Hybrid Moving Bed Biofilm Reactor-membrane Research Articles

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.

Reduction of Cost and Environmental Impact in the Treatment of Textile Wastewater Using a Combined MBBR-MBR System.

A hybrid Moving Bed Biofilm Reactor—Membrane Bioreactor (MBBR-MBR) was developed for the treatment of wastewater from a Spanish textile company. Compared with conventional activated sludge (CAS) treatment, the feasibility of this hybrid system to reduce economic and environmental impact on an industrial scale was conducted. The results showed that, technically, the removal efficiency of COD, TSS and color reached 93%, 99% and 85%, respectively. The newly dyed fabrics performed with the treated wastewater were qualified under the standards of the textile industry. Economically, the values of Capital Expenditure (CAPEX) calculated for the hybrid MBBR-MBR system are profitable because of the reduction in Operational Expenditure (OPEX) when compared with CAS treatment, due to the lower effluent discharge tax thanks to the higher quality of the effluent and the decolorizing agent saved. The result of Net Present Value (NPV) and the Internal Rate of Return (IRR) of 18% suggested that MBBR-MBR is financially applicable for implantation into the industrial scale. The MBBR-MBR treatment also showed lower environmental impacts than the CAS process in the life cycle assessment (LCA) study, especially in the category of climate change, thanks to the avoidance of using extra decolorizing agent, a synthetic product based on a triamine.

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).

Maximum Influent Salinity Affects the Diversity of Mineral-Precipitation-Mediating Bacterial Communities in Membrane Biofilm of Hybrid Moving Bed Biofilm Reactor-Membrane Bioreactor

Two hybrid moving bed biofilm reactor-membrane bioreactors were used for the treatment of variable-salinity influent wastewater with maximums of 4.5 and 8.5 mS cm−1 electric conductivity. Operational conditions of the bioreactors were 6 h hydraulic retention time and 2500 mg L−1 total solids. The membrane operated in a cycle of 9 min draw-1 min backwash and at 23.6 L h−1 m−2 flux rate. Membrane biofilm was collected from both systems and cultured in growth media for precipitation of carbonate and phosphate minerals, yielding only Bacillus stratosphericus for the 4.5 mS cm−1 scenario and Bacillus stratosphericus, Bacillus toyonensis, Microbacterium esteraromaticum, Comamonas testosteroni, and Janibacter meloni for the 8.5 mS cm−1 scenario. Scanning electron microscopy and X-ray analysis showed similarities in morphology and composition for the carbonate crystals from both salinity conditions and differences for the phosphate minerals. Study of the bacterial community of membrane biofilm and mixed liquor showed close similarities between them for the same salinity conditions, with both dominated by genera Rhodanobacter, Chujaibacter, and Thermomonas.

Biofouling Formation and Bacterial Community Structure in Hybrid Moving Bed Biofilm Reactor-Membrane Bioreactors: Influence of Salinity Concentration

Two pilot-scale hybrid moving bed biofilm reactor-membrane bioreactors were operated in parallel for the treatment of salinity-amended urban wastewater under 6 hours of hydraulic retention time and 2500 mg L−1 total solids concentration. Two salinity conditions were tested: the constant salinity of 6.5 mS cm−1 electric conductivity (3.6 g L−1 NaCl) and the tidal-like variable salinity with maximum 6.5 mS cm−1 electric conductivity. An investigation was developed on the biofouling produced on the ultrafiltration membrane surface evaluating its bacterial community structure and its potential function in the fouling processes. The results showed that biofouling was clearly affected by salinity scenarios in terms of α-diversity and β-diversity and bacterial community structure, which confirms lower bacterial diversity under variable salinity conditions with Rhodanobacter and Dyella as dominant phylotypes. Microorganisms identified as bio-mineral formers belonged to genera Bacillus, Citrobacter, and Brevibacterium. These findings will be of help for the prevention and control of biofouling in saline wastewater treatment systems.

Effect of salinity variation on the autotrophic kinetics of the start-up of a membrane bioreactor and hybrid moving bed biofilm reactor-membrane bioreactor at low hydraulic retention time

A membrane bioreactor (MBR) and a hybrid moving bed biofilm reactor-membrane bioreactor (hybrid MBBR-MBR) for municipal wastewater treatment were studied to determine the effect of salinity on nitrogen removal and autotrophic kinetics. The biological systems were analyzed during the start-up phase with a hydraulic retention time (HRT) of 6 h, total biomass concentration of 2,500 mg L-1 in the steady state, and electric conductivities of 1.05 mS cm-1 for MBR and hybrid MBBR-MBR working under regular salinity and conductivity variations of 1.2-6.5 mS cm-1 for MBR and hybrid MBBR-MBR operating at variable salinity. The variable salinity affected the autotrophic biomass, which caused a reduction of the nitrogen degradation rate, an increase of time to remove ammonium from municipal wastewater and longer duration of the start-up phase for the MBR and hybrid MBBR-MBR.

