Moving-bed Sequencing Batch Biofilm Reactor Research Articles

Dynamic pH regulation drives Nitrosomonas for high-rate stable acidic partial nitritation

How to intensify the ammonia oxidation rate (AOR) is still a bottleneck impeding the technology development for the innovative acidic partial nitritation because the eosinophilic ammonia-oxidizing bacteria (AOB), such as Nitrosoglobus or Nitrosospira, were inhibited by the high-level free nitrous acid (FNA) accumulation in acidic environments. In this study, an innovative approach of dynamic acidic pH regulation control strategy was proposed to realize high-rate acidic partial nitritation driven by common AOB genus Nitrosomonas. The acidic partial nitrification process was carried out in a laboratory-scale sequencing batch moving bed biofilm reactor (SBMBBR) for long-term (700 days) to track the effect of dynamic acidic pH on nitrifying bacterial activity. The results indicated that the influent NH4+-N concentration was about 100 mg/L, the nitrite accumulation ratio was exceeding 90%, and the maximum AOR can reach 14.5 ± 2.6 mg N L−1 h−1. Although the half-saturation inhibition constant of NOB (KI_FNA(AOB)) reached 0.37 ± 0.10 mg HNO2-N/L and showed extreme adaptability in FNA, the inactivation effect of FNA (6.1 mg HNO2-N/L) for NOB was much greater than that of AOB, with inactivation rates of 0.61 ± 0.08 h−1 and 0.06 ± 0.01 h−1, respectively. The effluent pH was gradually reduced to 4.5 by ammonia oxidation process and the periodic FNA concentration reached 6.5 mg HNO2-N/L to inactivate nitrite-oxidizing bacteria (NOB) without negatively affecting Nitrosomonas during long-term operation. This result provides new insights for the future implementation of high-rate stabilized acidic partial nitritation by Nitrosomonas.

Changes in Nitrification Kinetics and Diversity of Canonical Nitrifiers and Comammox Bacteria in a Moving Bed Sequencing Batch Biofilm Reactor—A Long-Term Study

A lab-scale pure moving bed sequencing batch biofilm reactor (MBSBBR) was employed to investigate changes in nitrification kinetics and microbial diversity. The MBSBBR operated under different aeration strategies (defined by the ratio of the duration of the subphases with (t1) and without (t2) aeration (R = t2/t1)) − continuous (R = 0) and intermittent (with constant time of non-aerated subphases (t2 = 10 min) and variable duration of subphases with aeration (t1 = 40 min–R = 1/4, t1 = 30 min–R = 1/3, t1 = 20 min–R = 1/2) and dissolved oxygen (DO) concentrations (6 mg/L; 3.5 mg/L). Moreover, the reactor’s organic (OLR) and nitrogen (NLR) loading rates were changed in the following ranges: OLR—537–402 gCOD/m3·d, NLR—64–48 gN/m3·d. The obtained results showed that, irrespective of changes introduced in particular series, a highly effective nitrification process (93.36 ± 2.13%) was achieved. The activity of bacteria capable of oxidizing ammonia nitrogen changed differently from that of bacteria capable of oxidizing nitrites (NOB). An increase in R was the primary factor changing the activity of ammonia-oxidizing microorganisms. NOB activity was affected only by the reduction of OLR and NLR. NOB were the predominant bacterial group, consistent with the kinetics studies. A DO decrease caused an increase in the abundance of AOB, NOB, and Comammox bacteria. Comammox bacteria were the most abundant at R = 1/2 and DO = 3.5 mg/L.

Decrease in Oxygen Concentration for the Fast Start-Up of Partial Nitritation/Anammox without Inoculum Addition

