GB2534377A

GB2534377A - Water treatment apparatus and method

Info

Publication number: GB2534377A
Application number: GB1500970.7A
Authority: GB
Inventors: Turley David; Collins Duncan
Original assignee: ZEROPEX GROUP Ltd
Current assignee: ZEROPEX GROUP Ltd
Priority date: 2015-01-21
Filing date: 2015-01-21
Publication date: 2016-07-27
Also published as: GB201500970D0

Abstract

A water treatment apparatus 2 comprises a turbine 6 that is driven by a water supply pipeline 4, which drives an electrical generator 10. An ultraviolet (UV) disinfection system is powered by the generator and irradiates the water, possibly through a transparent section of pipeline 4a. The turbine may be a positive displacement e.g. lobe type machine. There may be a bypass pipeline (22, figure 2). The ultraviolet treatment apparatus may be used in a water distribution system prior to reaching the end users (figure 3).

Description

Water Treatment Apparatus and Method The present invention relates to a water treatment apparatus and method, and in particular but not exclusively to an apparatus and method for disinfecting a water supply that is intended for human consumption and use.

A supply of clean, potable water is extremely important for health, drinking contaminated water being a major cause of illness and death around the world particularly in less developed regions. Disinfection of water involves the destruction of pathogens including microorganisms, viruses, bacteria and oocysts.

Conventionally, water is treated for use by a combination of filtration and chemical treatment with chlorine and other chemicals. Treating the water removes contaminants and impurities and kills harmful bacteria that can potentially cause disease. Treatment is usually carried out at a central water treatment plant and the treated water is then delivered by a network of pipes to the consumers.

A problem with this approach is that the treated water can become contaminated while it is being transported to the end users, owing to leaks in the pipe network. This is a particular problem in less developed regions where leakage rates can be very high. Although it is possible to re-treat the water at a secondary treatment plant prior to being delivered to the end users this requires additional infrastructure, which may be unavailable. Also, in some regions the use of chemicals such as chlorine may be restricted as their explosive potential leads to safety and terrorism threats.

As an alternative to chemical treatment, it is possible to disinfect water using ultraviolet radiation in a process known as ultraviolet germicidal irradiation (UVGI). In this process the water is exposed to UV-C radiation which is effective in destroying the nucleic acids of microorganisms, thereby disinfecting the water. However, operating a UV water disinfection plant requires a reliable source of electrical power, which may be unavailable, particularly in remote locations.

It is an object of the present invention to provide a water treatment apparatus and a method of water treatment, which mitigate at least some of the aforesaid disadvantages.

According to one aspect of the invention there is provided a water treatment apparatus comprising a turbine configured to be driven by a flowing water supply, an electrical generator that is connected to the turbine and is configured to be driven by the turbine to generate electrical power, and a UV disinfection system that is configured to irradiate the water supply with UV radiation, wherein the UV disinfection system is connected to receive electrical power generated by the electrical generator.

The water treatment apparatus allows water to he disinfected without the use of chemicals, and without the need for an external power supply. This means that water disinfection can take place in almost any location, providing that the pressure and flow rate of the water is sufficient to drive the generator. Disinfection can therefore be performed close to the point where the water is supplied to an end user, thus reducing the risk of re-contamination.

Because chemicals are not required the risk of potentially dangerous chemicals falling into the hands of terrorists is reduced. As an external electricity supply is not required water disinfection can take place in remote locations, where an electricity supply is unavailable or too costly to implement.

The turbine preferably comprises a positive displacement machine, for example a reverse driven lobe pump as described in US 4390331, or a machine as described in EP 2035691B, which has a pair of counter-rotating impellers Advantageously, the water treatment apparatus includes a water supply pipeline that caries the water supply. The UV disinfection system is preferably configured to irradiate the water supply within a transparent part of the water supply pipeline.

The water treatment apparatus may optionally include a bypass line connected to the water supply pipeline upstream and downstream of the turbine, through which water can bypass the turbine. The bypass line can be used to divert an excess flow of water away from the turbine 6 to avoid damage if, for example, the pipeline develops a major leak downstream of the water treatment apparatus. Preferably, the water treatment apparatus includes a valve that controls the flow of water through the bypass line.

The water treatment apparatus preferably includes a control device that controls the supply of electricity from the generator to the UV disinfecting system.

The water treatment apparatus may include a storage battery, for example an uninterruptable power supply (UPS) or similar power back-up system, that is connected to receive electrical energy from the generator and to deliver energy to the UV disinfecting system. This allows the water treatment apparatus to store any excess energy that is generated and use that energy later, when required.

