Finding a solution for settled sludge in Mirabel, Quebec's wastewater treatment plant

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The City of Mirabel, Quebec, Canada, was created in 1971 from the merger of 14 municipalities and is home to over 59,000 citizens. The city is constantly growing due to the many opportunities available, so it is important that all the city's utilities, such as a wastewater treatment plant, are always up and running. 

What did they need?

In the wastewater treatment process, the primary clarifier is designed to dispose of floatable solids from the surface by skimmers, while allowing the heavier and settleable solids to form a layer of sludge at the bottom of the clarifier. This sludge is then collected by a rake and pumped out to a sludge thickener tank. 

To operate the pumps, the operators would use a sludge judge sampler to manually measure the level of sludge in the clarifier. Since the sludge was being measured manually, it was difficult to know when to stop pumping the sludge due to variables such as the insertion angle, timing, and experience level of the person verifying the level. When pumping too much, excess water goes to the sludge tanks and affects the subsequent dewatering process, which increases operational cost and energy consumption. When pumping too little, the mud accumulates and gets too thick to be pumped. This causes an increase in maintenance costs and reduces the efficiency of the primary clarifier.  

Finding the right interface measurement solution

To ensure the safety and well-being of the Mirabel team, a non-contacting solution would be ideal. The team reached out to Pulsar Measurement to find out about the Sludge Finder 2 and Viper transducers to see if they could help improve and alleviate the frequent monitoring of their clarifier.  

Why the Sludge Finder 2 and Viper Transducers?

Pulsar Measurements Sludge Finder 2 provides reliable and continuous sludge blanket level measurement that requires no maintenance. The meter features a microprocessor and multifunction display that shows the blanket level, complete echo profile, alarm points, tank depth, and multiple tank's statuses. With six programable relays, it can automate the process as the Sludge Finder relays can be set on and off at different set points to activate alarms or to start the pumps to efficiently remove the sludge.  

The Viper transducer has a measurement range of 300 mm to 10 m (11.8 in to 32.8 ft). To measure the sludge blanket, the Viper is immersed just below the liquid surface of the tank and has a 6-degree beam angle with sophisticated echo processing algorithms to ensure that the Sludge Finder 2 can accurately operate in difficult tanks and rotating equipment with ease. 

Success with an ultrasonic measurement solution for wastewater treatment

After the 30-day trial with the Sludge Finder 2 and Viper Transducer, it was proven that this was the right solution for the application as it allows for the optimization of the activated sludge wastewater treatment and dehydration plant. After a successful installation by PR’eautech, Pulsar Measurement partners in Quebec, Gabriel Claveau, Environmental Technical Operator at the City of Maribel said, “I liked the approach, the support, and especially what the probe gives me in optimizing my wastewater treatment”.