Bioreactor Process Research Articles

A combined culture-independent and simulation reactor approach to assess the microbial community of an operational denitrifying bioreactor treating As-bearing metallurgical wastewater

The biological treatment of metal(loid) bearing wastewater can be impacted by a multitude of biological and physicochemical parameters, providing challenges for in situ process optimisations. This study uses a combination of cultivation-independent sequencing, multivariate analysis and simulation reactors to characterise the microbial community in an operational bioreactor treating As- and nitrate-bearing wastewaters, and evaluate its response to higher arsenic concentrations. Over one year, whilst the denitrification performance was relatively stable (96%), time, sampling depth, pH, nitrate and arsenic all impacted the microbial community, which was dominated by nitrogen and sulfur cycling representatives. To identify the arsenic tolerance of the microbial community, down scaled simulation reactors were seeded from the operational bioreactor and treated with As(V) and As(III), however, no impact on denitrification was observed up to 1 g L−1 As(III). Overall, this study provides a framework of analyses and ex situ methods, which has wider implications for bioreactor process control.

Large-Scale Production of Cronobacter sakazakii Bacteriophage Φ CS01 in Bioreactors via a Two-Stage Self-Cycling Process.

Cronobacter sakazakii is an opportunistic pathogenic bacterium found in powdered infant formula and is fatal to neonates. Antibiotic resistance has emerged owing to overuse of antibiotics. Therefore, demand for high-yield bacteriophages as an alternative to antibiotics has increased. Accordingly, we developed a modified mass-production method for bacteriophages by introducing a two-stage self-cycling (TSSC) process, which yielded high-concentration bacteriophage solutions by replenishing the nutritional medium at the beginning of each process, without additional challenge. pH of the culture medium was monitored in real-time during C. sakazakii growth and bacteriophage CS01 propagation, and the changes in various parameters were assessed. The pH of the culture medium dropped to 5.8 when the host bacteria reached the early log phase (OD540 = 0.3). After challenge, it decreased to 4.65 and then recovered to 4.94; therefore, we set the optimum pH to challenge the phage at 5.8 and that to harvest the phage at 4.94. We then compared phage production during the TSSC process in jar-type bioreactors and the batch culture process in shaker flasks. In the same volume of LB medium, the concentration of the phage titer solution obtained with the TSSC process was 24 times higher than that obtained with the batch culture process. Moreover, we stably obtained high concentrations of bacteriophage solutions for three cycles with the TSSC process. Overall, this modified TSSC process could simplify large-scale production of bacteriophage CS01 and reduce the unit cost of phage titer solution. These results could contribute to curing infants infected with antibiotic-resistant C. sakazakii.

Removal efficiency of organic micropollutants in successive wastewater treatment steps in a full-scale wastewater treatment plant: Bench-scale application of tertiary treatment processes to improve removal of organic micropollutants persisting after secondary treatment

The goal of this study was to investigate the occurrence and removal of 52 organic micropollutants (OMPs) during each wastewater treatment step in a full-scale wastewater treatment plant (WWTP). Pharmaceuticals such as metformin, acetaminophen, caffeine, ibuprofen, cimetidine and naproxen were found with high average concentrations in the influent. Most OMPs were not affected by the primary treatment (removal <10%), while secondary biological treatment contributed the most to overall removal of the OMPs. Among the three lanes of the secondary treatment of the WWTP, a combined anaerobic-anoxic-oxic process followed by a membrane bioreactor (A2O–MBR) process effectively facilitated removal of the OMPs (96%) using a different redox: a conventional activated sludge (CAS) process exhibited removal of approximately 85% of total concentrations of the OMPs, while a Modified Ludzack-Ettinger (MLE) process achieved approximately 92.1% removal. Removal of more than 50% of the concentrations of 13 targeted OMPs was observed in the secondary effluent (except for metformin showing only 3.8% removal) via adsorption with powdered activated carbon (PAC) as additional tertiary treatment. Metformin, inadequately removed by additional tertiary treatments, was effectively removed by a biological activated carbon (BAC) process, reaching a removal efficiency of 90.5%. To increase the removal of the amounts and types of OMPs with various physico-chemical properties, hybrid processes through a combination of diverse advanced treatment should be tailored to WWTPs.

