ABSTRACT
A Case History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1205 28.6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1210 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1210
Metal industries use substantial quantities of water in processes such as metal nishing and galvanized pipe manufacturing in order to produce corrosion-resistant products. Ef uent wastewaters
be treated, such as detergents, oil, and grease. These ef uents may cause interference with bio logical treatment processes at sewage treatment plants. In the case when the ef uents are to be discharged directly to a watercourse, treatment requirements will be more stringent and costly.1-8
Laser cutting, welding, and hot working leave a discolored oxidized layer or scale on the surface of the worked steel. This must be removed in order to perform many of the surface nishing processes. The acid pickling process is used to remove the oxide or scale of metals and corrosion products, in which acids or acid mixtures are used.
