Ultrafiltration recovery of entomotoxicity from supernatant of Bacillus thuringiensis fermented wastewater and wastewater sludge

The study investigates the recovery of active components (crystal proteins, spores and other factors of virulence) of Bacillus thuringiensis (Bt) based biopesticides from centrifuged supernatant, by ultrafiltration. The centrifuged fermented broths comprised, starch industry wastewater, non-hydrolyzed and hydrolyzed wastewater sludge and semi-synthetic soya medium (as control). The ultrafiltration membrane of 5 kDa gave highest recovery of the active components and increased the entomotoxicity in the retentates by 7.9%, 10.5%, 9.0%, 5.7%, for semi-synthetic soya medium, starch industry wastewater, non-hydrolyzed and hydrolyzed wastewater sludge, respectively. However, the retention of suspended solids on the membrane (measured via mass balance) varied with the type of fermented broths and was very high for hydrolyzed sludge (soya-15%; starch industry wastewater-12%; non-hydrolyzed sludge-7% and hydrolyzed sludge-68%). This reflected the deposit on the membrane. In the given context, scale-up of the ultrafiltration process will give better efficacy for non-hydrolyzed sludge and starch industry wastewater in comparison to soya and hydrolyzed sludge medium.     

Batch and fed-batch fermentation of Bacillus thuringiensis using starch industry wastewater as fermentation substrate

Bacillus thuringiensis var. kurstaki biopesticide was produced in batch and fed-batch fermentation modes using starch industry wastewater as sole substrate. Fed-batch fermentation with two intermittent feeds (at 10 and 20 h) during the fermentation of 72 h gave the maximum delta-endotoxin concentration (1,672.6 mg/L) and entomotoxicity (Tx) (18.5 × 10⁶ SBU/mL) in fermented broth which were significantly higher than maximum delta-endotoxin concentration (511.0 mg/L) and Tx (15.8 × 10⁶ SBU/mL) obtained in batch process. However, fed-batch fermentation with three intermittent feeds (at 10, 20 and 34 h) of the fermentation resulted in the formation of asporogenous variant (Spo−) from 36 h to the end of fermentation (72 h) which resulted in a significant decrease in spore and delta-endotoxin concentration and finally the Tx value. Tx of suspended pellets (27.4 × 10⁶ SBU/mL) obtained in fed-batch fermentation with two feeds was the highest value as compared to other cases.     

Impact of different pH control agents on biopesticidal activity of<Emphasis Type="Italic"> Bacillus thuringiensis</Emphasis> during the fermentation of starch industry wastewater

Different pH control agents (NaOH/H₂SO₄—SodSulp, NaOH/CH₃COOH—SodAcet, NH₄OH/CH₃COOH—AmmoAcet and NH₄OH/H₂SO₄—AmmoSulp) were used to investigate their effects on growth, enzyme production (alkaline protease and amylase), and entomotoxicity of Bacillus thuringiensis var. kurstaki HD-1 (Btk) against eastern spruce budworm larvae (Choristoneura fumiferana) using starch industry wastewater (SIW) as a raw material in a 15-l fermentor. AmmoSulp and SodSulp were found to be the best pH control agents for alkaline protease and amylase production, respectively; whereas, the fermented broth obtained by using SodAcet as pH control agents recorded the highest delta-endotoxin production of 1043.0 mg/l and entomotoxicity value 18.4 × 10⁹ SBU/l. Entomotoxicity of re-suspended centrifuged pellet in one-tenth of original volume in case of SodAcet as pH control agents was 26.7 × 10⁹ SBU/l and was the highest value compared to three other pH control agents.     

Screening of different adjuvants for wastewater/wastewater sludge-based Bacillus thuringiensis formulations

Screening of different adjuvants, namely, suspending agents, phagostimulants, stickers, antimicrobial agents, and UV screens to develop aqueous biopesticidal suspensions of Bacillus thuringiensis (Bt) variety kurstaki HD-1 fermented broths, specifically, nonhydrolyzed sludge, hydrolyzed sludge, starch industry wastewater, and soya (commercial medium), were investigated. The selected suspending agents [20% (wt:vol)] included sorbitol, sodium monophosphate, and sodium metabisulfite with corresponding suspendibility of 74-92, 69-85, and 71-82%, respectively. Molasses [0.2% (wt:vol)] increased adherence by 84-90% for all fermented broths. The optimal phagostimulants [0.5% (wt:vol)], namely, soya and molasses, caused entomotoxicity increase of 3-13 and 7-13%, respectively. Sorbic and propionic acids showed high antimicrobial action [0.5% (wt:vol)], irrespective of fermentation medium. Sodium lignosulfonate, molasses, and Congo red, when used as UV screens [0.2% (wt:vol)], showed percent corresponding entomotoxicity losses of 3-5, 0.5-5 and 2-16, respectively. The Bt formulations, when exposed to UV radiation, showed higher half-lives (with and without UV screens) than the fermented broths or semisynthetic soya medium and commercial Bt formulation. UV screen-amended nonhydrolyzed, hydrolyzed, and starch industry wastewater formulations showed 1.3-1.5-fold higher half-lives than commercial Bt formulation. Thus, the recommended formulation comprises sorbitol, sodium monophosphate, sodium metabisulfite (suspending agents); molasses, soya flour (phagostimulants); molasses and skimmed milk powder (rainfasteners); sorbic and propionic acids (antimicrobial agents) and sodium lignosulfate; and molasses and Congo red (UV screens). These waste-based Bt formulations offer better UV resistance in comparison with commercial formulation.     

Industrial wastewaters and dewatered sludge: rich nutrient source for production and formulation of biocontrol agent, <Emphasis Type="Italic">Trichoderma viride</Emphasis>

Axenic cultivation of biocontrol fungus Trichoderma viride was conducted on a synthetic medium and different wastewaters and wastewater sludges in shake flasks to search for a suitable raw material resulting in higher biocontrol activity. Soluble starch based synthetic medium, dewatered municipal sludge, cheese industry wastewater sludge, pre-treated and untreated pulp and paper industry wastewater and slaughter house wastewater (SHW) were tested for T. viride conidia and protease enzyme production. The maximum conidia production followed the order, soluble starch medium (>10⁹ c.f.u./mL), untreated pulp and paper industry wastewater (4.9 × 10⁷ c.f.u./mL) > cheese industry wastewater (1.88 × 10⁷ c.f.u./mL) ≈ SHW (1.63 × 10⁷ c.f.u./mL) > dewatered municipal sludge (3.5 × 10⁶ c.f.u./mL) > pre-treated pulp and paper industry wastewater (1.55 × 10⁶ c.f.u./mL). The protease activity of T. viride was particularly higher in slaughterhouse wastewater (2.14 IU/mL) and dewatered municipal sludge (1.94 IU/mL). The entomotoxicity of soluble starch based synthetic medium was lower (≈6090 SBU/μL) in contrast to other raw materials. The entomotoxicity inversely decreased with carbon to nitrogen ratio in the growth medium and the conidia concentration and protease activity also contributed to the entomotoxicity. The residual c.f.u./g formulation of T. viride conidia were up to approximately, 90% after 1 month at 4 ± 1 °C and about 70% after 6 months at 25 ± 1 °C. Thus, production of T. viride conidia would help in marketability of low cost biopesticide from the sludge and safe reduction of pollution load.     

Starch industry wastewater-based stable Bacillus thuringiensis liquid formulations

Liquid formulations were developed from Bacillus thuringiensis (Bt)-fermented broths of starch industry wastewater (SIW) and of soya medium. Stability studies were carried out for 1 yr. Storage stability was tested by studying various physical and chemical (e.g., viscosity, particle size, corrosion, and suspendibility) and biological (e.g., microbial contamination, viable spores, and entomotoxicity) parameters at different pH levels and temperatures. Three suspending agents, sorbitol, sodium monophosphate, and sodium metabisulfite, were added to fermented broth in different concentrations. Sorbitol and sodium monophosphate in the ratio 3:1 was the best suspending agent combination for both formulations. Starch industry wastewater fermentation yielded cell and viable spore counts 10- and 4-fold greater than those from soya medium, respectively, and a 1.7-fold increase in entomotoxicity. However, both formulations started deteriorating at pH 6 and 6.5 and 40 and 50 degrees C. There were no signs of corrosion and microbial contamination in both types of formulations.     

