What you need to know
About one-fifth of the approximately 575,000 km long public sewer systems in Germany have damages that must be repaired in the short or medium term. A large amount of the damage is due to biogenic sulfuric acid corrosion (BSA) with a combined organic-chemical attack. The selection of suitable construction materials, depending on the respective stress scenarios, is particularly important. However descriptive building material models often reach their limits. Especially models where the performance of the product must be proven for maximum stress scenarios and life expectancy of up to 100 years.
The evaluation of the resistance as well as the performance and durability of the building products to be used against the above-mentioned stress in the area of the BSK can be carried out using a variety of test methods. Long-term tests or time-lapse tests in sulphuric acid with different pH values and stress scenarios are often used. These tests are partly regulated by standards. The evaluation criteria are determined depending on the material and the respective test procedure.
The "MIC-Performance-Test" from Kiwa
The "MIC-Performance-Test" offers the possibility of testing the resistance of building products under real and particularly critical conditions in wastewater engineering plants against biogenic sulphuric acid corrosion (BSK). The facility is located in a former pumping station of the Berliner Wasserbetriebe. In addition to the tests focusing on material resistance and the associated qualification of the biofilm under wastewater stress scenarios, investigations into the prevention of odour pollution are also carried out at this facility.
The advantages of the "MIC-Performance-Test"
With the help of the "MIC-Performance-Test" we make a meaningful prediction of the service life of building materials. This means that repair work can be reliably planned in the long term and failure costs can be reduced.
Compared to other testing methods, the "MIC-Performance-Test" offers the following advantages:
- The test procedure is carried out under real conditions on a large-scale, with data (on e.g. the "drivers" of the damaging BOD, such as temperature, humidity,H2S content) being registered and controlled by extensive monitoring.
- Microbially induced sulphuric acid corrosion (MIC) can produce material-specific results that differ from those of simulation tests with storage in acid baths. The interaction between the microorganisms and the building material, which influences bacterial growth and the degree of damage, is tested under real conditions.
- The temperature, humidity and H2S concentration are adjustable so that different degrees of attack (time-lapse effects) can be simulated.