Groundwater Sustainability Through Indirect Potable Reuse:  Concept Feasibility Project in Southeastern Virginia

Holloway, Daniel

Groundwater Sustainability Through Indirect Potable Reuse: Concept Feasibility Project in Southeastern Virginia

Monday, June 6, 2016: 11:00 a.m.

Daniel Holloway, P.G. , Water Business Group, CH2M, Newport News, VA

Ted Hennifin, P.E. , General Management, Hampton Roads Sanitation District, Virginia Beach, VA

Mark Lucas, P.G. , Water Business Group, CH2M, Fort Lauderdale, FL

Over the past several decades the Virginia Coastal Plain Aquifer System has experienced groundwater withdrawals totaling over 100 mgd, which are unsustainable through natural recharge to the system. This has resulted in continuous water level declines and has contributed to regional land subsidence and contamination from saltwater intrusion, compromising the continued use of the aquifers. In light of these challenges, Hampton Roads Sanitation District (HRSD) evaluated the costs and benefits of adding advanced water treatment to their existing wastewater treatment processes to provide more than 75 mgd of clean water to recharge the deep aquifers in Eastern Virginia, creating a sustainable groundwater supply while greatly minimizing discharges to Chesapeake Bay tributaries.

HRSD conducted a concept feasibility study to evaluate: (1) potential advanced treatment processes, (2) the suitability of the aquifer for recharge, (3) benefits to the aquifer system, (4) geochemical compatibility of the treated water with the native groundwater and aquifer, and (5) high level cost estimates. Three advanced water treatment flow sheets were evaluated for implementation following HRSD’s existing treatment processes: (1) reverse osmosis-based train, (2) nanofiltration (NF) based train, and (3) BAC/GAC based train. Geochemical compatibility was modeled comparing water quality from each treatment train with the native groundwater and aquifer mineralogy. Groundwater flow models were used to evaluate the hydraulic capacity of the aquifer system and the sustainability of withdrawals following recharge. Capital and O&M costs were prepared for each of the treatment processes and associated facilities.

The treatment trains produce high quality water and include multiple barriers for pathogen and organics removal; however, only the BAC/GAC and NF treatment processes produce water qualities compatible for injection without significant post-treatment additives. Groundwater flow modeling indicates significant regional benefit to the aquifer system. Recharge provides a sustainable source for permitted groundwater withdrawals and may also slow land subsidence and prevent saltwater intrusion.

Daniel Holloway, P.G., Water Business Group, CH2M, Newport News, VA

Daniel Holloway is a Senior Project Manager and Hydrogeologist in CH2M HILL’s Water Business Group. He has been with the firm since 2002 and worked five years in the groundwater field prior to that. He earned a bachelor’s degree in Geology from James Madison University in 1994, a master’s degree in Geology from Old Dominion University in 2002, and is a professional geologist in Virginia and North Carolina. He has led various groundwater supply efforts in the Coastal Plain of Virginia including groundwater withdrawal permitting, investigations, supply development, design of well facilities, and operation and maintenance for large municipal withdrawals as well as small community water systems.

Ted Hennifin, P.E., General Management, Hampton Roads Sanitation District, Virginia Beach, VA

Ted Henifin joined Hampton Roads Sanitation District in 2006 as General Manager. He previously served as Director of Public Works for the City of Hampton. Henifin holds a bachelor’s of science in civil engineering from the University of Virginia. He is a registered professional engineer.

Mark Lucas, P.G., Water Business Group, CH2M, Fort Lauderdale, FL

Mark Lucas serves as a Senior Technologist with CH2M, specializing in recharge projects comprising aquifer storage and recovery, deep well injection of wastewater, stormwater injection, and recharge basins. He holds B.S. and M.S. degrees in Geology and Geophysics from Rutgers University.