Moving Bed Biofilm Process Research Articles

Solar driven photocatalysis using iron and chromium doped TiO2 coupled to moving bed biofilm process for olive mill wastewater treatment

TiO2 based-photocatalysts doped with Fe and/or Cr was evaluated as pre- and post-treatment method of a moving bed biofilm reactor (MBBR) as possible solution for the treatment of real olive oil mill wastewater (OMW). Photocatalysts were synthesized by wet chemical method and their chemical-physical properties were accurately investigated through X-ray diffraction (XRD), Raman spectroscopy, UV–Vis diffuse reflectance spectroscopy (UV–Vis DRS) and specific surface area measurements. UV–Vis DRS measurements evidenced that the simultaneous doping of TiO2 lattice with Fe and Cr improves the optical absorption into the visible region leading to a narrow band gap (2.1 eV) with respect to undoped TiO2 (3.2 eV) and Fe-doped TiO2 (2.8 eV) while, Cr-doped TiO2 showed the lowest bandgap value (1.9 eV). XRD patterns and Raman spectra showed that anatase is the predominant crystalline phase for all the prepared photocatalysts and Fe and Cr ions were effectively inserted into the TiO2lattice. The TiO2 doping with Cr did not change the average crystallites size that was equivalent to that of TiO2(8 nm), whereas, for Fe- doped TiO2, it was lower than the others and equal to 6 nm. The specific surface area values of doped catalysts were higher than TiO2 and the value for Fe-Cr-codoped TiO2 resulted to be 97 m2g−1. Photocatalytic treatment of OMW was evaluated in terms of total polyphenols (TPHs), Chemical Oxygen Demand (COD), Biological Oxygen Demand (BOD5) and biodegradability (as BOD5/COD ratio) in 3 h of treatment under simulated solar light irradiation. Fe-doped TiO2 showed the highest TPHs removal for both un-treated and biologically treated OMW. When H2O2 was added (optimum dosage 0.5 gL-1), Fe-Cr-TiO2 resulted in the best photocatalytic performance with TPHs removal as high as 97% and increased biodegradability (0.22 to 0.33), making the effluent suitable for the subsequent biological process. When photocatalytic process was investigated as post-treatment of OMW, Fe-TiO2 showed the best activity and the addition of 0.5 g L-1 of H2O2 was sufficient to make the effluent in compliance with Italian regulation for effluent disposal into surface water.

Effect of biofilm media application on biomass characteristics and membrane permeability in the biological spatiotemporal phase-separation process

In this study, the effect of moving-bed biofilm carrier, a membrane, and simultaneous employment to solve the settleability problem derived from readily biodegradable organics application in the biological spatiotemporal phase separation and variation of biomass characteristics by biofilm media application were investigated. No significant differences of the treatability among each case were observed. Although the moving-bed biofilm process is commonly used for the treatment of organics and nitrogen in wastewater, phosphorus was also removed perfectly owing to the detached biomass containing orthophosphate was discarded sufficiently. Additionally, the concentration of the suspended biomass decreased significantly, and the settled volume index was improved dramatically from 700 to 100 mL/g after the addition of the biofilm carrier. Although the extracellular polymeric substance (EPS) concentration increased with media addition, the back-flushing interval of the membrane was lengthened. The increment of polysaccharide in the EPS and the non-existence of protein in the soluble EPS were clearly observed. Thus, the suspended-biomass decrement due to media addition and the protein concentration in the EPS played important roles for fouling control. This study provides valuable information on state alternation of biomass by biofilm media application on biological suspended growth wastewater treatment process.

PENGOLAHAN AIR LIMBAH DOMESTIK DENGAN ANOKSIK-AEROBIK MOVING BED BIOFILM REACTOR (STUDI KASUS: PENYISIHAN AMONIA DAN KARBON DALAM AIR LIMBAH DOMESTIK)

