Various corrosion problems can occur in wastewater installations, which can be resolved through cathodic protection. Underwater motors, aeration systems, scrapers, ladders, and even concrete reinforcement can be affected by corrosion due to pollution and any chlorides that increase electrical conductivity, as well as the introduced oxygen and the turbulence of the fluid.
Typical anodes used for this purpose are activated tubular MMO anodes. Due to the presence of chlorides (urea, road salt), wastewater impressed current systems are treated as if they were offshore installations. Therefore, all components of the CP system must be manufactured to high quality standards. This includes the use of Kynar HMWPE cable, MMO anodes with a seaworthy coating, and high-quality measuring electrodes.
Installations in wastewater basins are always potential-controlled, given that various metal types are used, ranging from steel to stainless steel in various designs. Another reason for this potential control is the varying electrical conductivity of the water, e.g., due to the use of road salt, hotel occupancy, holiday periods, etc. An automatically controlled adjustment of the installation is therefore a must.
