Largest MBR from Hamworthy

Hamworthy Water Systems has delivered its largest ever membrane bioreactor (MBR) wastewater treatment plant for installation on board a cruise ship. The twin process tank system, delivered to Meyer Werft’s Papenburg yard in Germany is being installed on board a cruise ship of passenger capacity 5,600 due for delivery to an unspecified shipowner later in 2010.

The system features 64 membranes and has the capability to treat all of the ship’s black and grey water, which is expected to be in the region of 1,800m³ per day. Its two process tanks each have a capacity of 250m³. Strict restrictions imposed by the yard required Hamworthy to deliver tanks weighing no more than 40 tonnes apiece, necessitating the incorporation of an internal ‘space frame’ of minimum weight for good structural stiffness and load distribution.

Finite element analysis techniques were used to optimise the design in terms of stress distribution. Particular consideration went to stresses during the lifting of the tanks onto the ship. Other than the internal space frame there are no stiffeners inside the tank, giving ‘clean’, accessible internal surfaces for the epoxy coating. The tanks were fabricated by Hamworthy’s supplier in northeast Germany and transported by sea to Papenburg.

The company’s head office in Poole took responsibility for plant design, overall project management and critical equipment procurement, while the Hamworthy plant in Suzhou, China, completed the preliminary auxiliary skid fabrication and outfitting, with Hamworthy Serck Como in Germany finalising the skids for installation. Hamworthy Serck Como also supplied the internal and external aeration and other pipework for the main process tanks. PST