The most important factor in treating industrial wastewater with Reverse Osmosis (RO) is the pretreatment that protects the membrane against organic fouling, mineral scaling and chemical degradation. Before reverse osmosis should be considered, a complete cation/anion balance is required and potential foulants must be identified. High BOD and COD levels can also contribute to membrane fouling. A wide range of pretreatment technologies is available.

The effluent discharged to the sewer typically contains between 200 to 10,000 parts per million (ppm) total dissolved solids (TDS). With the proper pretreatment technology followed by RO, this water can be recycled.

Ion exchange treatment of the RO product water can further polish the water and make it suitable for all rinses. To design a successful and cost-effective system, Siemens Water Technologies evaluates each individual application because the pH, oxidizing potential and concentration of soluble salts of the wastewater effluents often exceed the operating limits of the RO systems. After the detailed evaluation of the wastewater is complete, Siemens determines the optimum preconditioning chemistry and selects the best pretreatment technology for the application.

Applications include treatment and recycle of wastewaters generated from metal finishing and plating operations; printed circuit board and semiconductor manufacturing (treatment and recycle of rinsewaters used in electroplating processes); automotive manufacturing (treatment and recycle of water used for cleaning and painting); food and beverage (concentration of wastewater for reuse and reduction of BOD prior to discharge); groundwater and landfill leachate (removal of salts and heavy metals prior to discharge).