The project is a cooperation with the medium-sized companies Schult-Bau GmbH, POMA Maschinen- und Anlagenbau GmbH Porschendorf and Hotho-Data GmbH and is financed within the framework of the Central Innovation Programme for SMEs (ZIM) of the Federal Ministry of Economics and Energy over a period of 2 years (01.01.2019 - 31.01.2021).

In sewers, the reduced volume of waste water results in an increased service life of the waste water with the same organic content. These conditions favour the formation of biofilms in the sewers. The biochemical conversion of sulphate via hydrogen sulphide to sulphuric acid leads to biogenic (sulphuric acid) corrosion of concrete (BKS) and a considerable odour nuisance. Surveys of wastewater sewer operators have shown that the reduction of biogenic corrosion and the associated odour nuisance are among the most urgent problems in the operation of wastewater disposal systems.

Biogenic corrosion is caused by the interaction of sulfur-reducing and sulfur-oxidizing bacteria. The sulphur-reducing bacteria (SRB), which are located in the aqueous phase at the bottom of the sewer, reduce elemental sulphur to hydrogen sulphide under anaerobic conditions. Sulfur oxidizing bacteria (SOB), which are located at the apex of the sewer pipe, use the hydrogen sulfide from the sewer atmosphere for aerobic respiration. The resulting sulphuric acid causes corrosion of the concrete pipe.

Within the scope of the cooperation project, a dynamic ventilation solution for problem sections in sewers to reduce emissions and biogenic corrosion is to be developed. The method to be newly developed differs from previous methods in that it is operated effectively and cost-effectively by real-time measurement of the H2S control variable using a probe without chemicals, only the air supply (ventilation).

For this purpose, the Multiparameter Diagnostics Working Group of BTU will characterize the biofilm, which is the main cause of biogenic corrosion, depending on the seasonal and external influences of the duct. The development and construction of a laboratory test rig will be carried out, which imitates and quantitatively records various weathering conditions in the canal (such as H2S content, temperature, pH value) with simple and manual steps. The model parameters obtained serve as the basis for the ventilation technology, which is subsequently installed in the canal to dry out the biofilm.

The analysis of the 16S rRNA metagenome by means of next generation sequencing (NGS) enables us to identify the microorganisms (genus/species) independently of their cultivability. Our focus is on the proportion of sulfur oxidizing bacteria and their ability to form a biofilm. The characterization of the three-dimensional biofilm is performed with our proprietary imaging platform technology VideoScan, which is a versatile, fully automated fluorescence microscopy platform. The platform provides information about the number of bacteria, the colonized area and the maximum thickness of the biofilm. By using fluorescence-labeled DNA probes (Fluorescence in situ hybridization, FISH) we can specifically identify bacteria by their genus in mixed biofilms and, in combination with other dyes such as Calcoflour and fluorescence-labeled lectins, we can simultaneously characterize the components of extracellular polymeric substances essential for bacterial agglomerates.