Initiating the partial nitritation and anammox (PN/A) process without inoculation poses a significant challenge. Thus, there is a notable amount of interest in devising a straightforward strategy for the start-up of PN/A. This study demonstrates the feasibility of achieving the rapid start-up of a one-stage PN/A process within a moving-bed sequencing batch biofilm reactor (MBSBBR) by reducing the oxygen concentrations: 3.0 mg O2/L (Stage I), 2.0 mg O2/L (Stage II), and 1.0 mg O2/L (Stage III). The anammox activity was observed 15 days after a gradual decrease in the oxygen concentration and confirmed using a specific anammox activity test (5.9 mg N/gVSS∙h). During Stage III, the average total inorganic nitrogen (TIN) removal efficiency was 60.6%. The relative abundance of planctomycetes, a typical phylum representing anammox microorganisms, increased almost three times from Stage I (2.8%) to Stage III (7.1%). These results demonstrate the potential of a decrease in oxygen concentration for the fast start-up of the one-stage partial nitritation and anammox process without inoculation. The implementation of the studied DO strategy has practical implications for wastewater treatment plant operators, particularly in the start-up of the PN/A processes. Additionally, batch assays allow for the rapid assessment of treatment plant performance, providing real-time insights into its functionality and, thereby, optimizing wastewater treatment practices.

The microbiome of two strategies for ammonia removal with the sequencing batch moving bed biofilm reactor treating cheese production wastewater.

Cheese production facilities must abide by sewage discharge bylaws that prevent overloading municipal water resource recovery facilities, eutrophication, and toxicity to aquatic life. Compact treatment systems can permit on-site treatment of cheese production wastewater; however, competition between heterotrophs and nitrifiers impedes the implementation of the sequencing batch moving bed biofilm reactor (SB-MBBR) for nitrification from high-carbon wastewaters. This study demonstrates that a single SB-MBBR is not feasible for nitrification when operated with anerobic and aerobic cycling for carbon and phosphorous removal from cheese production wastewater, as nitrification does not occur in a single reactor. Thus, two reactors in series are recommended to achieve nitrification from cheese production wastewater in SB-MBBRs. These findings can be applied to pilot and full-scale SB-MBBR operations. By demonstrating the potential to implement partial nitrification in the SB-MBBR system, this study presents the possibility of implementing partial nitrification in the SB-MBBR, resulting in the potential for more sustainable treatment of nitrogen from cheese production wastewater.

Study on the Efficacy of Polyethylene Filled SBMBBR Process for Treating Low Temperature Municipal Wastewater

To tackle the hassle of low efficiency of low temperature denitrification in wintry weather in northern region,Sequencing Batch Moving Bed Biofilm Reactor (SBMBBR) used to be used for deep treatment of low temperature municipal wastewater and polyethylene fillers have been compared. The outcomes confirmed that the Sequencing Batch Activated Sludge Reactor (SBR) used to be started correctly at 64 d beneath the prerequisites of water temperature 9-12 °C,pH 7-8 and HRT of 48 h,and two polyethylene fillers had vast biofilm after 7 d operation,and the elimination rates of COD,Ammonia Nitrogen and TP in polyethylene K3 fillers have been stabilized at 83.6%,74.4% and 60.8% respectively as the quality fillers after 24 d operation. After optimizing the process parameters,the steady effluent evaluation effect used to be determined for 27 d operation beneath the most advantageous anoxic (3 h) and aerobic time (7 h) modes of the reactor,and the corresponding elimination quotes of COD and Ammonia Nitrogen were 87.7% and 93.5%,respectively,and the corresponding average effluent concentrations had been 44.4 mg/L and 1.9 mg/L,which reached the Pollutant Discharge Standard for Urban Sewage Treatment Plants (GB 18918-2002). Two vital factors,Dissolved Oxygen (DO) concentration and Hydraulic retention time (HRT) in the aerobic part were studied,and the great HRT of 82 h was once performed in the biointensive domestication SBR machine under the stipulations of the foremost vary of DO attention of 6.0-7.5 mg/L in the aerobic part at low water temperature.

A Comparison of Biosolids Production and System Efficiency between Activated Sludge, Moving Bed Biofilm Reactor, and Sequencing Batch Moving Bed Biofilm Reactor in the Dairy Wastewater Treatment

