Solid Pollutants and Solid Pollution...

Solid Pollutants and Solid Pollution Solid Pollutants are more popularly known as solid wastes. The types and quantity of solid pollutants generated in iron and steel industry differ from plant to plant. Thus, a steel plant based on direct reduced iron – electric furnace (electric arc furnace or induction furnace) route generates different types and quantities of solid wastes than the integrated steel plant based on the blast furnace – basic oxygen furnace route. The solid wastes generated in iron and steel industry can be broadly categorized as (i) process solid wastes, and (ii) non-process solid wastes. Examples of process solid wastes are slag, dust, sludge, scrap, refractories, scale, muck, and debris etc. Examples of non-process waste materials are rubber, packing materials, electric wires, plastics and glass, and office and canteen wastes, etc.  Solid waste materials are usually generated in mixed condition which means that during generation, one solid waste material gets contaminated with other waste material. These waste materials are to be segregated for their recycling and reuse.  There are two types of waste streams which generates solid wastes. One stream is related to the production process, which also includes the waste from laboratories and sludge from effluent treatment plants. The second solid waste stream is due to the maintenance of offices and canteens.   The type and quantity of solid wastes’ generation depends on production process and the production technology employed. The quantity of solid waste generation is mainly dependent on two factors namely (i) the size of production unit, and (ii) efficiency of the technology. The solid wastes generated of iron and steel industry are of two types, i.e., ferruginous wastes and non-ferruginous wastes (Fig 1). The major ferruginous wastes are iron bearing wastes and consist of iron bearing dust and fines,...