Due to unforeseen limitations in the pilot system, only two stages of second generation stacks (36 and 1.25 liter per minute, respectively) could be rigorously tested at the Sunnyvale wastewater treatment plant for a total of 16 hours of operation. Based on the pilot testing results, an ideal HDS system saves about 40 kWh/mgd and about $1,650/mgd/year in energy costs when compared to a conventional activated sludge plant. If an HDS system had performance similar to what was achieved during the pilot study, it would use about 220 kWh/mgd and cost about $9,335/mgd/year more to operate than a conventional activated sludge plant
PARC manufactured Hydrodynamic Separation (HDS) channels that separated and concentrated organic solids from primary effluent at a wastewater treatment plant. Rigorous testing occurred at the Sunnyvale Wastewater Treatment Plant for a total of 16 hours. The best performance of 70% and 63% harvest efficiencies (HE – is the mass capture rate in the concentrate stream) for the first and second stage, respectively, was documented at the beginning of testing. HE performance deteriorated during testing due to channel fouling. Cleaning the first stage channels using backflow and high pressure (20 pounds per square inch) returned HE to pre-pilot performance.
Increased onsite biogas production results in increased electricity generation at wastewater plants in California.
Palo Alto Research Center, Inc.