THE INFLUENCE OF INDUSTRIAL WASTE ON NITRIFICATION
Felix F. Sampayo, Member
Dail C. Hollopeter, Project Engineer
Jones and Henry Engineers, Limited
Toledo, Ohio 43606
INTRODUCTION
The City of Kalamazoo, Michigan has a population of about 88,000.   The Metropolitan Area is highly industrialized with most of the industrial activity being generated
by paper, pharmaceutical, and automotive parts manufacturing.
The area is served by a wastewater treatment plant that provides secondary treatment
to domestic, commercial, and industrial wastewaters.    Approximately half of the wastewater reaching the City's secondary treatment plant is of industrial origin.   Most of the
wastes from paper manufacturing receive primary treatment at the mills and are discharged directly to the plant's aeration tanks.   Figure 1 is a diagram of the existing
process.
The flows to the plant are expected to reach 53.3 mgd in the year 2000.   The
paper mill wastes are expected to contain about 250 mg/1 SS and 300 mg/1 BOD.   The
remaining wastes including domestic, commercial, pharmaceutical, and miscellaneous
industries are expected to contain about 335 mg/1 SS and 380 mg/1 BOD.   At the projected flow rate, daily total loading to the plant will average approximately  138,300 lb
SS and 158,900 lb BOD.   The existing plant does not have capacity for the projected
loads and will necessitate substantial expansion and upgrading.
The NPDES Permit conditions require that the plant produce an effluent with 10 mg/1
BOD and 2 mg/1 NH3-N during the summer months.   During the winter the restriction
is 30 mg/1 BOD.   The average suspended solids discharge is limited to 10 mg/1 and
30 mg/1 during the summer and winter, respectively.   Phosphorus concentrations are not
to exceed 1.0 mg/1 throughout the year.
During the approximately two years that it took to complete the planning process,
numerous studies covering physical-chemical treatment, disinfection, filtration, odor control, sludge dewatering, etc., were conducted.   This paper covers a discussion of the
nitrification studies, pilot investigations, the   effects of industrial waste on nitrification,
and the program findings.   The selected treatment process is also presented.
NITRIFICATION
Nitrification is the microbial mediated oxidation of ammonia to nitrites and finally
to nitrates.   The bacterial mediators are the aerobic autotrophs Nitrosomonas and Nitro-
bacter.    Several researchers have recently discussed the stoichiometric relationships and
kinetics of the process [1,2,3,4].
Although the concept of nitrification is well understood, the process is often difficult
to operate with any degree of consistency. The performance of a nitrification system is
greately dependent upon such things as temperature, pH, and the presence of toxins.
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