81    DESIGN, CONSTRUCTION AND OPERATION OF
INDUSTRIAL WASTEWATER TREATMENT PLANT
Arul Ayyaswami, Project Engineer
Randall K. Drazba, Principal Engineer
Floyd Browne Associates, Inc.
Marion, Ohio 43302
INTRODUCTION
The United States Environmental Protection Agency (USEPA) effluent guideline limitations for the
metal finishing point source categories limit the allowable discharge of heavy metals to navigable
waters and to publicly owned treatment works (POTW). Communities have often placed additional
restrictions in an effort to protect wastewater treatment plant (WWTP) performance and to extend
usable life of sludge land application sites.
The following is a case history of design, construction and operation of metal finishing wastewater
treatment facility for DTR Industries, a Japanese manufacturing firm, for their manufacturing plant
located in Bluffton, Ohio. This company uses a zinc phosphating process to treat the metal portion of
the anti-vibration rubber parts in preparation for painting. The spent rinse wastewater from this
process is regulated by the metal finishing pretreatment standards for new sources, Federal Register
40 CFR 433.
Industrial wastewater enters the Industrial Wastewater Treatment Plant (IWTP) from the zinc
phosphate treatment system. The phosphate system prepares metal parts for painting by immersing
the parts in a series of tanks which are essentially used for degreasing, cleaning and treatment with
chemicals. Rinse tanks which are included with the phosphate system provides the source of wastewater requiring pretreatment before discharge to the POTW.
Floyd Browne Associates, Inc. was contracted by DTR Industries to design, construct and place
into operation an IWTP to pretreat this waste. Floyd Browne Associates, Inc. a wholly owned
subsidiary of BMA Technologies served as a general contractor.
DTR Industries placed special emphasis on space constraints, and designed effluent quality to meet
the pretreatment limits as established by the Village of Bluffton.
CONCEPTUAL DESIGN
DTR Industries provided FBA with chemical characteristics of wastewater from a similar plant
which was built in Japan. From the review of the chemical characteristics, it was seen that zinc has
exceeded the pretreatment limit established by Village of Bluffton's POTW. A treatment plant has to
be designed to meet the limits without any conventional jar tests.
Initially FBA proposed a batch operating systems. The plant will receive an average flow of 10,000
gallons per day (gpd) from DTR's manufacturing plant. The pretreatment facility will consist of two
painted steel batch tanks with mixers and pH controller. Decant from the batch tank will flow to the
pH control tank with mixer and pH controller to adjust final pH before discharge to the Bluffton
Sanitary Sewer System. Sludge from the batch tanks will be pumped by air operated diaphragm
pumps to filter press. The filerate from the filter press will be pumped back to batch tanks. Dewatered
sludge from the filter press will be discharged into 55 gallon drums for final disposal.
DTR Industries preferred a continuous flow system instead of original batch treatment system that
was proposed. The design was modified to provide a continuous flow treatment system. The modified
treatment process consists of flow equalization, chemical precipitation, sedimentation and filtration.
The filtered effluent is stored in effluent storage tank and discharged to Bluffton's POTW. The solids
are thickened using a sludge decant tank and dewatered using a filter press. The dewatered sludge cake
is disposed at sanitary landfill. The block flow diagram of the process is shown on Figure 1. The basic
design data for the treatment plant is as follows:
45th Purdue Industrial Waste Conference Proceedings, © 1991 Lewis Publishers, Inc., Chelsea, Michigan 48118.
Primed in U.S.A.
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