Modular filtration system

DETAILED DESCRIPTION In the present invention apparatus and methods are provided in which the head pressure developed by the weight of a fluid is used to drive a plurality of filters to produce a permeate, and in at least some level (i.
e.
at some depth) within the apparatus at least 30% of the permeate produced is collected within a single filter casing.
The inventive subject matter can thereby reduce or eliminate clustering in channel-based and other filtration systems, and thus provide for improved efficiency and cost effectiveness.
In preferred embodiments substantially all of the filter material at a given depth is wrapped about one or more permeate collectors within a single filter casing.
In still more preferred embodiments the filters and lengths of collector tube(s) form the inner cores of a series of production modules.
In especially preferred embodiments each of the production modules further includes a transport zone for transporting brine and a transport zone for transporting permeate.
In other aspects the ends of adjacent production modules may be designed to mate with one another using a slip fit joint, and the production modules may be maintained in mating relationship through connections to supporting cables or rods.
In still other aspects of the inventive subject matter a submerged pump may be used to raise permeate towards the surface.
In preferred embodiments having this feature, the pump can operate at least using centrifugal and/or air lift principles, and where an air lift principle is used an energy recovery system can be employed to recover energy from the rising fluid and gas.
It is also contemplated to employ a gas produced via electrolysis to assist in the pumping.
In still other aspects feed fluid can be provided from a salty or brackish water source such as an ocean or bay using pipes having removable inlet plugs which resist clogging.
It is also contemplated that such pipes can be laid using an underwater sled which digs a trench while concurrently laying the pipe