Before online instrumentation, process adjustments to biological activated sludge processes were made based on delayed results from laboratory testing. The introduction of online instrumentation to the process tanks improved the response time and allowed operations staff to make process adjustments based on real-time data. The evolution continued when online instrumentation signals were fed to programmable logic controllers (PLCs) to automate the process adjustments based on real-time feedback. The current state of the practice uses online instrumentation and advanced process control logic to not only optimize the process stability and energy efficiency at the facility, but provide ease of use to the operations staff tasked with supporting the facility.
A well-developed advanced process controller has a backbone that consists of both product and process expertise. Without understanding both the functionality of the products and the needs of the process, the controller will not be able to deliver meaningful and measurable improvements to both energy efficiency and process stability.