Four different quality drainages were treated and detailed results tabulated. Appropriate unit operations, from water collection to sludge disposal were considered for eight different reagents (calcium/magnesium carbonate, oxide and hydroxide; caustic soda and soda ash). Necessary process variations were possible with a versatile 500,000 gpd facility. Limestone has the least cost per neutralization equivalent and may be used with drainage containing up to 500 mg/l iron II. The resulting sludge is dense, rapid settling and dewaterable. Thickeners are preferred to settling lagoons to separate sludge in larger plants. Dewatered sludge requires least disposal volume.