Practical experiences with reducing industrial use of water and chemicals in the galvanising industry

Abstract

While ‘Soft’ factors, like employee training, experience and work instructions can significantly reduce the consumption of water and chemicals by galvanising companies, further significant improvements can be achieved by technical measures. This article demonstrates that the reduction of water and chemicals use can yield significant financial benefits to a company, without compromising product quality or productivity.

Based on the results of a benchmarking survey, a systematic optimisation approach was developed to identify all options that help to minimise water consumption and the use of chemicals, and therefore also sludge generation, while at the same time saving the companies money.

Five case studies identified and implemented measures, including changing the rinsing technology in three pickling plants at the wire producer Joh. Pengg GmbH, the use of spent caustic for neutralisation and an electrolysis plant for copper recovery at the printed circuit board manufacturer AT&S, changing the rinsing technology in the production of printing cylinders by Rotoform and a reorganisation of acid management at the Mosdorfer hot-dip zincing plant.

All these measures generally reduced wastewater generation by at least 40 % and the amounts of spent process chemicals that have to be treated by half. All measures paid back according to the financial investment standards used by the companies. The paper also discusses the optimal diffusion of this knowledge.