Talk:Population equivalent

Definition needs reworking[edit]

I dont think the definition is correct. The EU definition is 'One population equivalent (p.e.) means the organic biodegradable load having a five-day biochemical oxygen demand (BOD5) of 60 g of oxygen per day'. Hollycot (talk) 10:23, 30 October 2012 (UTC)[reply]

This article limits the definition to industrial waste water. In applications where the population is also contributing to the BOD load (e.g. sewage treatment) this formula would not apply. Hence a more general definition such as suggested by Hollycot would be more suitable. Rajbpl (talk) 09:35, 24 November 2015 (UTC)[reply]

I agree. Currently don't have time to work on it but will add it to-do list... Pinging also Thewellman and Velella.EMsmile (talk) 02:02, 15 October 2021 (UTC)[reply]

I don't have enough information to make a meaningful contribution, but reproducability of these values should be explored. I would expect fairly significant variation depending on the seed culture used for the BOD test, and even greater variation based on absence or presence and concentration of disinfectants or toxins in the industrial waste streams. If these criteria are defined, they should be described. The equivalents are presumably based on the industrial rates of production (cans of peas, number of chickens, gallons of refined petroleum, etc.), but I wasn't able to determine the unit(s) used in the table. Thewellman (talk) 03:27, 15 October 2021 (UTC)[reply]

The EU definition was coined in the context of the Urban Wastewater Treatment Directive. This is a complex and far reaching directive which establishes standards of treatment of waste waters across the EU and has to cover an enormously wide spectrum of waste water streams, not least to determine what is, and what is not covered by the directive. It is defined by a precise BOD value because anything less precise would lead to interminable wrangling. It should not be assumed that anyone formulating this directive actually thought that this value was the single definitive value. It is arbitrary but adequate to enable the directive to be applied uniformly across the EU. That is all it is. It has no greater significance. For the sake of clarity and openness I can clarify that I was part of those discussions and gave evidence to the commission and yet I believe that the Wikipedia definition is a better world view of a population equivalent. But then my view, a personal view, should not hold any sway here. Velella ^{Velella Talk} 22:16, 25 October 2021 (UTC)[reply]