VWS Westgarth, which operates the sulfate reduction membrane systems, specified that all wetted parts of the chemically-enhanced backwash pumps should be made from titanium in order to withstand the corrosive fluid.
This includes the casings, impellers, and shafts.
According to Amarinth, titanium must be cast under a full vacuum using copper crucibles to prevent molten titanium from attacking the crucible walls. The company worked with a foundry in the UK with the capability to cast large titanium components in optimizing the design of the castings, in order to maintain the correct flow of the molten titanium over changes of dimensions and directions.
Amarinth completed delivery of the pumps within the 28-week deadline.