Control Units for Sewage Treatment Plants & Greywater Recycling

Decentralized Sewage Treatment Plants can be of different types. The most common ones are: Continuous Flow Systems, such as MBBR, fixed bed, and SAF, and Sequential Batch Reactors (SBR). Each category requires a distinct approach to process control, which is reflected in the logic of the Control Unit.

SBR systems operate in a sequential manner, meaning the control logic is structured into clearly defined steps. Each phase of the treatment process—such as filling, aeration, settling, and decanting—is programmed as a separate function function, and runs sequentially one after another. In contrast, Continuous Systems rely on parallel operations, where each component—such as blowers, pumps, and valves—is managed independently through dedicated timers. 

For example, the blower and valve operations are each governed by their own timing cycles, but may also be interlinked (e.g., valve activation triggering blower operation). Synchronization with the Real Time Clock (RTC) is also common in these systems to enhance energy efficiency.

BONNEL has developed a range of Control Units tailored to both types of logic. Some Units are specialized for SBR systems, others for Continuous Flow Systems, and several are designed to accommodate both, offering flexible and efficient solutions for various plant configurations. This flexibility allows using certain Controllers also for Greywater Recycling Systems.