Paper industry wastewater treatment by electrocoagulation and aspect of sludge management

Abstract

The paper production process comprises various manufacturing steps and generates an enormous amount of effluent, which consists of a large variety of contaminated chemicals. The higher color and chemical oxygen demand (COD) of the wastewater create a negative effect on all living forms and the natural environment. Electrocoagulation is a versatile process for the elimination of color and COD content from wastewater. In this study, the EC treatment has been used to identify the ideal conditions using several process variables such as pH, current density, time, and the dose of electrolyte. COD and color were reduced by up to 68% and 94%, respectively. Afterward, the treated water was compared with the standards of the world health organization (WHO) and the central pollution control board (CPCB) to find out the suitability of treated water for reuse for farming purposes. Germination tests of mung beans were conducted, and it was observed that the EC treated water is suitable for irrigation. The corrosion rate of mild steel was determined to be 2.85 mils/year, which has shown the short life span of mild steel electrodes. Furthermore, sludge produced by the EC process was analyzed and characterized for physicochemical analyses by using a variety of analytical techniques. The 69.93% iron content of the sludge was also recovered using the acid digestion method. After the physicochemical analyses, it was observed that sludge could also be utilized as a compelling supplement for plant growth, energy recovery, and industrial applications. According to this study, treated water could be a powerful alternative for reducing freshwater consumption in agricultural areas and increasing water availability in water-scarce areas. Effect of operating parameters on electrocoagulation treatment of pulp and paper industry wastewater, treated water and sludge management. • The higher COD and color 68% and 94%, respectively, were removed from wastewater by using EC treatment. • The greater removal of pollutants occurred at a near neutral pH. • It was observed that there was an encouraging improvement in the biodegradability index of wastewater after EC process. • Treated water is found to be suitable for reuse in agriculture. • The produced sludge could be a compelling supplement for plant growth, energy recovery, and industrial applications.