Sulzer Mixers Designed To Tackle Digested Sludge

The wastewater treatment plant of Crispijana, operated by the municipal water and sewage company Amvisa (Aguas Municipales de Vitoria-Gasteiz, S.A.), treats the wastewater from the city of Vitoria-Gasteiz, Álava, Spain. The plant has a capacity of 120’000 m³/day, 500’000 population equivalent. It has undergone a number of changes and extensions since it was opened in 1984. During the latest upgrade in 2016, the mixing problem caused by the high sludge content was solved.

Four submersible mixers of type ABS RW 6533 A100/12 were installed in the Crispijana WWTP several years back. Before this, the treatment plant used another manufacturer’s brand. After a short period of time, however, all mixers started experiencing frequent bearing failures and motor burnouts. This was due to the high concentration of sludge, which makes mixing a tough task.