Electrochemical treatment of livestock waste streams. A review

Abstract

Wastewater from the livestock industries contains high concentration of nutrients, organic pollutants, suspended solids, and pathogenic microorganisms. Discharge of livestock wastewater without proper treatment can therefore cause serious pollution, calling for advanced treatment methods. For instance, electrochemical treatments are gaining attention because they are clean and flexible. Compared to conventional biological treatment methods, electrochemical processes exhibit higher pollutant removal efficiencies within shorter time periods. Here, we review the electrochemical treatment of livestock wastewater with focus on electrocoagulation, electrooxidation, and electro-disinfection. We present factors controlling effective process design and operation. Pollutants removal from livestock wastewater, economic analysis, and scaling-up considerations are also discussed. The oxidation of electrodes during electrocoagulation induces periodical replacement and thus influences the operational cost. Dimensionally stable metal oxide-layered titanium electrodes such as Ti/PbO2, Ti/RuO2, Ti/IrO2, and Ti/IrO2–Ta2O5–Pt are becoming popular due to their stability. Reactor design and operational parameters govern the effectiveness of the treatment process. Further pilot-scale studies are required to scale up and demonstrate the potential of electrochemical livestock wastewater treatment techniques.