Membrane bioreactor and hybrid moving bed biofilm reactor-membrane bioreactor for the treatment of variable salinity wastewater: Influence of biomass concentration and hydraulic retention time

A membrane bioreactor and two hybrid moving bed biofilm reactor-membrane bioreactor systems were operated for the treatment of wastewater with tidal salinity fluctuations under hydraulic retention times of 6, 9.5 and 12 h, and operational solids concentrations of around 2500 and 3500 mg L−1. The three configurations were studied in terms of carbon and nitrogen removal, heterotrophic and autotrophic kinetics, and bacterial community structure. The performance of the systems was good in terms of organic matter removal – between 85–100% and 95–100% for COD and BOD5, respectively, showing higher efficiencies at higher solids concentration and hydraulic retention times. Nitrogen removal obtained was in the range of 30–50%. The bacterial community structure of the suspended and attached biomass in the systems was more influenced by the operational solids (80% clustering cutoff) and hydraulic retention time (60% clustering cutoff) than by technological configuration (40% clustering cutoff), as determined by ordination analyses. Massive parallel sequencing showed the presence of Nitrobacter and Rhodanobacter at almost all operation scenarios, and thus were identified as major players in treatment of tidal salinity variation wastewater. Overall, this research proved that the MBR and hybrid MBBR-MBR systems could successfully treat urban wastewater subjected to tidal salinity variations. Nevertheless, more research is needed in order to enhance nitrogen removal performance under these conditions.

Effect of hydraulic retention time on the performance of a hybrid moving bed biofilm reactor-membrane bioreactor system for micropollutants removal from municipal wastewater

This study evaluated micropollutants removal and membrane fouling behaviour of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR) system at four different hydraulic retention times (HRTs) (24, 18, 12 and 6h). The results revealed that HRT of 18h was the optimal condition regarding the removal of most selected micropollutants. As the primary removal mechanism in the hybrid system was biodegradation, the attached growth pattern was desirable for enriching slow growing bacteria and developing a diversity of biocoenosis. Thus, the efficient removal of micropollutants was obtained. In terms of membrane fouling propensity analysis, a longer HRT (e.g. HRTs of 24 and 18h) could significantly mitigate membrane fouling when compared with the shortest HRT of 6h. Hence, enhanced system performance could be achieved when the MBBR-MBR system was operated at HRT of 18h.

Performance and kinetics of membrane and hybrid moving bed biofilm‐membrane bioreactors treating salinity wastewater

A pilot‐plant membrane bioreactor (MBR) and two pilot‐plant hybrid moving bed biofilm reactor–membrane bioreactors (MBBR–MBRs), divided into three aerobic and one anoxic chambers, were started up for the treatment of salinity‐amended urban wastewater. The MBBR–MBR systems worked with and without carriers in the anoxic zone (MBBR–MBRanox and MBBR–MBRn/anox, respectively). The systems were operated from start‐up to stabilization, showing high removal of organic matter—a maximum of 90% chemical oxygen demand and 98% biochemical oxygen demand on the fifth day for MBBR–MBRn/anox in the stabilization phase—but low nitrogen elimination—30% maximum for MBBR–MBRn/anox in the stabilization phase. Biofilm attached to carriers reached less than 50 mg L−1 in the hybrid system. MBR showed faster kinetics than the two MBBR–MBR systems during start‐up, but the opposite occurred during stabilization. Maximum specific growth rates for heterotrophic and autotrophic biomass were 0.0500 and 0.0059 h−1 for MBBR–MBRn/anox in the stabilization phase. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3329–3342, 2017

