Bundamba Purified
Recycled Water Tour
Pure Drinking Water
Purified recycled water is water that has been filtered, disinfected and purified to a very high standard using
advanced technologies including microfiltration, reverse osmosis and ultraviolet light.
The Western Corridor Recycled Water Scheme provides this water to industry, potentially to agriculture, and can
replenish Brisbane’s drinking water supply, when required.
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The Water Treatment Process
So much is happening at this plant that a complex
computer system is needed to manage it. A
1. Control room
Supervisory Control and Data Acquisition, or SCADA,
system, monitors, controls and safeguards each stage
of the treatment process.
Pure fresh water can be recycled from used water.
2. Source water
The used water comes from a wastewater treatment
plant. Here, treated water is sent by pipes to the water
purification plant.
Water is pumped to a clarification tank which removes
dissolved phosphorus and suspended particles. The
3. Pre-treatment
particles bind together into small clumps and settle at
the bottom of the tank. The clear water then flows
into a large storage tank. The water is now ready for
microfiltration.
The water is forced through straw-like microfiltration
4. Microfiltration
fibres to remove microscopic particles. The filtered
water is now ready to pass through reverse osmosis
membranes.
Reverse osmosis involves forcing water though
special plastic membrane sheets to remove salts,
5. Reverse osmosis
micro-organisms, organic compounds and viruses.
Membranes allow water molecules to pass through
and reject contaminants.
This step is an additional safety barrier to remove any
remaining chemical or organic molecules. Water
6. Advanced oxidisation
passes through chambers that emit strong ultra violet
light. Hydrogen peroxide is added to aid the process.
By now the water is ultra-pure.
There are more than 190 analysers throughout the
7. Water quality analysers
plant that constantly measure water quality indicators
such as turbidity, dissolved oxygen, conductivity and
pH levels.
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Purified recycled water is so pure that minerals have
8. Remineralisation
to be added to it. Small amounts of lime and carbon
dioxide are added to stabilise the water. The purified
water is also known as Six-Star quality water.
The pure water is stored in a large 20 megalitre tank
9. Pure water tank
before it is pumped to power stations and, when
required, to replenish Brisbane’s drinking water
supplies.
Purified recycled water is pumped in a pipeline to
10. Pure water pipeline
Swanbank Power Station and to the Tarong Power
Station. A branch of the pipeline also extends to
Wivenhoe Dam.
Excessive nutrients can damage our rivers and
11. Nitrogen removal
waterways. Water purification plants can help to
reduce the amount of nutrients that flow into Brisbane
River, Bremer River and Moreton Bay.
12. Residuals treatment
Residues from the treatment are processed to allow
for their proper disposal.
The left-over water is piped to Goodna and released
13. Concentrate water pipe
in the Brisbane River, where it mixes with the river’s
water.
Solid residue from the pre-treatment process is
14. Residue removal
emptied into large bins and taken away by trucks for
landfill.
3
Control Room
Welcome to the Control Room.
So much is happening at this plant that a complex computer system is needed to manage it. A Supervisory
Control and Data Acquisition, or SCADA, system, monitors, controls and safeguards each stage of the treatment
process.
Source Water
Four large wastewater treatment plants - at Oxley, Wacol, Goodna and Bundamba – pipe their treated water to
the Bundamba water purification plant instead of releasing it into the Brisbane or Bremer River.
The treated water is already of a good standard. It is clarified and looks quite clean.
Most of the organic matter, contaminants and nutrients have been removed. From here it begins the purification
process at Bundamba.
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Pre-treatment
Clarification works by mixing a coagulant, called ferric chloride, in the water. The coagulant reacts with traces of
dissolved phosphate and binds suspended particles into small clumps which settle to the bottom of the tank.
The sediment is pumped from the tank floor and removed for treatment in another part of the plant.
A chlorine residual chemical is also added to prevent any algal growth in pipes or tanks.
Extra information
Water is pumped into a mixing tank where ferric chloride is added to react with phosphate and destabilise
suspended solids. This process enables the solids to bind together and form bigger particles which sink.
This process is called 'flocculation'.
Monochloramine is introduced to prevent biological fouling of the downstream membranes.
