The primary cost associated with nitrified effluent from a conventional activated sludge plant is indeed due to the blower electrical cost. Nitrification is a biological process that converts ammonia into nitrate, which requires the presence of aerobic microorganisms. To ensure that these microorganisms thrive and efficiently carry out the nitrification process, adequate aeration is necessary.
The blowers' role is crucial, as they introduce air into the aeration tanks, thus providing the oxygen needed for the aerobic bacteria. This oxygen consumption can lead to a substantial increase in energy usage, as blowers operate continuously to maintain the appropriate oxygen levels. As a result, the electrical costs associated with running the blowers can be significant when the treatment process requires a heightened oxygen demand due to nitrification.
While other options could incur costs, none compare to the continuous and energy-intensive requirement of blowers in a process where oxygen supply is critical for effectively treating the wastewater and achieving the desired nitrification outcome.