Brief Project Description

The Spotsylvania County-Massaponax Wastewater Treatment Plant is currently rated for 8.0 MGD average daily flow. The facility is capable of achieving Biological Nitrogen Removal (BNR) as a result of a prior WQIF-funded project, with an annual average performance limit of 8.0 mg/l total nitrogen (TN).

                                            

The County’s goal under the subject grant agreement is to complete the necessary retrofitting of the treatment process to comply with the nutrient waste load allocations (WLA) in State regulations directed at Chesapeake Bay cleanup. The County will transfer 1.4 MGD of capacity and the associated WLA from their FMC facility (5.4 MGD WLA basis) to the Massaponax WWTP, for a total average daily design flow of 9.4 MGD.   The County intends to operate under a bubble permit, managing its overall annual TN and TP load discharges to be under the total of its WLAs listed in the Watershed General Permit for Chesapeake Bay Nutrient Discharges (9 VAC 25-820-10).

 

In summary, the objectives of the Massaponax WWTP Upgrade & Expansion project are to:

• Increase hydraulic capacities of selected treatment processes to handle the peak flows associated with an additional 1.4 MGD.
• Increase average and peak treatment capacities of selected treatment processes to treat additional flows and loadings.
• Modify the existing BNR process to ensure Enhanced Nutrient Removal (ENR) performance capability, achieving annual average concentrations of 4.0 mg/l TN and 0.30 mg/l TP.
• Update and renovate other WWTP facilities where identified by the County.

 

The upgraded and proposed liquids and solids treatment facilities for the 9.4 MGD Expansion and ENR upgrade project are as follows, with the associated WQIF grant eligibility:

• Influent screening, grit removal and pumping upgrades - ineligible for grant funds.
• Modify Bioreactor Distribution Box and Bioreactors, including a new secondary anoxic zone, additional primary and secondary swing zones, and baffle wall hydraulic modifications – partially eligible for grant funds.
• Facility for storage and feed of supplemental carbon for denitrification – eligible for grant funds.
• Addition of two aeration blowers – partially eligible for grant funds.
• Construction of a new Secondary Clarifier – partially eligible for grant funds.
• Scum Pump Station and Return Activated Sludge pumping – partially eligible for grant funds.
• Cloth media retrofit of existing effluent filters – partially eligible for grant funds.
• Provisional flocculent contact tank attached to new effluent filter distribution box – partially eligible for grant funds.
• Ultraviolet disinfection and modified Waste Activated Sludge storage – ineligible for grant funds.