Evaluation of primary and secondary treatment of distillery wastewaters
Thesis (MScEng (Process Engineering))--University of Stellenbosch, 2005.
The thesis reports the investigation of various distillery processes and wastewater streams. The aim was to evaluate the processes and thereafter design interventions for improved wastewater treatment at the respective distilleries. An integrated environmental approach was adopted based on the principle that prevention of pollution is the preferred option and end-of-pipe treatment the least favoured option. As such, feed material to the processes was studied to determine whether some of the components that are not required in the distillation process could in fact be removed prior to entering the system. The results indicate that organic constituents such as phenol and tartaric acid could be removed using physico-chemical and biological treatment methods. The treatment of effluent was studied using an Upflow Anaerobic Sludge Blanket (UASB) set-up to determine the reduction in Chemical Oxygen Demand (COD) in the wastewater. Thereafter the UASB treated effluent was exposed to aeration for further treatment. Summary of conclusions • Pretreatment of wine feed material with calcium hydroxide is effective in removal of 98% tartaric acid, 30% COD and a total phenol content of 57%. • Bio-augmentation results showed that the soil inoculum was the most effective treatment method with reductions of 61% COD at a temperature of 30°C, tartaric acid removal of 98% at the same temperature and 25% reduction in total phenol at 26°C. • UASB was effective with soil inoculum and removed approximately 90% of COD although operational problems were experienced and hindered the operation of the plant. • Aeration of UASB effluent further reduced the COD by a further 60% with a total COD reduction of 96% after both UASB and aeration treatment. • Effective reduction of total phosphorus by 70% and the total phenol content by 80% was achieved by UASB treatment followed by aeration.