The protection and conservation of natural resources is one of the main priorities of modern society. Water is perhaps our most valuable resource, and thus should be recycled. Many of the current ...recycling techniques for polluted water only concentrate the pollutant without degrading it or eliminating it. In this sense, advanced oxidation processes are possibly one of the most effective methods for the treatment of wastewater containing organic products (effluents from chemical and agrochemical industries, the textile industry, paints, dyes, etc.). More conventional techniques cannot be used to treat such compounds because of their high chemical stability and/or low biodegradability. This article describes, classifies, and analyzes different types of advanced oxidation processes and their application to the treatment of polluted wastewater.
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•Membrane-based treatments and AOP combination was assessed for wastewater reclamation.•MBR and MBBR-MBR can regenerate wastewater with highest quality set in ...2018/0169/COD.•Pharmaceuticals in urban wastewater can be completely removed using MBBR-MBR + AOP.•The heterotrophic kinetics of biomass is affected by the presence of pharmaceuticals.
This research was performed to assess the production of reclaimed water from urban wastewater in membrane bioreactor – advanced oxidation process (MBR-AOP) and moving bed biofilm reactor – membrane bioreactor – advanced oxidation process (MBBR-MBR-AOP) combined treatments to study the effect of biofilm incorporation. Both combined treatments were operated at the same conditions (10 h of hydraulic retention time, 6500 mg/L of mixed liquor suspended solids and 25 mg/L of hydrogen peroxide dosage over 15 min). Additionally, the removal capacity of some pharmaceuticals (carbamazepine, ciprofloxacin and ibuprofen) and their impact on the kinetic behaviour of the biomass in both systems were evaluated. From the results, it was found a membrane-based bioreactor can achieve both wastewater secondary treatment and pre-treatment for advanced oxidation process, so both MBR-AOP and MBBR-MBR-AOP treatments have a great potential to produce high quality reclaimed water (biological oxygen demand <0.5 mgO2/L, suspended solids <1 mg/L, turbidity <1 NTU and no presence of E. coli), according to European Commission proposal 2018/0169/COD. The addition of carriers improved the biodegradation of the most persistent pharmaceuticals in the biological treatment (from 69.20 ± 1.54% to 75.14 ± 2.71% for carbamazepine and from 60.41 ± 2.16 to 63.14 ± 2.70% for ciprofloxacin). It had, as a consequence, the MBBR-MBR-AOP system showing a complete degradation of pharmaceuticals after 5 min AOP treatment compared to the MBR-AOP system. The loss of biomass in the MBR-AOP (from 5233.45 to 4451.92 mg/L) and the increase of the substrate degradation rate for organic matter in both treatments (from 37.27 to 41.42 and from 30.25 to 33.19 mgO2/(L·h) in MBR-AOP and MBBR-MBR-AOP, respectively) are some of the consequences of pharmaceuticals in urban wastewater.
•Comparison of systems combining moving bed biofilm reactor with membrane bioreactor and membrane bioreactor configuration.•Kinetic parameters which characterised the moving bed biofilm reactor and ...the membrane bioreactor processes were analysed.•Not statistically significant differences between the experimental plants regarding the organic matter and nutrients removal.•Improvement of nitrogen and phosphorus removal of the MBBR-MBR system which contained carriers only in the aerobic zone.•MBR had a better performance from the point of view of the kinetic parameters.
New technologies regarding wastewater treatment have been developed. Among these technologies, the moving bed biofilm reactor combined with membrane bioreactor (MBBR-MBR) is a recent solution alternative to conventional processes. This paper presents the results obtained from three wastewater treatment plants working in parallel. The first wastewater treatment plant consisted of a membrane bioreactor (MBR), the second one was a MBBR-MBR system containing carriers both in anoxic and aerobic zones, and the last one consisted of a MBBR-MBR system which contained carriers only in the aerobic zone. The reactors operated with a hydraulic retention time of 26.47h. During the study, the difference between the experimental plants was not statistically significant concerning organic matter and nutrients removal. However, different tendencies regarding nutrients removal are shown by the three wastewater treatment plants. In this sense, the performances in terms of nitrogen and phosphorus removal of the MBBR-MBR system which contained carriers only in the aerobic zone (67.34±11.22% and 50.65±11.13%, respectively) were slightly better than those obtained from another experimental plants. As a whole, the pilot plant which consisted of a MBR showed better performance from the point of view of the kinetics of the heterotrophic and autotrophic biomass with values of μm,H=0.00858h−1, μm,A=0.07646h−1, KM=2.37mgO2L−1 and KNH=1.31mgNL−1.
•Resource recovery from urban wastewater to promote shift towards a circular economy.•Pilot and full-scale studies show MBBR as suitable system for treated wastewater reuse.•Numerous methods ...developed for nutrient recovery from WWTP’s effluents.
