The SENTRY platform was featured in the January 2020 edition of Treatment Plant Operator as a validated tool for the Three Rivers wastewater treatment plant in Prince Edward Island, Canada.
The treatment facility had been experiencing some biological imbalance issues at the facility and suspected the arrival of two new micro-breweries in the town may have been impacting the plant. The sensors were installed at 3 distinct locations at the facility (influent, aerobic digester and effluent). These locations allowed the operators at the plant to see the exact moments organic conditions entering the plant were changing ans also provided operators an ability to track this impact through the facillity.
Some great feedback from the on-site operations team included:
System Installation and Maintenance:
"Island Water Technologies installed everything in less than two days. If there is a problem with the control panel or sensors, they repair it,” MacLeod says. “Except for checking that nothing has caught on the influent sensor, the system is maintenance-free, and the technology is great.”
Data and identifying events:
“Data is presented with options to view on hourly, daily, weekly, monthly or customized intervals. Spotting changes in the normal pattern is easy, and when those spikes are consistent, it’s time to investigate.”
Identifying brewery discharge events:
At first the plant team tested CBOD every second Wednesday, and the results were always less than 10 mg/L. Then the sensor data showed huge spikes on Thursdays, indicating a biological feeding frenzy. Testing on Thursdays revealed 240,000 mg/L BOD in the waste stream. “We traced it to one brewery dumping trub — sediment including hops debris, spent yeast or yeast slurry,” MacLeod says. “Our provincial discharge limit is 300 mg/L BOD.”
Impact of rain events on wastewater treatment plant performance:
“We always saw the result of inflow and infiltration when it rained, but we didn’t have a clue how much it took to affect the plant,” he says. “Now we have an advantage. If heavy rains are forecast, there is a nine-hour delay before the water arrives. If the solids are high in the clarifier, we have time to waste enough to reduce the risk of a hydraulic overflow.”