Mr. Drehwing has more than 50 years of experience in civil and environmental engineering, including positions as Vice President and Sr. VP with the firms O'Brien & Gere (OBG), and Blasland, Bouck & Lee (BBL), consistently ranked in the top 50 USA Engineering & Design Firms by Engineering News Record (ENR). Currently Mr. Drehwing serves in his 14th year in an elected position as Commissioner of the Hilton Head Public Service District No.1 South Carolina.

During his career, Mr. Drehwing also designed and launched the research and laboratory division of O’Brien & Gere, and ran this research group for approximately five years. Projects under his supervision totaled more than $1B in design and construction.

Mr. Drehwing’s experience covers a wide range of engineering through study, planning, design and construction programs for water and wastewater applications. Some of the primary areas relate to tertiary treatment, nutrient removal, high rate filtration and disinfection, CSO abatement and treatment, bio-solids management, sustainable water supplies, energy reduction & efficiency alternatives and stormwater management.