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Lecture: New storm water treatment


Lecture on the current topic:

Performance and testing of decentralized stormwater treatment systems“

The progressive sealing of land and anthropogenic contamination require solutions in the field of stormwater treatment. Nearby treatment and infiltration help to relieve hydraulically stressed drainage systems, contribute to the restoration of the natural water balance and take targeted action at the point of pollution. Decentralized stormwater treatment plants can offer an alternative.

In Germany, but also in other countries, requirements are already being placed on these systems and they are being tested under laboratory conditions. The presentation shows the current problems, gives an overview of the different treatment systems and their possible applications, and presents the test requirements and the tests itself.

 Speaker: Daniela Schmitz, Time: 09.02.2022 at 10:00 a.m., Language: English

Duration: Max. approx. 30 minutes each + 10 minutes questions / discussion / feedback

 If you are interested, you can register here:

On June 1, 2021, additional requirements for discharging wastewater into the Baltic Sea enter into force!


In order to reduce nutrient discharges from ships into the Baltic Sea the HELCOM - Baltic Marine Environment Protection Commission proposal to designate the Baltic Sea as MARPOL Annex IV special area was sent to International Maritime Organization in 2010. Although the designation of the Baltic Sea already entered into force in 2013 the applicable date of enforcement has been set for June 1, 2021 for existing IMO registered passenger ships. For direct passages between St. Petersburg and the North Sea there is an extension until 1 June 2023.​

In the meantime, it has been recognized that further measures are needed to ensure the effectiveness of the environmental protection measures in MARPOL Annex IV. In addition to the revision of the type approval in MEPC.227(64), this also includes methods for inspection of installations and discharges on board during operation.

For more information and assistance on how to comply with these new requirements, please feel free to contact us.

Designation as DIBt test center


Since March 2021, PIA GmbH has been a designated testing body by Deutsches Institut für Bautechnik (DIBt) for the testing of systems in accordance with the approval principles for storm water treatment systems Part 1: Systems for the decentralized treatment of wastewater from motor vehicle traffic areas for subsequent infiltration into soil and groundwater.

The testing of the plants includes the retention of fine particles with Millisil W4, the retention of mineral oil hydrocarbons and the retention of the heavy metals zinc and copper. The latter test is carried out on a scaled-down filter element. In order to obtain building authority approval for the system, a particle retention of at least 92 % and a hydrocarbon retention of at least 80 % must be demonstrated. Within the scope of the heavy metal test, the effluent values of ≤ 1,875 µg/l for zinc and ≤ 144 µg/l for copper must be complied with. In addition, heavy metals may only be redissolved by de-icing salt within specified limits.

To date, ten storm water treatment plants of various designs have been tested in the test hall built by PIA GmbH for this purpose. The existing infrastructure allows the testing of plants with a connection size of up to 8,000 m². Underground storage tanks guarantee a receiving water volume of 80 m³. The discharge water is cleaned on site via buffer tanks and a light liquid separator before it is discharged into the sewer.

At the international level, test requirements vary with regard to the rainfall donors used, the pollutant load and the composition of the test media. The use of alternative test media helps to understand the effectiveness of the system under real-world conditions. For example, rubber dust can be used to represent tire abrasion and microplastics. In addition, different requirements for feeding the plant require individual solutions, which are implemented in a practical manner at the test institute.