Optimization of a Chemical-Pharmaceutical Industry's Wastewater Treatment Plant

The goal of the thesis is to optimize the exploitation costs and parameters of a Chemical-Pharmaceutical Industry's WWTP in Switzerland. After having described the WWTP's scheme and its performance over time, an economical assessment was made. The two major costs components were found to be the excess sludge disposal and the energy consumed by the air compressors in the biological basins: the rest of the thesis focuses on trying to reduce these costs. First, a feasibility study, a lab test and a pilot test were done on a decanter in order to evaluate the economical advantage that a dehydration treatment step could have. It was found that the investment would have a PBP of one year and it could reduce the annual costs by 200 000 CHF/y. Second, to calculate the theoretical air flow demand of the compressors, the activated sludge treatment was designed. Respirometric OUR tests were performed on the WWTP's sludge to find the microorganism growth Y and the maximum substrate utilization rate k. The biological treatment static design showed that one of the three biological basins could be bypassed while still having the desired effluent quality. In conclusion, the industrial WWTP was analysed in detail in order to find solutions for the optimization of the plant's performance and exploitation costs.