Pulp Mill Effluent Treatment Using Plasma Obtained by High Voltage Electrolysis

Abstract

Effluents from pulp mills have a high organic load and can still contain high organic bio-recalcitrant material that is harmful to the aquatic environment, even after undergoing biological treatment in effluent treatment plants. This study presents a novel treatment method tested on effluents (prior to and after biotreatment) from a Brazilian kraft pulp mill, based on hydroxyl radical production and hydrogen peroxide obtained by plasma generated by high-voltage electrolysis. These species present significant oxidation potential that could enable the complete breakdown of the organic matter. From the application of plasma to treat pulp mill effluent for a 7-hour period, it was obtained a chemical oxygen demand (COD) removal between 88.2 and 99.7%, total organic carbon (TOC) removal of 90.3 to 95.6%, and a color removal of 95.0 to 98.0%. The final pH of the treated effluent was 11.6 to 11.9. The results obtained in this study showed that the high-tension plasma treatment, applied on effluent from kraft pulp mills before and after biological treatment, can be an attractive alternative.