59    A SUCCESSFUL STORY OF OPERATING A
PHYSICAL-CHEMICAL WASTEWATER TREATMENT
PLANT
Li-Yin Lin, Environmental Engineer
Robert E. Game, Director
Douglas N. Crocker, Chief Operator
Department of Wastewater Facilities
City of Niagara Falls
Niagara Falls, New York 14302-0069
INTRODUCTION
Niagara Falls Wastewater Facilities
The City of Niagara Falls Wastewater Treatment Plant (WWTP), served the community in the early
1970s, and was a primary treatment facility. In the 1970s a large industrial base existed in the city
which discharged wastewaters of a significant chemical nature into the wastewater plant. The primary
treatment plant did not have the capacity to treat these industrial wastes. Therefore, a facilities plan
was conducted to upgrade the city's wastewater facility.
Both conventional biological and physical-chemical treatment options were considered. The industries would need to pretreat their wastes to a degree which in turn would allow the city to build a
conventional biological treatment plant. On the contrary, industries would not significantly pretreat
their discharges if the city has a physical-chemical treatment plant. Furthermore, a centralized treatment facility would provide an economy of scale, because it would be cost-effective for all parties to
share in the cost of the city to build one large treatment system rather than have the industrial
community build a series of small ones. Accordingly, the choice was made to proceed with the
construction of a physical-chemical activated carbon wastewater treatment plant. The unit operations
of the WWTP include chemical coagulation, flocculation, primary sedimentation, granular activated
carbon (GAC) treatment and effluent chlorination. Sludge treatment consists of thickness, chemical
conditions, and vacuum filters. A flow diagram showing the Niagara Falls WWTP is presented in
Figure 1.
Failure of Underdrain System
The Niagara Falls WWTP was constructed in 1973-1977. The carbon system was fully on-line in
early 1978. However, the carbon underdrain system failed in July 1978. The underdrains broke and
carbon was lost through the underdrains to the chlorination basin. The carbon system was shut down
until the WWTP completed the rehabilitation of the carbon underdrain system in 1985. The current
underdrain system is a leopold system with a gravel support system. The cross section of carbon bed
with the underdrain system is illustrated in Figure 2.
ODOR PROBLEMS
The Niagara Falls WWTP has experienced an odor problem since the carbon bed system began
operation in 1985. The odorous compounds generated from carbon system, mainly hydrogen sulfide
(H2S). Although the WWTP tried to control this bothersome odor situation, the problem became
even worse in 1987 and 1988. In 1988, New York Department of Health threatened that action will be
undertaken against the city. Also, the tourists' complaints of unpleasant odors, coupled with similar
complaints from residents, gained extensive public attention. A comprehensive investigation was
conducted to identify the causes of the odor problems and to develop an odor control plan.1,2
46th Purdue Industrial Waste Conference Proceedings, 1992 Lewis Publishers, Inc., Chelsea, Michigan 48118.
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