Kent Logan, President

Donald Massier, Vice President

Donald Markgraf, ClerklTreasurer

Lloyd Hawks, Trustee

Roger Erkert, Trustee

Dean Falkner, District Director

RECEIVED

March 1, 2002

CLERK’S

OFFw~r

MAR 5

2002

STATE OF IWNOIS

Pollution Control Board

RE:

Support for IEPA Carbonaceous BOD Proposal

Before the IPCB

Dear Ms. Gumi:

The use of carbonaceous BOD as a parameter for measuring the efficiency of secondary

treatment processes has been a standard for many decades. Also, the concern of interference

from nitrogenous compounds in the

BOD-5

test has been a concern traceable in literature from

the 1930s. It has further been demonstrated that while the nitrogenous interference is sufficiently

high to need correction, it is nevertheless a small portion of the total BOD from nitrogenous

compounds.’ Consequently, in 1984 the USEPA authorized the use of CBOD for determining

secondary treatment process efficiencies.

In general, treatment plants strive for the highest efficiency and, therefore, the lowest CBOD

effluent that their individual processes can achieve. Typical CBOD effluents range from 3 to 9

mg/i. It is the District’s belief it is not necessary to deviate from IEPA’s suggested CBOD

parameters. The BOD tests by theirvery nature, have a large standard deviation. For example, a

fmal effluent CBOD of 6 mg/l could easily have a standard deviation of plus or minus 2 or a

range from 4 to 8 mg/l and, therefore, statistically all numbers between 4 and 8 are the same as

the mean of6.

It is further suggested that rather than reduce the limits suggested by IEPA, the Board may

consider an approach ofsetting warning limits or limits that would rather than trigger compliance

enforcement, initiate investigations by the POTWs into the reasons for the higher-than-usual

reported values. As example, the warning limit could be triggered when a POTW discharges

CBOD above the

80th

percentile ofstandard.

1

Chemistry for Sanitary Engineers published 1960. Clare N. Sawyer, Chapter 23

Lation

1-

3333 Kishwaukee Street

P.O. Box 7480

Rockford, Illinois 61126-7480

I~8-r~4~r~

815) 387-7400

ii 11

Illinois Pollution Control Board

Attn: Dorothy Gunn, Clerk, re Docket R02-11

James R. Thompson Center

100 West Randolph Street, Suite 11-500

Chicago, Illinois 60601

y

---

Dorothy Gunn, IPCB

Page 2

In conciusion, it is the District’s position that the standards as proposed by the IEPA for

carbonaceous BOD are adequate and fully protective ofthe environment. Treatment plants strive

to do the most efficient job of treatment that their individual processes will allow. Last, the

Board may wish to consider a standard with warning limits to trigger actions at the POTWs.

Thank you foryour consideration in this matter.

Sincerely,

Dean Faikner

District Director