Dairy industry wastewater is rich in organic content, presenting a high biodegradability, and therefore biological treatments are widely employed. This study aimed to evaluate biosolids production in three systems: activated sludge (AS), movingbed biofilm reactor (MBBR), and sequencingbatch movingbed biofilm reactor (SBMBBR). Simulated dairy wastewater was used at different organic load rates (OLRs): 1.22, 2.87, and 5.44 gCOD L−1d−1. Besides biosolids production, COD, total carbon (TC), and total nitrogen (TN) removal efficiency was evaluated. Biosolids production was measured in the mixed liquor, carrier-adhered biomass, treated wastewater, and surplus sludge. The operational conditions were kept similar for the three systems, with a carrier filling ratio of 50% for MBBR and SBMBBR. The SBMBBR proved to have better performance in the removal efficiencies of COD, TC, and TN for all OLRs studied. The MBBR presented a similar COD and TC removal efficiency as the SBBR for the two highest OLRs (2.87 and 5.44 gCOD L−1d−1). Concerning biosolids production, the MBBR system produced less biomass and delivered the lowest amount of adhered biomass inside the carriers. The AS treatment generated the highest amount of sludge and offered the worst treatment capability for all OLRs evaluated.

Biofilm morphology and microbiome of sequencing batch moving bed biofilm reactors treating cheese production wastewater

Compact, on-site treatment of cheese production wastewater is required to meet increasing regulations. This study investigates the treatment of cheese production wastewater of a sequencing batch moving bed biofilm reactor (SB-MBBR); the effects of anaerobic staging times and aeration rates on biofilm morphology, dry-mass, thickness, mean dry-density, biomass viability, and microbiome. Increasing anaerobic staging time from 72 to 168 min improved carbon removal rates from 24.8 ± 0.5 to 41.6 ± 1.3 g·m−2 d−1, likely due to a rougher biofilm morphology, lower mean dry-density and therefore enhanced biofilm mass transport. The microbiome community shifts from a population dominated by denitrifiers and possibly putative polyphosphate accumulating organisms, Brachymonas, Dechloromonas, and Rhodoferax, to a lower abundance of fermenting bacteria with increasing anaerobic staging time and lower aeration. This study provides new evidence of polyphosphate accumulating organisms in SB-MBBRs treating cheese production wastewater, supporting the feasibility of the SB-MBBR for on-site treatment of carbon, nitrogen and phosphorous.

Selection and synthesization of multi–carbon source composites to enhance simultaneous nitrification–denitrification in treating low C/N wastewater

Low carbon/nitrogen ratio (C/N) wastewater is widespread and difficult to treat. To find a resolution to this issue, this study systematically evaluated the constituents of composite solid carbon (i.e., skeletons, carbon sources and crosslinking agents), and proposed a new multi-carbon source composite S1 (MCSC.S1). The effects on nitrogen removal were further determined through a sequencing batch moving bed biofilm reactor (SBMBBR). The results showed that MCSC.S1, which was composed of polyvinyl alcohol-sodium alginate (PVA-SA), corncob + poly (R-β-hydroxybutyrate) (CC + PHB), and H3BO3-4% CaCl2+Na2SO4 had high stability and absorption. With MCSC.S1, total nitrification removal was enhanced by more than 48.56% through releasing carbon and absorbing the attached denitrifying bacteria. In addition, it was found that MCSC.S1 can simulate the simultaneous nitrification and denitrification (SND) process and contribute to 29.85% of the total nitrogen removal. 16S gene-based analysis attributed this supplementary nitrogen removal to the enrichment of nitrification (i.e., Proteobacteria, Actinobacteria and Chloroflexi), denitrification of associated bacteria (i.e., Nitrospirota) in MCSC.S1 added reactor, and the increase in nitrogen recycling associated genes. These findings collectively demonstrate that the new MCSC.S1 could effectively enhance nitrogen removal efficiency in low C/N ratio wastewater.

Two moving bed biofilm reactors in series for carbon, nitrogen, and phosphorous removal from high organic wastewaters

