SEW geared motors clean Victoria’s water

Significant upgrades to water treatment plants in North East Victoria mean residents can now enjoy cleaner, better-tasting drinking water flowing from their taps.

The Corryong water treatment plant provides a significant improvement to the quality of water for Corryong and Cudgewa residents. The opening of Whitfield’s Water Treatment Plant marked a new beginning for a town that previously endured regular water restrictions, water carting, and boil water notices.

Jack Timmins is a process engineer with Laurie Curran Water who designed and built both water treatment plants. He said the projects have been highly successful with SEW-EURODRIVE equipment to drive the critical flocculators in the system.

“With considerable experience using SEW-EURODRIVE products, the client had no hesitation in specifying SEW equipment on both these projects,” Timmins said.

Laurie Curran Water is a leading process engineering firm specialising in designing and constructing water and wastewater treatment facilities. It is well known throughout Australia for its Dissolved Air Flotation and Filtration (DAFF) process expertise.

“For the Corryong water treatment plant project, we were contracted by the local water authority, North East Water, to design and construct a 3.2ML/d (Mega Litres per day) DAFF water treatment plant for potable water for the towns of Corryong and Cudgewa,” said Timmins. “We used SEW-EURODRIVE geared motors on our vertical inline flocculators. The system required two heavy-duty filters and four flocculators, each driven by a SEW-geared motor. We also used a SEW-EURODRIVE geared motor on a thickening mechanism for the washwater treatment.”

Corryong water treatment plant improves water for NE Victorians

He explained they used SEW’s geared motors with MOVIMOT integrated frequency inverters on all five projects.

“We like to use a decentralised motor control system instead of having it in the central computer. This allows us to walk up and adjust the speed of the flocculators while looking down into the system. Using a decentralised system, we can physically see the rotation of the flocculators instead of walking down, looking at the computer, then walking up again, adjusting the flocculator, and back to the computer until we got it right,” he said.

Timmins explained that each filter is about 5m high and would typically need two people to set the flocculators up. One tells the other what is going on.

“And it was the same for the sludge thickening system, with its 3.3m high thickener vessel.

“Using a decentralised system, we can fine-tune the system so that the speed of the flocculators and thickeners matches the speed we use in our jar testing.

“Normally, once it’s done, it’s set. You might need to put different energies in with different water quality and jar testing. It’s based on jar testing and water quality at the time.

“As well as the accuracy of the settings, using a decentralised system eliminates the need for a control house mounting of the VSD (Variable Speed Drive) and the associated wiring and set-up,” he said.

Corryong water treatment plants benefits from SEW-Eurodrive geared motors

Timmins explained that the Corryong water treatment plant was the first project he had been involved with using SEW-EURODRIVE products.

“We have been delighted with the products, the service and the advice we get from SEW, making sure the most applicable equipment/model is used,” he said. “The client worked closely with us regarding torque levels to ensure the geared motors were not over or undersized. We also had to check that we had the right configuration and output shaft to suit our standard paddle design. We use a PLC computer-based Citect system to start and stop the systems. The speed control is done integrally using the MOVIMOT drives. This allows us to optimise the system through our process to allow for the ever-changing quality of the water. The MOVIMOT drives provide us with the flexibility to adjust the system. Plus, we have achieved turbidity of under 0.1NTU (Nephelometric Turbidity Units). This is very low by industry standards and other parameters.”

Multiple modules satisfied by SEW-Eurodrive geared motors

Timmins said the Corryong water treatment plant project also included a dual water treatment module for the treatment of raw water drawn from the Hamilton Hill reservoir, chemical dosing systems for aluminium, caustic soda, polyelectrolyte and gaseous chlorine, a 300kL washwater tank to accept filtered washwater and DAF float, and a 2.5kL sludge storage tank.

However, he said the Whitfield water treatment plant in Victoria’s King Valley wine region was slightly different.

“This plant used a mechanical float-off removal mechanism instead of a sludge thickener. It is also a smaller plant at just 150kL/d with two flocculators. This was an interesting project. The client made changes to the design during the tender process. We put a DAFF option in the tender with a pressure filter option. However, the client changed the tender to make it more cost-effective, with a mechanical float-off removal mechanism instead of a thickener. We only needed three MOVIMOT drives on the Whitfield water treatment plant. But while it’s a much smaller site, we went through the same design issues with SEW. This was particularly important for the mechanical float-off removal mechanism. There was a lot of work required on the housing and mounting details and the speed configuration that suits our process,” Timmins said.

Whitfield water treatment plant upgrade

Major components of the Whitfield water treatment plant included a 300kL raw water tank, which accepts water from the King River pump station, chemical dosing systems for caustic soda, aluminium chlorohydrate and sodium hypochlorite, a 235kL transparent water tank, and 25kL washwater tank and a 15kL sludge storage tank.

Timmins explained that flocculation is widely employed in the purification of drinking water as well as sewage treatment, storm-water treatment and treatment of other industrial wastewater streams.

“During flocculation, gentle mixing accelerates the particle collision rate, and the destabilised particles are further aggregated and enmeshed into larger precipitates.”

He said flocculation is affected by several parameters, including mixing speeds, mixing intensity, and mixing time.

“The product of the mixing intensity and mixing time is used to describe the flocculation process,” Timmins said.

He said that both water treatment plant projects had been very successful, and the residents in the areas now enjoy cleaner, better-tasting drinking water flowing from their taps.

“The client, North East Water, is also very happy with the treatment plants. We have had no issues working with SEW-EURODRIVE or with their products. Their service was excellent and delivery was always on time. This is even though we only gave them a couple of weeks’ notice,” Timmins said.

Geared motors

Michael Sposato, a sales engineer with SEW-EURODRIVE, said the MOVIMOT is a tried-and-tested combination of a geared motor locally integrated with a digital frequency inverter.

He explained that despite the fully integrated frequency inverter, the MOVIMOT geared motor only requires slightly more installation space than standard geared motors.

“The MOVIMOT geared motors can be supplied in all standard versions and mounting positions, with and without a brake,” Sposato said. “When Timmins first contacted me regarding the Whitfield water treatment plant, it was clear SEW-EURODRIVE had the perfect solution for the project. He provided me with some specifications for the style of geared motor he required. Timmins also provided an indication of how he would like to control the units. We made a couple of selections for him. We recommended our geared moto and integrated onboard MOVIMOT controller as the solution. This allowed the integrator to reduce the amount of wiring, with less mounting space required in the central control location. A decentralised system eliminates the need for a control house to wire and store standalone VSD controllers. After some minor specification changes, we ended up going with our first order for one of the jobs. Since then, we have been involved with three further projects.”

SEW-Eurodrive geared motors known for longevity and durability

Sposato said reliability is crucial in these critical applications, and SEW-EURODRIVE products are renowned for their longevity and durability.

“Timmins was after a high-quality geared motor control system. That’s why he chose SEW-EURODRIVE. I understand he did approach other geared motor suppliers, but our quality and short delivery times are hard to beat. For projects like this, we have a one to two-week turnaround. We can offer such a quick delivery because of the huge amount of stock we carry, plus the engineering backup we have in Melbourne,” Sposato said.

“Our geared motors are also heavy-duty and are designed for the tough environments the units were put into,” he said.

He explained that the MOVIMOT geared motors have an IP55 enclosure as standard but are also available with IP65 and IP66 enclosures on request.

“SEW-EURODRIVE has established a reputation for quickly solving the most difficult power transmission and motion control challenges,” Sposato said.

For more information, call 1300 SEW AUS or email enquiries@sew-eurodrive.com.au