BOD Removal Efficiency Calculator
Removal efficiency compares the average influent and effluent concentrations for the parameter and reporting period your permit specifies.
Result
Removal efficiency
94.5%
Your plant removed about 94.5% of the influent concentration for this period.
At or above the general 85% removal in federal secondary treatment standards (40 CFR 133.102). Your permit controls the actual limit.
Running this daily? Get a free trending log
We'll email you a spreadsheet log for tracking this number over time, plus today's result and inputs. Or see how ComplyFlo calculates it automatically from your daily readings.
The formula
Removal (%) = (C influent,avg − C effluent,avg) ÷ C influent,avg × 100- C
- C = concentration (mg/L)
- C influent,avg
- Average influent concentration for the period (mg/L)
- C effluent,avg
- Average effluent concentration for the period (mg/L)
Good to know
- Average the period's concentrations first, then apply the formula. Averaging daily removal percentages is a different method and can give a different answer.
- Your permit sets the parameter, sampling locations, averaging period and calculation basis.
Read the full guide: The Wastewater BOD Removal Efficiency Formula
Frequently asked questions
What does C stand for in the formula?
C = concentration (mg/L).
Should I average daily removal percentages?
Average the period's concentrations first, then apply the formula. Averaging daily removal percentages is a different method and can give a different answer.
What removal percentage do I need?
Federal secondary treatment standards (40 CFR 133.102) generally call for 85% removal, but your permit sets the actual parameter, period and limit.
Stop running this math by hand
ComplyFlo for wastewater plants can calculate and trend SRT, F/M, HRT, RAS, SVI and removal efficiency from your daily readings, next to your plant dashboard and DMR-ready reports.
See ComplyFlo for wastewater plantsFree checklist
TPDES Permit Compliance Checklist
Review permit-specific DMR submissions, sampling, SSO reporting, renewal milestones, and applicable pretreatment responsibilities.
Want to see it on your plant's data?
Book a free 1-hour demo with a ComplyFlo team member.