Government regulations require on-site treatment of industrial wastewater prior to sewage discharge to prevent environmental degradation of receiving waterbodies. The sequencing batch moving bed biofilm reactor (SB-MBBR) can permit on-site treatment of high organic and nutrient content of cheese production wastewater. However, the critical challenge exists of maintaining both an active heterotrophic and an autotrophic population in a single biofilm system treating carbon and ammonia to low discharge levels from cheese production wastewater. Two SB-MBBRs in series separate the heterotrophic and autotrophic communities, circumventing the competition between the heterotrophic and autotrophic populations in a single biofilm system treating wastewater with high carbon to nitrogen ratios. The first reactor (AN/AE) was operated by cycling between anaerobic and aerobic stages to select for polyphosphate accumulating organisms, and the AN/AE reactor degraded carbon and phosphorous. The second reactor (NIT) was operated with aerobic conditions to promote nitrifying bacteria and treat total ammonia nitrogen. The performance of this system for carbonaceous constituents and ammonia was evaluated by quantifying the kinetics, biofilm morphology, thickness, dry-mass, and dry-density of the two SB-MBBR in series technology. The AN/AE reactor achieved 97.5 ± 1.7%, 58.8 ± 5%, and 49 ± 1% soluble chemical oxygen demand, total nitrogen, and total phosphorous removal efficiencies respectively. The NIT reactor achieved 98.7 ± 2.4 % total ammonia nitrogen removal, though partial nitritation at rates of 1.09 ± 0.03 g-N·m-2d-1, indicating this system can be incorporated in an anammox system. The study demonstrates that enhanced biological phosphorous removal, and potentially anaerobic removal of ammonia can be achieved for on-site treatment of cheese production wastewater.

Phosphorus removal from industrial discharge impacted municipal wastewater using sequencing batch moving bed biofilm reactor

This study aimed to investigate the performance of a sequencing batch moving bed biofilm reactor (SB-MBBR) for biological P removal (Bio-P) treating diluted municipal wastewater at 10 °C and 20 °C, with volatile fatty acid (VFA) dosing during weekdays and without VFA dosing during weekends to simulate an industrial influenced wastewater. The overall results revealed that phosphorus removal efficiency for weekdays reached 53 % and 81 % at cold and moderated temperatures respectively. However, phosphorus removal efficiency for the weekend was 49 % for cold temperature and 52 % for moderate temperature. It was concluded that low temperature and low VFA might have suppressed the phosphate accumulating organisms (PAOs) performance. Besides, high extracellular polymeric substance (EPS) production might have hampered the PAOs activity, which could be linked to the observed high consumption of soluble chemical oxygen demand (SCOD) to P release ratio and thick biomass growth in the cold system.

Investigation of sequencing batch moving-bed biofilm reactor to biodegradation of cefixime as emerging pollutant in percent of easily degradable co-substrate

ABSTRACT In the present study, sequencing batch moving-bed biofilm reactor (SBMBBR) was developed as a new treatment system and was used to treat wastewater containing cefixime antibiotic (CFX). The effect of initial concentration of CFX (0–122 mg/L) on common parameters including total nitrogen (TN), nitrite (NO2 −), nitrate (NO3 −), and chemical oxygen demand (COD) was also evaluated. When a small concentration of CFX (45 mg/L) was added to the SBMBBR, good removal efficiencies were obtained for CFX, COD, and TN. Slight changes in mixed liquor-suspended solids (MLSS) and specific oxygen uptake rates (SOUR) in the reactor containing 92 mg/L of CFX showed that microorganisms had high adaptation in the new SBMBBR system. Biological removal of TN, COD, and CFX was decreased from 70.75, 74.81, and 70.9% to 27.38, 23.2, and 34.8%, respectively, when the initial CFX concentration was increased from 45 to 122 mg/L. Also, value of MLSS was decreased at CFX concentrations of 92 and 122 mg L-1, indicating that bacterial growth was inhibited. CFX degradation products were detected by performing the liquid chromatography-mass spectroscopy (LC-MS/MS) and the results obtained from analysis showed that the CFX was first converted into 5-vinyl-3,6-dihydro-2H-1,3-thiazine-4-carboxylic acid and thiazol-2-amine by breaking C-N bond and chain ring. Then, acetic acid and ethyl (methyl) sulphone were formed with further destruction of the chain ring and ring opening. Finally, these by-products can be converted into CO2 and H2O. Accordingly, the results of the present study demonstrated that hybrid process of SBMBBR with minimal reduction in the concentration of MLSS and SOUR can be a good alternative to processes alone in treatment of high concentrations of CFX.

