Description Equivalent Andritz S 150-330 Open Impeller Pump with mechanical seal cover the requirements for municipal and for industrial wastewater disposal. Alternative Andritz S series single-stage process centrifugal pumps are available with closed, semi-open or open impellers. These wear-resistant pumps are suitable for working with a wide range of media. Depending on the type of impeller, they can transport contaminated liquids with amount of solids up to 8%. They are used as process pumps in paper, chemical, sugar, energy, food industries, water, sewage treatment, drainage or other systems.