Wastewater electrolysis part 2 – Pilot reactor study for resource efficient applications in metal industry

Abstract

Electrochemical precipitation with rotating electrodes is investigated by a two-chamber pilot reactor. While deposits from disk surface of rotating electrodes are commonly removed by wipes this pilot reactor comprises of cathodic disks with newly developed composite materials for mitigation of deposits. The cathodic and anodic chamber were used for precipitation and neutralization reactions, respectively. Original wastewater samples with a total volume of 25 m³ were treated to remove the heavy metals Mn²⁺, Ni²⁺, Zn²⁺ as hydroxides below 0.5 mgMe²⁺/L. The coupling of precipitation and neutralization with same wastewater in one system was demonstrated without addition of chemicals such as acid, base, precipitation and flocculation chemicals thus demonstrating a resource efficient treatment option for wastewater of the metal industry. The complete removal of heavy metals was ensured by proper control of pH through adjustment of power input into the electrolysis system independently of wastewater input composition.