Illinois Administrative Code
Title 35 - ENVIRONMENTAL PROTECTION
Part 301 - INTRODUCTION
Section 301.345 - Population Equivalent

"Population Equivalent" is a term used to evaluate the impact of industrial or other waste on a treatment works or stream. One population equivalent is 100 gallons (380 l) of sewage per day, containing 0.17 pounds (77 g) of BOD5 (five day biochemical oxygen demand) and 0.20 pounds (91 g) of suspended solids. The impact on a treatment works is evaluated as the equivalent of the highest of the three parameters. Impact on a stream is the higher of the BOD5 and suspended solids parameters.