The flocculated water passes through a clarifier tank, where the flocs are captured on angled plates called
lamellar plates and ultimately sink to the tank floor. The clarified water overflows into a separate tank.
The sediment, rich in ferric chloride, is pumped from the bottom of the clarifier tank to a thickening tank,
before flowing into a large centrifuge machine, which recovers most of the water. The cake-like residue is
then sent to landfill. Water recovered from the centrifuges is pumped back into the pre-treatment tank and
recycled through the clarification process.
The clarified water is fed into a 15 megalitre storage tank. It is now ready for microfiltration.
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Microfiltration
During microfiltration, water is forced through racks of vessels, with each vessel containing thousands of hollow
fibres.
The outer wall of each fibre is made up of tiny pores – only 0.4 microns in size – or about 300 times smaller than
the width of a human hair.
The fibres filter out microscopic particles such as silt, protozoa cysts, bacteria and even viruses.
Microfiltration vessels are backwashed every 30 minutes to remove any build-up of particles on the membrane
walls. The backwashed water is returned to the pre-treatment tank for reprocessing. This helps the plant to
recover a higher amount of pure water.
Extra information
Regular chemical cleaning of membrane fibres is undertaken to remove scale or adhered particles.
The integrity of filters is checked in two ways. First, by continuous monitoring of water passing through
turbidity meters which measure the level of suspended matter in the water. Second, by regular 'air
pressure' tests of each membrane vessel to detect if any fibres are broken.
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Reverse Osmosis
Reverse osmosis works by forcing water through a special plastic membrane sheet to remove compounds such
as salt, organic compounds, micro-organisms and viruses.
Rolls of membrane sheets are wound into cylinder-shaped elements. There are several elements inside each
long pressure vessel. As water enters the vessel, it flows over the membrane surface as it moves from one end of
the vessel to the other.
The membrane layer is extremely thin. It allows water to pass through, or permeate, while preventing other
compounds from passing through.
Membranes remove molecules based on their size, shape and charge. Generally, contaminants larger than water
molecules will not pass through including most chemical contaminants, and all micro-organisms, such a viruses,
and bacteria.
Two streams of water are produced.
Pure, clean water, called permeate, flows across the membrane sheets and passes through the membrane layer
to the inside core tube.
Water that does not permeate through the membrane becomes more highly concentrated in salt and other
substances. This water is called concentrate. The pure permeate water flows out the core tube at one end of the
pressure vessel and the concentrate water flows out another outlet.
The concentrate water can then flow into other pressure vessels for the same process to happen again. So even
more pure permeate water can be recovered. About 82 per cent of all the source water becomes purified water.
Extra information
Reverse osmosis is a common process to remove salt and other dissolved substances from water.
In between each membrane layer is a mesh separator that allows the pure water (permeate) to flow one
way, and the rejected water (concentrate) to flow another way.
High pressure pumps force water through semi-permeable membrane sheets. The permeate flows
around the spiral bound membrane element towards a central collection tube. There are several
elements inside each pressure vessel.
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Rejected water (concentrate) is separated and removed through another outlet at the end of the pressure
vessel.
The concentrate water can then flow into other pressure vessels for the same process to happen again.
With each pass more pure permeate water is recovered. Typically, about 85 per cent is recovered as pure
water.
Reverse osmosis membranes are regularly cleaned to remove particle build-up on the membrane surface,
so that their performance can be maintained.
Advanced Oxidisation
The next stage is ultra-violet light and advanced oxidation.
The water is dosed with hydrogen peroxide and exposed to strong UV light. This process removes any trace
organic molecules.
The UV energy instantly destroys the genetic material (DNA) within any virus that may have somehow passed
through previous barriers. Intense UV light and oxidation breaks down contaminant molecules.
The process is similar to the one used in medicine and dentistry to sterilise equipment.
Extra information
The UV-advanced oxidation process destroys chlorine-resistant viruses through a combination of UVphotolysis and UV-oxidation. Intense UV light breaks down contaminant molecules in water two ways.
UV-photolysis is the process by which chemical bonds of the contaminants are broken by the energy
associated with UV light.
