CST Wastewater Solutions introduced the latest Smith and Loveless (S&L) 95% grit removal technology, which is ideally suited for wastewater treatment plants operating in sandy environments throughout Australasia, at OzWater 2017.

Michael Bambridge (right) and S&L general manager Joe Gill pose with a scale model of the PISTA360 technology at Ozwater 2017

The latest S&L PISTA360 technology eliminates the build-up of grit in downstream aeration basins and sludge digesters of wastewater treatment plants.

The high-performance technology removes 95% of grit as small as 105 microns and is particularly relevant to councils and utilities serving the more than 80% of Australia's population who live often in sandy areas within 50km of the coast.

According to managing director CST Wastewater Solutions Michael Bambridge - who was on hand at OzWater to explain the new features of the technology, the PISTA360:

  • Reduces damage from abrasions to downstream equipment;
  • Enhances the reliability of wastewater treatment plants;
  • Reduces OH&S hazards involved in unclogging systems; and
  • Helps to prevent environmental spills from blocked and flooded systems.

"PISTA technology has set the global benchmark or grit removal for many years," Bambridge told those in attendance at OzWater 2017.

"It far exceeds the established standard for grit removal, which has been 95% removal at 250 microns.

"We are now achieving the same removal efficiency at 105 microns (140 mesh), this latest technology sets an entirely new benchmark."

The latest PISTA360 uses an integral flow chamber baffle for both the inlet and outlet of the main chamber.

The V-Force Baffle is designed to direct the inlet flow into the chamber in a manner that ensures the proper vortex flow and prevents short-circuiting.

The baffle allows for a full 360 degrees rotation through the inlet and outlet, providing maximum travel of the wastewater for the most effective grit removal before proceeding to downstream treatment process. 

It also acts as a "slice weir" to control the water level in the main chamber and in the inlet channel - achieving a 10:1 turn down in performance. 

"This innovation further enhances the world's best grit removal system from PISTA, which incorporates many engineering and cost saving considerations," Bambridge said. 

"By increasing chamber velocity during low flow periods, the baffle extends the grit extraction path within the vortex grit chamber.

"This is the key, because a longer path increases the amount of grit being captured on the chamber's flat floor." 

The PISTA360 with V-Force Baffle permits design flexibility so that water elevations can be controlled, which Bambridge says is important because it allows the user to uphold the proper velocities approaching the grit chamber.

"Previously, the common way to accomplish water level control was to back up the flow with a downstream submerged weir," Bambridge adds. 

"The PISTA360 with its pre-set inlet and outlet opening supplants the need for the submerged weir. 

"By integrating the water elevation settings with the baffle, the outlet footprint requirements decrease by as much as half the typical size, and the resulting smaller footprint provides significant construction cost savings."