Moving Bed Biofilm Reactor Carriers Research Articles

Simultaneous veterinary antibiotics reduction and biomass production from pig slurry by microalgae co-immobilization in Moving Bed Biofilm Reactors

The objective of the study was to assess, for the first time, the effectiveness of using either freely suspended or co-immobilized microalgae on Moving Bed Biofilm Reactor carriers in removing lincomycin from the liquid fraction of pig slurry, while ensuring the safe production of biomass. To this end, continuous-mode (HRT = 8 d) and batch-mode (10 d) experiments were conducted on bench-scale reactors. In the continuous-mode experiment, co-immobilized microalgae removed 99% of lincomycin and 94% of ammonium, whereas the control reactors and free-microalgae reactors showed significantly lower ammonium removals (69% and 87%, respectively). The removal rates for lincomycin and ammonium in co-immobilized microalgae reactors were higher (0.85 and 0.32 d-1, respectively) than the removal rates of the free-microalgae reactors (0.32 and 0.19 d-1) and control reactor (0.18 and 0.12 d-1). Furthermore, the microalgae reactors were linked with the production of lincomycin transformation products following ammonium and nitrate removal. In contrast to the control reactors, the suspended biomass of both free microalgae and co-immobilized microalgae reactors showed no accumulation of lincomycin. This characteristic makes this biomass particularly appealing in the context of a circular economy. The study introduces an innovative method for producing biomass from pig slurry, with the goal of obtaining high-value products while minimizing pollutant content.

Comparing biofilm reactors inoculated with Shewanella for decolorization of Reactive Black 5 using different carrier materials.

This study assessed the performance of biofilm reactors inoculated with azo dye degrading Shewanella for the decolorization of Reactive Black 5 (RB5), using three different carrier materials, namely almond shell biochar, moving bed biofilm reactor (MBBR), and polypropylene carrier (PPC). The reactors were fed with low-nutrient artificial wastewater containing RB5, and all three carriers showed good RB5 decolorization performance, with varying efficiencies. Liquid Chromatography-Mass Spectrometry analysis revealed distinct RB5 degradation pathways associated with each carrier, influenced by carrier materials and microbial communities. The MBBR carrier exhibited good stability due to its rough surface and microbial aggregates. Sequencing results highlighted differences in the microbial community structures among the carriers. Shewanella predominated the functional bacteria in the MBBR and PPC carriers, while the biochar carrier fostered highly efficient degrading microbial communities. The physicochemical properties of carrier materials significantly influenced the microbial community and RB5 degradation efficiency. These findings provide valuable insights for optimizing biofilm reactors for dye-containing wastewater treatment.

Ex-situ manometric activity test for evaluation of mainstream anammox in Moving Bed Biofilm Reactors

ABSTRACT Implementing anammox based processes in the mainstream at municipal wastewater treatment plants is challenging and requires carefully constructed control strategies in order to be successful. A method to measure the specific anammox activity was further developed and implemented in the mainstream anammox pilot plant at Sjölunda Wastewater Treatment Plant. The method was found to be reliable and reproducible. The influence of initial nitrite and ammonium concentrations on the activity as well as temperature dependency were analysed. The continuously monitored manometric batch tests were performed on Moving Bed Biofilm Reactor carriers type K1®. The activity showed a dependency of initial nitrite concentrations below 75 mg N L−1 whereas the activity was independent of initial nitrite concentrations in the interval of 75–125 mg N L−1. Temperature dependency of the specific anammox activity as expressed in activation energy Ea increased at lower temperatures (10–20°C) compared to higher temperatures (20–30°C). Decreasing temperature from 30°C to 10°C resulted in 95–98% loss of the anammox activity.

Tailored Surface Porosity of Polyethylene-Based Co-continuous Structures for Moving Bed Biofilm Reactor Carriers

Moving bed biofilm reactors (MBBRs) are often used in wastewater treatment. Using MBBR carriers with a porous surface is beneficial to the adhesion of microorganisms and the growth of biofilms. Pol...