UV-oxidation is a process that breaks down organic constituents in water by the process of oxidation
initiated by UV light plus an oxidant such as hydrogen peroxide. When UV photons are absorbed by
hydrogen peroxide dissolved in water, hydroxyl radicals are formed. Hydroxyl radicals are highly reactive
chemical species that then attack the contaminant molecule, breaking it into its component forms.
Hydrogen peroxide is quite safe and decomposes into oxygen and water after a very short period.
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Water quality analysers
Each analyser is connected to control room computers. Technicians can monitor water quality parameters at
various points. If any indicator exceeds set levels, the plant can be shut down.
Water samples are tested each week by Queensland Health and other commercial laboratories. The tests
measure over 250 parameters and a range of compounds including inorganic chemicals, disinfection by-products,
hormones, pesticides and pharmaceuticals.
In 2009, over 64,000 water quality tests were done. The tests show that the plant is consistently producing safe,
high quality water.
Extra information
Purified recycled water meets and exceeds the Public Health Regulation and Australian Drinking Water
Quality Guidelines. Water quality is monitored at the plant and regularly tested by independent
laboratories.
Queensland's Water Supply (Safety and Reliability) Act requires the plant to have a recycled water
management plan approved by the Office of the Water Supply Regulator before purified recycled water is
added to Wivenhoe Dam. In the plan, recycled water quality specifications are specified.
For purified recycled water to be added to Lake Wivenhoe, it is expected that the water quality will be
equal to, or better than, drinking water.
In 2009, approximately 64,000 tests of water quality were undertaken. The tests show that the plant is
consistently producing safe, high quality water.
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Remineralisation
After purification, the water has low alkalinity, and needs to be ‘softened’. Its pH and hardness are adjusted in a
process known as stabilisation.
Lime and carbon dioxide are added in a process similar to what happens naturally – rain collects carbon dioxide
as it falls and absorbs calcium as it flows over the ground. Remineralisation helps the water to match more closely
other water sources, such as treated dam water.
Chlorine is also added to ensure water quality in the pipe network.
Extra information
Due to pH adjustment and the removal of dissolved salt, the water can be corrosive to concrete tanks and
cement-lined pipes. It is stabilised by lime dosing and by injecting carbon dioxide to control its pH. It is also
chlorinated to control biological growth in the pipelines in the same way as drinking water is chlorinated at
a water treatment plant.
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Pure water tank
The plant recovers approximately 82 per cent of all the source water it receives from the wastewater treatment
plants. This superior quality water (also known as Six Star water) meets the Public Health Regulation standards
and Australian Drinking Water Guidelines.
Extra information
Daily water production can vary depending on demand. Instructions on how to operate the Grid are issued
by the South East Queensland Water Grid Manager to ensure supply is managed in the most efficient way.
The plant can produce between 20 and 66 million litres of water a day.
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Pure water pipeline
Purified recycled water is pumped along pipelines to where it is needed.
One pipeline moves water to Swanbank Power Station. Another pipeline, called the Western Pipeline, moves
water to Tarong Power Station.
There is a branch from the Western Pipeline to Wivenhoe lake, the major source of drinking water for Brisbane.
This branch, called the Wivenhoe Release pipeline, can be opened to release water into the lake, when it is
needed.
If water is added to Wivenhoe lake, it will be de-chlorinated in this pipeline to make it compatible with the dam
ecosystem.
Extra information
The 80 kilometre Western Pipeline stretches from the Bundamba water purification plant north-west to
Caboonbah. It includes a pump station at Lowood and balance tanks at Lowood and Esk. Another pipeline
transports the water to Tarong and Tarong North power stations.
At Coominya a 16 kilometre pipeline branches to feed water into Wivenhoe lake.
Another pipeline from the plant transports the water to Swanbank power station.
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Nitrogen removal
Nitrogen is removed from the reverse osmosis concentrate water in several stages.
The concentrate water contains high levels of ammonia.
The first stage, called nitrification, transforms the ammonia into nitrate. The concentrate water is added to an
aeration tank where special bacteria, growing on plastic disks, use the ammonia as an energy source and convert
it into nitrate.
