This paper addresses three empirical methods used to determine degree of Base Infiltration (BI) in 45 isolated sewer basins throughout the Orange County Sanitation District (OCSD) collection system. These include a common estimation method called night-time "Wastewater Production",
a secondmethod called "Minimum Flow Factor", and a third empirical method employing the "Stevens/ Schutzbach" equation. These empirical methods were tested against a chemical parameter verification method that involves regressing hourly concentrations of several common wastewater chemical
analysis parameters (Chemical Oxygen Demand — COD, etc.) with hourly sewage flow rates. The chemical parameter method results were also compared to BI estimates based on potable water use records. Results to date indicate that the "Minimum Flow Factor" method and a slightly modified
version of the "Wastewater Production" method provide more accurate estimates of BI in basins yielding flowscomprised of more than 25% BI. Alternatively, the "Stevens/ Schutzbach" empirical method providesgood estimations of BI in basins yielding BI flows less than 25% and is also far more
stable in such basins (i.e., less sensitive to errors in minimum night-time flow measurements).
Proceedings of the Water Environment Federation is an archive of papers published in the proceedings of the annual Water Environment Federation® Technical Exhibition and Conference (WEFTEC® ) and specialty conferences held since the year 2000. These proceedings are not peer reviewed. WEF Members: Sign in (right panel) with your IngentaConnect user name and password to receive complimentary access.