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AssigneeZenon Environmental Inc.
InventorsSteven Kristian Pedersen, Henry Behmann
Estimating the term…
The outer surfaces of hollow fiber membranes in a skein, or a bank or cassette of stacked skeins, are kept essentially free of solids by maintaining a substantially uniform flow of a stream of coarse bubbles through each of plural orifices in an aerator disposed beneath the fibers. Aerators for skeins used in microfiltration of wastewater in a tank are periodically flushed when their air orifices are fouled, by injecting a flushing fluid into a fouled aerator. The flushing fluid may be a two-phase mixture of flushing liquid and air, or flushing liquid only. The flushing liquid may be permeate, clean water or wastewater (substrate). When air is injected into the flushing liquid flowed to an aerator for less than 5 min, preferably less than 20 sec, the flushing fluid produces discrete masses of liquid which are flowed laterally through the body of the aerator, cleaning its walls and maintaining the orifices essentially free from plugging. When only flushing liquid is flowed through the fouled aerator for less than 5 min, preferably less than 20 sec, the flushing liquid is highly effective to keep the air orifices clean.
In a method for maintaining production of permeate at equilibrium flux, in a skein submerged in a solids-containing substrate held in a tank, continuously, by scrubbing hollow fiber membranes (“fibers”) of said skein with bubbles generated from scrubbing gas flowed into an aerator's air plenum at a pressure greater than the liquid head between the surface of substrate in the tank and the surface of the substrate in the plenum so as to maintain a substantially uniform flow of a stream of said bubbles through each of plural air orifices in lateral walls of said aerator, in which stream the majority are coarse bubbles have an effective diameter in excess of 3 mm and rise at a velocity in the range from about 5 ft/sec to 10 ft/sec (1.5 m/sec to 3 m/sec), the improvement comprising,
A system for maintaining a skein submerged in a tank, and operating at equilibrium flux to produce permeate from a solids-containing substrate continuously, by scrubbing fibers of said skein with an inert scrubbing gas in the form of coarse bubbles generated in a coarse bubble aerator disposed beneath said skein, said aerator having an inlet for said scrubbing gas and flushing liquid, wherein said scrubbing gas is supplied at a predetermined pressure sufficient to maintain a substantially uniform flow of a stream of said bubbles through each of plural orifices in lateral walls of said aerator, in which stream the majority are coarse bubbles having an effective diameter in excess of 3 mm and rise at a velocity in the range from about 5 ft/sec to 10 ft/sec (1.5 m/sec to 3 m/sec), said system comprising in combination,
In a method for maintaining production of permeate at equilibrium flux, in a skein submerged in a solids-containing substrate held in a tank, continuously, by scrubbing hollow fiber membranes (“fibers”) of said skein with bubbles generated from scrubbing gas flowed into an aerator,
A system for maintaining a skein submerged in a tank, and operating at equilibrium flux to produce permeate from a solids-containing substrate continuously, by scrubbing fibers of said skein with an inert scrubbing gas in the form of coarse bubbles generated in an aerator, said system comprising in combination,
Dependencies are inferred from the claim text.