Combined Treatment of Leather Tanning
And Municipal Wastes at Grand Haven, Michigan
CARL V. HUBER, Vice President
GORDON E. JONES, Sanitary Engineer
Prein & Newhof, Consulting Engineers
Grand Rapids, Michigan 49505
INTRODUCTION
The City of Grand Haven and the Village of Spring Lake located in lower Western
Michigan joined together in 1969 to form the Grand Haven-Spring Lake Sewer Authority.
The purpose of such an Authority was to provide the most economical wastewater
treatment for both municipalities.
Located within the City of Grand Haven is the Eagle Ottawa Leather Company, a
chrome tanner of approximately 2,000 cattle hides per day. The need for updated treatment
facilities for both municipalities and Eagle Ottawa became apparent when Michigan Water
Resources Commission ordered each to remove 80% of the phosphorus, and set a
maximum limit from all three sources of 4,000 pounds per day of BOD5 and 40 mg/1 of
suspended solids. These limits necessitated removals of 70% BOD and 94% suspended
solids.
With this goal in mind, preliminary design including pilot and laboratory studies were
begun to determine the most effective and economical way of treating the combined
wastewaters. The volume of wastewater attributed to the tannery was only 20%, however,
the BOD and suspended solids share was approximately 90-95%.
WASTE CHARACTERISTICS
Table I indicates the expected domestic and tannery waste characteristics and the
hypothetical combination of both. The concentrations as shown are average concentrations
over a 24 hour period.
TABLE I
WASTE CHARACTERISTICS
Domestic
Tannery
Combined
Volume, MGD
4.0
1.0
5.0
BODs. mg/1
150
1000
320
Suspended Solids, mg/1
150
2500
620
pH
7.6
11.0
9.5
Phosphorus, mg/1
6.0
-
4.8
Nitrogen (Total N), mg/1
10.0
250
58
Chrome, mg/1
-
140
30
Sulfides, mg/1
-
280
56
Other problem characteristics exist with the tannery wastewater which are less
definitive than mentioned above. These are well known in the tannery industry as they relate
to the treatment of the wastewaters. They include: 1) high lime, grease, and hair
concentrations contribution to pipe clogging and scale build-up in all treatment units; 2)
release of odor causing sulfides; 3) toxicity from the chrome interferring with any biological
treatment process; and 4) color.
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