Manufacturing of coated steel products generates a significant amount of waste in the form of metallic, non-metallic scraps, used oil, solvents, and other hazardous wastes/byproducts. Of the various categories of waste, handling, and management of hazardous waste (in the form of sludge, used solvents, and/or oil) is most challenging for manufacturing plants due to concerns related to its storage, transportation, treatment, or disposal activities.
Hazardous wastes generated include but are not limited to zinc byproducts, waste oil from plants, and sludge (phosphate sludge, sludge from effluent treatment, and chemical sludge from wastewater treatment). Of these, phosphate sludge is the most hazardous waste. Its storage and disposal are carried out according to guidelines of country-specific regulations & currently it is landfilled in many countries. Opportunities are sought for sustainable reuse and recycling of hazardous phosphate sludge which can help prevent storage and/or landfill.