Population equivalent
The population equivalent ( EGW ) serves as a reference value for the pollution load in the water industry . It can be related to the biochemical oxygen demand (BOD 5 ) , the chemical oxygen demand (COD) , the nitrogen , the phosphorus , the total organic carbon , the suspended solids or the water consumption . It indicates the population equivalent of the daily quantities of these substances or consumption in wastewater from industry, commerce, agriculture, etc.
The sum of the actual population (EZ) and population equivalents (pe) gives the for the design of wastewater treatment plants important population equivalent (pe).
- The following applies: EW = EZ + EGW
With the help of the population value, the expected biological pollution of sewage treatment plants can be estimated.
The population equivalents can differ from country to country, even from sewage treatment plant to sewage treatment plant, as the level of development, industrialization, the proportion of urban or rural areas and other factors play a role.
The following values are used as population equivalents in Germany , Austria and Switzerland :
- Water consumption 180 ℓ / d
- BOD 5 60 g / d
- COD 120 g / d
- TOC 45 g / d
- Suspended matter 70 g / d
- Kjeldahl nitrogen (total N without nitrate and nitrite) 11 g / d
- Phosphorus (total P) 1.8 g / d
In the USA , BOD 5 loads of around 75 g of oxygen are used per person per day.
Industrial companies in Germany have the option of assessing the fees for discharged wastewater using the EGW; causes a company BSB 5 -Fracht of 10 kg O 2 / day, this corresponds to the volume of waste water of about 167 inhabitants (10,000 g BOD 5 /60 g BOD 5 / inhabitant).
literature
- Definition and standardization of indicators for wastewater disposal , Association of Swiss Wastewater and Water Protection Experts , 2006
Individual evidence
- ↑ Willi Gujer: Siedlungswasserwirtschaft , Springer, 3rd edition, 2007, ISBN 978-3-540-34329-5 , pages 71 and 93