Integrated thermophilic submerged aerobic membrane bioreactor and electrochemical oxidation for pulp and paper effluent treatment - towards system closure

Department of Chemical Engineering, Lakehead University, 955 Oliver Road, Thunder Bay, ON, Canada P7B 5E1.
Bioresource Technology (Impact Factor: 4.49). 04/2012; 116:1-8. DOI: 10.1016/j.biortech.2012.04.045
Source: PubMed


A novel integrated thermophilic submerged aerobic membrane bioreactor (TSAMBR) and electrochemical oxidation (EO) technology was developed for thermomechanical pulping pressate treatment with the aim of system closure. The TSAMBR was able to achieve a chemical oxygen demand (COD) removal efficiency of 88.6 ± 1.9-92.3 ± 0.7% under the organic loading rate of 2.76 ± 0.13-3.98 ± 0.23 kg COD/(m(3) d). An optimal hydraulic retention time (HRT) of 1.1 ± 0.1d was identified for COD removal. Cake formation was identified as the dominant mechanism of membrane fouling. The EO of the TSAMBR permeate was performed using a Ti/SnO(2)-Sb(2)O(5)-IrO(2) electrode. After 6-h EO, a complete decolourization was achieved and the COD removal efficiency was increased to 96.2 ± 1.2-98.2 ± 0.3%. The high-quality effluent produced by the TSAMBR-EO system can be reused as process water for system closure in pulp and paper mill.

7 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: Anionic residues and pitch deposits in whitewater negatively impact the operation of paper-forming equipment. In order to remove these substances, a macroporous resin based on a methyl acrylate matrix was synthesized and coated with chitosan of various molecular weights through glutaraldehyde cross-linking. Pectinase from Bacillus licheniformis and lipase from Thermomyces lanuginosus were immobilized on the resin coated with chitosan by a Schiff base reaction. The highest hydrolysis activities of the immobilized enzymes were achieved by using chitosan with 10×10(5)DaMW for coating and 0.0025% glutaraldehyde for cross-linking chitosan. The cationic demand and pitch deposits in whitewater were reduced by 58% and 74%, respectively, when treating whitewater with immobilized dual-enzymes for 15min at 55°C and pH 7.5. This method is useful for treatment of whitewater in the papermaking industry.
    Bioresource Technology 08/2012; 123:616-9. DOI:10.1016/j.biortech.2012.07.074 · 4.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Effects of wastewater and mixed liquor characteristics on membrane fouling in both a submerged anaerobic membrane bioreactor and a thermophilic submerged aerobic membrane bioreactor were studied with four types of industrial wastewaters. Significant differences in particle size distribution, colloidal content, the protein to polysaccharide ratio, and soluble compounds molecular weight distribution were observed among the four types of wastewaters and mixed liquors. Differences in wastewater and mixed liquor characteristics were correlated to the changes in membrane filtration behavior in both systems. The colloidal content in feed and mixed liquor plays a dominant role and is more important than the quantity of total suspended solids in controlling membrane fouling. The ratio of proteins to polysaccharides is more important than the total quantity of soluble organic substances in controlling membrane fouling. A full characterization of feed and mixed liquor may be used as a tool to predict membrane performance.
    Bioresource Technology 10/2012; 128C:207-214. DOI:10.1016/j.biortech.2012.10.075 · 4.49 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Sludge properties, cake layer structure, and membrane fouling in a membrane bioreactor were studied under various hydraulic retention times (HRT). A decrease in HRT resulted in an increase in extracellular polymeric substance production in bulk sludge and changes in cake layer structure from gel layer to one or two cake layers. Particle size distribution in cake sludge changed with respect to HRT. An evolution in cake layer thickness and porosity was observed with trans-membrane pressure (TMP) jump. The change in cake layer structure might bear more responsibility for the TMP jump than the quantity of cake layer.
    Separation Science and Technology 05/2013; 48(10). DOI:10.1080/01496395.2012.749284 · 1.17 Impact Factor
Show more