No abstract

An investigation into aerobic biological wastewater treatment was conducted over the temperature range 25–75°C in a semi‐batch bioreactor using waste metalworking fluids (MWFs) generated from Liverpool John Moores University's engineering workshop. The best treatment performance in terms of chemical oxygen demand (COD) removal occurred at 50°C (97.27%), with an operational time of 77.5 h. Cell viability was observed throughout the operation and it was found that higher temperature did not directly correlate to low viability. Effluent turbidity reduced considerably from 35 to 50°C and increased thereafter. Even when the system encountered alkaline shock, the overall performance was not affected, thus indicating how stable the system was. The results of this study indicate that an existing industrial‐activated sludge plant could be used to treat waste MWFs under thermophilic conditions. The COD reduction was significant but further investigation into biodegradation of recalcitrant compounds is needed to achieve optimum performance.