Sequential removal of selenate, nitrate and sulfate and recovery of elemental selenium in a multi-stage bioreactor process with redox potential feedback control

Bioreduction can facilitate oxyanions removal from wastewater. However, simultaneously removing selenate, nitrate and sulfate and recovering high-purity elemental selenium (Se0) from wastewater by a single system is difficult and may lead to carcinogenic selenium monosulfide (SeS) formation. To solve this issue, a two-stage biological fluidized bed (FBR) process with ethanol dosing based on oxidation-reduction potential (ORP) feedback control was developed in this study. FBR1 performance was first evaluated at various ORP setpoints (between −520 and −360 mV vs. Ag/AgCl) and elevated sulfate concentration. Subsequently, ethanol-fed FBR2 was used to reduce sulfate from FBR1 effluent, followed by an aerated sulfide oxidation reactor (SOR). At − 520 mV≤ ORPs≤ −480 mV, FBR1 removed 100 ± 0.1% nitrate and 99.7 ± 0.3% selenate without sulfate reduction. At ORPs ≥ −440 mV, selenate reduction was incomplete, whereas nitrate removal remained stable. Se0 recovery efficiency from FBR1 effluent was 37.5% with 71% Se purity. FBR2 converted 86% of the remaining sulfate in FBR1 effluent to hydrogen sulfide, but the over-oxidation of dissolved sulfide in SOR decreased the overall sulfate removal efficiency to ~46.3%. Overall, the two-stage FBR process with ORP feedback dosing of ethanol was effective for sequentially removing selenate, nitrate and sulfate and recovering Se0 from wastewater.

Assessment of Microbial and Ecotoxicological Qualities of Industrial Wastewater Treated with Membrane Bioreactor (MBR) Process for Agricultural Irrigation

Assessment of Microbial and Ecotoxicological Qualities of Industrial Wastewater Treated with Membrane Bioreactor (MBR) Process for Agricultural Irrigation

Decolourization of azo dye using a batch bioreactor by an indigenous bacterium Enterobacter aerogenes ES014 from the waste water dye effluent and toxicity analysis

Effluents of textile industries caused serious environmental problem throughout the world. In this study, a total of 23 bacterial strains from five bacterial species were isolated from the dye effluent. Of these strains, a unique and novel Enterobacter aerogenes ES014 was utilized for dye decolourization and toxicity analysis. The selected strain could effectively decolourize three selected azo dyes. It showed the capability for decolourizing acid orange (82.3 ± 3.6%), methyl orange (78.2 ± 3.3%), and congo red (81.5 ± 3.2%). The selected bacterial strain significantly decolourized 100 mg/L acid orange at 35 °C, pH 7.5 with 6% sodium chloride concentration. Most of the tested nitrogen and carbon sources effectively enhanced decolourization process. It showed the ability to decolourize acid orange in the culture medium containing 1.5% glucose (100 ± 2.8%) and 0.8% beef extract (100 ± 3.1%). A laboratory-scale batch bioreactor was used to decolourize azo dye at optimized culture conditions. The decolourizing ability improved with 100 mL/h hydraulic retention time. The treated wastewater quality was improved due to sharp depletion of Total Dissolved Solids (TDS), pH, Chemical Oxygen Demand (COD), alkalinity and sulphate concentration. The selected bacteria has the potential to produce dye degrading laccase. Laccase was detected during fermentation process in batch bioreactor as a key enzyme for decolourization produced by E. aerogenes ES014. Phytotoxicity and acute toxicity analysis were performed using Arachis hypogaea (pea nut) seed and first instar larvae of Artemia parthenogenetica (brine shrimp). The seed germination rate of treated wastewater was improved (94.3 ± 1.8%) and enhanced survival rate (91.7 ± 2.9%) in the first instar Artemia larvae treated with wastewater after 24 h. Overall, E. aerogenes ES014, might be a promising bacterial strain for the treatment of textile effluents with high azo dye concentrations.

A high cell density perfusion process for Modified Vaccinia virus Ankara production: Process integration with inline DNA digestion and cost analysis.