Domestic wastewater contains high organic carbon and ammonium concentration which can be treated by moving bed biofilm process. It is a biologycal hybrid between attached and suspended growth process. The purposes of this research were to determine the removal percentage of organic carbon and ammonium concentration in domestic wastewater, and to investigate optimum hydraulic residence time. Experiment was carried out in a laboratory scale to study the combine anoxic and an aerobic reactor condition. The treatment process is preceeded by a 4-week seeding process continued with variation of hydraulic residence time. Based on these results, the removal percentage of COD for each hydraulic residence time of 12, 16, and 20 hours were 75,7%; 83,7%; and 91,0%, the removal percentage of ammonium were 79,4%; 91,0%; and 92,3%. The optimum hydraulic residence time in removing organic carbon and ammonium concentration domestic wastewater using anoxic aerobic MBB is 20 hours. This biological hybrid treatment can be an alternative to remove organic carbon and ammonium in domestic wastewater. Keyword: domestic wastewater, ammonium removal, organic carbon removal, moving bed biofilm reactor

Optimization of surface area loading rate for an anaerobic moving bed biofilm reactor treating brewery wastewater

Three acclimated anaerobic moving bed biofilm reactors filled to 40% by volume with cubic AC920 media (protected surface area of 680 m2 m−3) were studied to treat brewery wastewater at hydraulic retention times of 6–24 h and mesophilic condition (35.0 ± 0.1 °C). The reactors were seeded with media that had developed mature anaerobic biofilm prior to the start of this study. Soluble chemical oxygen demand of the brewery wastewater was equal to 4.0 ± 1 kg m−3, total chemical oxygen demand 5.2 ± 2.1 kg-COD m−3, and the ratio of 5-day biological oxygen demand to chemical oxygen demand was equal to 0.77 ± 0.02. Dissolved oxygen concentration in the influent wastewater was below detection limit (0.1 mg-O2 L−1). This study focused on the assessment of optimal design surface area loading rates for an anaerobic moving bed biofilm process by varying the hydraulic retention times from 6 to 24 h. Volumetric removal rates of 3.0 ± 0.2, 4.2 ± 0.3, 7.2 ± 0.6, 12.4 ± 0.8, 13.4 ± 1.0, and 12.0 ± 1.1 g-sCOD d−1 were achieved at 24, 18, 12, 10, 8, and 6 h hydraulic retention times. Hydraulic retention time of 18 h exhibited the highest chemical oxygen demand removal, at 88 ± 2.5%, and the highest carbon conversion into methane at 0.34 ± 0.06 m3-CH4 kg-sCOD−1. At this hydraulic retention time the specific surface area activity was 13 ± 1 g-sCOD m−2d−1, considering that the organic loading rate was 4.0 ± 0.3 kg-sCOD m−3d−1. Biogas composition was 71 ± 2% methane and 26 ± 4% carbon dioxide. Media clogging and mass transfer limitations due to overgrowing biomass in the interior media channels was observed at surface area loading rates above 54 g-sCOD m−2 d−1. However, kinetic tests revealed that mass transfer limitation started at surface area loading rate of 44 g-sCOD m−2d−1. Anaerobic moving bed biofilm reactor has been shown to be a reliable treatment option for high-strength wastewaters and could be used in brewery wastewater management as a resource to comply with the discharge limit regulation.

Accelerated startup of moving bed biofilm process with novel electrophilic suspended biofilm carriers

In the biofilm wastewater treatment process, the start-up period of biofilm process is affected by the biofilm formation on the surface of carriers. Controlling surface charge property of carriers could accelerate the biofilm formation. The surface of conventional biofilm carriers, such as polyethylene (PE), polypropylene (PP) and high-density polyethylene (HDPE) is negatively charged, as is the surface of bacterial cells of activated sludge, which could lead to electrostatic repulsion between the biofilm carriers and the bacteria. Herein, the conventional high-density polyethylene (HDPE) carriers were modified by two kinds of positively charged polymers with different charge strength, which were noted as polyquaternium-10 (PQAS-10) and cationicpolyacrylamides (CPAM), respectively, to accelerate the startup of biofilm-based wastewater treatment process. The results showed that the positive Zeta potential was measured on the surface of modified carriers, whereas the surface Zeta potential of unmodified carriers was negative. It indicated that the modified carriers carried positive charge. Furthermore, the positive charge on the modified PQAS-10 carriers was higher than that on the modified CPAM carriers. The reactor with modified PQAS-10 carriers achieved shorter reactor start-up time and higher attached biomass compared to that with unmodified carriers and modified CPAM carriers. As a result, the removal efficiencies of COD, NH4+-N and TN in the reactor with the modified carriers were higher than that with the unmodified carriers. These findings demonstrated that the success of electrophilic modification on the surface of carriers was expected to accelerate the startup of biofilm-based reactors and improve the reactor performance in the practical application.