Moving bed biofilm reactor to treat wastewater

This review carries out a comparative study of advanced technologies to design, upgrade and rehabilitate wastewater treatment plants. The study analyzed the relevant researches in the last years about the moving bed biofilm reactor process with only attached biomass and with hybrid biomass, which combined attached and suspended growth; both could be coupled with a secondary settling tank or microfiltration/ultrafiltration membrane as a separation system. The physical process of membrane separation improved the organic matter and NH4 +-N removal efficiencies compared with the settling tank. In particular, the pure moving bed biofilm reactor–membrane bioreactor showed average chemical oxygen demand, biochemical oxygen demand on the fifth day and total nitrogen removal efficiencies of 88.32, 90.84 and 60.17%, respectively, and the hybrid moving bed biofilm reactor–membrane bioreactor had mean chemical oxygen demand, biochemical oxygen demand on the fifth day and total nitrogen reduction percentages of 91.18, 97.34 and 68.71%, respectively. Moreover, the hybrid moving bed biofilm reactor–membrane bioreactor showed the best efficiency regarding organic matter removal for low hydraulic retention times, so this system would enable the rehabilitation of activated sludge plants and membrane bioreactors that did not comply with legislation regarding organic matter removal. As the pure moving bed biofilm reactor–membrane bioreactor performed better than the hybrid moving bed biofilm reactor–membrane bioreactor concerning the total nitrogen removal under low hydraulic retention times, this system could be used to adapt wastewater treatment plants whose effluent was flowed into sensitive zones where total nitrogen concentration was restricted. This technology has been reliably used to upgrade overloaded existing conventional activated sludge plants, to treat wastewater coming from textile, petrochemical, pharmaceutical, paper mill or hospital effluents, to treat wastewater containing recalcitrant compounds efficiently, and to treat wastewater with high salinity and/or low and high temperatures.

Anaerobic/anoxic/oxic configuration in hybrid moving bed biofilm reactor-membrane bioreactor for nutrient removal from municipal wastewater

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%.

New functional biocarriers for enhancing the performance of a hybrid moving bed biofilm reactor–membrane bioreactor system

In this study, new sponge modified plastic carriers for moving bed biofilm reactor (MBBR) was developed. The performance and membrane fouling behavior of a hybrid MBBR–membrane bioreactor (MBBR–MBR) system were also evaluated. Comparing to the MBBR with plastic carriers (MBBR), the MBBR with sponge modified biocarriers (S-MBBR) showed better effluent quality and enhanced nutrient removal at HRTs of 12h and 6h. Regarding fouling issue of the hybrid systems, soluble microbial products (SMP) of the MBR unit greatly influenced membrane fouling. The sponge modified biocarriers could lower the levels of SMP in mixed liquor and extracellular polymeric substances in activated sludge, thereby mitigating cake layer and pore blocking resistances of the membrane. The reduced SMP and biopolymer clusters in membrane cake layer were also observed. The results demonstrated that the sponge modified biocarriers were capable of improving overall MBBR performance and substantially alleviated membrane fouling of the subsequent MBR unit.

Behaviour of the solids retention time in relation to the operative variables in a hybrid moving bed membrane bioreactor treating urban wastewater

The present research studies the influence of the operative variable of a hybrid moving bed biofilm reactor–membrane bioreactor (hybrid MBBR–MBR) in the attached biomass, and analyses the effect of the variables on the evolution of solids retention time (SRT) treating real urban wastewater in a pilot-scale experimental plant. This was operated under mixed liquor suspended solids (MLSSs) between 2,414 ± 166 and 4,594 ± 47 mg/L, the temperature ranged between 5.00±1.58 and 27.88 ± 1.52°C and the regimes of 10 and 24 h HRT with 20, 35 and 50% of the filling ratio. The biofilm density changes between 2,618 ± 272 and 6,991 ± 843 mg/L of the carrier show statistically significant differences in relation to the operative variables, so it depends mainly on MLSS and temperature, and is not dependent on the filling ratio under the condition studied. The multivariable analysis showed that the most influential operative variables in the SRT were MLSS and temperature, so two models have been proposed to consider these effects. The SRT can be modelled in relation to the HRT and MLSS throughout the F/M rate with the hyperbola 5.469×(F/M)-0.833;2.1976×(F/M)-1.181;2.2831×(F/M)-1.207 for 20, 35 and 50% of the filling ratio, respectively. In relation to the temperature, the SRT increases linearly with it between approximately 5 and 30°C with linear coefficients that also increase with the filling ratio presenting the values of 0.2825, 0.3438 and 0.4615 d/°C to 20, 35 and 50% of the filling ratio, respectively.

Evaluation of micropollutant removal and fouling reduction in a hybrid moving bed biofilm reactor–membrane bioreactor system

A hybrid moving bed biofilm reactor–membrane bioreactor (MBBR–MBR) system and a conventional membrane bioreactor (CMBR) were compared in terms of micropollutant removal efficiency and membrane fouling propensity. The results show that the hybrid MBBR–MBR system could effectively remove most of the selected micropollutants. By contrast, the CMBR system showed lower removals of ketoprofen, carbamazepine, primidone, bisphenol A and estriol by 16.2%, 30.1%, 31.9%, 34.5%, and 39.9%, respectively. Mass balance calculations suggest that biological degradation was the primary removal mechanism in the MBBR–MBR system. During operation, the MBBR–MBR system exhibited significantly slower fouling development as compared to the CMBR system, which could be ascribed to the wide disparity in the soluble microbial products (SMP) levels between MBBR–MBR (4.02–6.32mg/L) and CMBR (21.78 and 33.04mg/L). It is evident that adding an MBBR process prior to MBR treatment can not only enhance micropollutant elimination but also mitigate membrane fouling.

