Pilot Treatment of OCC-based Paper Mill Wastewater Using Pulsed Electrocoagulation

Abstract

There is an increasing trend towards the closure of white water recirculation loops in papermaking, often leading to need for system modification. A pilot-scale study was conducted using pulsed electrocoagulation technology to treat the wastewater of an old corrugated containerboard (OCC)-based paper mill, to evaluate its treatment performance. The operating variables were: a current density of 0 to 240 A/m2, a hydraulic retention time of 8 to 16 min and a coagulant (anionic polyacrylamide) dosage of 0 to 30 mg/L. The water quality indicators investigated were electrical conductivity, suspended solids (SS) and chemical oxygen demand (COD). The results obtained during the pilot-scale studies were favourable. Under the operating conditions without coagulant addition, the highest removals for conductivity, SS and COD were 47.7%, 99.3% and 75%, respectively. The use of coagulant remarkably enhanced the removal of both conductivity and COD. Using a coagulant dosage of 30 mg/L, the highest removal rates achieved for the three water quality indicators were 54.5%, 99.6% and 92.7%, respectively. These water quality levels are adequate to allow for the reuse of at least a part of the treated wastewater as makeup process water in papermaking.

Treatment of Pulp Mill D‐Stage Bleaching Effluent Using a Pilot‐Scale Electrocoagulation System

“…Thus, during treatment in the reactor, the reduction in conductivity of the wastewater was the result of charge neutralization of ionic species contained in it. Charge neutralization de-charges ionic species causing them to become insoluble substances, which are removed through induced micro-aggregation and coagulated macro-aggregation (floc formation) (Butler et al, 2011;Martinez-Huitle and Brillas, 2009;Perng et al, 2007a).…”

“…Bejankiwar (2002) applied an electrocoagulation unit fitted with iron electrodes to treat effluent from a cigarette paper mill; at a current of 3.5 A and an electrolysis time of 5 hours, the removal of COD and BOD was 56 and 84%, respectively. Perng et al (2007a;2007b;) used a pilot-scale pulsed electrocoagulation system to treat old corrugated containerboard (OCC) and specialty paper mill effluents that effectively reduced the electrical conductivity, suspended solids (SS), COD, and true color of the effluents. In addition, Perng et al (2008) developed a laboratory electrooxidation process to treat an OCC mill effluent.…”

“…Effects of the operating parameters (i.e., electrode material, current density, and hydraulic retention time [HRT] of the system), and water quality indicators, including electrical conductivity, SS, COD, true color, and hardness of the treated wastewater were investigated. This study is one in a series of pulp and paper industrial effluent treatments using pulsed electrocoagulation technology (Perng et al, 2007a;2007b;). Because elemental chlorine-free pulp bleaching is becoming a prominent sector of the pulp-bleaching scene, effective treatment of the D-stage effluent for reuse entails industrially important and useful information.…”

Augmentation of biodegradability of pulp and paper industry wastewater by electrochemical pre-treatment and optimization by RSM

“…Electrochemical coagulation of pulp and paper effluent has been reported by five researchers [1,[24][25][26][27]. All the researchers supported the technical feasibility of the process.…”

“…Combining Eq. (25)(26)(27) the expression for the rate of substrate utilization can be written as follows:…”