Population equivalent
From Coastal Wiki
Population equivalent (p.e.) is a measure of pollution representing the average organic biodegradable load per person per day: it is defined in Directive 91/271/EEC as the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day.
References
The European Commission, Glossary of terms related to Urban Waste Water [1]