Kinetic study of the combined processes of a membrane bioreactor and a hybrid moving bed biofilm reactor-membrane bioreactor with advanced oxidation processes as a post-treatment stage for wastewater treatment

Two membrane bioreactors with different mixed liquor suspended solid concentrations and a hybrid moving bed biofilm reactor-membrane bioreactor which contained carriers only in the aerobic zone of the bioreactor were used in parallel with the same municipal wastewater and compared. The hydraulic retention time was 18h. Kinetic parameters for heterotrophic, autotrophic and nitrite-oxidizing bacteria were evaluated and related to organic matter and nitrogen removals. Three different advanced oxidation process technologies, i.e., H2O2/UV, Fe2+/H2O2/UV and TiO2/H2O2/UV systems, at two H2O2 concentrations of 1gL−1 and 2gL−1, were used to treat the effluents of each biological treatment in batch and were assessed regarding the kinetic performance. The hybrid moving bed biofilm reactor-membrane bioreactor had the best kinetic behavior for the heterotrophic and autotrophic biomass, with a value of TN removal of 72.39±7.57%. The maximum rate of total organic carbon degradation (ηmax,TOC) was higher in the TiO2/H2O2/UV system for a constant H2O2 concentration, and was independent of the effluent. The Fe2+/H2O2/UV process was more suitable for the effluent from the hybrid MBBR-MBR since ηmax,TOC was higher at the two H2O2 concentrations used, i.e., 83.07% and 81.54% at 1gL−1 and 2gL−1, respectively.

Effect of the Filling Ratio, MLSS, Hydraulic Retention Time, and Temperature on the Behavior of the Hybrid Biomass in a Hybrid Moving Bed Membrane Bioreactor Plant to Treat Urban Wastewater

AbstractSeven cycles of operation in relation to the filling ratio, mixed liquor suspended solids (MLSS), hydraulic retention time (HRT), and temperature were studied in a pilot-scale experimental plant of a hybrid moving bed biofilm reactor-membrane bioreactor (MBBR-MBR). The aim of the present research was to study the influence of the operative variables on the behavior of a hybrid MBBR-MBR in relation to organic matter removal and nitrification activity through the kinetic constants for the autotrophic and heterotrophic biomass. Biofilm density during the present research depended on the operative variables changing from 4,403±188 to 5,844±268 mg/L of the carrier, increasing with the increase in MLSS and with the decrease in the HRT. The removal rate was higher than 87.40±4.90 and 94.88±2.41% for chemical oxygen demand (COD) and biological oxygen demand (BOD) BOD5, respectively, increasing process efficiency with the MLSS, HRT, and temperature. Yield for heterotrophic biomass (YH) was between 0.506±0...

Kinetic modeling and microbiological study of two-step nitrification in a membrane bioreactor and hybrid moving bed biofilm reactor–membrane bioreactor for wastewater treatment

Abstract 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 9.5 h. 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 μ m,H = 0.02665 h −1 , K M = 8.88081 mg O 2 L −1 , μ m,NOB = 0.53690 h −1 and K NOB = 2.16702 mg N L −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.

Effects of scale-up on a hybrid moving bed biofilm reactor – membrane bioreactor for treating urban wastewater

A hybrid moving bed biofilm reactor–membrane bioreactor (hybrid MBBR–MBR) system has been tested in this study at two scales to analyse the scale-up effect. Two municipal wastewater treatment plants were used, one at laboratory scale (hybrid MBBR–MBRL) with a reactor working volume of 24 l and one at pilot scale (hybrid MBBR–MBRP) with a reactor working volume of 358 l. Hybrid MBBR–MBRL and hybrid MBBR–MBRP showed that the hybrid MBBR–MBR systems used in this research were reliable for organic matter removal with COD removal percentages of 90.97±2.55% and 95.56±2.01% for hybrid MBBR–MBRL and hybrid MBBR–MBRP, respectively. In hybrid MBBR–MBRL, the sludge retention time was higher but the biofilm density was lower due to the wall effect, so the two effects cancelled one another out and the COD removal efficiencies were found to be similar. The study identified the most influential variables and their effects on the process. Hybrid MBBR–MBRL and hybrid MBBR–MBRP were influenced by the attached and suspended biomass and temperature, while the influent loading rate only affected hybrid MBBR–MBRP. On the whole, hybrid MBBR–MBRP showed a better performance from the point of view of the kinetics of the heterotrophic biomass, with values of YH=0.6130mgVSSmgCOD−1, μm,H=0.0146h−1, KS=9.8852mgO2L−1, and bH=0.0031h−1.