The next stage, called de-nitrification, converts the nitrate into nitrogen gas. Here, the water passes through a
sand filter which hosts more bacteria that use nitrate as an oxygen source.
Methanol, a source of carbon, is added to the filter to help these bacteria convert the nitrate into harmless
nitrogen gas, which is vented into the atmosphere.
The treated concentrate water - now with much lower levels of nitrogen – is ready to be released into Brisbane
River.
Extra information
Nitrogen is removed from the reverse osmosis concentrate water through the biological oxidation of
nitrogen from ammonia (nitrification) to nitrate, followed by denitrification, the reduction of nitrate to
nitrogen gas. Denitrifying bacteria convert nitrates to nitrogen gas.
Nitrogen gas is released to the atmosphere and thus removed from the water.
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Residuals treatment
The residual treatment area includes the following tanks:

The Microfiltration backwash tank, the Reverse osmosis concentrate tank, Clarifiers and a de-nitrification
tank.

Water from backwashing the microfiltration vessels is recycled back into the pre-treatment tank for
reprocessing.

Concentrated water from the reverse osmosis process is treated to remove nitrogen.
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Concentrate water pipe
The left-over concentrate water – now with 95% less phosphorus and almost 40% less nitrogen – is pumped to
Goodna where it is released into the Brisbane River.
The water mixes with the tidal flow. It is regulated by the Department of Environment and Resource Management.
Studies show that the released water has no adverse effect on the river environment.
Extra information
The quality and quantity of the reverse osmosis concentrate water is monitored before it's released into the
Brisbane River. Monitoring is regulated by the Department of Environment and Resource Management.
Total chlorine, dissolved oxygen, turbidity, pH and ammonia are monitored at the plant on a daily basis.
Dissolved metals, nutrients, bio-chemical oxygen demand, and chemical oxygen demand are monitored on
a weekly basis.
An underwater diffuser disperses and mixes the water into the surrounding river water at the Goodna
release site.
WaterSecure organises regular tests of the tidal river area to ensure water quality is maintained and there
is no impact on the surrounding environment.
The South East Queensland Healthy Waterways Partnership also monitors the ecosystem health of the
river and surrounding waterways.
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Residue removal
Solid residue is a soupy mixture of water and solid waste created mainly from the pre-treatment process.
It is rich in the coagulant, ferric chloride.
The residue is thickened and then ‘de-watered’ as it passes through a large centrifuge machine that spins on an
axis to separate the solid material from the water.
Centrifugal force pushes the water to the outside. The water is removed from one end and the solid waste from
another end.
The solid waste is then transported by special waste trucks to a licensed landfill site.
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SEQ Water Grid
South East Queensland’s Water Grid comprises of over 530 kilometres of pipelines, pumping stations, new dams
and reservoirs, a desalination plant and three water purification plants.
The Water Grid can move large amounts of water throughout the region to where it’s needed most.
This flexible approach allows the Water Grid to meet the demands of an increasing population and changing
weather patterns - making it a good investment now and for the future.
Purified recycled water is now a crucial part of the Water Grid.
The Western Corridor Recycled Water Scheme – one of the largest water recycling schemes in the world – is a
major part of the Grid. The scheme can produce up to 232 million litres of purified recycled water a day,
equivalent to 93 Olympic size swimming pools. This water meets Public Health Regulation standards and
Australian Drinking Water Quality Guidelines, and is strictly regulated by the Office of the Water Supply
Regulator.
Frequently Asked Questions
What is recycled water?
Stormwater, greywater, rainwater and treated wastewater are all alternative water supplies that, when treated as
required, are suitable for a range of purposes. This can include irrigating grazing land and crops, horticulture,
industrial processing, residential dual pipe schemes, and to keep our public parks and gardens green. 'Recycled
water' generally refers to fully treated water from wastewater treatment plants. Recycled water is a valuable
resource. It contributes to conservation of drinking quality water, improves the reliability of our water supplies,
frees up water for the environment or growth, and reduces the amount of treated effluent discharged into our bays
and oceans.
What is purified recycled water?
