Sewage, also called domestic wastewater or municipal wastewater, is a type of wastewater that is released from households after use for various purposes like
washing dishes, laundry, and flushing the toilet.

Untreated sewage may contain a range of chemicals and specialized wastes including nutrients, heavy metals, pharmaceuticals, medical wastes, oils and greases. These result in additional threats to both human health and the environment. Thus, essential treatment is required before sewage is discharged into water bodies, onto soil or for reuse applications.

Compared to traditional physical-chemical treatment, electrolytic processes are much better for screened sewage clarification, disinfection and phosphate removal with the aim of reducing costs and process detention times.

On supplying an external current to an electrolytic cell, oxidation of organic compounds occurs at the anode and reduction of organic compounds occur at the cathode. Direct oxidation takes place by breaking down organics on the anode surface without the participation of other oxidants. Indirect oxidation happens through the mediation of reactive oxidant species (free radicals and superoxides) generated at the anode surface that oxidise the organic compounds.

Electrodes made from ruthenium-oxide coated titanium are active anodes deployed globally for water treatment processes, especially in the tertiary chlorination phase due to their excellent chlorine evolution properties. They are efficient for colour reduction and COD removal.