Over the last years, an increasing concern has emerged regarding the eco-friendly management of wastewater. Apart from the role of wastewater treatment plants (WWTPs) for wastewater and sewage sludge treatment, the increasing need of the recovery of the resources contained in wastewater, such as nutrients and water, should be highlighted. This would allow for transforming a wastewater treatment plant (WWTP) into a sustainable technological system.
The objective of this review is to propose a moving bed biofilm reactor (MBBR) as a novel technology that contributes to the circularity of the wastewater treatment sector according to the principles of circular economy. In this regard, this paper aims to consider the MBBR process as the initial step for water reuse, and nutrient removal and recovery, within the circular economy model.
•Two hybrid MBBR-MBR and an MBR were compared for biological nutrient removal.•Hybrid MBBR-MBRap with anaerobic, anoxic and aerobic carriers had the best TP removal.•Hybrid MBBR-MBRap had the highest ...COD removal with the best heterotrophic kinetics.•Hybrid MBBR-MBRbp with anaerobic and anoxic carriers showed the highest TN removal.•MBRp and hybrid MBBR-MBRbp had the best kinetics regarding NOB and AOB, respectively.
A membrane bioreactor (MBRp), a hybrid moving bed biofilm reactor-membrane bioreactor containing carriers in the anaerobic, anoxic and aerobic zones (hybrid MBBR-MBRap) and a hybrid moving bed biofilm reactor-membrane bioreactor which contained carriers only in the anaerobic and anoxic compartments (hybrid MBBR-MBRbp) were used in parallel and compared regarding the nutrient and organic matter removal from municipal wastewater. The hydraulic retention time (HRT) was 18h. A kinetic study for the heterotrophic and autotrophic bacteria, mainly nitrite-oxidizing bacteria (NOB), was carried out and related to the nutrient and organic matter removal. The hybrid MBBR-MBRap performed best regarding chemical oxygen demand (COD) and total phosphorus (TP) removals, with values of 85.82±2.12% and 81.42±3.85%, respectively. This system had a higher phosphorus release under anaerobic conditions and a higher phosphorus uptake under aerobic conditions. The highest TN removal efficiency was obtained for the hybrid MBBR-MBRbp, with a value of 61.39±10.71%.
Aim: Mediterranean terrestrial ecosystems serve as reference laboratories for the investigation of global change because of their transitional climate, the high spatiotemporal variability of their ...environmental conditions, a rich and unique biodiversity and a wide range of socio-economic conditions. As scientific development and environmental pressures increase, it is increasingly necessary to evaluate recent progress and to challenge research priorities in the face of global change. Location: Mediterranean terrestrial ecosystems. Methods: This article revisits the research priorities proposed in a 1998 assessment. Results: A new set of research priorities is proposed: (1) to establish the role of the landscape mosaic on fire-spread; (2) to further research the combined effect of different drivers on pest expansion; (3) to address the interaction between drivers of global change and recent forest management practices; (4) to obtain more realistic information on the impacts of global change and ecosystem services; (5) to assess forest mortality events associated with climatic extremes; (6) to focus global change research on identifying and managing vulnerable areas; (7) to use the functional traits concept to study resilience after disturbance; (8) to study the relationship between genotypic and phenotypic diversity as a source of forest resilience; (9) to understand the balance between storage and water resources; (10) to analyse the interplay between landscape-scale processes and biodiversity conservation; (11) to refine models by including interactions between drivers and socio-economic contexts; (12) to understand forest-atmosphere feedbacks; (13) to represent key mechanisms linking plant hydraulics with landscape hydrology. Main conclusions: (1) The interactive nature of different global change drivers remains poorly understood. (2) There is a critical need for the rapid development of regional-and global-scale models that are more tightly connected with largescale experiments, data networks and management practice. (3) More attention should be directed to drought-related forest decline and the current relevance of historical land use.
•Conventional MBR, hybrid MBBR–MBR and pure MBBR–MBR were compared.•Pure MBBR–MBR has the highest potential of nitrogen removal.•Pure MBBR–MBR shows the best kinetic performance.•Hybrid MBBR–MBR has ...the highest performance of COD and BOD5 removal.•Attached biomass enhances the process of wastewater treatment.
The moving bed biofilm reactor–membrane bioreactor (MBBR–MBR) is a novel solution to conventional processes. In this study, a conventional membrane bioreactor (MBR), a hybrid MBBR–MBR and a pure MBBR–MBR were compared. The hybrid MBBR–MBR contained suspended and attached biomass, while the pure MBBR–MBR mainly had attached biomass. The reactors operated with a hydraulic retention time of 9.5h. The pure MBBR–MBR had the highest efficiency of nitrogen removal with a value of 71.91±16.04%. As a whole, the pure MBBR–MBR showed the best performance from the point of view of the kinetics of the heterotrophic and autotrophic biomass with values of μm,H=0.018h−1, μm,A=0.751h−1, KM=2.679mgO2L−1 and KNH=2.191mgNL−1. The presence of the attached biomass improved the organic matter and nitrogen removal in a pure MBBR–MBR system.
