Sewage Parameters 3: Population Equivalent (PE) Part 1

Next up in our Education Blog series is Population Equivalent or PE. It is the term most used to describe the size of package sewage treatment plants.  It can be defined as; ‘The equivalent, in terms of a fixed population, of a varying or transient population (e.g. Restaurant or Airport) based upon a figure of 60 grams/BOD/hd/day and 200 litres/hd/day.

Sewage Parameters 1: BOD

Before discussing package sewage treatment it is best to explain the parameters used to define sewage both when it comes into a treatment plant (influent) and when it leaves a sewage treatment plant (effluent)  One of the main parameters to consider is BOD or BOD5 which means Biochemical Oxygen Demand (the ’5′ refers to the sewage being tested for BOD over 5 days, which is standard when testing BOD levels)

Waste/Surface Water Education Blog -Introduction


this is my first post as part of our new education blog which will be focusing on all areas of package wastewater and surface water treament.  The aim of the blog will be to explain different elements of the waste/surface water treatment process/terminology in easy to understand bite size chunks.