Anglian Water has halved aerator energy costs at the Swallow unmanned therapy functions in Lincolnshire by installing an ABB variable -pace drive.
Working this way, there were frequent stops and starts that triggered shock loads on gear box and the motor, as well as needing frequent process of the contactor to change the motor off and on.
“This occasionally led to mechanical and electric failure of the aerator, creating disruptions to a possible subsequent failure plus sewage treatment to consent.“ This sewage treatment works h AS descriptive consent which specifies that all plant should be working but does not establish an ammonia limitation.
The center of the aerator has a tube to pull on effluent to the very best of the tank, just like an aquarium air lift, which guarantees all the content is handled from the bottom of the tank. The aged 20 minute duty cycle let detritus to settle in the bottom of the tank during the off period, inducing the tube to block over time. We needed a solution that would solve these issues and hopefully also produce energy savings by fitting sewage treatment more strongly to demand.”
Barleycorn approached ABB, Anglian Water’s framework associate for variable-velocity drives. Carrying out a site survey by ABB’s Authorised Value Supplier, Inverter Drive Methods, an ABB machinery drive, ACS355, was advocated. The drive’s timer outputs that are inner signals to switch the motor on and off and to change the frequency to reach different rates at different times.
So we could find the minimum that will still attract the effluent and aerate the sewerage We experimented together with the timings and rates,” says Barleycorn. Although We settled on four different time durations, where the motor will be always on but working at different rates to match the requirement at these times.
Any lower than 40 Hz and we discovered that we got no updraw in to enough or aeration area oxygenation.
“These adjustments imply the aerator motor achieved the absolute minimum of 10 percent decrease in speed even at times, while the soft and ramping start capability means we prevent shock loading to gear box and the motor.” A start attribute also prevents constant substitution of the contactor and motor which may lead to failure of gear with time, and reduces torsion and the large load during startup, placed on the motor gearbox and powertrain.