Phenol-mediated improved performance of active biomass for treatment of distillery wastewater

Activated sludge from a wastewater treatment plant consists of a consortium of microbes that utilize various organic molecules including persistent organic pollutants for their survival. Phenolic compounds and their derivatives along with dibenzofuran (DBF) are found as dominating pollutants in distillery waste. The acclimatization process leads to selective enrichment of the microbial community; and in this study, we report the acclimatizing effect of phenol on improving the treatment efficiency of two different distillery sludges—sludge from conventional aeration tanks (CAT), and from an extended aeration tank (EAT). The adaptation-dependent performance of activated biomass was studied by monitoring the increase in colony-forming units (CFUs) on mineral media and the utilization pattern for phenol (300×10³ and 530×10³ CFU for CAT and EAT sludge, respectively) and DBF (260×10³ and 430×10³ CFU for CAT and EAT sludge, respectively). The study showed that the acclimatization process remarkably improved the performance sludge for treatment of distillery wastewater. There was an improvement in chemical oxygen demand (COD) removal efficiency from 19% (unacclimatized sludge) to 31% in the case of acclimatized sludge (raw wastewater), which improved further to 82% and 87% with dilution of wastewater by 10 times (0.1×) and by 50 times (0.02×), respectively. Highest growth yields were observed with 0.1× wastewater (0.324 and 0.308 g g⁻¹ d⁻¹ for CAT and EAT sludges, respectively), while lower values are reported for the remaining two forms of wastewater. The study proposes that acclimatization step could be included as part of a treatment plant where the activated biomass could be intermittently metabolically charged by exposing it to selected molecules to increase treatment efficiency.     

Denitrification of nitrified and non-nitrified swine lagoon wastewater in the suspended sludge layer of treatment wetlands

One method for managing livestock-wastewater N is the use of treatment wetlands. The objectives of this study were to (1) assess the magnitude of denitrification enzyme activity (DEA) in the suspended sludge layers of bulrush and cattail treatment wetlands, and (2) evaluate the impact of nitrogen pretreatment on DEA in the suspended sludge layer. The study used four wetland cells (3.6 m × 33.5 m) with two cells connected in series. Each wetland series received either untreated or partially nitrified swine wastewater from a single-cell anaerobic lagoon. The DEA of the suspended sludge layers of the constructed wetlands was measured by the acetylene inhibition method. The control DEA treatment for the sludge layer had a mean rate of 18 μg N₂O-N g^?1 sludge h^?1. Moreover, the potential DEA (nitrate-N and glucose-C added) mean was very large, 121 μg N₂O-N g^?1 sludge h^?1. These DEA rates are consistent with the previously reported high levels of nitrogen removal by denitrification from these wetlands, especially when the wastewater was partially nitrified. Stepwise regression using distance within the wetland, wastewater nitrate, and wastewater ammonia explained much of the variation in DEA rates. In both bulrush and cattail wetlands, there were zones of very high potential DEA.     

Microencapsulating aerial conidia of Trichoderma harzianum through spray drying at elevated temperatures

Conidia of Trichoderma harzianum produced from either solid or liquid fermentation must be dried to prevent spoilage by microbial contamination, and to induce dormancy for formulation development and prolonged self-life. Drying conidia of Trichoderma spp. in large scale production remains the major constraint because conidia lose viability during the drying process at elevated temperatures. Moreover, caking must be avoided during drying because heat generated by milling conidial chunks will kill conidia. It is ideal to dry conidia into a flow-able powder for further formulation development. A method was developed for microencapsulation of Trichoderma conidia with sugar through spray drying. Microencapsulation with sugars, such as sucrose, molasses or glycerol, significantly (P < 0.05) increased the survival percentages of conidia after drying. Microencapsulation of conidia with 2% sucrose solution resulted in the highest survival percentage when compared with other sucrose concentrations and had about 7.5 × 10¹⁰ cfu in each gram of dried conidia, and 3.4 mg of sucrose added to each gram of dried conidia. The optimal inlet/outlet temperature setting was 60/31 °C for spray drying and microencapsulation. The particle size of microencapsulated conidia balls ranged from 10 to 25 μm. The spray dried biomass of T. harzianum was a flow-able powder with over 99% conidia, which could be used in a variety of formulation developments from seed coatings to sprayable formulations.     

