PRE-TREATMENT, SURFACE PREPARATION, DEGREASING & CLEANING Plastratum provides complete control and substantial operational cost savings

Pretreatment of parts requires quality rinse water to provide a quality product, whether used in the make-up of the pretreatment chemistry or the rinsing of the parts following chemical treatment.

Plastratum has recently supplied water and effluent treatment plant to a company that has a large roof area and low mains water pressure. Plastratum chemical engineers designed, manufactured, installed and commissioned a rainwater harvesting system which saved the customer incoming water costs and provided consistent water pressure to the new metal finishing facility. This fed into the new fully automatic alkali non cyanide zinc plating plant also supplied by Plastratum, with rinse water recirculation systems and an effluent treatment plant. This technology saved the customer even more realisable operational costs.

The harvested rainwater was filtered and exposed to UV radiation to prevent biological contamination of the ion exchange filters. The water was treated using separate, duty/ standby cation and anion exchange resins, to produce deionised water at a conductivity of <20µScm-1. This provided excellent rinse water quality and allowed for rinse water recirculation and reprocessing of the water through the ion exchange equipment, which reduced the discharge volume by approximately 80%.

As required, the ion exchange filters were regenerated using small amounts of acid and alkali chemicals, with the standby ion exchange unit automatically complimenting the operational role to ensure no loss of rinse water supply. The regenerant waste was then treated using a small total loss system to comply with the local parameters suitable for discharge to foul sewer. This provided the benefit of complete control and substantial operational cost savings over the rinse water and effluent treatment processes.