Hubbell, Roth & Clark, Inc. (HRC) has provided wastewater-related engineering services to the City of Detroit for most of the company's 90-year history.  In fact, the genesis of wastewater treatment in Detroit was a report prepared by Clarence W. Hubbell in 1916 entitled "Preliminary Report on Sewage Disposal for the City of Detroit."

HRC were consultants on the design of the pumping station, grit chambers, and special baffles for the rectangular tanks for the first wastewater treatment plant in 1940.

The grit chambers were an innovative design of HRC's, which were tested in a hydraulic scale model in 1936.  The rectangular settling tanks were fitted with inlet baffles designed and tested by HRC.  Between 1966 and 1985, HRC engineered 47 projects totaling $326 million (at that time) in construction.  These additions further reduced solids, biochemical oxygen demand, and, for the first time, phosphorus, made it the largest-rated secondary treatment facility in one location in the world, at one billion gallons per day.  The plant's innovative and patented treatment units also resulted in tremendous savings in construction and real estate costs in a densely populated and developed section of southwest Detroit.

Innovative HRC design features included:

• The largest circular primary clarifiers in the United States
• Patented covered rectangular primary clarifier baffles
• One of the first uses of high purity oxygen activated sludge treatment
• Patented high rate secondary clarifiers