By integrating continuous cell cultures with continuous purification methods, process yields and product quality attributes have beenimproved over the last 10 years for recombinant protein production. However, for the production of viral vectors such as Modified Vaccinia virus Ankara (MVA), no such studies have been reported although there is an increasing need to meet the requirements for a rising number of clinical trials against infectious or neoplastic diseases. Here, we present for the first time a scalable suspension cell (AGE1.CR.pIX cells) culture-based perfusion process in bioreactors integrating continuous virus harvesting through an acoustic settler with semi-continuous chromatographic purification. This allowed obtaining purified MVA particles with a space-time yield more than 600% higher for the integrated perfusion process (1.05 × 1011 TCID50 /Lbioreactor /day) compared to the integrated batch process. Without further optimization, purification by membrane-based steric exclusion chromatography resulted in an overall product recovery of 50.5%. To decrease the level of host cell DNA before chromatography, a novel inline continuous DNA digestion step was integrated into the process train. A detailed cost analysis comparing integrated production in batch versus production in perfusion mode showed that the cost per dose for MVA was reduced by nearly one-third using this intensified small-scale process.

The Safety of Agalsidase Alfa Enzyme Replacement Therapy in Canadian Patients with Fabry Disease Following Implementation of a Bioreactor Process.

Background and ObjectiveFabry disease, an X-linked lysosomal storage disorder characterized by absent or reduced alpha-galactosidase activity, is a lifelong disease that impairs patients’ quality of life. Patients with Fabry disease have a considerably shortened lifespan, with mortality being mainly due to renal failure, cardiovascular disease, or cerebrovascular disease. Enzyme replacement therapy with agalsidase alfa has been shown to attenuate the renal, cardiovascular, and neuropathic disease progression associated with Fabry disease. The objective of this study was to investigate the safety of a new animal component-free version of agalsidase alfa.MethodsA phase III/IV, open-label, single-arm, multicenter safety study was conducted in Canadian patients with Fabry disease between August 2011 and September 2017 as a regulatory requirement to assess the safety of agalsidase alfa produced using an animal component-free bioreactor process. Eligible patients had a documented diagnosis of Fabry disease and satisfied current Canadian guidelines for receiving enzyme replacement therapy for Fabry disease. Following treatment with animal component-free bioreactor-processed agalsidase alfa, treatment-emergent adverse events were monitored, and post hoc analyses of infusion-related reactions by antidrug antibody and neutralizing antibody statuses were conducted. The data were analyzed using descriptive statistics.ResultsA total of 167 patients (mean [standard deviation] age, 48.9 [14.8] years), including six pediatric patients (< 18 years of age), received at least one full or partial infusion of agalsidase alfa animal component-free. Fewer than 5% of treatment-emergent adverse events (212/4446) observed in 40 patients were reported as infusion-related reactions. Antidrug antibody and neutralizing antibody status did not affect the proportion of patients with infusion-related reactions. No clinically significant changes in vital signs were observed in patients over the course of the study.ConclusionsLong-term treatment with bioreactor-produced agalsidase alfa animal component-free did not reveal new safety signals in this population of Canadian patients with Fabry disease. The treatment-emergent adverse event profile was consistent with the clinical manifestations of the disease and the known safety profile of roller bottle-produced agalsidase alfa.Clinical Trial RegistrationClinicalTrials.gov identifier NCT01298141.

The circulating fluidized bed bioreactor as a biological nutrient removal process for municipal wastewater treatment: Process modelling and costing analysis

Emerging technologies for wastewater treatment face an uphill battle to be adopted in practice because no large-scale costing data exists to prove their cost competitiveness. Similar technologies and their costing data offer some insight to the approximate cost, but more detailed estimates are required for a final decision on process selection. The circulating fluidized bed bioreactor (CFBBR) is one such technology, proven at the lab and pilot and scale, but is yet to be used on a large scale. In order to demonstrate the potential economic competitiveness of the CFBBR, a method of modifying the CapdetWorks costing software by first modeling the CFBBR in the GPS-X process simulation software was employed. The modelling was used to determine the necessary changes to a moving bed bioreactor (MBBR) process (media size, density, surface area, and bed fill fraction) in CapdetWorks to simulate the CFBBR and then generate costing estimates for both capital cost (CapEx) and operation and maintenance cost (OpEx). Benchmarking the cost estimates against simulations of conventional suspended and attached growth processes and external costing data from the US EPA was performed to both validate the costing method and analyze the CFBBR's economic competitiveness. The calculation of the net present value from the CapEx and OpEx showed that the CFBBR is predicted to have 10%–30% lower costs at low flows of 1.5 and 4.6 MGD and comparative costs to conventional processes at higher flows from 10 to 30 MGD. Furthermore, the smaller land footprint of the CFBBR-based plants and lower landfilled biosolids implies that the CFBBR's environmental footprint is superior to its competitors and offers advantages for both small-sized plants and large urban plants.

