73-09: Sewage Plant Effluent as Cooling Tower Makeup -- A Case HistoryTreated municipal sewage has been a source of industrial water for more than 25 years. It was first used for one through cooling and quenching sprays in a steel mill. Initial attempts to use it as cooling tower makeup ere retarded by serious operating problems caused by excessive growth of bacterial slimes, development of calcium phosphate deposits, and formation of horrendous amounts of foam until it was found that these troubles could be minimized