GRANULAR ACTIVATED CARBON REMOVAL
OF PRIORITY POLLUTANTS IN A COMBINED
MUNICIPAL/INDUSTRIAL WASTEWATER
Anne Marie C. McManus, Engineer
Paul H. Werthman, Project Manager
Malcolm Pirnie, Inc.
Niagara Falls, New York 14303
John R. Westendorf, Chief Chemist
City of Niagara Falls
Niagara Falls, New York 14304
INTRODUCTION
Granular activated carbon (GAC) is finding increasing application in wastewater treatment as
public concern and regulatory momentum build over the discharge of toxic organic compounds to
surface waters. While GAC is the only technology to date which has shown practical promise in
achieving efficient removal of these compounds, the cost-effective use of GAC is dependent on development of a rigorous data base to characterize the system dynamics for a specific application.
In particular, the phenomenon of competitive adsorption on activated carbon has been recognized
for some time, but its implications in the treatment of complex and variable wastewaters are of
particular concern regarding the operating costs of a GAC system, system predictability, and reliability in maintaining consistent compliance with effluent limitations.
Most studies addressing competitive adsorption reported in the literature have investigated single
and multiple solute batch adsorption phenomena from a clean water matrix. This paper presents the
results of a six-month GAC pilot plant study on a combined municipal/industrial wastewater and
compares the results to single solute adsorption capacities.
BACKGROUND
The City of Niagara Falls, New York with a population of approximately 70,000 is located along
the Niagara River bounding Western New York and Ontario, Canada. Not only has the Falls historically been an attraction for tourists, but since the turn of the Century has been a center for the
electrochemical industry heavily reliant upon cheap hydro-electric power to produce a wide array of
products.
In January of 1970, the City of Niagara Falls initiated efforts to upgrade the City's publicly owned
treatment works (POTW). Construction of system improvements, including a new wastewater treatment plant, began in 1973 and were placed in operation in April 1977.
The physicochemical wastewater treatment plant was designed to treat 2.1 m'/sec (48 MGD) of
combined industrial and municipal wastewater. Structural failures of the carbon filter beds during
plant start-up rendered the activated carbon system inoperable. The carbon adsorption system has
since been redesigned and is expected to be fully operational in mid-1985. A schematic illustration
of the treatment system is presented in Figure 1.
Since the plant's opening, an average flow of approximately 2.63 m'/sec (60 MGD) has been
introduced to the plant. Through a flow reduction program and decreased industry production levels,
flows were reduced to 2.36 m'/sec (53.8 MGD) in 1982. Approximately 16% of the flow has been
identified as commercial/residential, 32% from Significant Industrial Users (SIU's) and 52% infiltration/inflow. Continuing flow reduction efforts are expected to further reduce the influent of the
plant to design levels. Meanwhile, substantial quantities of toxic organic priority pollutants dis-
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