There are a number of control strategies in wastewater applications that vary in complexity. Having better control and automation in wastewater treatment plants allows the maintenance of standards as well as cost reduction. Take a look below at a few different control strategy methods.
Manual
This is the traditional method for wastewater process control. Manual changes and adjustments are made to maintain parameters in their desired ranges, such as dissolved oxygen. Manual testing was also done to take biochemical oxygen demand measurements (BOD) and total suspended solids (TSS). This process is fine and is able to meet industry standards but was not designed to be an optimized process.
Automatic
There are a few different automatic processes available now thanks to technological advances. There are multiple different levels of automation that can be applied.
Open-Loop Control
An open-loop control using a timer is the simplest form of automation processes. The most common implementation of open-loop control is used with the operation of blowers, mixers and pumps. An operator can make observations of manual adjustments on the process and take manual samplings and measurements to optimize this process.
Feedback Control
This is the next level of automatic control that is implemented in SCADA and uses online measurements. Any changes in wastewater characteristics causes a disturbance in the process, and this causes a response that can be measured and reported to the controller. The controller will then react to eliminate the difference between the measurement and desired setpoint by sending a signal to an actuator.
The most inexpensive option of feedback control is on/off control. This process is controlled by simple relays that start and stop equipment in response to a disturbance.
Feed Forward Control
Feed forward control consists of measuring a disturbance and calculating the required response. A common use of this strategy is an extension of cascade control for feedback control.
Regardless of your wastewater control needs, Taber Solids Control can help you with any instrumentation for the field, laboratory and any continuous online process control instrumentation. Contact us today for more information!