NEORSD Southerly 1st Stage Final Settling
Osborn Engineering, as subconsultant to Brown & Caldwell, rehabilitated the existing tunnel access buildings, operating gallery and final settling tanks 1-12, and added a new settling tank (number 13) at the Southerly treatment plant. The site, located adjacent to the plant entrance and the canal, accommodates surface and groundwater management. Site plans included grading, drainage and SWPP.
The HVAC design included updating the systems with new equipment and/or refurbishing equipment, confirming that systems and ventilation rates comply with current codes, connecting HVAC controls to the central plant DDC system, and installing new duplex storm water lift stations.
The electrical design included a code review and classifications of the renovated and new areas per NFPA 820. The existing lighting and lighting controls were replaced. LED lighting was utilized outside in the tunnel areas, gallery and start wells. Occupancy sensors with 5 minute blink warnings were added for on/off control. Additional sludge pumps were added along with the associated VFDs. The motor control centers were replaced with “smart” motor control centers.
The rehabilitation of the tunnel access and operating gallery buildings included extensive repairs to the exterior walls, including tuck-pointing, lintel replacement, and patching and painting of the exterior cementitious coating system. Doors, windows and roofing systems were replaced to improve the overall energy efficiency of the buildings. Osborn was responsible for the code review of the existing tunnel system and for the expansion of the tunnels to serve the new settling tank. Osborn also designed the new access structure that provides egress from the new tunnel section.
Several alternative locations were studied for the new reinforced concrete below-grade settling tank number 13. The team recommended the location with the least impact on plant operations, site utilities, entrance drives and groundwater conditions.
Other design components on the project included a redesigned site at the main entrance, an addition to the security/guard building, and an extensive steam process piping system as part of a new grease unloading station building.