Techno-economic characteristics of wastewater treatment plants retrofitted from the conventional activated sludge process to the membrane bioreactor process

Techno-economic characteristics of wastewater treatment plants retrofitted from the conventional activated sludge process to the membrane bioreactor process

Effects of microplastics accumulation on performance of membrane bioreactor for wastewater treatment

The effective interception of membrane leads to the accumulation of microplastics (MPs) in membrane bioreactor (MBR) process for long-term operation. However, the influence of MPs accumulation on the performance of MBR hasn't been well understood. In this study, the accumulation of polypropylene microplastics (PP-MPs) in two MBRs run for 3 yr with or without discharging sludge was simulated by operating the lab-scale MBRs for 84 days. The variations of pollutant removal, membrane fouling, composition of soluble microbial product (SMP) and extracellular polymeric substance (EPS), and microbial community of MBRs were systematically investigated. The results show that the removal efficiency of COD and NH4+-N was not depressed by PP-MPs accumulation. However, the presence of PP-MPs in the range of 0.14–0.30 g/L could inhibit the growth of microorganisms, enhance the secretion of SMP and EPS, and reduce the microbial richness and diversity. In the contrary, the high concentration of PP-MPs (2.34–5.00 g/L) exhibited the opposite effects and mitigated membrane fouling, suggesting the important role of MPs concentration. It was also found that the exposure to high concentration of PP-MPs enhanced relative abundance of Clostridia, and inhibited the growth of Proteobacteria. The findings of this study provide a foresight to understand the effects of MPs accumulation on the performance of MBRs.

Dynamic Modeling of the Impact of Temperature Changes on CO2 Production during Milk Fermentation in Batch Bioreactors.

Knowledge of the mathematical models of the fermentation processes is indispensable for their simulation and optimization and for the design and synthesis of the applicable control systems. The paper focuses on determining a dynamic mathematical model of the milk fermentation process taking place in a batch bioreactor. Models in the literature describe milk fermentation in batch bioreactors as an autonomous system. They do not enable the analysis of the effect of temperature changes on the metabolism during fermentation. In the presented extensive multidisciplinary study, we have developed a new mathematical model that considers the impact of temperature changes on the dynamics of the CO2 produced during fermentation in the batch bioreactor. Based on laboratory tests and theoretical analysis, the appropriate structure of the temperature-considered dynamic model was first determined. Next, the model parameters of the fermentation process in the laboratory bioreactor were identified by means of particle swarm optimization. Finally, the experiments with the laboratory batch bioreactor were compared with the simulations to verify the derived mathematical model. The developed model proved to be very suitable for simulations, and, above all, it enables the design and synthesis of a control system for batch bioreactors.

Intensified phenol and p-cresol biodegradation for wastewater treatment in countercurrent packed-bed column bioreactors

An intensified biodegradation process in packed-bed column bioreactors (PBCB) with microbial cells attached to packing/micro-particles surface was proposed and simulated via a dynamic 3D model with continuity, momentum, and species (comprising biomicro-particles) balance equations in liquid/gas, accumulation of biomicro-particles in packed-bed, diffusion and enzymatic reaction within biofilm and liquid film. Phenol and phenol/p-cresol biological removal by Pseudomonas putida was chosen to discuss the enhanced biodegradation efficiency. The biodegradation in single/dual-substrate systems is significantly upgraded as biomass loading on micro-particles surface increases. Microbial cells addition to the surface of micro-particles is more efficient when the foremost extent of biomass is attached to packing via large biofilms with increased resistance to mass transfer, at low phenol concentrations and liquid velocities. These intensified biodegradation systems aim at maximizing the mass transfer in PBCB for treatment of wastewater having high phenols concentration, without reducing the residence time of liquid or diluting the effluent.

Enhancing the recombinant protein productivity of Yarrowia lipolytica using in situ fibrous bed bioreactor

In this study, the ability of Yarrowia lipolytica to produce the recombinant lipase CalB from Candida antarctica, used as a model protein has been compared across different bioreactor processes using glycerol, a byproduct from the biodiesel industry as the main carbon source. Batch, pulsed fed-batch (PFB), and continuous fed-batch (CFB) strategies were first compared using classical stirred tank (STR) bioreactors in terms of biomass production, carbon source uptake, and lipase production. Additionally, an in situ fibrous bed bioreactor (isFBB) was developed using sugarcane bagasse as a cell immobilization support. The maximum lipase titer achieved using the isFBB culture mode was 38%, 33%, and 49% higher than those obtained using the batch, PFB, and CFB cultures, respectively. The lipase productivity in isFBB mode (142U/mL/h) was 1.4-fold higher than that obtained using batch free cell cultures. These results highlight that isFBB is an efficient technology for the production of recombinant enzymes.

