UM - WW - JBPHH WWTP HEADWORKS SCREENS REPLACEMENT

Project scope involves replacing the existing Headworks screens with new screens of equal capacity to provide removal of large solids prior to the liquid settling and aeration portion of the JBPHH WWTP treatment process. After purchasing replacement parts for one screen (out of two screens, only one left operating) that has been out of service for almost a year, after installing the parts, the screen is still mis-aligned (due to wear-and-tear and objects hitting the screen over time); the manufacturer's representative recommended that we replace both screens (the screens are not repairable). Additionally, the existing screens are not the most efficient when it comes to removing solids, because they are 6 millimeter step (slotted) screens that directly face the flow direction; whereas the proposed future screens, while also being slotted (bar) screens, would have the slots orientation horizontally opposed to the flow direction, creating a greater capture efficiency by forcing the flow to change direction 90 degrees. Furthermore, step screens utilize thin plates to separate the screen openings, versus bar screens that utilize thick and more robust bars that are less prone to losing alignment and screen mechanism failures. Replacement of the screens will also require replacement of the wash-presses that compress and remove "excess" water from the screenings. The regulatory agencies (EPA and State DOH) expect that the JBPHH WWTP can continuously screen wastewater influent.