Insights into electroactive biofilms for enhanced phenolic degradation of coal pyrolysis wastewater (CPW) by magnetic activated coke (MAC): Metagenomic analysis in attached biofilm and suspended sludge

To investigate the role of electroactive biofilms for enhanced phenolic degradation, lignite activated coke (LAC) and MAC were used as carriers in moving-bed biofilm reactor (MBBR) for CPW treatment. In contrast to activated sludge (AS) reactor, the carriers improved degradation performance of MBBR. Although two MBBRs exerted similar degradation capacity with over 92% of COD and 93% phenols removal under the highest phenolics concentration (500 mg/L), the effluent of MAC-based MBBR remained higher biodegradability (BOD5/COD = 0.34 vs 0.18) than that of LAC-based MBBR. Metagenomic analysis revealed that electroactive biofilms determined phenolic degradation of MAC-based MBBR. Primarily, Geobacter (17.33%) started Fe redox cycle on biofilms and developed syntrophy with Syntrophorhabdus (6.47%), which fermented phenols into easily biodegradable substrates. Subsequently, Ignavibacterium (3.38% to 2.52%) and Acidovorax (0.46% to 8.83%) conducted biological electricity from electroactive biofilms to suspended sludge. They synergized with dominated genus in suspended sludge, Alicycliphilus (19.56%) that accounted for phenolic oxidation and nitrate reduction. Consequently, the significantly advantage of Geobater and Syntrophorhabdus was the keystone reason for superior biodegradability maintenance of MAC-based MBBR.

Investigating the most appropriate methods for attached solids determination in moving-bed biofilm reactors.

Moving-bed biofilm reactors (MBBR) have been employed worldwide as an efficient technology for the treatment of a diverse set of wastewaters. Although the attached biomass represents the major fraction of solids in MBBR systems, there is still no standard for its reliable quantification. An extensive literature review indicated that several methods for attached biomass assessment are applied, hindering the comparability of results issued from different studies. Therefore, the most reported methods for biofilm quantification in the MBBR literature were compared using three different carriers. The results revealed that the performance of each method was biased depending on the carrier type and shape. Moreover, differences in total attached solids (TAS) concentrations varied from 13% up to more than 90%, depending on the employed method for a given carrier. Overall, direct weighing of the carrier containing the biofilm, accounting for the clean carrier weight, and manual extraction of the biofilm, preceded or not by sonication for at least 15min, were the most suitable techniques for assessing TAS and the volatile/total solids ratio in non-porous medias, respectively. The results here presented may be used as a frame of reference for standardization of the methods for assessing the biofilm mass in MBBR carriers.

Hydrophilization of Polyurethane Foam Carriers in MBBR with Hyperbranched Polymeric Diazonium Salts

In recent years, there has been a considerable research interest in moving-bed biofilm reactor(MBBR) for its efficiency and stability. This work proposes a new way to modify the hydrophilicity of polyurethane foam(PU) carriers via the layer-by-layer self-assembly of hyperbranched polymeric diazonium salt(M-HB-DAS) and poly(sodium-p-styrenesulfonate)(PSS). Modified carriers showed very good adsorption for microbes according to the results of scanning electron microscope(SEM). Biochemical experiments on wastewater treatment confirm that the modified PU carriers can improve the removal rate of chemical oxygen demand(COD).

