified biochar was obtained when the biochar was modified by soaking it in HNO3 6M and NaOH 0.3M for 8h and 24h, respectively. The high adsorption capacity of the modified biochar suggested that it is a promising adsorbent for NH4+-N remediation from water.
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•Modified conditions for biochar prepared from corncob were studied.•Materials' features before and after modification were determined by BET, FTIR, SEM.•Highest adsorption capacity of NH4+-N on modified material is 22.6mg/g.•Adsorption kinetics of NH4+-N by MBCC2 followed the pseudo-second order kinetic model.•Langmuir, Sips adsorption isotherm models could simulate well the adsorption behavior.
•The filling fraction exhibited significant effect on TN removal and SND performance.•DNR was affected more obviously than NR by the filling fractions.•The difference between NR and DNR decreased ...with the filling fraction increasing.•DNR is the controlling factor that affecting nitrogen removal performance of MBBR.•The carriers showed the largest amount of biomass in the 20% filling fraction MBBR.
Cubic-shaped polyurethane sponges (15×15×15mm) in the form of biofilm carriers were used in a moving bed biofilm reactor (MBBR) for treating synthetic domestic wastewater. Results indicated there was no significant difference in total organic carbon (TOC) and ammonia (NH4+-N) removal at different filling fractions. Three reactors exhibited high removal efficiencies of over 93% TOC and 95% NH4+-N on average at an HRT of 12h and aeration flow of 0.09m3/h. However, total nitrogen (TN) removal and simultaneous nitrification and denitrification (SND) increased with increasing the filling fraction. TN removal averaged at 77.2, 85.5% and 86.7% in 10%, 20% and 30% filling fraction reactor, respectively. Correspondingly, SND were 85.5±8.7%, 91.3±9.4% and 93.3±10.2%. Moreover, it was observed that sponge carriers in the 20% filling fraction reactor achieved the maximum biomass amount per gram sponge, followed by the 10% and 30% filling fraction reactors.
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•Denitrifying anaerobic methane oxidation (DAMO) process is systematically summarized.•DAMO process is important to the carbon and nitrogen cycling.•DAMO-centered technologies may be ...a solution for sustainable operation of WWTPs.
With the world’s increasing energy crisis, society is growingly considered that the operation of wastewater treatment plants (WWTPs) should be shifted in sustainable paradigms with low energy input, or energy-neutral, or even energy output. There is a lack of critical thinking on whether and how new paradigms can be implemented in WWTPs based on the conventional process. The denitrifying anaerobic methane oxidation (DAMO) process, which uses methane and nitrate (or nitrite) as electron donor and acceptor, respectively, has recently been discovered. Based on critical analyses of this process, DAMO-centered technologies can be considered as a solution for sustainable operation of WWTPs. In this review, a possible strategy with DAMO-centered technologies was outlined and illustrated how this applies for the existing WWTPs energy-saving and newly designed WWTPs energy-neutral (or even energy-producing) towards sustainable operations.
Constructed wetlands (CWs) have been used as a green technology to treat various wastewaters for several decades. CWs offer a land-intensive, low-energy, and less-operational-requirements alternative ...to conventional treatment systems, especially for small communities and remote locations. However, the sustainable operation and successful application of these systems remains a challenge. Hence, this paper aims to provide and inspire sustainable solutions for the performance and application of CWs by giving a comprehensive review of CWs' application and the recent development on their sustainable design and operation for wastewater treatment. Firstly, a brief summary on the definition, classification and application of current CWs was presented. The design parameters and operational conditions of CWs including plant species, substrate types, water depth, hydraulic load, hydraulic retention time and feeding mode related to the sustainable operation for wastewater treatments were then discussed. Lastly, future research on improving the stability and sustainability of CWs were highlighted.
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•Concentrations of VFA components were observed at different pH in AnMBR.•Acetic acid was predominant VFA component at pH 6.0 and 7.0.•Highest concentration for isobutyric acid was ...observed at pH 12.0.•The highest overall VFA yield was 48.74 ± 1.5 mg VFA/100 mg CODfeed.
This study investigated the production of major volatile fatty acid (VFA) components in an anaerobic membrane bioreactor (AnMBR) to treat low-strength synthetic wastewater. No selective inhibition was applied for methane production and solvent-extraction method was used for VFA extraction. The results showed acetic and propionic acid were the predominant VFA components at pH 7.0 and 6.0 with concentrations of 1.444 ± 0.051 and 0.516 ± 0.032 mili-mol/l respectively. At pH 12.0 isobutyric acid was the major VFA component with a highest concentration of 0.712 ± 0.008 mili-mol/l. The highest VFA yield was 48.74 ± 1.5 mg VFA/100 mg CODfeed at pH 7.0. At different pH, AnMBR performance was evaluated in terms of COD, nutrient removal and membrane fouling rate. It was observed that the membrane fouled at a faster rate in both acidic and alkaline pH conditions, the slowest rate in membrane fouling was observed at pH 7.0.
Water pollution caused by Cu2+ ions poses a significant threat to the ecosystem and human health, hence the development of highly cost-effective, highly operation-convenient and highly efficient ...natural polymer-based adsorbents is urgently needed. To overcome this serious problem, a novel cost-effective magnetic chitosan composite adsorbent (CsFeAC) was prepared with magnetic macroparticles and highly porous activated carbon carrier using the sol-gel method. Several methods, namely SEM, BET, FTIR, XRD, TGA and VSM, were applied to characterize the adsorbent. Batch tests were conducted to investigate Cu2+ adsorption properties of CsFeAC at different pH values, contact time, initial Cu2+ concentrations and temperatures. The adsorption fits better to the Langmuir isotherm and follows the pseudo-second-order model, suggesting that it is a monolayer adsorption and the rate-limiting step is the chemical chelating reaction. The saturated adsorption capacity is found to be 216.6 mg/g. Thermodynamics analysis suggests that the adsorption process is endothermic, with increasing entropy and spontaneous in nature. BET and XRD tests confirm that the higher specific surface area and lower crystallinity of CsFeAC significantly improve the absorption capacity and rate. FTIR spectra reveal that the amino and hydroxyl groups play an important role in the chelating adsorption. The supermagnetic property of CsFeAC facilitates its easy separation characteristic. Further recycling experiments show that CsFeAC still retains 95% of the original adsorption following the 5th adsorption-desorption cycle. All these results demonstrate that CsFeAC is a promising recyclable adsorbent for removing Cu2+.
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•A novel magnetic chitosan composite adsorbent was prepared by the sol-gel method.•The adsorbent was characterized by SEM, BET, FTIR, XRD, TGA and VSM methods.•The adsorption fits well with the Langmuir isotherm and pseudo-second-order model.•The adsorbent exhibited high adsorption capacity for the Cu2+ irons.•Easy separation and good reusability make the adsorbent attractive for further practical application.
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