AU2017202557A1

AU2017202557A1 - Fully air operated membrane ultra or micro filtration system with automatic backflush

Info

Publication number: AU2017202557A1
Application number: AU2017202557A
Authority: AU
Inventors: Samandar Milani
Original assignee: Advanced Waste Water Systems Pty Ltd
Current assignee: Advanced Waste Water Systems Pty Ltd
Priority date: 2017-04-19
Filing date: 2017-04-19
Publication date: 2018-11-08

Abstract

Abstract: A membrane ultra or micro filtration system with automatic backflush fully operated by air is disclosed. This invention relates to the method utilised to pump and backflush a liquid through an ultra or micro 5 membrane filtration device using air only. In this invention the pumping of liquid through an ultra or micro membrane filter and the backflush of the ultra or micro membrane material is performed in such way, that the liquid never comes in contact with any mechanical parts of a liquid or air pump nor with the interior of the hollow fibre membrane. The filtration and backflush in this invention is achieved by using compressed air in conjunction with a clean liquid storage chamber, liquid level switches, a 10 motorized valve, and a programmable electronic controller. This invention provides for a longer lasting, more robust, reliable, energy efficient and low maintenance way to filter a liquid through an ultra or micro filtration membrane.

Description

AUSTRALIA Patent Act 1990

COMPLETE SEPCIFICATIONS INNOVATION PATENT

FULLY AIR OPERATED MEMBRANE ULTRA OR MICRO FILTRATION SYSTEM WITH AUTOMATIC BACKFLUSH

The following statement is a fill description of the invention, including the best methods of performing it known to me:

Background:

This invention relates to ultra or micro hollow fibre membrane filtration of a liquid and more specifically the manner in which the liquid is pumped and back-flushed through the ultra or micro membrane filter with compressed air (no liquid pump are used), where the air does not come in contact with interior of the Hollow fibre membrane. MBR (Membrane Bioreactors) are being increasingly used in many applications to clean liquids from very fine particles and bacteria. In many parts of the world, MBR have been mostly used to filter and treat rainwater and wastewater in order to provide for safe alternative water sources. In addition due to the increasing environmental problems caused by the release of high in nutrients partially treated wastewater into the natural streams, MBR have been used to polish treated wastewater so as to provide for advanced wastewater treatments and reduce pollution. In more recent years MBR have also been used for fine liquid filtration in various scientific applications.

Traditionally liquid pumps have been used to push or suck the liquids through the ultra or micro membrane hollow fibres in order to filter and backflush. Depending on the quality and chemical contents of the liquids to be filtered, liquid pumps have a limited maximum operating duration and life, and may require more regular maintenance. Up to date Air has not been used due the fact that ultra or micro membranes are not designed to handle pressurized air and would deteriorate rather rapidly if air was in contact with the interior of the hollow fibres. In addition air would slow down the filtration process when caught within the hollow fibres and therefore reduce the filtration efficiency.

On the other hand pressurized air is relatively easy to generate and air pumps are known for their reliability, low maintenance requirements, and their ability to run non-stop for long periods of time. In addition compressed air is readily available in most wastewater treatment plants where existing compressed air lines can be used as a source of pressure with no additional power requirements. The use of existing compressed air to operate an MBR would mean that no extra energy would be needed to polish wastewater after the primary and secondary treatment. As a result this new technology has the potential to save a considerable amount of energy. In addition the new technology offers great advantages in applications where corrosive liquids are to be filtered by preventing the liquid to be in contact with any mechanical parts of a liquid pump.

The new invention:

The present invention aims to provide all these advantages.

In order to obtain these results, the invention combines a container (1), with a liquid inlet (2) and an overflow (3), which houses an ultra or micro membrane filter (4), connected to a clean liquid chamber (5), with an internal discharge pipe (6), leading via a one way valve (7), through a two way normally open motorized valve (8) to a discharge point (9). The clean liquid chamber also houses a low level float switch (10) and a high level float switch (11) and is connected to an air pump (12), via a pipe (13). The float switches and the air pump are all wired to an electronic controller (14).

The dirty liquid flows into the container (1) through the liquid inlet (2), passes through the submerged ultra or micro filter membranes (4) filling the clean liquid chamber (5). Once the liquid within the clean Liquid chamber (5) reaches the high level float switch (11) the air pump (12) is turned on by the electronic controller (14) and pressurised air is pumped through a pipe (13) into the clean liquid chamber (5). The clean liquid is then pushed through the internal pipe discharge (6), the one way (7), and the normally open motorized valve (8), to finally reach the discharge point (9) part of the liquid is pushed back through the ultra or micro filter membranes (4) resulting in a short backflush event during every pump out sequence. Once the liquid level in the clean liquid chamber reaches the low level float switch (10), the air pump (12) is turned off, allowing the sequence of event described above to take place again.

