Part 1: Prefabricated septic tanks

Additional tests for septic tanks according to EN 12566-1

Daniela Schmitz, M.Sc.

Testing Engineer

  +49 241 75082-19

  +49 241 75082-29

 

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Defining the nominal capacity

Along with the water tightness test, the usable volume of a septic tank must be measured and defined. To do this, the volume of water is measured at the height of the outlet with a calibrated measuring device (magnetic induction).

 

Test of the hydraulic efficiency

The hydraulic efficiency is used to measure of the retention of the settleable solids and floating material from septic tanks. To do this, polystyrene beads are utilised to simulate the settleable solids and floating matter. The result is expressed by the amount of polystyrene beads collected in the effluent of the septic tank in grams.

Part 3: Packaged and/or site assembled domestic wastewater treatment plants

Part 6: Prefabricated treatment units for septic tank effluent

In addition to testing the septic tanks as a first treatment stage in accordance with EN 12566-1, you can also individually CE-mark the second treatment stage so that you can place them on the market. Plants of the second treatment stage (usually bioreactors), which generally treat wastewater coming from septic tanks, are tested according to the relatively new standard EN 12566-6. Here too, the 38-week test with different test modes is used to verify the treatment efficiency. The tests of the tank, however, are carried out according to the standard EN 12566-3. We can show you various combinations so that you can reduce costs. Talk to us.

Part 7: Prefabricated tertiary treatment units

EN 12566-7 defines the requirements for prefabricated tertiary treatment units for small wastewater treatment systems. The procedures described in the standard enable a further purification to improve the quality, which cannot be achieved by the first treatment stage (primary treatment) and the second treatment stage (biological treatment) alone. The third purification stage and its plant modules are usually not independent treatment systems. They are only used in combination with a primary clarification and a biological treatment and concentrate on a specific treatment objective, such as the additional reduction of phosphorus or nitrogen.

Depending on the type of process, two different test sequences are prescribed for determining the cleaning performance. The test duration for chemical and electrical processes is seven weeks, for biological and physical processes 16 weeks. For the test, the manufacturer specifies the daily inflow and the daily pollution load for COD, BOD, SS and the parameters that are in focus for the plant. The inflow dynamics are also relevant. This is usually oriented either to the flow diagram of an SBR system or a gravity-flow system and thus also specifies the later area of application. The transferability of the performance of the plant to other inlet conditions is generally not possible. Therefore, in order to make the application of small sewage treatment plant modules for the third purification stage meaningful, it is necessary to also specify the inflow conditions during the test in addition to the results and the specific purification target that is in focus.

• Biological processes:
  Treatment mainly by microorganisms
  Priority objective: reduction of COD, BOD, SS and nitrogen
  
  
• Physical processes:
  e.g. by filtration
  Priority objective: reduction of SS and phosphorus
  
  
• Chemical processes:
  Treatment mainly by addition of chemical substances
  Priority objective: reduction of SS and phosphorus
  
  
• Electrical process:
  Treatment mainly by the use of electricity
  Primary objective: Reduction of microorganisms

The following manufacturers have successfully performed a test according to EN 12566-7 at PIA GmbH and agree to be listed on this website: