Damage from chemical and biological processes

With regard to durability, wastewater structures have a special position in the field of reinforced concrete construction, as these structures are subject to many different and in some cases very strong chemical and biological attacks. Especially in sewage treatment plants, the different chemical and biological treatment processes, which can vary greatly depending on the methods used, can lead to a wide range of different durability problems. However, under the common present-day conditions some damage mechanisms have been identified as typical for sewage treatment plants. Nevertheless, this phenomenon is often not confronted sensitively or consistently enough, either in new construction or during repairs.

Attacks from biogenic sulphuric acid corrosion

The essential problems in sewage treatment plants are a frost/thawing salt exposure combined with abrasion of the scraper trackways and a chemical attack by the wastewater on the concrete surface. While wastewater generally only attacks the concrete surface moderately, the biogenic sulphuric acid corrosion in the gas room (covered containers, pipes…) from putrid wastewater should be emphasized.

Extraction units alone cannot reduce the risk of biogenic sulphuric acid corrosion sufficiently; the professional protection of the concrete surface is required here.