278248 Performance of a Continuous Reactor for Electrochemical Treatment of Pulp Mill Wastewater

Wednesday, October 31, 2012: 9:25 AM
331 (Convention Center )
Indra Mani Mishra1, S Mahesh2, Basheshwar Prasad3 and I. D. Mall3, (1)Department of Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee, India, (2)Environmental Engineering, S.J. College of Engineering, Mysore, Mysore, India, (3)Chemical Engineering, Indian Institute of Technology Roorkee, Roorkee, India

The present paper reports the performance characteristics of a continuous electrochemical reactor (ECR) for the treatment of black liquor (BL) discharged from an agri-based pulp and paper mill. The ECR had a working volume of 2 dm3 and used six iron electrode plates with an active electrode area per unit volume of 54 m2 m-3. The ECR operated at an optimal galvanostatic state at a current density of 55.56 Am-2 with a corresponding cell voltage of ~ 3.1V at near neutral pH without any additives. The residence time (t) in the range of 2-4 h favors the degradation of chemical oxygen demand (COD), color and turbidity. A COD removal of 78.2 and 82.15% was achieved at flow rates of 1 and 0.5 dm3 h-1, respectively, with a corresponding color removal of ~90 and 79%. The ECR showed good performance at flow rate spikes from 0.5®1®2 dm3h-1 and 1®2 dm3h-1 with ~79 and ~73 % COD removal, respectively. The specific energy consumption (SEC) decreased in a narrow range from 16.3 to 14.3 kWh kg-1 of COD removed for t varying from 4 to1 h. For a charge of 0.625 Ahdm-3, the current efficiency (CE) values of 310 and 274% were obtained for t = 2 and 1 h, respectively. Batch and continuous study results compared well at t = 2 and 1 h. The ECT showed deterioration in the COD removal efficiency on long time runs with the anode plates swarmed with micro flocs which necessitate their removal.

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