Papers and Reports

The Sacramento Regional Wastewater Treatment Plant (SRWTP) has experienced struvite (magnesium-ammonium-phosphate) scale buildup on certain equipment and pipes at the Solids Storage Basins (SSBs). Over the last 20 years this scale has been most troublesome in the SSB supernatant piping system (supernatant drawoff and recycle system) and on the blades of the SSB surface mixers. Buildup of scale on some pipes is restricting the quantity of supernatant that can be drawn off the SSBs. As part of the SRWTP biosolids facilities modification work in the last 1 1/2 years, considerable effort has been undertaken to evaluate the current struvite buildup problems and determine how they can be eliminated or at least minimized with certain modifications to the system. This paper describes the changes and modifications that are likely to be made and how they have been developed.