IMPLEMENTING A ZERO EFFLUENT PHILOSOPHY AT A CANE SUGAR FACTORY

Towards the end of 1998, capital was approved to implement zero effluent technology at Maidstone Mill, South Africa. In order to minimise the risks associated with the technology, the project was split into 2 phases. The first phase involved containment and recycle of spillages, the minimisation of external water supplied to the factory and the re-processing of factory effluent. The primary aim of phase 1 was to achieve the situation where all surplus water leaves the factory as cooled condensate. Phase 2 of zero effluent includes, inter alia, the physical removal of COD from the cooled condensate to meet general discharge standards. This paper discusses the design, implementation and performance of phase 1 of the zero effluent, which was cokpleted during 1999. The performance of the zero effluent system at Maidstone, provides clear evidence that zero effluent is in fact achievable at a cane sugar mill over a range of normal operating conditions, including maintenance shutdowns. Over and above the environmental benefits, zero effluent is shown to have real commercial and operational benefits,