The thorough backflush of the ultra or micro membrane (4) is initiated through the programmable electronic controller (14), after a set number of pump out event or when prompted by a relatively slower pump-out of the clean Liquid chamber (5) indicated by the time elapsed between the activation of the upper float switch (10) and the de-activation of the lower float switch (11). The backflush sequence activates the air pump (12) and the normally open solenoid valve (8) (closes the valve), once the liquid reaches the high level float switch (11). The air is then trapped within the clean liquid chamber (5) pushing the liquid present in the chamber (5) back down through the ultra or micro membrane (4) into the container (1) and out to waste through the overflow (3). The backflush sequence is stopped when the liquid level in the clean liquid chamber (5) reaches the level of the lower float switch (10). Once the backflush sequence is completed the programmable controller (14) goes back to the normal filtration sequence mode described above.

In all form of the invention an extra air pump (15) can be added to provide external aeration via a pipe (16) to the ultra or micro membrane filters in order to improve the filtration and backflush process.

In all form of the invention a high level float switch (17) in conjunction with an audio and visual alarm (18) can be used to provide for malfunction alerts.

In all form of the invention, where an existing external airline (19) is available, the air pumps (12) is substituted by a three way motorized solenoid valve and the second air pump (15) is substituted by a two way motorized solenoid valves.

In all form of the invention, in order to avoid small backflush events to occur at each pump out sequence and to allow only for the thorough backflush, a one way valve (20) is added at the entrance of the clean liquid chamber, the two way normally open motorized valve (8) is substituted by a three way valve, a connecting pipe (21) is added from the three way valve (8) back to the ultra or micro membrane filter via an additional one way valve (22).

In all form of the invention, in order to provide for faster or more effective air venting of the clean liquid chamber (5) and improve the suction power of the liquid through the ultra or micro membrane filter (4), an air vacuum pump (23) is connected to the venting side of the three way valve (12).

In all form of the invention the float switches (10, 11 and 17) can be substituted by other form level sensor switches.

In all form of the invention the motorized solenoid valve (8, 12 and 15) can be substituted by other form of electrically, hydraulically, or pneumatically activated valves.

To assist with understanding the invention, reference will be made to the accompanying drawings which show the various installation mode and configuration of the new invention:

Fig 1. Shows the basic form of the air operated ultra or micro membrane filtration without the use of any liquid pump.

Fig 2. Shows the air operated ultra or micro membrane filter system with an additional air pump to provide exterior membrane aeration and improve the filtration and backflush process.

Fig 3. Shows the air operated ultra or micro membrane filter system with an additional high liquid level switch and an audio and visual alarm to provide for malfunction alerts.

Fig 4. Shows the air operated ultra or micro membrane filter system where air is not generated by air pumps but is produced by an external air supply and is supplied to the system via a dedicated airline.

Fig 5. Shows the air operated ultra or micro membrane filter system where the small backflush event during the pump out sequence is eliminated to improve the operating efficiency of the system.

Fig 6. Shows the air operated ultra or micro membrane filter system where the suction power of the liquid through the membrane is improved by the introduction of air vacuum pump.

Claims

The Claims defining the invention are as follows:

1. An ultra or micro membrane filtration system with automatic backflush fully operated by air (without a liquid pump), comprising an ultra or micro membrane hollow fibre element, an air pump, a programmable electronic controller, a clean liquid chamber with two level float switches, a motorized solenoid valve, is disclosed. This invention relates to the method used to pass liquid back and forth through an ultra or micro membrane filter element using pressurized air only.
2. An ultra or micro membrane filtration system with automatic backflush fully operated by air of anyone claims 1 wherein the air is generated externally and its introduction into the system is controlled by valves.
3. An ultra or micro membrane filtration system with automatic backflush fully operated by air of anyone claims 1 to 2 wherein the small backflush events occurring during the pump out sequences are eliminated by redirecting the pump out liquid during the backflush sequence directly back to the ultra or micro membrane element.
4. An ultra or micro membrane filtration system with automatic backflush fully operated by air of anyone claims 1 to 3 wherein the suction power used to pass water through the membrane is improved by introducing an air vacuum pump.
5. An ultra or micro membrane filtration system with automatic backflush fully operated by air of anyone claims 1 to 4 wherein other forms of the level switches and fast activating valves are used.
6. An ultra or micro membrane filtration system with automatic backflush fully operated by air can substantially as herein described with reference to figure 1 to 6 ofthe accompanying drawings.