D-Galacturonic acid reduction by S. cerevisiae for L-galactonate production from extracted sugar beet press pulp hydrolysate

Pectin-rich residues are considered as promising feedstocks for sustainable production of platform chemicals. Enzymatic hydrolysis of extracted sugar beet press pulp (SBPP) releases the main constituent of pectin, d-galacturonic acid (d-GalA). Using engineered Saccharomyces cerevisiae, d-GalA is then reduced to l-galactonate (l-GalOA) with sorbitol as co-substrate. The current work addresses the combination of enzymatic hydrolysis of pectin in SBPP with a consecutive optimized biotransformation of the released d-GalA to l-GalOA in simple batch processes in stirred-tank bioreactors. Process conditions were first identified with synthetic media, where a product concentration of 9.9 g L-1 L-GalOA was obtained with a product selectivity of 99% (L-GalOA D-GalA-1) at pH 5 with 4% (w/v) sorbitol within 48 h. A very similar batch process performance with a product selectivity of 97% was achieved with potassium citrate buffered SBPP hydrolysate, demonstrating for the first time direct production of L-GalOA from hydrolyzed biomass using engineered S. cerevisiae. Combining the hydrolysis process of extracted SBPP and the biotransformation process with engineered S. cerevisiae paves the way towards repurposing pectin-rich residues as substrates for value-added chemicals.Key points• Efficient bioreduction of D-GalA with S. cerevisiae in stirred-tank reactors• Batch production of L-GalOA by engineered S. cerevisiae with high selectivity• Direct L-GalOA production from hydrolyzed sugar beet press pulpGraphical abstractBioreduction of D-galacturonic acid to L-galactonate with recombinant Saccharomyces cerevisiae enables for the first time the valorization of hydrolysates from extracted sugar beet press pulp for the sustainable production of value-added chemicals.

Modified Approach of NaFA based on its Step Size and its Performance in Bioreactor Processes

Objectives: The objective of this work is to fine tune the variant of FA (Firefly Algorithm), NaFA (Firefly Algorithm with neighbourhood Attraction) by parameter tuning such as a, b , g . Furthermore, a new variant called Step Size Modified FA with neighbourhood attraction (SSMFA-N) has been proposed in which the step size is updated during the algorithm run so that a balance between local and global search is achieved. The considered objective functions are PO and ITAE. Methods: It is well known that parameters that are considered initially for any metaheuristic algorithms are purely trial and error basis and this leads to erroneous optimized results. While analysing the algorithms, NaFA (a variant of FA) has been considered for efficient convergence and good performance. On analysing it is noticed that FA and its variants’ performances and convergence depend on Step Size(a), brightness (b ) and adsorption coefficient(g ). In both the FA and NaFA the parameters to be tuned for effective convergence are a, b and g . It is also understood that the parameter b had been done separately and the parameters a and g cannot be fine-tuned simultaneously. Therefore, in NaFA the parameter tuning for a has been done for the processes FOPDT, stable and unstable SOPDT and the new variant SSMFA-N is thus proposed. Findings: The algorithm is made to run in MATLAB and Simulink environment for three different processes such as FOPDT, Stable and Unstable Second order Process (bioreactor processes) with the objective functions of less PO and ITAE. The obtained results from all the three processes are compared with the conventional and optimization methods (PSO) and shown that SSMFA-N outperforms the conventional and optimization approaches in both the time domain and performance indices. Novelty: The novelty is the modification of step size of NaFA, which ultimately leads to a new variant called SSMFA-N. Keywords: FA; FA with neighbourhood attraction; Step size tuning; Bioreactor Process

Removal of antibiotic resistance genes (ARGs) in various wastewater treatment processes: An overview

