ILLINOIS

POLLUTION

CONTROL BOARD

October 26, 1971

SCHOOL BUILDING COMMISSION

v.

)

PCB 71—247

Environmental Protection Agency

Supplemental Statement (by Mr. Dumelle)

I would like to amplify on the opinion in this case with

which I fully concur, on the matter of infiltration and sewer

repair. The testimony of Mr. Brian P. Nays and his engineering

notes (mt. School Ed. Ex, 6) detail the estimated hydraulic loads

to the sewer in question as follows:

Residential

450,000 gpd

High School

74,000

Elementary School

6,000

Elementary School

19,000

Water Plant (Peaks)

554,400

Infiltration (Normal)

12,600

1,116,000 gpd

Since the sewer does in fact surcharge, it is obvious that

hydraulic loads to it are in excess of its capacity of 1,670,000 gpd

during rainy weather. That additional 554,000 gpd must come from some-

where. It must be due to infiltration or illegal connections.

Even if the usual design (~normal~)infiltration rate of 500 gpd

per inch of diameter per mile of sewer is increased ten—fold (from

12,600 gpd to 126,000 gpd) the storm induced excess flow would

not be accounted for.

The sewer is evidently about 2.1 miles in length judging

from Mr. Mays~infiltration computation. It should be a relatively

simple matter to detect illegal storm connections to short length

of sewer and to repair the worst leaks sufficient to reduce hydraulic

loads during rains to the sewer~s capacity. The Village of Flossmoor

ought to do this now before frost in the ground makes excavation too

difficult.

I would also like to focus on Mr. Currie~s statements about the

hazard of raw sewage in streets and basements. The Board in recent

hearings on sewer ban regulations at Waukegan heard testimony from

a Lake County public health official telling of 22 cases of hepa~

titis there with a common factor of basement inundation by sewage.

Further, the recently issued report by the Lake Michigan And

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