Performance and modeling of a moving bed biofilm process: nickel and chromium heavy metal removal from industrial wastewater

The process of a lab-scale moving bed biofilm reactor (MBBR) using simulated sugar-manufacturing wastewater as feed was investigated.

Biological Phosphorus and Nitrogen Removal from Wastewater Using Moving Bed Biofilm Reactor (MBBR)

In this research, an experimental study to evaluate nutrient removal from Al-Rustamiyah wastewater by a moving bed biofilm process was investigated.The moving bed biofilm reactorMBBR consisted of five reactors in series with one anoxic reactor MBBR-1, two aerobic reactor MBBR-2 and MBBR-3, outlet chamber and the flocculation part with dosing unit, that were operated continuously at different loading rates of phosphorus and nitrogen.The MBBR tankswere filled with suspended plastic carriers (AnoxKaldnes K5), with a 50% filling ratio. Under optimum conditions, almost complete nitrification with average ammonium removal efficiency of 82% was achieved.The average phosphorus and total nitrogen removal efficiencies were 76.79% and70%, respectively.

Modelling of moving bed biofilm membrane reactors (MBBMR) for on-site greywater treatment.

The study evaluates with a mechanistic model the pilot plant results of a combined moving bed biofilm process and membrane filtration (MBBMR) treating single household greywater. It mainly includes the simulation of reactor hydraulics, degradation of pollutants, development of biomass and settlement of sludge. Iterative calibration was made with steady-state results of a 10-month pilot test. The model shows good predictions of readily biodegradable chemical oxygen demand and ammonium removal, as well as biomass concentration on carriers and in suspension. Also, a sensitivity analysis was made which calculates the relative significance factor of each model coefficient and by this provides comparability with other studies. Simulation data and actually measured parameters show that the suggested process was rather independent of ambient temperatures and short-term load fluctuations. Obtained datasets and model structure could be of use for future designers, as well as sellers and users of this process for on-site greywater reclamation.

Distribution, mass load and environmental impact of multiple-class pharmaceuticals in conventional and upgraded municipal wastewater treatment plants in East China.

The occurrence, fate and environmental impact of 30 pharmaceuticals including sulfonamides, fluoroquinolones, tetracyclines, macrolides, dihydrofolate reductase inhibitors, β-blockers, antiepileptics, lipid regulators, and stimulants were studied in two municipal wastewater treatment plants (WWTPs) located in Wuxi City, East China. A total of 23 pharmaceuticals were detected in wastewater samples, with a maximum concentration of 16.1 μg L(-1) (caffeine) in the influent and 615.5 ng L(-1) (azithromycin) in the effluent; 19 pharmaceuticals were detected in sludge samples at concentrations up to 12.13 mg kg(-1), with ofloxacin, azithromycin and norfloxacin being the predominant species. Mass balance analysis showed that biodegradation primarily accounted for the removal of sulfonamides, most of the macrolides, and other miscellaneous pharmaceuticals, while adsorption onto the sludge was the primary removal pathway for fluoroquinolones, tetracylines, and azithromycin during biological treatment. The total mass loads of target pharmaceuticals per capita in the two WWTPs were in the ranges of 2681.8-4333.3, 248.0-416.6 and 214.6-374.5 μg per day per inhabitant in the influent, effluent and dewatered sludge, respectively. The upgraded Plant A adopting the combined anaerobic/anoxic/oxic and moving bed biofilm process exhibited a much higher removal of target pharmaceuticals than the conventional Plant B adopting the C-Orbal oxidation ditch process. The concentration levels of sulfamethoxazole, ofloxacin, ciprofloxacin and clarithromycin in the effluent, ofloxacin in the sludge, and the mixture of all target pharmaceuticals in both effluent and sludge posed a high risk to algae in aquatic environments.