ABSTRACT
Erosional scars, slumps, slides and debrites (mass‐transport deposits) on submarine slopes form relief that influences turbidity current behaviour. However, the interaction of mass‐transport ...deposit emplacement kinematics (i.e. rapid emplacement versus creep), the morphology of the evolving seafloor topography and subsequent flow types is complicated. This study describes two outcrop examples of deep‐water, predominantly turbiditic, deposits overlying mass‐transport deposits, from the Eocene slope succession of the Aínsa Basin (Spanish Pyrenees). In both examples, the mass‐transport deposit substrate continued to creep contemporaneously with turbidity current deposition and bypass. In the first case study, structures in the mass‐transport deposits are extensional and oriented parallel to flow. In the second, structures are compressional and oriented perpendicular to flow. Mudstones dominate the slope succession, but deposits overlying mass‐transport deposits form sandstone‐prone accumulations. Lateral confinement by flow‐parallel extensional faults enhanced channel‐formation. Channel incision occurred close to the exhumed fault plane on the hangingwall. Incision ceased as the fault gradually locked‐up, and channels avulsed to the hangingwall of a newly active normal fault, while the abandoned channel was filled by a thinning and fining‐upward succession. Barriers formed where the long axes of compressional anticlines developed in mass‐transport deposits formed perpendicular to flow. Here, turbidites filled the bathymetric lows in the axes of synclines. Continued tightening of synclinal depocentres led to repeated stoss side trapping and upslope accretion of coarse‐grained sediment accumulation. This generated thickening and coarsening‐up, followed by thinning and fining‐upward successions, tracking the decreasing, then increasing flow bypass associated with topographic expression on the mass‐transport deposit. This study shows how post‐emplacement creep, and orientation of topographic features on mass‐transport deposits, influence the routing and deposition of contemporaneous turbidity currents, and illustrates examples of facies successions that could be misinterpreted as the product of other autogenic submarine slope processes, such as lateral migration of sinuous channels, or compensational lobe stacking.
AbstractEmerging contaminants are a global concern, as Directive 2013/39/UE shows. Given the possible consequences that may lead to the presence of these compounds in water resources, different ...proposals are being evaluated to avoid their discharge into the environment. This study focuses on the use of a biological and physicochemical combined treatment formed by a membrane bioreactor with an H2O2/UltraViolet (UV) advanced oxidation process coupled subsequently to degrade contaminants of emerging concern in real urban wastewater. The membrane bioreactor operated at 16 h of hydraulic retention time and 4,250 mg/L of mixed liquor suspended solids. Different hydrogen peroxide dosages (25, 50, and 100 mg/L) were tested in the photoreactor at 20°C and the natural pH of the wastewater. Different initial concentrations of a mix of pharmaceuticals (carbamazepine, ciprofloxacin, and ibuprofen) were tested. Removal efficiencies obtained in the biological stage ranged from 66.23%–96.18%, 90.63%–100%, and 90.04%–96.48%, respectively. However, complete removal was achieved after the physicochemical stage when the concentrations of contaminants in the mix were similar to current concentration levels in urban wastewater.
•Conventional MBR and two hybrid MBBR–MBR systems were compared.•Hybrid MBBR–MBR systems have the highest nitrifying activities and nitrate formation.•Hybrid MBBR–MBR systems show the highest ...potential capacity to remove total nitrogen.•WWTP with carriers only in aerobic zone has the best heterotrophs and NOB kinetics.
A membrane bioreactor (MBR), a hybrid moving bed biofilm reactor–membrane bioreactor (MBBR–MBR) containing carriers in the anoxic and aerobic zones of the bioreactor and a hybrid MBBR–MBR which contained carriers only in the aerobic zone were used in parallel with the same urban wastewater and compared. The reactors operated with a hydraulic retention time (HRT) of 9.5h. Kinetic parameters for heterotrophic and autotrophic biomasses, mainly ammonium-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB), were evaluated and related to organic matter and nutrients removals. The microbial communities of each wastewater treatment plant (WWTP) were analyzed by 454 pyrosequencing methods to detect and quantify the contribution of nitrifying bacteria in the total bacterial community. All three systems showed similar performance in terms of pollutant removal although the hybrid MBBR–MBR containing carriers only in the aerobic zone of the bioreactor (WWTP 3) showed the best performance from the point of view of the kinetics of heterotrophic and nitrite-oxidizing bacteria, with values of μm,H=0.02665h−1, KM=8.88081mgO2L−1, μm,NOB=0.53690h−1 and KNOB=2.16702mgNL−1. It supported the efficiencies of chemical oxygen demand (COD) and total nitrogen (TN) removals and the concentrations of nitrite and nitrate in the different effluents.
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