Ill. Admin. Code tit. 35, pt. 373, subpt. C, app A

Current through Register Vol. 48, No. 49, December 6, 2024

Appendix A - Maximum Critical Length

The maximum critical length of a receiving stream is the distance (downstream from the wastewater source) required at 7-day 10-year low flow to reestablish an instream BOD₅ of 5 mg/l. The amount of time required to reestablish the 5 mg/l BOD₅ is termed the critical time of travel. The maximum critical length can be estimated by computing the maximum critical time of travel, which can be approximated using the following equation:

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This relationship assumes that BOD₅ decays according to ordinary first order reaction kinetics.

Ill. Admin. Code tit. 35, pt. 373, subpt. C, app A