Treatment of Pretreated Textile Wastewater Using Modified Mbbr

Currently, water pollution control is one of the major logical zones. The textile industry is a major pollution causing industry among the industrial pollutions. Treatment of textile effluent utilizing customary physical as well as chemical strategies is costly, produces enormous amounts of sludge and needs the expansion of lethal chemicals. BOD to COD proportion of textile effluent is low. Thus it is not appropriate to treat textile effluent by a solitary physicochemical or biological process. In this investigation, the textile effluent is dealt with utilizing Moving Bed Bio-film Reactor (MBBR) with the magnetic field after improving the biodegradability by the solar photo-Fenton process. The carriers in MBBR is inoculated with azoarcus bacteria isolated from textile sludge. The fundamental parameters as pH, carrier filling ratio and contact time were optimized utilizing Box Behnken factual design. The MBBR process has most extreme efficiency at pH 7, filling ratio of 62% and a contact time 2.4 days. In this optimum condition 68.9% BOD and 80% COD are expelled. At the point when the pretreated wastewater was dealt with MBBR reactor under the influence of magnetic field, the efficiency of the treatment is additionally expanded, so 87.4% COD expulsion and 87% BOD evacuation were accomplished at 12 mT attractive field power when exposure time was at 12 hrs.

Influence of MBBR carriers’ geometry on its flow characteristics

MBBR (Moving Bed Biofilm Reactor) technology in many respects is a flexible alternative to the traditional method of wastewater treatment, which is an activated sludge method. One of the key features of this solution is economy of the construction site, construction costs and the operation of the system. The benefits of this technology can be increased by improving parameters of the most important elements of the system, which are biofilm carriers. A multitude of carrier parameters and their impact on the growth of microorganisms, and also the effectiveness of treatment, allows for optimization of solutions, which means such a construction of a carrier, suiting the conditions in which the carriers will be used. Therefore, mathematical modelling for example using software COMSOL®, can facilitate the selection of the optimum geometry of the carrier so that it was characterized by a sufficient capacity for mass transfer and transport oxygen.

Performance of moving bed biofilm reactor using effective microorganisms

Abstract This work shows the feasibility of using effective microorganisms (EM) to improve the performance of a moving bed biofilm reactor (MBBR) in treating primary settled wastewater. Two MBBR systems were compared, one inoculated with activated sludge only, and the other inoculated with a mixture of activated sludge and EM, under steady-state conditions, and under organic and hydraulic shock loadings. Results after a startup period showed that carriers in MBBR inoculated with activated sludge had only a thicker biofilm compared to MBBR inoculated with a mixture of activated sludge and EM. When compared to MBBR inoculated with activated sludge only, adding EM to the activated sludge was found to improve slightly the removal of particulate chemical oxygen demand (pCOD) and total ammonia nitrogen (TAN), while no improvement in the removal of soluble chemical oxygen demand (sCOD) was achieved. The average removal efficiencies for chemical oxygen demand (COD), sCOD, pCOD, and TAN were found to be 76.71%, 81.87%, 68.13%, and 45.92%, respectively in MBBR inoculated with activated sludge only for a period of 30 days; while those for MBBR inoculated with a mixture of activated sludge and EM were found to be 67.79%, 61.12%, 76.26%, and 56.97%, respectively, during the same period. Both MBBR systems were affected by shock loadings. Performance of MBBR inoculated with activated sludge only was much better than that for MBBR inoculated with a mixture of activated sludge and EM under both organic and hydraulic shock loadings with respect to removal of COD and TAN. MBBR inoculated with activated sludge only took much less time to reach steady-state conditions after the removal of both organic and hydraulic shock loadings when compared to MBBR inoculated with a mixture of activated sludge and EM. MBBR inoculated with a mixture of activated sludge and EM was able to reach steady-state conditions 5 h from removal of organic shock loading, while it was not able to reach original conditions after removal of hydraulic shock loading.

Biofilm development, activity and the modification of carrier material surface properties in moving-bed biofilm reactors (MBBRs) for wastewater treatment

