Filterable substances
Filterable substances (AFS) are sinking, suspended and floating substances contained in wastewater and are separated off by filtration . They usually result in a visible cloudiness. Their content is given in mg / l.
backgrounds
If the secondary clarifier of a sewage treatment plant is adequately dimensioned and the activation works without any problems, a content of around 10 mg / l can be expected in the drain. If the above conditions are not met, 30 to 50 mg / l can be exceeded. The total phosphate parameter in the effluent of a sewage treatment plant is influenced by these undissolved substances. In addition, the substances that can be filtered off are an important parameter for nitrification . In the inlet to the biological stage, the values are around 200 mg / l.