The apparatus preferably includes a control device for controlling operation of the turbine. The control device may he configured to control operation of the turbine by adjusting an electrical load on the output of the generator. The control device may optionally be configured to control the pressure drop of water across the turbine and/or the flow rate of water through the turbine. This allows the water treatment apparatus to act as a pressure reduction valve to reduce the pressure safely from the high pressure that is required within the network of delivery pipelines to the much lower pressure required at the point of delivery.

The apparatus preferably includes a central control unit that controls operation of the water treatment apparatus. Optionally the apparatus includes a data transmitter/receiver that is connected to the central control unit and transmits data signals to and/or from the central control unit.

According to another aspect of the invention there is provided a water treatment method comprising driving a turbine from a flowing water supply, generating electrical power using an electrical generator that is driven by the turbine, supplying electrical power generated by the electrical generator to a UV disinfection system, and irradiating the water supply with UV radiation provided by the UV disinfection system.

The method preferably comprises controlling the supply of electricity from the generator to the UV disinfecting system.

Optionally the method includes storing electrical energy generated by the generator in a storage battery and optionally delivering stored electrical energy from the battery to the UV disinfecting system.

The method preferably comprises controlling operation of the turbine with a control device. Operation of the turbine is preferably controlled by adjusting an electrical load on the output of the generator.

The method preferably comprises controlling the pressure drop of water across the turbine and/or the flow rate of water through the turbine.

The method preferably includes controlling the flow of water through a bypass line that is connected to the water supply pipeline upstream and downstream of the turbine.

Certain embodiments of the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Figure 1 is a schematic representation of a water treatment apparatus; Figure 2 is a schematic representation of another water treatment apparatus, and Figure 3 is a schematic representation of another water treatment apparatus.

The water treatment apparatus 2 shown in Figure 1 is configured to disinfect a flow of water flowing through a pipeline 4.

The apparatus 2 includes a turbine 6, which is configured to be driven by the water flowing through the pipeline 4. The term "turbine" is used herein in a generic sense, which includes any machine that can be driven by a flow of fluid to provide a rotary mechanical output. This includes both traditional turbines, for example impulse turbines and reaction turbines, and also positive displacement machines. In a preferred example the turbine comprises a reverse driven lobe pump, for example of the type described in US 4390331, or a machine as described in EP 2035691B, which has a pair of counter-rotating impellers.

The turbine 6 has an output shaft 8 through which rotary drive is transferred to an electrical generator 10. Electrical power generated by the generator 10 is supplied through power lines 11a,b,c to an ultraviolet water disinfecting system 12, which includes UV lamps that arc arranged to irradiate the water passing through a transparent section 4a of the pipeline 4 with UV-C radiation. The transparent section 4a of the pipeline may be located downstream of the turbine 6 as shown in Figure 1, or alternatively upstream of the turbine 6.

The water treatment apparatus 2 also includes a turbine control unit 14 that controls operation of the turbine 6, and a UV lamp control unit 16 that controls the supply of electrical power to the ultraviolet disinfection system 12. The turbine control unit 14 is connected to the generator 10 through power line l la and the UV lamp control unit 16 is connected to the UV disinfection system 12 through power line 11c. The turbine control unit 14 and the UV lamp control unit 16 are configured to control the flow of electrical power from the generator 10 to the UV disinfection system 12. The turbine control unit 14 controls the turbine 6 by adjusting the electrical load on the electrical output of the generator 10. This allows the turbine control unit 14 to control the pressure drop of the water supply across the turbine 6 and/or the flow rate of water through the turbine.

In use, the flow of water through the pipeline 4 drives the turbine 6, which in turn drives the generator 10 to generate electricity. The electrical energy is supplied to the UV disinfection system 12, which irradiates the water passing through the transparent pipe section 4a with UV-C light to eradicate pathogens including microorganisms, viruses, bacteria and oocysts in the water.

The maximum power generated by the generator 10 will generally be approximately proportional to the rate of flow of water through the pipeline 4. The power supplied to the UV disinfection system 12 can therefore increase as the flow rate increases, ensuring that the water receives a substantially uniform level of irradiation regardless of the flow rate. The level of disinfection is therefore substantially unaffected by the flow rate of water through the water treatment apparatus 2.

The UV lamp control unit 16 controls the supply of electrical power to the UV disinfection system 12. As indicated above, the maximum power supplied to the UV disinfection system 12 is substantially proportional to the flow rate of water through the pipeline 4. The control unit 16 distributes this power in an appropriate manner, for example by turning on more UV lamps as the water flow rate increases, and reducing the number of operative UV lamps as the flow rate decreases.

