LAN designed a new 0.5-MGD treatment plant to replace the existing 0.15-MGD plant. The new plant is a conventional activated sludge plant, designed for expansion in three phases, with an ultimate capacity of 1.5-MGD average daily flow and 4.5-MGD peak wet weather flow. The plant will be constructed on the existing site while maintaining operation of the existing plant throughout construction.

The preliminary engineering phase included an extensive evaluation of applicable technologies to identify the most advantageous treatment process to meet the City’s needs. A conventional activated sludge process was identified to provide the most benefits, meet City preferences, and accommodate numerous site constraints. Because the existing plant had to remain in operation throughout construction, there was extremely limited site on which to construct a new plant. This led LAN to utilize a modified bullseye design, which provided a space-saving, modular design.

LAN also designed a replacement lift station adjacent to the Pirates Beach WWTP and rehabilitation of two off-site lift stations that discharge directly into the existing WWTP’s biological treatment units. LAN will perform a hydraulic analysis of the force mains, and resize the lift station pumps to meet the hydraulic requirements to discharge those force mains into the new on-site lift station.