Microfauna communities as performance indicators for an A/O Shortcut Biological Nitrogen Removal moving-bed biofilm reactor

The microfauna communities present in the mixed liquor and biofilm of an Anoxic/Oxic Shortcut Biofilm Nitrogen Removal moving-bed biofilm process were characterised in order to optimise process control through the use of bioindicators. The system operated at high ammonium concentrations, with an average of 588 ± 220 mg N–NH4+ L−1 in the influent, 161 ± 80 mg L−1 in the anoxic reactor and 74 ± 71.2 mg L−1 in the aerobic reactor. Up to 20 different taxa were identified, including ciliates (4), flagellates (11), amoebae (4) and nematodes (1). Compared to conventional wastewater treatment processes (WWTPs), this process can be defined as a flagellates-predominant system with a low diversity of ciliates. Flagellates were mainly dominant in the mixed liquor, demonstrating high tolerance to ammonium and the capacity for survival over a long time under anoxic conditions. The data obtained provide interesting values of maximum and minimum tolerance ranges to ammonium, nitrates and nitrites for the ciliate species Cyclidium glaucoma, Colpoda ecaudata, Vorticella microstoma-complex and Epistylis cf. rotans. The last of these was the only ciliate species that presented a constant and abundant population, almost exclusively in the aerobic biofilm. Epistylis cf. rotans dynamics showed a high negative correlation with ammonium variations and a positive correlation with ammonium removal efficiency. Hence, the results indicate that Epistylis cf. rotans is a good bioindicator of the nitrification process in this system. The study of protozoan communities in unexplored WWTPs sheds light on species ecology and their role under conditions that have been little studied in WWTPs, and could offer new biological management tools.

Moving Bed Biofilm Reactor – A New Perspective in Wastewater Treatment

A new advanced biological reactor for waste water treatment, Moving Bed Biofilm Reactor (MBBR) is discussed. General description of expected setup of reactor is given. The proposed results from different applications when used for domestic waste water will be discussed. Moving Bed technology presents several operational advantages, compared to other conventional biological treatments. Different applications of this technology for small plants will be studied, considering main investment and operating costs. Processes will take account of Moving Bed Biological Reactors (MBBR) with some sort of modifications. Conditions which may be studied will include COD removal, or COD and nutrients removal, with different primary treatments. Smaller biological reactor volumes and smaller secondary settling surface are needed. In conclusion, the results can indicate that MBBR with polyethylene media as Biofilm carrier may possess great potential to be used for OMs removal from water and wastewater. This study can be helpful to check possibility that the moving bed Biofilm process may be used as an ideal and efficient option for the total nutrient removal from municipal wastewater. Index Terms: Waste water, Moving Bed, Biofilm, Bioreactor, Biofilm carriers, Hybrid processes, nutrient removal, sewage, Treatment

Post-treatment of anaerobically degraded azo dye Acid Red 18 using aerobic moving bed biofilm process: Enhanced removal of aromatic amines

The application of aerobic moving bed biofilm process as post-treatment of anaerobically degraded azo dye Acid Red 18 was investigated in this study. The main objective of this work was to enhance removal of anaerobically formed the dye aromatic metabolites. Three separate sequential treatment systems were operated with different initial dye concentrations of 100, 500 and 1000 mg/L. Each treatment system consisted of an anaerobic sequencing batch reactor (An-SBR) followed by an aerobic moving bed sequencing batch biofilm reactor (MB-SBBR). Up to 98% of the dye decolorization and more than 80% of the COD removal occurred anaerobically. The obtained results suggested no significant difference in COD removal as well as the dye decolorization efficiency using three An-SBRs receiving different initial dye concentrations. Monitoring the dye metabolites through HPLC suggested that more than 80% of anaerobically formed 1-naphthylamine-4-sulfonate was completely removed in the aerobic biofilm reactors. Based on COD analysis results, at least 65–72% of the dye total metabolites were mineralized during the applied treatment systems. According to the measured biofilm mass and also based on respiration–inhibition test results, increasing the initial dye concentration inhibited the growth and final mass of the attached-growth biofilm in MB-SBBRs.

