The Village of Williamsburg owns and operates a wastewater treatment plant (WWTP) that discharges treated effluent to the East Fork of the Little Miami River. Starting in 2006, relatively frequent permit violations were registered. The violations, coupled with infrastructure and equipment in the 20- to 50-year age range, lead to development of a three-phase improvement plan that would upgrade all treatment equipment and pumps, provide influent flow equalization and onsite biosolids handling, end liquid waste sludge transport to another WWTP, and implement biological nutrient removal (BNR) of phosphorus using a continuous flow process.
As part of a comprehensive study updated in 2007, five alternatives were developed to upgrade and expand the WWTP with regards to reliability, efficiency, and capacity. Conversion of the sequencing batch reactors (SBRs) and sludge holding tanks to BNR basins was the most cost-effective approach to repurpose existing facilities to meet anticipated future, more stringent permit requirements. Process modeling that demonstrated efficient use of converted existing basin volume would allow the Village to double the capacity of their plant and maintain receiving stream effluent loadings.
A phased approach was developed so the most problematic situations could be corrected first. This approach allowed the Village to meet future permits that will most likely contain nutrient limitations for phosphorus and nitrogen, accommodate additional customers as the Williamsburg area grows in population, and correct operational limitations in the current configuration of the WWTP. Phasing also allowed apportioned outlay of Village money for these improvements.
B&N’s Mark Upite and Sam Swanson will join Kyle Cribbet from the Village of Williamsburg to discuss the phased improvements, summarize the approach to grant-funding projects with low-interest loan backups, provide tips in piloting an interim phosphorus-reducing chemical system, and detail specific steps in converting existing tanks from a conventional batch activated sludge system to a continuous flow BNR treatment system.