Degradation of p-nitroaniline from aqueous solutions using ozonation/Mg-Al layered double hydroxides integrated with the sequencing batch moving bed biofilm reactor

In this study, two treatment steps were performed to completely remove p-nitroaniline (PNA). In the first stage, the catalytic ozonation process (COP) using the synthesized nanoparticles of magnesium–aluminum layered double hydroxide (MgAl-LDH) was applied for pre-treatment. Effective parameters in the COP, including initial pH, initial PNA concentration, catalyst dose, and contact time has been investigated. Response Surface Method)RSM(was applied to optimize process conditions in the COP. The effluent from the COP entered the sequencing batch moving bed biofilm reactor (SBMBBR). The optimum conditions for the COP process were initial PNA concentration: 120 mg/L, pH: 8.25, LDH dose: 750 mg/L, and reaction time: 70 min. Under these conditions, the maximum removal efficiency of PNA, COD, and TOC was about 91.5, 83, and 70%, respectively. The biological reactor was operated under conditions of hydraulic retention time (HRT) of 24 h, pH of 6.5–7, mixed liquor suspended solids attached to bio-carriers (MLSSatt.) of 4700 mg/L, mixed liquor volatile suspended solids attached to bio-carriers (MLVSSatt.) of 3200 mg/L, MLSS of 1000 mg/L, and MLVSS of 880 mg/L. In this study, using the COP/SBMBBR system, the complete PNA analysis and maximum removal efficiency of COD and TOC were about 99 and 97%, respectively.

Effect of anaerobic phases length on denitrifying dephosphatation biocenosis \u2013 a case study of IFAS-MBSBBR

BackgroundThe study aimed to evaluate the influence of the duration times of anaerobic phases on the bacterial biocenosis characterisation while denitrifying dephosphatation in the Integrated Fixed-Film Activated Sludge – Moving-Bed Sequencing Batch Biofilm Reactor (IFAS-MBSBBR). The experiment was conducted in a laboratory model. The study consisted of four series, which differed in terms of the ratio of the anaerobic phases.duration concerning the overall reaction time in the cycle. The anaerobic phases covered from 18 to 30% of the whole cycle duration. During the reactor performance that took 9 months, the influent and effluent were monitored by analysis of COD, TKN, NH4-N, NO2-N, NO3-N, TP, PO4-P, pH, alkalinity and the phosphorus uptake batch tests. Characterisation of the activated sludge and the biofilm biocenosis was based on fluorescent in situ hybridisation (identification of PAO and GAO) and the denaturing gradient gel electrophoresis patterns.ResultsThe organic compounds removal was high (more than 95.7%) independently of cycle configuration. The best efficiency for nitrogen (91.1%) and phosphorus (98.8%) removal was achieved for the 30% share of the anaerobic phases in the reaction time. Denitrifying PAO (DPAO) covered more than 90% of PAO in the biofilm and usually around 70% of PAO in the activated sludge. A substantial part of the polyphosphate accumulating organisms (PAO) community were Actinobacteria. The denitrifying dephosphatation activity was performed mainly by Accumulibacter phosphatis.ConclusionsHigh nutrient removal efficiencies may be obtained in IFAS-MBSBBR using the denitrifying dephosphatation process. It was found that the length of anaerobic phases influenced denitrification and the biological phosphorus removal. The extension of the anaerobic phases duration time in the reaction time caused an increase in the percentage share of denitrifying PAO (DPAO) in PAO. The biocenosis of the biofilm and the activated sludge reveal different species patterns and domination of the EBPR community.

Biodegradation of mono azo dye-Reactive Orange 16 by acclimatizing biomass systems under an integrated anoxic-aerobic REACT sequencing batch moving bed biofilm reactor

This study dealt with the biodegradation of Reactive Orange 16 (RO16) containing wastewater via a novel integrated anoxic-aerobic REACT sequencing batch moving bed biofilm reactor (SBMBBR). The chemical oxygen demand (COD) removal and biodecolorization from three design schemes pertinent to the effects of (i) dye concentration under stepwise approach, Scheme 1; (ii) dye concentration under shock load approach, Scheme 2 and (iii) hydraulic retention time (HRT) coupled with the increase of biocarrier filling ratio, Scheme 3 were evaluated orderly along the evaluation. A complete biodecolorization and over 97 % of COD removal were attained in Scheme 1. Although both COD removal and biodecolorization in Scheme 2 was deteriorated to approximate 40 % by successive RO16 shocks, the microbial strength in removing RO16 molecules (mg RO16/mg biomass) reflected a two-fold amelioration from 0.015 to 0.0304 as the result of actively metabolic system. The maximum co-substrate uptake also reduced from 100 % to 69 %. At higher biocarrier filling ratio (10 % (v/v)) in Scheme 3, the difference in COD removal and biodecolorization rates reflected an improvement of 0.16 and 0.30 % hour-1, respectively, throughout the anoxic-REACT period. However, the performance changed insignificantly due to the reduction of HRT. The presence of the attached-growth biomass system was of great importance, although the suspended-growth biomass dominated more than 76 % of the biomass system in SBMBBR.