Particle Separation in Moving Bed Biofilm Reactor: Applications and Opportunities

Different solid/liquid separation techniques for particle separation after a moving bed biofilm reactor are discussed. Conventional technologies such as sedimentation, floatation, and depth filtration are reviewed based on reports and articles in the literature. Optimal operating parameters that lead to satisfactory solids removal rates were given for each technology. Disc and membrane filtration are also discussed as relatively new technologies that offer advanced solids separation process. The potential of membrane separation, especially submerged membrane reactors (sMBR), were found and they are therefore proposed as a good alternative to conventional solid/liquid separation technologies. The nature and characteristics of the biofilm process also opens for a variety of possible configurations of submerged MBR that could be employed for advanced treatment of effluent from a moving bed biofilm process.

Modelling respirometric tests for the assessment of kinetic and stoichiometric parameters on MBBR biofilm for municipal wastewater treatment

Moving Bed Biofilm Reactor (MBBR) technology is a suitable option for up-grading and retro-fitting wastewater treatment plants. Although being introduced in late 80s, design and operational guidelines of MBBR are mainly based on empirical approaches. This work was aimed to assess the biokinetics on both detached and undisturbed biofilm samples from a large pilot-scale MBBR treating pre-settled municipal wastewater. Experimental OUR profiles of heterotrophic biomass in detached and undisturbed biofilm have been obtained with respirometric tests and then modelled with an extended version of ASM3 which assumes biomass growth to take place on both readily biodegradable substrate and storage products. Results indicated the storage mechanism to be prevalent for heterotrophic biomass growth, with a 80% fraction of soluble substrate converted into storage products. The active heterotrophic biomass in the film was estimated in detached biofilm samples; on average, it corresponded to a 39% fraction of particulate COD. Tests on undisturbed biofilm were carried out to quantify autotrophic ammonia and nitrite removal, showing an effective specialisation of the nitrifying biomass. The parameters obtained could support a more rational design approach for the moving-bed biofilm process.

Influence of carrier type on nitrification in the moving-bed biofilm process

Two different types of carriers differing fundamentally in size, shape and structure were evaluated in parallel testing for nitrification potential using the moving-bed biofilm reactor (MBBR) technology. One of the carriers used was a cylindrical high-density polyethylene ring shaped carrier (AnoxKaldnes, K1 carrier) and the other was a spherical polyvinyl alcohol (PVA) gel bead shaped carrier (Kuraray, PVA-gel carrier). For each MBBR process, using artificial wastewater under autotrophic conditions, high maximal nitrification rates at 20 degrees C were obtained. For the K1 carrier up to 27 mgNH(4)-N/L.h (at 37% filling fraction) was found, corresponding to 49 mgNH(4)-N/L.h at the recommended maximum filling fraction of 67%. This corresponds to a nitrification area rate of 3.5 gNH(4)-N/m(2).d for the K1 carrier at 20 degrees C. For the PVA-gel carrier up to 32 mgNH(4)-N/L.h (at 9.6% filling fraction) was found, corresponding to 50.0 mg NH(4)-N/L.h at the recommended maximum filling fraction of 15%. At the recommended filling fractions, the two carriers therefore required about the same reactor volume to reach the maximum observed nitrification rate. This presumption allowed us to estimate the effective specific surface area for the PVA gel carrier up to 2,500 m(2)/m(3) versus 1,000 m(2)/m(3) when only the outer surface is considered.

Application of Moving Bed Biofilm Process for Biological Organics and Nutrients from Municipal Wastewater

In this study, experiments have been conducted to evaluate the organics and nutrients removal from synthetic wastewater by a laboratory scale moving bed biofilm process. For nutrients removal, moving bed biofilm process has been applied in series with anaerobic, anoxic and aerobic units in four separate reactors. Moving bed biofilm reactors were operated continuously at different loading rates of nitrogen and Phosphorus. During optimum conditions, close to complete nitrification with average ammonium removal efficiency of 99.72% occurred in the aerobic reactor. In the aerobic reactor, the average specific nitrification rate was 1.8 g NOx-N kg VSS −1 h −1 . The results of the average effluent soluble COD concentration from each reactor showed that denitrification process in the second anoxic reactor consumed most of the biodegradable organic matter. As seen from the results, denitrification rate has increased with increasing NOx-N loading in the second anoxic reactor. The aerobic phosphate removal rate showed a good correlation to the anaerobic phosphate release rate. Moreover, phosphate removal rate showed a strong correlation to the phosphate loading rate in the aerobic reactor. In optimum conditions, the average SCOD, total nitrogen and phosphorus removal efficiencies were 96.9, 84.6 and 95.8%, respectively. This study showed that the moving bed biofilm process could be used as an ideal and efficient option for the total nutrient removal from municipal wastewater.

