Zenon Environmental Inc.

Nicholas Adams

Pierre Lucien Cote

Arnold Frederic Janson

Manwinder Singh

Jason Cadera

Hadi Husain

Steven Kristian Pedersen

Hidayat Husain

Hamid R Rabie

Steven Pederson

A process for operating filtering membranes submerged in a tank involves, in one aspect, periodically deconcentrating the tank by partially emptying and refilling the tank with fresh water. The emptying and refilling may be performed generally simultaneously or sequentially. In another embodiment, the membrane modules are arranged in a series of filtration zones between a feed water inlet and a retentate outlet of a tank and the zone adjacent the outlet is emptied and refilled.

Water filtration using immersed membranes

A process for operating filtering membranes submerged in a tank involves, in one aspect, periodically deconcentrating the tank by at least partially emptying and refilling the tank with fresh water while permeation continues. In another aspect, long trains of membranes modules are placed in series along a flow path in the tank. In one embodiment, constant aeration is provided to prevent tank water from by-passing the membrane modules while proving controlled mixing such that the average concentration of solids in the tank is lower than the concentration of solids in the tank near an outlet for removing retentate from the tank. In another embodiment, the membrane modules are arranged in a series of filtration zones between a feed water inlet and a retentate outlet of a tank. Permeate is withdrawn from the filtration zones by separate means associated with each filtration zone. Tank water containing rejected solids flows in a tank flow through the filtration zones, increasing in concentration from one zone to the next. A preferred membrane module has membranes transverse to the tank flow and fills a substantial portion of each filtration zone. With either embodiment, aeration, backwashing or packing density of membranes varies between filtration zones and the flow pattern in the tank may be periodically reversed.

Modules of ultrafiltration or microfiltration membranes are arranged in a tank open to the atmosphere to substantially cover the cross sectional area of the tank. A filtration cycle has permeation steps and deconcentration steps. During permeation, supply of feed substantially equals feed removed and little if any aeration is used During deconcentration, aeration with scouring bubbles is provided with one or both of backwashing and feed flushing. In feed flushing, feed water is supplied to the tank from below the modules. Excess tank water created during deconcentration flows generally upwards through the modules and out through a retentate outlet or overflow at the top of the tank.

Immersed membrane filtration system and overflow process

In an apparatus for providing a continuous integrity test for suction driven filtering membrane assemblies a monitoring line diverts a portion of permeate to a monitoring device (e.g. a turbidimeter). Both ends of the monitoring line are connected to the permeate pipe upstream from the permeate pump and at points of relatively higher and lower pressures respectively, to cause fluid to flow through the monitoring line. The relatively higher and lower pressures may be caused by a source of head loss (e.g. a valve) in the permeate line. The source of head loss may be adjusted to provide a required flow through the monitoring device by a control communicating with a flow meter in the monitoring line. Membrane assemblies may be individually monitored although many of them may be connected to a common permeate pump (FIG. 2).

Distributed on-line integrity testing for immersed membranes

An improvement to an outside/in hollow fiber membrane filtration system includes a source of suction on the lumens of the membranes or pressure on the outside of the membranes operable without producing permeate and an air collector to collect any air that passes from the outside of the membranes to their lumens during an integrity test. A method for testing the integrity of filtering membranes involves exposing a first side of the membranes to air while a second side of the membranes remains exposed to water. A transmembrane pressure forces air through defects of concern in the membranes. Air that passes through a set of membranes is collected and its amount measured and compared to an acceptable amount of air to indicate whether there is a defect in the set of membranes. Preferably, air is collected individually from a plurality of membrane units in a filtration train and the amounts so collected compared to indicate if one of the membrane units is defective.

Method and apparatus for testing the integrity of filtering membranes

A filtration process for filtering water with immersed microfiltration or ultrafiltration membranes in a batch mode includes repeated cycles comprising the steps of filling the tank to a level above the membranes, withdrawing permeate through the membranes, aerating the membranes to dislodge solids from the membranes and backwashing the membranes while draining the tank. The backwashing steps involve backwashings with a cleaning chemical interspersed with backwashings with permeate. The backwashings with a cleaning chemical follow a regimen of maintenance cleaning chosen to maintain acceptable permeability of the membranes or to reduce the rate of decline in permeability of membranes,over extended periods of time.

Growing community of inventors

Hamilton, Canada

Nicholas Adams