Effects of physical properties for starch acetate powders on tableting

The aim of the study was to investigate particle and powder properties of various starch acetate powders, to study the effect of these properties on direct compression characteristics, and to evaluate the modification opportunity of physical properties for starch acetate powders by using various drying methods. At the end of the production phase of starch acetate, the slurry of starch acetate was dried using various techniques. Particle, powder, and tableting properties of end products were investigated. Particle size, circularity, surface texture, water content and specific surface area varied according to the particular drying method of choice. However, all powders were freely flowing. Bulk and tapped densities of powders varied in the range of 0.29 to 0.44 g/cm³ and 0.39 to 0.56 g/cm³, respectively. Compaction characteristics revealed that all powders were easily deformed under compression, having yield pressure values of less than 66 MPa according to Heckel analysis. All powders possessed a significant interparticulate bond-forming capacity during compaction. The tensile strength values of tablets varied between 10 and 18 MPa. In conclusion, physical properties of starch acetate could be affected by various drying techniques. A large specific surface area and water content above 4% were favorable properties by direct compression, especially for small, irregular, and rough particles.     

Comparative Survival Rates of Human-Derived Probiotic Lactobacillus paracasei and L. salivarius Strains during Heat Treatment and Spray Drying

Spray drying of skim milk was evaluated as a means of preserving Lactobacillus paracasei NFBC 338 and Lactobacillus salivarius UCC 118, which are human-derived strains with probiotic potential. Our initial experiments revealed that NFBC 338 is considerably more heat resistant in 20% (wt/vol) skim milk than UCC 118 is; the comparable decimal reduction times were 11.1 and 1.1 min, respectively, at 59°C. An air outlet temperature of 80 to 85°C was optimal for spray drying; these conditions resulted in powders with moisture contents of 4.1 to 4.2% and viable counts of 3.2 × 10⁹ CFU/g for NFBC 338 and 5.2 × 10⁷ CFU/g for UCC 118. Thus, L. paracasei NFBC 338 survived better than L. salivarius UCC 118 during spray drying; similar results were obtained when we used confocal scanning laser microscopy and LIVE/DEAD BacLight viability staining. In addition, confocal scanning laser microscopy revealed that the probiotic lactobacilli were located primarily in the powder particles. Although both spray-dried cultures appeared to be stressed, as shown by increased sensitivity to NaCl, bacteriocin production by UCC 118 was not affected by the process, nor was the activity of the bacteriocin peptide. The level of survival of NFBC 338 remained constant at ~1 × 10⁹ CFU/g during 2 months of powder storage at 4°C, while a decline in the level of survival of approximately 1 log (from 7.2 × 10⁷ to 9.5 × 10⁶ CFU/g) was observed for UCC 118 stored under the same conditions. However, survival of both Lactobacillus strains during powder storage was inversely related to the storage temperature. Our data demonstrate that spray drying may be a cost-effective way to produce large quantities of some probiotic cultures.     

Recycle in upflow anaerobic sludge blanket reactor on treatment of real textile dye effluent

The discharge of textile wastewater containing dye in the environment is varying for both toxicology and esthetical reasons as dyes impede light penetration, damage the quality of the receiving streams. Upflow anaerobic sludge blanket reactor with anaerobic digester sludge treating starch wastewater has been used to investigate the removal efficiency of chemical oxygen demand (COD) and colour of textile dye wastewater. In this study, the starch and textile dye wastewater was mixed at 70 and 30%, respectively, and the experiments were carried out with recycle of treated wastewater at different percentage as 10, 20, 30 and 40. Maximum removal of COD and colour was 96% and 93.3%, respectively, at 30% recycle. At various OLR and HRT, the maximum removal of COD, colour was 95.9%, 93% at 6.81 kg COD/m³d and 96%, 93% with 24 h of HRT. The maximum production of biogas at 24 h of HRT with 30% recycle was about 355 l/d. The Volatile fatty acid/Alkalinity ratio of methanogenic reactor was found to be 0.049–0.053. The result provided evidence, the starch and dye wastewater have wide variation in their characteristics was treated on combination, this new technology supports the effective utilization of starch waste in destruction of dye.     