Oxidation of Excess Organic Sludge from a Moving-bed Biofilm Process

Oxidation of Excess Organic Sludge from a Moving-bed Biofilm Process

Innovations in wastewater treatment: –the moving bed biofilm process

This paper describes the moving bed biofilm reactor (MBBR) and presents applications of wastewater treatment processes in which this reactor is used. The MBBR processes have been extensively used for BOD/COD-removal, as well as for nitrification and denitrification in municipal and industrial wastewater treatment. This paper focuses on the municipal applications. The most frequent process combinations are presented and discussed. Basic design data obtained through research, as well as data from practical operation of various plants, are presented. It is demonstrated that the MBBR may be used in an extremely compact high-rate process (<1 h total HRT) for secondary treatment. Most European plants require P-removal and performance data from plants combining MBBR and chemical precipitation is presented. Likewise, data from plants in Italy and Switzerland that are implementing nitrification in addition to secondary treatment are presented. The results from three Norwegian plants that are using the so-called combined denitrification MBBR process are discussed. Nitrification rates as high as 1.2 g NH4-N/m2 d at complete nitrification were demonstrated in practical operation at low temperatures (11 degrees C), while denitrification rates were as high as 3.5g NO3-Nequiv./m2.d. Depending on the extent of pretreatment, the total HRT of the MBBR for N-removal will be in the range of 3 to 5 h.

Increasing the capacity for treatment of chemical plant wastewater by replacing existing suspended carrier media with Kaldnes Moving Bed(tm) media at a plant in Singapore

The Kaldnes biomedia K1, which is used in the patented Kaldnes Moving Bed(tm) biofilm process, has been tested along with other types of biofilm carriers for biological pretreatment of a complex chemical industry wastewater. The main objective of the test was to find a biofilm carrier that could replace the existing suspended carrier media and at the same time increase the capacity of the existing roughing filter-activated sludge plant by 20% or more. At volumetric organic loads of 7.1 kg COD/m3/d the Kaldnes Moving Bed™ process achieved much higher removal rates and much lower effluent concentrations than roughing filters using other carriers. The Kaldnes roughing stage achieved more than 85% removal of organic carbon and more than 90% removal of BOD5 at the tested organic load, which was equivalent to a specific biofilm surface area load of 24 g COD/m2/d. Even for the combined roughing filter-activated sludge process, the Kaldnes carriers outperformed the other carriers, with 98% removal of organic carbon and 99.6% removal of BOD5. The Kaldnes train final effluent concentrations were only 22 mg FOC/L and 7 mg BOD5/L. Based on the successful pilot testing, the full-scale plant was upgraded with Kaldnes Moving Bed™ roughing filters. During normal operation the upgraded plant has easily met the discharge limits of 100 mg COD/L and 50 mg SS/L. For the month of September 2002, with organic loads between 100 and 115% of the design load for the second half of the month, average effluent concentrations were as low as 9 mg FOC/L, 51 mg COD/L and 12 mg SS/L.

Advanced compact wastewater treatment based on coagulation and moving bed biofilm processes

Advanced compact wastewater treatment processes are being looked for by cities all over the world as effluent standards are becoming more stringent and land available for treatment plants more scarce. In this paper it is demonstrated that a very substantial portion of the pollutants in municipal wastewater appears as particulate and colloidal matter. Pre-coagulation, therefore, gives very efficient pre-treatment that results in considerable saving in the total space required by the plant, especially when combined with a biofilm process for the removal of the soluble matter. A new biofilm process for this purpose is described. The moving bed biofilm process is based on plastic carriers, that move in the reactor, on which biomass attach and grow. The carriers are kept withinthe reactor by a sieve arrangement and biomass that is sloughing off the carriers is separated before effluent discharge. In addition to combining the moving bed biofilm process with pre-coagulation, the paper discusses also the use of a high-rate moving bed process combined with coagulation directly after the biofilm reactor in order to enhance separability. This results in very compact treatment plants for secondary treatment and possibly phosphate removal.