Tertiary treatment of pulp and paper mill wastewater by iron–carbon micro-electrolysis coupled with h2 o2

Abstract

The conventional biological treatment of pulp and paper mill wastewater may not be enough to satisfy the discharge limits, more effective processes such as advanced oxidation technologies may be used as advanced treatments for the removal of color and refractory contaminants. In this study, biologically treated effluent from pulp and paper mill (BTEPM) has been examined by iron–carbon micro-electrolysis coupled with H2 O2 (ICME-H2 O2 ). Under the optimal treatment conditions (Fe/C = 1:2.5, pH = 2.5, 100 min reaction, 9 mmol/L H2 O2 added in three aliquots), the chemical oxygen demand (COD) removal efficiency attained 81% which is much more efficient than ICME without H2 O2 under its optimal experimental conditions (42%). In addition, the initial biodegradability of BTEPM, as shown by BOD5 /COD ratio, can be enhanced after treatment. The morphology and content of iron and the evolution of H2 O2 content in the system under the optimal operating parameters were studied.