Hyperproduction of chitinase influences crystal toxin synthesis and sporulation of <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>

Bacillus thuringiensis HD-73 was transformed with the endochitinase gene chiA74 under the control of a strong promoter (pcytA) and a 5′ mRNA stabilizing (STAB-SD) sequence (HD-73-pEBchiA74). Expression levels were compared with those observed from the wild type strain (HD-73) and the recombinant HD-73 strain expressing chiA74 under the control of its native promoter (HD-73-pEHchiA74). The chitinolytic activity of HD-73-pEBchiA74 was markedly elevated, being ~58- and 362-fold higher than, respectively, HD-73-pEHchiA74 and parental HD-73, representing the highest levels of chitinase expression in recombinant B. thuringiensis reported to date. Parasporal crystals measured under transmission electron microscopy showed that HD-73 produced crystals of 1.235 (±0.214) and 1.356 (±0.247) μm in length when the bacterium was grown in respectively, NBS and NBS with glucose. Otherwise, HD-73-pEBchiA74 synthesized crystals of 1.250 (±0.222) and 1.139 (±0.202) μm in length when cultivated in NBS and NBS with glucose, respectively, values that showed a diminution of ~10 and 20% compared with crystals produced by HD-73-pEHchiA74 grown under the same conditions. Comparison of viable spore counts per ml showed that HD-73-pEBchiA74 produced fewest viable spores (1.5 × 10⁹, 1.3 × 10⁹), compared to HD-73-pEHchiA74 (4.9 × 10⁹, 5.3 × 10⁹) and HD-73 (6.8 × 10⁹, 8.8 × 10⁹) when grown in NBS and NBS supplemented with glucose, respectively. No change in cellular protease activity was observed despite the overproduction of the chitinase.     

Solid-state fermentation of cornmeal with the ascomycete <Emphasis Type="Italic">Morchella esculenta</Emphasis> for degrading starch and upgrading nutritional value

The ability of the ascomycete Morchella esculenta to degrade starch and upgrade nutritional value of cornmeal during solid-state fermentation (SSF) was studied. On the basal medium, α-amylase activity of M. esculenta reached its maximum value of 215 U g⁻¹ of culture on day 20 after inoculation. Supplementation of glucose, yeast extract to the basal medium caused a significant increase in either the degradation rate of starch or the mycelial biomass as compared with control (P < 0.01). Through orthogonal experiments, the theoretical optimum culture medium for SSF of this fungus was the following: 100 g cornmeal, ground to 30-mesh powder, moistened with 67 ml of nutrient salt solution supplemented with 3 g yeast extract and 10 g glucose per liter. Under the optimum culture condition, the degradation rate of starch reached its maximum values of 74.8%; the starch content of the fermented product decreased from 64.5 to 23.5%.     

Removal of triethylamine from synthetic wastewater by acclimated mixed bacteria cultures

This aim of this study was to remove triethylamine by a biological method, as well as to understand the ability of mixed bacteria cultures to treat a triethylamine compound from synthetic wastewater. The mixed bacteria cultures could not remove triethylamine, whether the activated sludge came from an acrylonitrile–butadiene–styrene resin manufactured wastewater treatment system or a waterborne polyurethane resin manufactured wastewater treatment system. When the mixed bacteria cultures were acclimated to triethylamine, they could utilize 650 mg l⁻¹ triethylamine for growth. When the initial triethylamine concentration was below 200 mg l⁻¹, the triethylamine removal efficiency could reach 100%. The triethylamine removal rate of the acclimated GMIX sludge was faster than the acclimated EMIX sludge.     

The effect of ozone on tannery wastewater biological treatment at demonstrative scale

This paper reports the results obtained during an investigation aimed at transferring to the demonstrative scale an aerobic granular biomass system (SBBGR – Sequencing Batch Biofilter Granular Reactor) integrated with ozonation for the efficient treatment of tannery wastewater. The results show that the integrated process was able to achieve high removal efficiencies for COD, TSS, TKN, surfactants and colour with residual concentrations much lower than the current discharge limits. Furthermore, the process was characterised by a very low sludge production (i.e., 0.1 kg dry sludge/m³ of treated wastewater) with interesting repercussions on treatment costs (about 1 € per m³ of wastewater).     

Application of chemical precipitation and membrane bioreactor hybrid process for piggery wastewater treatment