Antibiotic resistance genes (ARGs) are emerging contaminants, which have been frequently detected in different aquatic environments, posing potential risk to public health and ecosystem. A properly designed and operated wastewater treatment process can be an effective final barrier for reducing the quantity of ARGs discharged into the environment. In order to control the propagation of antimicrobial resistance in the environment, it is essential to comprehensively understand the elimination and inactivation of ARGs by various wastewater treatment processes. This review systematically summarized and analyzed the feasibility and efficiency of ARGs removal in different wastewater treatment processes, including biological processes, such as membrane bioreactor process and constructed wetlands; chemical processes, such as ozonation, chlorination, Fenton oxidation and other advanced oxidation processes (AOPs); physicochemical processes, such as UV radiation, ionizing radiation; and physical processes, such as coagulation and membrane filtration. In addition, the advantages and limitations as well as future direction of these treatment processes for the elimination and inactivation of ARGs in wastewater were also discussed, aiming to provide better understanding and support for future research.

The Water Quality Management for Recirculating Aquaculture System by Applying Nano Adsorption Technology.

In a fish farm, the water quality is important to ensure fish growth and farm productivity. However, the study of the quality of water using in aquaculture has been ignored until now. Although there are several methods to treat water, nanomaterials have not yet been applied for indoor fish farming because it may difficult to supply a sufficient amount of water, and the operating parameters have not been developed for recirculating aquaculture systems. Nanotechnology can be applied to treat water, specifically through adsorption and filtration, to produce drinking water from surface water and to treat wastewater by processing a high volume of effluent. The adsorption and filtration of seawater has also progressed to allow for desalination of seawater, and this is recognized as a necessary tool for extended treatment protocols of various types of seawater. This study investigated the treatment of aquaculture water using nano-porous adsorbents (e.g., pumice stone) to control the contaminants in seawater in order to maintain the water quality required for aquaculture. The results are used to derive an analytical relationship between the ionic species in aquaculture water, and this provides empirical parameters for a batch reactor for aquaculture. The quality of the influent and effluent for aquaculture is compared using time-series analyses to evaluate the reduction rate of ionic components and thus suggest the optimum condition for fish farming using bioreactor processes.

Phosphate recovery from the P-enriched brine of AnMBR-RO-IE treating municipal wastewater via an innovated phosphorus recovery batch reactor with nano-sorbents

Municipal wastewater is a very unique pool full of energy and useful substances. Though the innovative integrated anaerobic membrane bioreactor and reverse osmosis-ion exchange (AnMBR-RO-IE) process can produce high-grade reclaimed water with high energy efficiency, phosphorus resources recovery in the WWTPs has been rarely reported thus far. This study evaluated the feasibility of a phosphorus recovery batch reactor (PRBR) as an approach for the phosphate production from the P-enriched brine from AnMBR-RO-IE. With operating PRBR for 162 cycles, high to 85% of P recovery rate was obtained for 145 cycles, leading to a P production rate of 6.17 g/m3 domestic wastewater with nano-sorbents (NSs) consumption rate of 10.2 g/m3. Acidification pretreatment efficiently improved the adsorption capacity and reduced the NSs renewing frequency. High adsorption selectivity of NSs contributed to low impurities (<0.3%) in the P-enriched reclaimed solution. Moreover, the integrated AnMBR-RO-IE-PRBR process saved 47% of energy consumption compared to the present NEWater production process in Singapore. The innovative PRBR reactor was competitive compared to the commonly-used chemical precipitation methods in conventional WWTPs in terms of phosphorus recovery/loss and energy balance. It is expected that the proposed integrated process can offer new insights into the direction of phosphorus reclamation in the future WWTPs.

Study on the Removal of Fluorescent Whitening Agent from Paper-Mill Wastewater Using the Submerged Membrane Bioreactor (SMBR) with Ozone Oxidation Process

In this study, paper-mill wastewater was treated using the Submerged Membrane Bioreactor (SMBR) process. In particular, the ozone oxidation treatment process is applied after SMBR to remove the fluorescent whitening agent, which is a trace pollutant and non-biodegradable. Fluorescent whitening agent concentration was indirectly measured by UV scanning and COD concentration. The concentration of COD before SMBR and ozone oxidation was 449.3 mg/L, and the concentration of treated water was 100.3 mg/ℓ. The COD removal efficiency of paper-mill wastewater through SMBR and the ozone oxidation process was about 77.68%. The optimized amount of ozone was required for the removal of the fluorescent whitening agent after SMBR was 95 mg·O3/ℓ calculated by UV scan results. Additionally, the optimized amount of required ozone to remove COD was calculated to 0.126 mg·COD/mg·O3.