Abstract: A centrifugal pump assembly includes a pump head, a pump base defining a pump inlet and a pump outlet, a fluid outlet channel from the pump head to the pump outlet, impellers, defining an impeller fluid channel between an impeller inlet and outlet and connected with one of rotor shaft segments including a positive fit coupling for torque transfer between at least two rotor shaft segments, and one or more pump stage housing segments arranged between the pump base and the pump head. The pump stage housing segments have a structure defining a guide passage for receiving pumped fluid from the impeller outlet of the impellers and for guiding pumped fluid to the impeller inlet of another one of the impellers or to the pump head. The pump stage housing segments each have a structure defining at least a part of a wall section of the fluid outlet channel.

Abstract: A centrifugal pump assembly includes a pump head, a pump base defining a pump inlet and a pump outlet, a fluid outlet channel from the pump head to the pump outlet, impellers, defining an impeller fluid channel between an impeller inlet and outlet and connected with one of rotor shaft segments including a positive fit coupling for torque transfer between at least two rotor shaft segments, and one or more pump stage housing segments arranged between the pump base and the pump head. The pump stage housing segments have a structure defining a guide passage for receiving pumped fluid from the impeller outlet of the impellers and for guiding pumped fluid to the impeller inlet of another one of the impellers or to the pump head. The pump stage housing segments each have a structure defining at least a part of a wall section of the fluid outlet channel.

Abstract: The present invention relates to a process and device for selectively removal of deflocculated sludge below a pre-selected size from a sludge mixed liquor. The invention resides in the concept of removing from the sludge mixed liquor deflocculated sludge. The removal is preferably carried out by a two-step separation providing a fraction comprising sludge flocs, substantially freed from deflocculated sludge, and a fraction containing mostly deflocculated sludge. The fraction comprising sludge flocs is returned into the sludge mixed liquor, while the fraction containing mostly deflocculated sludge is removed from the system.

Abstract: The present invention relates to a filtering device for a water treatment system comprising a biological treatment device adapted to provide a sludge from wastewater or filtrated wastewater, and/or the biological treatment device being fluidic connectable to or in fluidic connection with the filtering device for receiving filtrated wastewater from the filtering device and for delivering sludge to the filtering device. The filtering device is a cake filtration device comprising a fluid penetrable support structure and the support structure is provided as one or more tubular elements having a filtration cake provided on the inside of the fluid penetrable support structure.

Abstract: The present invention relates to a process and device for selectively removal of deflocculated sludge below a pre-selected size from a sludge mixed liquor. The invention resides in the concept of removing from the sludge mixed liquor deflocculated sludge. The removal is preferably carried out by a two-step separation providing a fraction comprising sludge flocs, substantially freed from deflocculated sludge, and a fraction containing mostly deflocculated sludge. The fraction comprising sludge flocs is returned into the sludge mixed liquor, while the fraction containing mostly deflocculated sludge is removed from the system.

Abstract: The present invention relates to a water treatment system comprising a pre-filtering device receiving water, such as waste water, to be treated and providing a filtrate, and a biological treatment device being fluidic connectable to or in fluidic connection with the pre-filtering device for receiving the filtrate from the pre-filtering device. The biological treatment device is adapted to perform a biological treatment of the filtrate and to provide sludge solids. The pre-filtering device is a cake filtration device having a filtration cake wherein the filtration cake is being provided by deposition of solids from the sludge formed in the biological treatment device. A water treatment process employing the system and a method of forming a filter cake are also described.

Abstract: The present invention relates to a filtering device for a water treatment system comprising a biological treatment device adapted to provide a sludge from wastewater or filtrated wastewater, and/or the biological treatment device being fluidic connectable to or in fluidic connection with the filtering device for receiving filtrated wastewater from the filtering device and for delivering sludge to the filtering device. The filtering device is a cake filtration device comprising a fluid penetrable support structure and the support structure is provided as one or more tubular elements having a filtration cake provided on the inside of the fluid penetrable support structure.