This packaged treatment plant (PTA) project uses three FINEGUARDTM screens, a Vortex Grit chamber, two SPIROWASH® screenings washer/compactors and a SANDSEP® grit classifier. The plant was designed such that it can be supported on galvanised steel beams elevated approximately 16ft (5m) above ground level, to enable flows to gravitate through downstream process units. Two SPIROWASH® screenings washer/compactors and a SANDSEP® grit classifier are installed on a concrete slab at ground level. The PTA assembly is prefabricated and transported to the site in such a manner that minimises installation and requires only a few bolted connections.
Sewage enters the inlet flow splitter and then passes over a fixed weir into a chamber feeding three FINEGUARDTM screens. The three fine screens work in a duty/duty/standby configuration to remove >3mm solids from the incoming flow. Each fine screen channel contains an electrically actuated penstock upstream of the fine screen. The penstock is in the closed position when its corresponding fine screen is in standby mode. The fine screens are capable of switching to duty/duty/duty mode if sewage levels upstream of the fine screens reach a predetermined level.
Screenings captured by the fine screens discharge to a horizontal shaftless spiral conveyor located above the channels. The conveyor transports screenings to two SPIROWASH® screenings washer/compactors via a drop chute. The screenings washers/compactors wash and compact the screenings before depositing them into a screenings bin.
Screened sewage passes from the fine screen channels to the vortex grit chamber where grit is separated from the sewage stream. A grit pump withdraws grit slurry from the grit tank and pumps it to a SANDSEP® grit classifier. The grit classifier washes, separates and transfers the grit to the grit bin.
As a decades-long supplier of spiral conveyors and screening handling equipment, the addition of an extensive screen range is a perfect fit to make SPIRAC a single source supplier for the primary wastewater treatment industry.