Enhancing Water Quality by Minimizing Total Nitrogen Discharges

The $70.4 million Phase 2 project expands on the Alternative 4A-1 Light, Phase 1 improvements completed in 2012. While Phase 1 segregated domestic flow from industrial flow, Phase 2 reduced the total nitrogen discharged to the Chesapeake Bay to below state and Environmental Protection Agency requirements. Before Phase 2, Hopewell Water Renewal purchased nitrogen credits to comply with regulations, but with the future of those credits uncertain, the HDR team offered a new solution yet faced several challenges.

These included high wastewater temperatures, variable influent characteristics, frequent spike loading, and high concentrations of volatile organic compounds. To resolve these concerns, the team chose an advanced moving bed biofilm reactor, coupled with a high-rate dissolved air flotation system. This unique, proprietary system will help Hopewell Water Renewal meet the new, more stringent discharge limits of the Clean Water Act.

Phase 2 also reduced the use of chlorine by disinfecting segregated treatment effluent instead of primary effluent — saving nearly $500,000 annually from day one, which will grow to nearly $1 million in annual savings by 2040. More specifically, the Phase 2 improvements included a new influent screen, a new pump station, force main improvements, the MBBR tanks, a new blower building, a dissolved air flotation building, effluent re-aeration, and solids handling improvements.

The improved facility will secure reliable and compliant wastewater treatment for the City of Hopewell's residents, industrial manufacturers and businesses into the foreseeable future. It will also improve James River and Chesapeake Bay water quality by decreasing the total nitrogen discharged to these water bodies. By contributing to water quality improvement, residents and visitors will continue to enjoy boating, fishing, hiking and swimming within the adjacent waterways.