This study was conducted to investigate the chemical precipitation (CP) and membrane bioreactor (MBR) hybrid process for the treatment of piggery wastewater. Average removal efficiencies for BOD, COD and turbidity in CP process were 64.3%, 77.3% and 96.4%, respectively. CP process had a moderate effect on NH₃–N removal (40.4%) which improved up to 98.2% mainly due to nitrification and filtration processes in MBR. The average removal efficiencies of BOD, COD and turbidity in MBR were 99.5%, 99.4% and 99.8%, respectively. Monod equation was used to explain the microbial activities in terms of specific growth rate. The specific growth rate of bacteria in aeration tank (N-batch) and anoxic tank (D-batch) were 0.013 and 0.005 d^?1 with a biomass yield of 0.78 and 0.43 mg MLSS produced/mg COD utilized, respectively. Microorganisms from the N-batch and D-batch showed a low-level of nitrifying and moderate-level of denitrifying capabilities which were 1.08 mg NH₃–N/(g MLVSS.h) and 2.82 mg NO₃–N/(g MLVSS.h), respectively. Carbohydrates were the main component in extracellular polymeric substance (EPS) compounds that could be attached to the membrane surface easily and led to membrane biofouling. The increase of MLSS, EPS and sludge viscosity concentration, decrease of sludge floc size and incomplete chemical cleaning procedure resulted in the increase of membrane resistance. Total membrane resistance increased from 3.19 × 10¹² m^?1 to 5.43 × 10¹⁴ m^?1.     

Microbial sulfate reduction at low (8 °C) temperature using waste sludge as a carbon and seed source

Biological treatment of sulfate and metal-containing wastewater (such as acid mine drainage) is a viable option due to lower cost and better sludge quality compared to conventional chemical treatment. Although several substrates can be used as carbon source, a low-cost substrate is required for large scale applications. This study was conducted to investigate the suitability of waste sludge as a carbon and seed source for sulfate reduction at 8 °C in batch bioassays. Around 7 mmol of sulfate was reduced when the waste sludge mixture (WS) (6700 mg SS l^?1) from primary and secondary settling tank was supplemented as a carbon and seed source. However, only 1.6 mmol of sulfate was reduced with anaerobic digester effluent (ADS) (5300 mg SS l^?1). The produced H₂S from 1 g VSS l^?1 WS and ADS oxidation can theoretically precipitate around 90 and 35 mg Fe²⁺, respectively. Both WS and ADS oxidized ethanol to acetate at similar rates. It appears that WS is a good candidate for carbon and start-up seed source of sulfate reduction at 8 °C, whereas sulfidogenic acetate oxidation was the limiting step. Denaturing gradient gel electrophoresis (DGGE) analysis of 16S rRNA genes showed that both sludge sources contain Desulfomicrobium apsheronum strain.     

Effect of sludge age on performance of an activated sludge unit treating 2,4 dichlorophenol-containing synthetic wastewater

Wastewaters containing chlorophenol compounds are difficult to treat by biological means because of toxic effects of chlorophenols on microorganisms. Synthetic wastewater containing 2,4 dichlorophenol (DCP) was biologically treated in an activated sludge unit at different sludge ages varying between 5 and 30 days while the feed COD, DCP contents and hydraulic residence time (HRT) were constant. Effects of sludge age on COD, DCP and toxicity removals were investigated. Increases in sludge age caused significant increases in biomass concentration in the aeration tank, which resulted in increases in percent COD, DCP and toxicity removals. COD removal increased from 58 to 90%, while DCP and toxicity removals increased from 15 to 100% and from 38 to 100%, respectively, when the sludge age was raised from 5 to 30 days. Resazurin method based on dehydrogenase activity was used for assessment of the feed and effluent wastewater toxicity. Sludge volume index (SVI) decreased with increasing sludge age indicating improved settling characteristics of the sludge at high sludge ages. Operation at a sludge age of 25 days resulted in more than 90% COD and nearly 100% DCP and toxicity removal with an SVI value of 108 ml g⁻¹ under the experimental conditions tested.     

A novel UASB–MFC–BAF integrated system for high strength molasses wastewater treatment and bioelectricity generation

An up-flow anaerobic sludge blanket reactor–microbial fuel cell–biological aerated filter (UASB–MFC–BAF) system was developed for simultaneous bioelectricity generation and molasses wastewater treatment in this study. The maximum power density of 1410.2 mW/m² was obtained with a current density of 4947.9 mA/m² when the high strength molasses wastewater with chemical oxygen demand (COD) of 127,500 mg/l was employed as the influent. The total COD, sulfate and color removal efficiencies of the proposed system were achieved of 53.2%, 52.7% and 41.1%, respectively. Each unit of this system had respective function and performed well when integrated together. The UASB reactor unit was mainly responsible for COD removal and sulfate reduction, while the MFC unit was used for the oxidation of generated sulfide with electricity generation. The BAF unit dominated color removal and phenol derivatives degradation. This study is a beneficial attempt to combine MFC technology with conventional anaerobic–aerobic processes for actual wastewater treatment.