ABSTRACTIn the last decades, moving-bed biofilm reactors (MBBRs) have found a niche in the treatment of municipal and industrial wastewaters due to advantages of compactness, simplicity, stability and increased reaction rates. Recently, the material surface properties of MBBR carriers and their modification have been investigated, as reviewed herein, in order to enhance the control of microbial attachment and biofilm development, and MBBR performance by faster reactor startups or increased specific activity per surface area. Biofilm formation is a complex process influenced by the solid substratum surface properties and microbial composition and characteristics. MBBR carriers can be made to facilitate biofilm formation by modifying their physico-chemical surface characteristics using blended polymers, mixed materials, coatings and incorporating different chemical functional groups. The chemical modification of the substratum polymeric surface for biofilm treatment reactors has comprised plasma oxidation treatment, radiolysis in a gas phase, liquid-phase oxidative treatment and polymer grafting. This review focusses on carrier material surface properties, the modification of such properties and carrier material choices relevant to biofilm development and functionality of MBBRs, in order to identify opportunities and challenges in future biofilm carrier development.

Transformation products of clindamycin in moving bed biofilm reactor (MBBR)

Clindamycin is widely prescribed for its ability to treat a number of common bacterial infections. Thus, clindamycin enters wastewater via human excretion or disposal of unused medication and widespread detection of pharmaceuticals in rivers proves the insufficiency of conventional wastewater treatment plants in removing clindamycin. Recently, it has been discovered that attached biofilm reactors, e.g., moving bed biofilm reactors (MBBRs) obtain a higher removal of pharmaceuticals than conventional sludge wastewater treatment plants. Therefore, this study investigated the capability of MBBRs applied in the effluent of conventional wastewater treatment plants to remove clindamycin. First, a batch experiment was executed with a high initial concentration of clindamycin to identify the transformation products. It was shown that clindamycin can be removed from wastewater by MBBR and the treatment process converts clindamycin into the, possibly persistent, products clindamycin sulfoxide and N-desmethyl clindamycin as well as 3 other mono-oxygenated products.Subsequently, the removal kinetics of clindamycin and the formation of the two identified products were investigated in batch experiments using MBBR carriers from polishing and nitrifying reactors. Additionally, the presence of these two metabolites in biofilm-free wastewater effluent was studied. The nitrifying biofilm reactor had a higher biological activity with k-value of 0.1813 h−1 than the reactor with polishing biofilm (k = 0.0161 h−1) which again has a much higher biological activity for removal of clindamycin than of the suspended bacteria (biofilm-free control). Clindamycin sulfoxide was the main transformation product which was found in concentrations exceeding 10% of the initial clindamycin concentration after 1 day of MBBR treatment. Thus, MBBRs should not necessarily be considered as reactors mineralizing clindamycin as they perform transformation reactions at least to some extent.

A novel approach for harnessing biofilm communities in moving bed biofilm reactors for industrial wastewater treatment

Moving bed biofilm reactors (MBBRs) are an effective biotechnology for treating industrial wastewater. Biomass retention on moving bed biofilm reactor (MBBR) carriers (biofilm support materials), allows for the ease-of-operation and high treatment capacity of MBBR systems. Optimization of MBBR systems has largely focused on aspects of carrier design, while little attention has been paid to enhancing strategies for harnessing microbial biomass. Previously, our research group demonstrated that mixed-species biofilms can be harvested from an industrial wastewater inoculum [oil sands process water (OSPW)] using the Calgary Biofilm Device (CBD). Moreover, the resultant biofilm communities had the capacity to degrade organic toxins (naphthenic acids—NAs) that are found in OSPW. Therefore, we hypothesized that harnessing microbial communities from industrial wastewater, as biofilms, on MBBR carriers may be an effective method to bioremediate industrial wastewater. Here, we detail our methodology adapting the workflow employed for using the CBD, to generate inoculant carriers to seed an MBBR. In this study, OSPW-derived biofilm communities were successfully grown, and their efficacy evaluated, on commercially available MBBR carriers affixed within a modified CBD system. The resultant biofilms demonstrated the capacity to transfer biomass to recipient carriers within a scaled MBBR. Moreover, MBBR systems inoculated in this manner were fully active 2 days post-inoculation, and readily degraded a select population of NAs. Together, these findings suggest that harnessing microbial communities on carriers affixed within a modified CBD system may represent a facile and rapid method for obtaining functional inoculants for use in wastewater MBBR treatment systems.

