Effect of temperature on the growth of wastewater bacteria

The wastewater bacterial growth was investigated at different temperatures (20, 40, 60 and 80°C), and the effect of crude oil and surfactant on the bacterial growth was tested. It was concluded that bacteria would grow rapidly in an aerated environment and temperatures in the range of 20 to 40°C. The maximum number of bacteria was observed at 20°C in a shaker. Shaking or stirring supplies oxygen to the wastewater bacteria, and expedites the growth rate. As temperature is increased to 60 and 80°C, bacteria die off because enzymes are denatured and cannot perform metabolic processes outside the cell. The presence of oil increases the bacterial growth in the mixed system, therefore, the wastewater bacteria can be employed to biodegrade petroleum hydrocarbons. The presence of surfactant also increases bacterial growth at 20 and 40°C, but has adverse impact at 60 and 80°C. Microorganisms suitable for petroleum hydrocarbons have significant applicability to Microbial Enhanced Oil Recovery (MEOR) as well as the biodegradation of crude oils.