Reliability

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“Bulletproof” reliability of the SRT system is a unique feature of SRTmaster^TM. A simple philosophy behind the SRTmaster^TM design is that all hardware will malfunction one day and your activated sludge system should not suffer because of it.

SRTmaster^TM continuously monitors the “health” of all hardware elements of the SRT control system. As soon as SRTmaster^TM suspects a potential problem, it informs an operator. SRTmaster^TM has the ability to distinguish between a major hardware problem and a minor one. Major hardware problems include catastrophic failure of TSS meters as well as suspicious readings of TSS. In the case of major problems, SRTmaster^TM not only notifies operators about the problems, but also changes the control algorithm so that the faulty readings are not used in the waste flow calculations. As soon as the problems are fixed, SRTmaster^TM automatically switches the algorithm to the original one.

Due to special software precautions, a control output signal generated by SRTmaster^TM will not cause drastic changes of waste flow even in the case of failure of control hardware (PC or embedded controller). In addition SRTmaster notifies operators about problems related to malfunction of waste flow meter or waste flow PID controller that usually are not part of our system.

Sludge wasting affects not only an activated sludge but also a sludge thickening process. To provide reliable and effective operation of a sludge thickening facility SRTmaster limits ranges of waste flow and waste mass variations to satisfy thickening facility requirements.

SRTmaster also serves as an expert system that helps to detect some of process related problems. For example, it informs operators of significant changes in biomass under aeration or changes in wasting pattern. It also informs operators when mixed liquor suspended solids concentration is outside of a desirable range.

Cordell Samuels, a shift control officer at the Toronto Main treatment plant, wrote about our automatic SRT control technology in his paper published in Water Environment and Technology:

“The control was robust. During the testing period, there were no occasions of a faulty signal being generated by the controller. On several occasions, RAS flow to the sampling sink was interrupted, and, as a result, the RASSS meters produced invalid readings.
The control system automatically detected problems with RASSS readings and not only initiated alarms but changed the control algorithm to disregard the faulty readings. Once conditions returned to normal, the controller automatically changed the control algorithm back to the one used prior to the encountered problems.”