Biogas plant – Protection against aggressive gases
In agricultural biogas plants animal excrement and plants are processed into nutrient rich manure by fermentation. This process releases high concentrations of biogenic sulphuric acid. The internal concrete or steel wall surfaces are attacked by these gases and can become corroded and porous. In isolated cases the destructive influence is so great that after only a few years there are many centimetres of concrete missing. Waterproofing specific to use and upkeep is indispensible as the plant operator is solely responsible for any water pollution claims. For this reason the main focus of all protective measures centres around the exposure of the interior to chemicals. The SCHOMBURG system products have a targeted anti-corrosive function and protect the surrounding wall areas from aggressive gases.
Static or water bearing cracks in concrete are to be professionally sealed (see the chapter on “crack repair“).
Apply ASOCRET-BIS-1/6 over the surface in one operation up to a thickness of 6 mm. Apply “wet in wet“ over a slurry bond coat of ASOCRET-KS/HB.
Brush apply ASOCRET-KS/HB. Then whilst this coat is still wet, produce a coved fillet with a minimum side length of 4 cm, by applying ASOCRET-BIS-5/40 “wet in wet“ by steel trowel or pointing trowel along the wall/floor junction.
Where there are flanges within the construction, apply the special primer ASODUR-SG2-thix over the flange construction using a short haired fur roller avoiding bubble formation and immediately broadcast with coarse quartz sand. Once adequately hardened further waterproofing measures can be carried out.
Wall: Firstly evenly apply ASODUR-SG2-thix with a short haired fur roller, followed by thoroughly working into the surface with a priming brush and then backrolling with the fur roller.
Floor: Apply ASODUR-SG2 in sections with a twin-bladed rubber squeegee, thoroughly brush in and back roll.
Blind the wet primer coat with coarse quartz sand in both cases.
Apply ASODUR-V2370 by roller, spray or brush. Wait approx. 16–24 hours between successive coats.
Apply another coat of ASODUR-V2370 using the same methods.