Purification of diazinon pesticide by sequencing batch moving-bed biofilm reactor after ozonation/Mg-Al layered double hydroxides pre-treated effluent

The catalytic ozonation process (COP) using MgAl-layered double hydroxide (MgAl-LDH) nanoparticles was used as a pre-treatment of the sequencing batch moving-bed biofilm reactor (SBMBBR) to degrade diazinon pesticide from aqueous solutions. The structure of the synthesized MgAl-LDH was investigated by X-ray diffraction pattern (XRD), field-emission scanning electron microscope (FESEM), energy dispersive spectroscopy (EDS) mapping, and Fourier-transform infrared spectra (FTIR). The response surface methodology (RSM) was adopted to optimize the COP variables, including LDH dose (0–1000 mg/L), initial diazinon concentration (50–200 mg/L), initial pH (3–10), and reaction time (10–90 min). Under the optimal conditions, COP effluent was introduced to the SBMBBR for further purification. The dispersive liquid–liquid microextraction (DLLME) method was employed to extract diazinon from aqueous samples. The GC-mass analysis was performed to determine by-products during diazinon degradation reactions. To evaluate system performance, the removal efficiency of chemical oxygen demand (COD), total organic carbon (TOC), and diazinon was compared in processes of aeration, single ozonation process (SOP), COP, SBMBBR, and COP/SBMBBR. The formation of the LDH nanoparticles was confirmed by XRD and EDS mapping analysis. In the COP reactor, under optimal conditions (initial diazinon concentration: 120 mg/L, pH: 8.25, LDH dose: 750 mg/L, and reaction time: 70 min), the removal efficiency of diazinon, COD, and TOC equaled 92, 80, and 74%, respectively. The effluent of COP reactor was treated further in the SBMBBR system with the pH of 6.5–7, hydraulic retention time (HRT) of 24 h, mixed liquor suspended solids attached to bio-carriers (MLSSatt.) of 4500 mg/L, mixed liquor volatile suspended solids attached to bio-carriers (MLVSSatt.) of 3600 mg/L, MLSS of 950 mg/L, and MLVSS of 830 mg/L. The use of COP/SBMBBR resulted in the complete degradation of diazinon pesticide and COD and TOC removal efficiency of 99.37 and 99%, respectively. Therefore, this method can be used for the purification of non-biodegradable industrial wastewater.

Impact of multiple wastewater feedings on the efficiency of nutrient removal in an IFAS-MBSBBR: number of feedings vs. efficiency of nutrient removal.

This article presents the results of research into the influence of one, two and three wastewater feedings in a cycle on efficiency and performance of combined biological nitrogen and phosphorus removal in an integrated fixed-film activated sludge and moving-bed sequencing batch biofilm reactor (IFAS-MBSBBR). The experiment lasted 158 days and was conducted in two laboratory models of the IFAS-MBSBBR with an active volume of 28 L. It was found that along with an increase in the number of wastewater feedings, an increase in nitrogen removal efficiency was observed (from 56.9 ± 2.30% for a single feeding to 91.4 ± 1.77% for three feedings). Moreover, the contribution of simultaneous nitrification/denitrification in nitrogen removal increased (from 2.58% for a single feeding to 69.5% for three feedings). Systems with a greater number of feedings stimulated the process of denitrifying phosphorus removal. Regardless of the way in which wastewater feeding was applied to the IFAS-MBSBBR, highly efficient chemical oxygen demand (COD) removal (94.8 ± 1.80%) and biological phosphorus removal (98.9 ± 0.87%) were achieved.

