Anaerobic-Aerobic Treatment of Toxic Pulping Black Liquor with Upfront Effluent Recirculation

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概要

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• Alkaline pulping liquors are problematic for anaerobic treatment due to their toxicity to methanogens and their relatively large fraction of inert lignin. In previous research, toxicity due to wood extractives was shown to be highly eliminated during aerobic wastewater treatment, but not during anaerobic treatment. These observations have led to the proposal of a detoxification strategy denominated upfront dilution, based on the sequenced anaerobic-aerobic treatment of the pulping liquor, recirculating the aerobic effluent to dilute the incoming influent to sub-toxic concentrations. In this study, the treatment of highly toxic hemp stem wood black liquor(HSWBL)in lab-scale UASB reactors with upfront dilution was compared with direct anaerobic treatment and with direct aerobic treatment. Direct anaerobic treatment of 12 g COD/lHSWBL led to almost complete inhibition of the methanogenic activity within 14 d. However, recirculation of 75% of the aerobic post-treatment effluent for upfront dilution of the toxic HSWBL, enabled anaerobic treatment at loading rates up to 21.5 g COD/l_<UASB>・d without significant inhibition of the methanogenic activity. Extensive detoxification was confirmed during anaerobic-aerobic treatment of 20 g COD/lHSWBL recirculating 86% of the aerobic effluent. COD and BOD removal was 72% and 97%, respectively, after anaerobic-aerobic treatment at an overall loading rate of 3.6 g COD/l・d, while 30-35% of the incoming COD was recovered as methane. Batch-assays demonstrated significant detoxification after anaerobic-aerobic treatment of HSWBL. Treatment efficiencies and detoxification during anaerobic-aerobic and aerobic treatment were similar. However, the anaerobic-aerobic treatment system provided 50% lower surplus sludge production, production of 0.16 m^3 methane/kg COD_<removed> as an energy source, less nutrient dosage and substantial reeductions in aeration costs. During anaerobic-aerobic treatment as well as aerobic treatment significant lignin removal was obtained, ranging from 28-58%. Lignin removal could be attributed to biodegradation of low molecular weight lignin(MW<2.2kD). The lignin which survived biological treatment was extensively polymerized to MW of>34kD.

• 1998-07-25

著者

• Lettinga Gatze

  Department Of Environmental Technology Wageningen Agricultural University

• Yan-ling He

  Department Of Pulp And Paper Engineering Northwest Institute Of Light Industry

• KORTEKAAS SJON

  Department of Environmental Technology, Wageningen Agricultural University

• VIDAL GLADYS

  Department of Chemical Engineering, University de la Frontera

• FIELD JIM

  Department of Environmental Technology, Wageningen Agricultural University

• Field Jim

  Department Of Environmental Technology Wageningen Agricultural University

• Vidal Gladys

  Department Of Chemical Engineering University De La Frontera

• Kortekaas Sjon

  Department Of Environmental Technology Wageningen Agricultural University

• Lettinga Gatze

  Deparment Of Environmental Technology Wageningen Agricultural University

関連論文

• Anaerobic-Aerobic Treatment of Toxic Pulping Black Liquor with Upfront Effluent Recirculation
• High-Rate Anaerobic Treatment of Wastewater under Psychrophilic Conditions
• Effect of Cobalt on the Anaerobic Degradation of Methanol
• Treatment of Low Strength Soluble Wastewaters in UASB Reactors
• Contribution of Extractives to Methanogenic Toxicity of Hemp Black Liquor
• The Continuous Anaerobic Treatment of Pulping Wastewaters
• Thermo-Tolerant Anaerobic Degradation of Volatile Fatty Acids by Digested Organic Fraction of Municipal Solid Waste
• Measurement of Low Molecular Weight Tannins : Indicators of Methanogenic Toxic Tannins

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