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Population equivalent

## Summary

Population equivalent (PE) or unit per capita loading, or equivalent person (EP), is a parameter for characterizing industrial wastewaters. It essentially compares the polluting potential of an industry (in terms of biodegradable organic matter) with a population (or certain number of people), which would produce the same polluting load.[1]: 65  In other words, it is the number expressing the ratio of the sum of the pollution load produced during 24 hours by industrial facilities and services to the individual pollution load in household sewage produced by one person in the same time. This refers to the amount of oxygen-demanding substances in wastewater which will consume oxygen as it bio-degrades, usually as a result of bacterial activity.[2]

## Equation and base value

A value frequently used in the international literature for PE, which was based on a German publication, is 54 gram of BOD (Biochemical oxygen demand) per person (or per capita or per inhabitant) per day.[1]: 65 [2] This has been adopted by many countries for design purposes but other values are also in use. For example, a commonly used definition used in Europe is: 1 PE equates to 60 gram of BOD per person per day, and it also equals 200 liters of sewage per day.[3][4][5] In the United States, a figure of 80 grams BOD per day is normally used.[6]: 171

If the base value is taken as 60 grams of BOD per person per day, then the equation to calculate PE from an industrial wastewater is:

${\displaystyle PE={\dfrac {BOD\ load\ from\ industry\ \left[{\dfrac {kg}{day}}\right]}{0.060\ \left[{\dfrac {kg}{inhab\cdot day}}\right]}}}$

## Population equivalents for industrial wastewaters

BOD population equivalents of wastewater from some industries[1]: 70
Type Activity Unit of production BOD PE

[inhab/(unit/d)]

Food Canning (fruit/vegetables) 1 ton processed 500
Pea processing 1 ton processed 85-400
Tomato 1 ton processed 50-185
Carrot 1 ton processed 160-390
Potato 1 ton processed 215-545
Citrus fruit 1 ton processed 55
Chicken meat 1 ton processed 70-1600
Beef 1 ton processed 20-600
Fish 1 ton processed 300-2300
Sweets/candies 1 ton produced 40-150
Sugar cane 1 ton produced 50
Dairy (without cheese) 1000 L milk 20-100
Dairy (with cheese) 1000 L milk 100-800
Margarine 1 ton produced 500
Slaughter house 1 cow / 2.5 pigs 10-100
Yeast production 1 ton produced 21000
Confined animals breeding Pigs live t.d 35-100
Dairy cattle (milking room) live t.d 1-2
Cattle live t.d 65-150
Horses live t.d 65-150
Poultry live t.d 15-20
Sugar-alcohol Alcohol distillation 1 ton cane processed 4000
Drinks Brewery 1 m3 produced 150-350
Soft drinks 1 m3 produced 50-100
Wine 1 m3 produced 5
Textiles Cotton 1 ton produced 2800
Wool 1 ton produced 5600
Rayon 1 ton produced 550
Nylon 1 ton produced 800
Polyester 1 ton produced 3700
Wool washing 1 ton produced 2000-4500
Dyeing 1 ton produced 2000-3500
Textile bleaching 1 ton produced 250-350
Leather and tanneries Tanning 1 ton hide processed 1000-3500
Shoes 1000 pairs produced 300
Pulp and paper Pulp 1 ton produced 600
Paper 1 ton produced 100-300
Pulp and paper integrated 1 ton produced 1000-10000
Chemical industrial Paint 1 employee 20
Soap 1 ton produced 1000
Petroleum refinery 1 barrel (117 L) 1
PVC 1 ton produced 200
Steelworks Foundry 1 ton pig iron produced 12-30
Lamination 1 ton produced 8-50