Efficiency of wastewater treatment in SBR and IFAS-MBSBBR systems in specified technological conditions

The objective of this study is to compare wastewater treatment effectiveness in sequencing batch reactor (SBR) and integrated fixed-film activated sludge-moving-bed sequencing batch biofilm reactor (IFAS-MBSBBR) systems in specific technological conditions. The comparison of these two technologies was based on the following assumptions, shared by both series, I and II: the reactor's active volume was 28 L; 8-hour cycle of reactor's work, with the same sequence and duration of its consecutive phases; and the dissolved oxygen concentration in the aerobic phases was maintained at a level of 3.0 mg O2/L. For both experimental series (I and II), comparable effectiveness of organic compound (chemical oxygen demand (COD)) removal, nitrification and biological phosphorus removal has been obtained at levels of 95.1%, 97% and 99%, respectively. The presence of the carrier improved the efficiency of total nitrogen removal from 86.3% to 91.7%. On the basis of monitoring tests, it has been found that the ratio of simultaneous denitrification in phases with aeration to the total efficiency of denitrification in the cycle was 1.5 times higher for IFAS-MBSBBR.

A study on the use of the BioBall® as a biofilm carrier in a sequencing batch reactor

Described in this study are experiments conducted to evaluate the removal of organics and nutrients from synthetic wastewater by a moving bed sequencing batch biofilm reactor using BioBall® carriers as biofilm media. The work involving a 15L-laboratory scale MBSBBR (moving bed sequencing batch biofilm reactor) model showed that the wastewater treatment system was based on biochemical processes taking place with activated sludge and biofilm microorganisms developing on the surface of the BioBall® carriers. Classical nitrification and denitrification and the typical enhanced biological phosphorus removal process were achieved in the reactor analyzed, which operated with a volumetric organic loading of 0.84–0.978gCODL−1d−1. The average removal efficiencies for COD, total nitrogen and total phosphorus were found to be 97.7±0.5%, 87.8±2.6% and 94.3±1.3%, respectively. Nitrification efficiency reached levels in the range 96.5–99.7%.

Modeling nitrate concentrations in a moving bed sequencing batch biofilm reactor using an artificial neural network technique

AbstractIn this study, the performance data of a moving-bed sequencing batch biofilm reactor (MBSBBR) treating synthetic wastewater were simulated using multi-layer perceptron neural-network technique. Multi-linear regression (MLR) technique is also used for a comparison. The performance of MBSBBR was evaluated using these models for a set of experimental results obtained from a model reactor operated with different cycle times and temperatures. The experimental data were retrieved from a previous reported work. Operational time, temperature, ammonium nitrogen, and pH were used as inputs for modeling, whereas nitrate concentration was the output variable. The results of the models were compared using statistical criteria, such as mean square error, mean absolute error, mean absolute relative error, and determination coefficient (R2). The results showed that the multi-layer perceptron neural-network produced more accurate results than those of MLR, although the latter gave reasonable results.

Investigation of decolorization kinetics and biodegradation of azo dye Acid Red 18 using sequential process of anaerobic sequencing batch reactor/moving bed sequencing batch biofilm reactor

The purpose of this study was to investigate the application of anaerobic sequencing batch reactor (An-SBR)/moving bed sequencing batch biofilm reactor (MB-SBBR) for treatment of wastewater containing Acid Red 18 (AR18). Based on statistical analysis, COD removal rate and anaerobic biomass concentration were increased with increasing initial AR18 concentration, while the specific COD removal rate was not significantly different among An-SBRs. The results revealed that the decolorization followed first-order kinetics in An-SBR1 receiving AR18 with concentration of 100 mg l−1. However, in two other reactors with the initial dye concentration of 500 and 1000 mg l−1, the dye was removed following two successive parts with two different reaction orders. The results showed that the dye decolorization rate increased with increasing its concentration in the feed solution. In MB-SBBRs, the ratio of attached-growth biofilm to suspended biomass concentration was increased gradually during the operation period. This ratio was measured 0.76, 0.70 and 0.51 in MB-SBBR1, 2 and 3 after three months of the reactors operation. Microscopic observations showed a large number of filamentous bacteria in the structure of attached-growth biofilm and suspended biomass in MB-SBBRs which speculated to be the reason for the different Sludge Volume Index (SVI) observed among these reactors.