Editor-in-Chief Elisabeth Lisican showcases a handful of features to read in the April 2017 issue of Water & Wastes Digest.
Australian utility eliminates clogging with wastewater pumping system
North East Water provides water and wastewater services to 41 localities across North East Victoria, Australia, serving an estimated 122,000 people in an area of approximately 20,000 sq km. The region extends from Corryong in the east, along the Murray River to Yarrawonga, then south to Benalla and the alpine towns of Bright, Mount Beauty and Dartmouth.
The municipal sewer pump station at Jordyn Terrace in Wangaratta, Victoria, receives challenging wastewater containing a large quantity of fibrous waste objects that cause ragging of the pumps. This resulted in pumps having to be lifted and unblocked two to three times every week.
In July 2016, North East Water became the first water business in Australia to install Xylem’s Flygt Concertor system, resolving this issue and delivering clog-free pumping to the Jordyn Terrace wastewater pump station.
Since installation, station managers have reported no blockages or clogging issues at the station, as well as a cleaner station with less visible material in the sump.
Jordyn Terrace is located in a busy residential area close to a retirement village. The pumping station receives challenging wastewater, including personal sanitary products and towelling, that causes the pumps to frequently clog.
“Regular clogging of the pump station was a serious issue for us,” said Grant Waite, manager of assets and operations for North East Water. “As a result, operation and maintenance staff had to leave their daily work schedules to travel to the pump station, unclog the pump, and get the station up and running again. In addition to man-power, a maintenance crane truck was needed to perform the pump lifts, which meant it had to be taken away from other projects, which added further expense to the repair job.”
In July 2016, North East Water agreed to have the Flygt Concertor installed at the Jordyn Terrace pump station in order to resolve its chronic clogging.
The team had high hopes in this new system. It combines self-cleaning hydraulics, Adaptive-N and intelligent functions like pump cleaning. This function activates when a clogging instance is detected and starts operating the impeller at different speeds and directions to remove the debris. It has been used in applications all over the world, and, together with other functions that ensure trouble-free pumping, offers a new level of reliability.
After installing the system, clogging issues at the Jordyn Terrace wastewater treatment plant were eliminated.
“We have found Xylem’s Flygt equipment to be of excellent quality, so we were happy to trial the new wastewater pumping system. The trial pump we received is still running in our station and so far we haven’t had one single case of clogging,” Waite said.
The short-term results were a relief for the station’s operators, but their main concern was to find a sustainable long-term solution.
This is where the system’s flexibility played a role. One of its main hardware elements, the pump impeller, is offered in three different materials to adapt to different conditions: hard iron, duplex stainless steel and stainless steel.
A high-chrome alloy, hard iron is five times more wear resistant than duplex stainless steel. It is a high-strength alloy containing 25% chromium and 3% carbon. During the solidification process, the chromium and carbon transform into hard carbides. This makes the material resistant to abrasive wear and erosion-corrosion. In accelerated wear tests, Hard-Iron kept working efficiently and showed minimal wear after pumping water with a high concentration of abrasive particles. This durability and reliability saves customers time and money.
“The Hard-Iron impeller will ensure that the current pump performance is maintained for extended periods,” Waite said. “In an application like this, with wastewater that contains a high level of non-biological solids, it is the best option.”
This system is an example of how new technologies with sophisticated integrated intelligence for wastewater pumping do not require more components or complexities; rather, Concertor is user-friendly and simple to install, commission and operate.
“Since Flygt Concertor has been installed we haven’t experienced any clogging issues at the station, which is a dramatic improvement to how the station’s old pumps had been running,” Waite said. “The new wastewater pumping system has also had a positive impact on the local community—less visits to the station by large maintenance trucks and personnel. Station managers have also reported that the sump is cleaner as a result.”