The turbine control unit 14 controls the turbine 6 by adjusting the electrical load on the output of the generator 10. The turbine control unit 14 is thus able to control the amount of resistance the turbine 6 provides to the flow of water through the pipeline 4, and can therefore control the pressure drop across the turbine 6 and/or the flow rate of water through the turbine. The turbine 6 can therefore be used to replace a traditional pressure reducing valve, as commonly used within water distribution networks.

Furthermore, by adjusting the electrical load on the generator the pressure drop across the turbine 6 and/or the flow rate of water through the turbine can be actively controlled according to demand and other use criteria. If more electrical power is generated than is required for the UV disinfection system 12 the excess energy can be used for other purposes, stored in a battery for later use, or dumped by being diverted to an electrical resistance, which can if required be cooled by the water supply.

Figure 2 illustrates a another embodiment of the invention, in which the water treatment apparatus 2' is similar in certain respects to the first embodiment shown in Figure 1 and includes a number of similar or identical components including a pipeline 4, a turbine 6, a generator 10 that is driven by a drive shaft 8 from the turbine 6, and a UV disinfection system 12 that is positioned around a transparent part 4a of the pipeline 4.

In addition, the water treatment apparatus 2' includes an electronic control device 18 that is connected to the generator 10 and the ultraviolet disinfection system 12 through power lines 19a, 19b respectively, and a storage battery 20, for example an uninterruptable power supply (UPS) or similar power back-up system, that is connected to the electronic control device 18 through power line 21 and is configured to store electrical energy generated by the generator 10, and to release that energy when required to the UV disinfection system 12. The apparatus also includes a bypass pipe line 22 that is connected to the pipeline 4 upstream and downstream of the turbine 6, and a control valve 24 that is operable to allow or prevent the flow of water through the bypass line 22.

The valve 24, the generator 10, the electronic control device 18 and the UV disinfection system 12 are all connected through control lines 25a-d to a central control unit 26, which monitors and controls operation of the water treatment apparatus. The central control unit 26 may be configured to operate fully automatically, manually or semi-automatically. The central control unit 26 is optionally connected to a data transmitter/receiver 28, which allows operation of the water treatment apparatus to be monitored and/or controlled from a remote location.

Operation of the water treatment apparatus 2' shown in Figure 2 is substantially as described above in relation to the apparatus of Figure 1. However, the electronic control device 18 and the storage battery 20 allow excess energy generated by the generator 10 to be stored and then used later to operate the UV disinfection system 12 when required. This may occur, for example, when the turbine 6 or the generator 10 is temporarily taken out of operation, for example for maintenance purposes. In that case the control valve 24 may be opened to allow water to bypass the turbine 6 through bypass line 22. The bypass line 22 may also be used to divert an excess flow of water away from the turbine 6 to avoid damage if, for example, the pipeline 4 develops a major leak downstream of the water treatment apparatus 2'.

Figure 3 illustrates schematically certain components of a water distribution network 30 that includes water treatment apparatus 2a-2d, for example of the type shown in Figure 1 or Figure 2, at various locations throughout the network. At its upstream end the distribution network includes an impounding reservoir 32 where water is collected prior to treatment and distribution. A large capacity supply line 34 leads from the impounding reservoir 32 to a central treatment works 36, which conventionally includes fillers for removing contaminants and impurities from the water and optionally chemical treatment systems.

A first UV water treatment apparatus 2a of the type described herein is located in this supply line 34 and is operable to destroy any chlorine-resistant parasites such as cryptosporidium that may be present in the water. The treated water from the central 30 treatment works 36 is carried by a mains water pipeline 38 to a service reservoir 40, where it is held prior to being distributed to the end users. A second ultraviolet water treatment apparatus 2b is located in this mains pipeline 38 and is configured to subject the water to a second disinfection process to destroy any microorganisms that have entered the water, for example through leaking pipework.

The water then flows from the service reservoir 40 through a distribution network of pipes 42 to the end users. Further UV water treatment apparatus 2c. 2d may be provided within this network 42 to provide secondary disinfection (water treatment apparatus 2c) within the network and point of use disinfection (water treatment apparatus 2d), as required.

Each UV water treatment apparatus 2a-2d is powered entirely by the flow of water through the pressurised water supply, thus avoiding the need for an external power supply. As well as disinfecting the water supply, each water treatment apparatus may also help to control the pressure of the water within the distribution network, thereby reducing or eliminating the need for conventional pressure reducing valves, flow restrictors and similar apparatus.

It will be appreciated that the water treatment apparatus described above may be modified in numerous different ways without departing from the invention. Components and features of the different embodiments described herein may also be combined or interchanged in any combination of ways, according to the circumstances in which the apparatus is implemented.