Reduction of the environmental impact of a soft drink manufacturing plant.

Abstract

South Africa is a water stressed country with an increasing demand for water. Pressure is being exerted by greater pollution loads and reduced flows in the rivers. Environmental legislation is therefore, becoming more stringent, in order to reduce environmental degradation and promote sustainable development. The soft drink industry in South Africa is a major water user and polluter. The primary objective of this thesis is to reduce the environmental impact of a soft drink factory. The study was conducted at a soft drink company located in the South African province of KwaZulu-Natal. This company had been experiencing trade effluent charges in excess of R 70 000 per month as well as additional fines being levied by the local municipality, due to the effluent being consistently out of specification with respect to Chemical Oxygen Demand (COD) and sugar concentration. The scope of the study has therefore, been defined to focus on the reduction of effluent strength and sugar content, hence reducing the environmental impact. The various concepts or tools to achieve sustainable development were investigated and the Resource Efficient and Cleaner Production (RECP) assessment methodology combined with the methodology to achieve materials efficiency were utilised in order to provide recommendations to solve the effluent issue at the soft drink plant. The RECP procedure follows a five phase approach of planning and organisation, pre-assessment, assessment, feasibility analysis and implementation and continuation. The methodology to achieve materials efficiency uses a 3 step approach of drawing a material flowchart, creating a material balance and generating options. The sources of the effluent were identified and quantified and the factors influencing the quantity and quality of the effluent from these sources investigated. It was found that the primary COD causing component is sucrose. Approximately 11.4% of the identified losses occurred as a result of staff negligence or a lack of staff training, while other losses were due to easily rectifiable technological shortcomings, or were unavoidable. Solutions were developed in the categories of source elimination or reduction and end-of-pipe treatment. End-of-pipe treatment options were only considered if source elimination and reduction techniques could not be implemented. A feasibility analysis from an environmental aspect yielded the optimum solution to be a combination of source elimination and reduction techniques and one of the end-of-pipe treatments. The end-of-pipe treatment entails the transporting of high strength effluent to a nearby co-digestion facility, where energy will be produced in the form of methane. The implementation of this optimum solution has the potential to reduce the COD load of the effluent by 10 583 kg COD/month which is 85% of the identified losses. Various other recommendations were developed to reduce the water consumption and hence decrease the volume of effluent to drain.