Wastewater Treatment Plant Upgrade and Expansion, Poplarville, MS

BH designed an upgrade and expansion for the Poplarville Wastewater Treatment Plant (WWTP) in Pearl River County, MS. Following Hurricane Katrina in 2005, the Pearl River County Utility Authority was tasked to develop water, wastewater, and stormwater infrastructure adequate to meet projected needs of the area. The goal was modernization and expansion of the WWTP while minimizing future operating and maintenance costs. Contract specifications and drawings suitable for bidding were prepared to facilitate construction of the $8.4 million upgrade effort.

Planning, design, and construction were coordinated with the parallel design of the new Picayune WWTP. This allowed process consolidation of activities such as sludge handling and laboratory services to achieve lower overall operating costs for the County. In addition, the use of similar plant equipment, building mechanicals, and control components eased maintenance and simplified parts inventories. Design activities included:

  • Increasing capacity from 0.6 to 1.1 MGD to meet a 20-year planning period
  • Evaluating each existing unit process to determine conditions, size, and capacity
  • Evaluating alternatives to modify existing sludge storage lagoon or eliminate it by closure-in-place
  • Designing individual unit processes including a new headworks structure; new influent wet well and suction lift pumps; upgrading aeration system capacity with two new 50-foot diameter circular final clarifiers; new return sludge pumping system; new channel UV disinfection system; new step aeration for effluent DO enhancement; a new two-cell aerobic digester with bubble membrane diffusers; new laboratory/controls building and electrical equipment; new process control and plant SCADA system; and new emergency generator
  • Performing necessary hydraulic calculations on the new unit processes
  • Preparing erosion and sedimentation plan and anti-degradation report
  • Evaluating the potential to use plant effluent as a utility water source
  • Preparing and submitting DEQ permit application for expansion and upgrades

Disinfection of the plant effluent was provided by two banks of low pressure, high intensity UV bulbs. The UV system has variable output to enable pacing the UV output in proportion to plant flow. The design flow rate for the UV system is 3.3 MGD. The UV bulbs are of the self-cleaning type using wipers and a chemical solution to clean the bulbs. A canopy roof was provided over the entire UV tank. Effluent from the UV system is discharged to a low head cascade to provide post aeration of the plant effluent.