After wastewater is processed at secondary treatment plants it can be purified to the highest standard. New
advanced water purification plants can remove minerals, nutrients, organic matter and bacteria. The highest
grade of water - even purer than drinking water - can be produced using technologies of microfiltration, reverse
osmosis and ultraviolet light. It can be used for kidney dialysis and industrial processes such as pharmaceutical
or boiler feed water. Purified recycled water is so clean and safe that, if needed, it can be blended with reservoir
water to increase our drinking water supply.
Is recycled and purified water recycled presently in use?
Recycled water is already being used in a wide range of applications, including the irrigation of agriculture,
parklands and golf courses. Purified recycled water is being used in South East Queensland by Tarong and
Swanbank power stations, and there are a large number of potential agricultural and industrial users. Current
state government policy is for purified recycled water to be added to Wivenhoe Dam should the region's
combined dam water level fall below 40 per cent.
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Why is recycled and purified recycled water being used?
Water is a precious resource, yet less than 10 per cent of Australia's urban and industrial water is recycled. As
South East Queensland grows in population, and to protect our water supply from future droughts, water
recycling, purification and desalination is a socially, environmentally and economically viable solution to help
preserve our drinking water supplies. Currently, almost 2.8 million people live in South East Queensland and this
figure could increase to more than 6 million by 2056. Even with significant new efficiency measures to reduce
water consumption, this sustained level of population growth is substantially increasing the region's demand for
water. Purified recycled water is expected to provide up to 30% of our water supply by 2056.
What are the benefits of recycling and reusing water?
Recycled water has many benefits. It reduces the demand on fresh water and makes use of a precious resource
that currently goes to waste. The major benefit of water purification and desalination is that it can continue to
deliver high quality drinking water for consumption, even during periods of drought. It also provides an alternative
source of water that will make our overall supply more diverse and less vulnerable to interruption. Water recycling
and purification schemes protect the environment by reducing the discharge of treated effluent into wetlands,
rivers, bays and the ocean. The purification process for purified recycled water will significantly reduce the
release of nutrients and other environmentally detrimental compounds to Brisbane River and Moreton Bay.
How can recycled and purified recycled water be used?
In general terms, most recycled water can be used for crops such as tree plantations, vineyards and general
agriculture, and irrigation of golf courses and parklands under controlled conditions. With further treatment, higher
grade recycled water can be used on an unrestricted basis for horticulture, irrigation of market gardens and open
space recreation, and for garden watering and toilet flushing through dual pipe residential development schemes.
In future, the highest quality (also known as 6-star) recycled water from advanced water purification plants can be
added, if needed, to dams and reservoirs to increase our drinking water supply. All purified recycled water passes
through numerous safety checks and water quality treatment systems.
Where does purified recycled water come from?
In metropolitan Brisbane, the source for purified recycled water is from WaterSecure's three advanced treatment
facilities - at Bundamba, Luggage Point and Gibson Island - which provide large amounts of purified recycled
water all year round. These plants are part of the Western Corridor Recycled Water Scheme and are part of the
South East Queensland Water Grid. The plants use world class technology and can produce up to 232 million
litres a day, which is equivalent to 93 Olympic-size swimming pools.
Is purified recycled water safe to drink?
Yes. Purified recycled water undergoes high standards of treatment to ensure it is safe to be added to our
drinking water supplies. There are standards and regulations that apply for its use. Regular monitoring and
reporting is required to ensure the water being supplied is of the highest quality.
Our water currently meets the requirements of the Public Health Regulation and Australian Drinking Water
Guidelines and will continue to do so. Queensland's Water Supply (Quality and Reliability) Act also regulates the
use of purified recycled water.
Purified recycled water is clear and odourless.
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Are there guidelines for purified recycled water use?
Yes. Purified recycled water can be safely used for a variety of purposes appropriate to the level of treatment they
have undergone, in accordance with Queensland's Water Supply (Quality and Reliability Act).
The Western Corridor Recycled Water's purified recycled water undergoes rigorous testing supervised by
Queensland Health and the Department of Environment and Resource Management. Both these agencies must
authorise its release into Wivenhoe Dam.
Queensland Health has developed health-based water quality criteria for purified recycled water, based on
national guidelines and recommendations from peak health bodies such as the World Health Organisation and
the National Health and Medical Research Council.
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