Experience in using a pilot plant for the treatment and reuse of laundries wastewater: electroflotocoagulation and adsorption

Abstract

The article considers the issues of purification and reuse of wastewater from industrial laundries by the electroflotocoagulation method, followed by additional purification on active charcoal. For this purpose, the dependence of the degree of wastewater treatment on the surface-active substances, color, and turbidity has been investigated. Treatment time, pH and current density have been selected as variable parameters. Along with this, the issue of heat recovery and its use for heating purified water when it comes to reuse have been studied. The study was carried out using a pilot plant with a volume of 500 L, consisting of two modules. The first module is associated with the transfer of heat from the wastewater through the heat exchanger to purified water for reuse. The second module is associated with combined wastewater treatment. 75-85% of the removal of the contaminants is achieved in the pH range of 4.0-5.5 and a wastewater treatment time of 11 min that is associated with the optimal amount of aluminum ions generation in the reactor. The dependency between the efficiency of removing pollutants and current density showed that at the 80 A/m(2), 80% of synthetic surfactants and color, so as 85% of turbidity are being removed. A deeper post-treatment of water in the adsorption column following the electroflotocoagulation reactor made it possible to achieve removal of synthetic surfactants and color up to 95%, and turbidity up to 97%. The percentage of energy savings was about 50%.