Brief Project Description
The original Vint Hill wastewater treatment facility (WWTF), taken over by the Fauquier County Water and Sanitation Authority (FCWSA) from the Federal government, was a trickling filter process with a design flow of 0.246 MGD not designed for nutrient removal. The process consisted of primary clarification, a single trickling filter unit followed by clarification, ultraviolet disinfection and discharge to South Run. The waste solids were anaerobically digested and dried on sand beds prior to disposal.
Under the proposal submitted for nutrient reduction cost share, FCWSA has upgraded the Vint Hill WWTF to add State of the Art Nutrient Reduction Technology (NRT). In addition, the design flow was expanded to 0.60 MGD. The expansion component was necessary to treat wastewater flow generated as a result of redevelopment of the former Federal facility (Vint Hill Army Base) and also due to the removal of three privately owned wastewater treatment facilities from service, as envisioned in the Occoquan Watershed Policy.
The upgraded/expanded wastewater plant consists of an entirely new headworks with grit and grease removal, dual 300,000 gallon Sequencing Batch Reactors (SBRs), alum addition for phosphorus removal, methanol addition as a supplemental carbon source for denitrification, tertiary denitrification filters, cascade post-aeration and ultraviolet (UV) disinfection. Two new aerobic digesters and a belt filter press comprise the solids dewatering system. Associated solids handling equipment (pumps, conveyor and building) were also constructed. The outfall was relocated and the new facility will discharge to Kettle Run.
The upgrade and expansion included the following components:
- Installation of new influent and effluent pumping stations and relocated discharge to Kettle Run (not grant eligible).
- Installation of new headworks [screening and grit removal] (not grant eligible).
- Installation of two Sequencing Batch Reactors and combined post-equalization structure (partially grant eligible).
- Installation of a coagulant [alum] feed system for phosphorous removal (grant eligible).
- Construction of a methanol feed facility system to provide a supplemental carbon source (grant eligible).
- Installation of 6-module "upflow" tertiary denitrification filters (partially grant eligible).
- Installation of cascade-type effluent post-aeration (not grant eligible).
- Installation of two new aerobic digesters and belt filter press dewatering (partially grant eligible).
- Installation of non-potable water [NPW] system, UV disinfection process, effluent flow monitoring and sampling (not grant eligible).