DsrAB-based analysis of sulphate-reducing bacteria in moving bed biofilm reactor (MBBR) wastewater treatment plants.

Sulphate-reducing bacteria (SRB) are important members of the sulphur cycle in wastewater treatment plants (WWTPs). In this study, we investigate the diversity and activity of SRB within the developing and established biofilm of two moving bed biofilm reactor (MBBR) systems treating municipal wastewater in New Zealand. The larger of the two WWTPs (Moa Point) generates high levels of sulphide relative to the smaller Karori plant. Clone libraries of the dissimilatory (bi)sulphite reductase (dsrAB) genes and quantitative real-time PCR targeting dsrA transcripts were used to compare SRB communities between the two WWTPs. Desulfobulbus (35-53% of total SRB sequences) and genera belonging to the family Desulfobacteraceae (27-41%) dominated the SRB fraction of the developing biofilm on deployed plastic carriers at both sites, whereas Desulfovibrio and Desulfomicrobium were exclusively found at Moa Point. In contrast, the established biofilms from resident MBBR carriers were largely dominated by Desulfomonile tiedjei-like organisms (58-100% of SRB sequences). The relative transcript abundance of dsrA genes (signifying active SRBs) increased with biofilm weight yet remained low overall, even in the mature biofilm stage. Our results indicate that although SRB are both present and active in the microbial community at both MBBR study sites, differences in the availability of sulphate may be contributing to the observed differences in sulphide production at these two plants.

Three-Dimensional Stratification of Bacterial Biofilm Populations in a Moving Bed Biofilm Reactor for Nitritation-Anammox

Moving bed biofilm reactors (MBBRs) are increasingly used for nitrogen removal with nitritation-anaerobic ammonium oxidation (anammox) processes in wastewater treatment. Carriers provide protected surfaces where ammonia oxidizing bacteria (AOB) and anammox bacteria form complex biofilms. However, the knowledge about the organization of microbial communities in MBBR biofilms is sparse. We used new cryosectioning and imaging methods for fluorescence in situ hybridization (FISH) to study the structure of biofilms retrieved from carriers in a nitritation-anammox MBBR. The dimensions of the carrier compartments and the biofilm cryosections after FISH showed good correlation, indicating little disturbance of biofilm samples by the treatment. FISH showed that Nitrosomonas europaea/eutropha-related cells dominated the AOB and Candidatus Brocadia fulgida-related cells dominated the anammox guild. New carriers were initially colonized by AOB, followed by anammox bacteria proliferating in the deeper biofilm layers, probably in anaerobic microhabitats created by AOB activity. Mature biofilms showed a pronounced three-dimensional stratification where AOB dominated closer to the biofilm-water interface, whereas anammox were dominant deeper into the carrier space and towards the walls. Our results suggest that current mathematical models may be oversimplifying these three-dimensional systems and unless the multidimensionality of these systems is considered, models may result in suboptimal design of MBBR carriers.

Organic removal activity in biofilm and suspended biomass fractions of MBBR systems

The moving bed biofilm reactor (MBBR) wastewater treatment process is usually designed based on the assumption that all activity in the process occurs in the biofilm on the MBBR carriers, although there is always some active biomass in the bulk liquid due to biofilm sloughing and, sometimes, free-growing bacteria. In this study the removal of organic matter is evaluated in laboratory-scale MBBR reactors under varying load, hydraulic retention time (HRT), oxygen concentration and volumetric filling degree of carriers in order to determine the heterotrophic activity in the different fractions of the MBBR biomass. The results showed that the heterotrophic conversions in an MBBR can show the same type of diffusion limited dependency on oxygen as nitrification, even for easily degradable substrates such as acetate. The contribution to the removal from the suspended biomass is shown to vary depending on HRT, as the amount of suspended solids changes. The developed method in this report is a useful tool for determining heterotrophic activity in the separate fractions of biomass in MBBRs.