Australian Country Spinners Pty Ltd (ACS), one of Australia's largest yarn manufacturers, is located at Wangaratta in rural Victoria. It produces in excess of 2,500 tonnes of finished yarn annually, with exports to New Zealand, Japan, USA and Korea.
The company's manufacturing focus is principally directed towards fine quality wools, but other fibres are also processed.
The wool dyeing industry is a large user of water, and traditionally up to one million litres of water was used daily by ACS. Each kilogram of finished yarn required 250 litres of water and three kilograms of chemicals.
Twenty different in-plant waste streams contributed to total effluent outfall from the ACS site, however, over half of the wastewater stream was generated from fibre rinsing operations. The effluent characteristics of greatest significance were total dissolved solids (TDS), biological oxygen demand (BOD), chemical oxygen demand (COD), colour and toxicity. This effluent was discharged to the local waterway after treatment at a common treatment plant.
Cleaner Production Initiatives
ACS commenced their cleaner production program in 1992 with a waste audit and preparation of a waste management plan (WMP). The audit measured all the waste streams, established mass balances across processes, identified potential areas for change and improvement and also opportunities for reductions in effluent volume. The findings from the audit provided the input for the development of the WMP. ACS established a team that was empowered to make changes to site operations and processes in order to implement the WMP objectives and cleaner production initiatives. Support was provided by top management for the involvement of the total workforce, including the provision of regular briefings to employees on cleaner production changes.
The company identified that approximately 90 per cent of its effluent was relatively clean. By segregating the waste streams ACS was able to recycle the clean waste water streams within the plant. ACS was also able to halve the use of sulphur based products, introduce alternative surfactants and set realistic targets for levels of TDS, BOD, COD, colour and toxicity. As a result of these initiatives, water usage has been reduced from 250 litres per kilogram of yarn to 130 litres.
ACS also introduced low temperature dyeing technology and carried out research and development work in dye bath recycling to the pilot plant stage, in conjunction with the CSIRO Division of Polymers and Chemistry. The result was that annual chemical and dye costs per kilogram of product did not change between 1992 and 1996, even though the company introduced some higher cost dyes. The company also absorbed some increases in raw material costs.