Wollongong Water Recycling Plant

Wollongong Water Recycling Plant is one of 30 water recycling treatment and wastewater treatment plants in greater Sydney, the Blue Mountains and the Illawarra. It serves Wollongong and surrounding suburbs.

Aerial photograph of Wollongong Water Recycling Plant.

Wollongong Water Recycling Plant is located on the coast of Wollongong City. 

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Location Port Kembla Road, Wollongong
Population served 200,000 people
Area served 71 km2

Including Port Kembla, Bellambi, Wollongong and surrounding suburbs.
Amount of wastewater treated each day 49.8 million litres
Treatment level Tertiary
Recycled water applications
  • We re-use some water on site for industrial purposes like washing down equipment and filter backwashes.
  • Wollongong City Council uses our recycled water to water grass and gardens at local sports fields.
  • Wollongong Golf Club uses our recycled water to water the greens.
  • Port Kembla Coal Terminal uses our recycled water for dust suppression.
  • BlueScope Steel uses our recycled water for steel manufacturing.
Environmental discharge We release any remaining recycled water to the ocean, about 1 km offshore.
Amount of biosolids produced each year 11,000 tonnes
Operating licence and regulation We operate the plant under three sets of rules:

Primary treatment

Wollongong plant flow chart

Treatment flow chart. Select the flow chart to see a larger version.

Primary wastewater treatment removes large solids using physical separation processes.

Most of the solids removed can be treated for beneficial re-use.
 

Screening

Screens trap and remove large solids as wastewater flows through.

Wipes, food scraps and plastic wrappers caught on the sceens.

Large solids like wipes, food scraps, rubbish, cotton tips and plastic are caught on the screens.


Grit removal

We inject air into a tank, causing the water to spiral. The air flings the grit, such as sand and coffee grounds, to the edges. It collects in the bottom of the tank where a scraper removes it.
 

Sedimentation

Wollongong uses two different types of sedimentation processes:

  • a traditional sedimentation tank
  • an inclined plate sedimentation process, sometimes called a 'multi-flow tank' or a 'lamella plate'.
Traditional sedimentation tanks allow solids to settle to the bottom of the tank while oil and grease float to the top. Scrapers at both the bottom and the top of the tanks remove the solids, oil and grease, which are then treated to produce biosolids.

The multi-flow tank uses a set of stacked inclined plates. Water travels up and over the inclined plate, but solids are too heavy and are captured on the plate. Mechanical scrapers remove the solids, which are then treated to produce biosolids.

Primary sedimentation tank.

In a traditional sedimentation tank, we use scrapers on top to remove floating scum and settled solids.


Secondary treatment

Secondary treatment removes phosphates and nitrates using physical, biological and chemical processes. Learn more about removing nitrogen and phosphorous.

Wollongong uses two types of secondary processes that work in a similar way:
  • a Conventional Activated Sludge system (CONVAS)
  • a bioreactor.
     

Conventional Activated Sludge

We add a high concentration of micro-organisms (activated sludge) to the wastewater. We use large mechanical aerators to introduce air into zones of the tank. By varying the amount of air in different parts of the tank, we ensure different types of micro-organisms are able to break down nutrients (like nitrogen and phosphorus).  

A large mechanical aerator in the CONVAS system.

The CONVAS system uses large mechanical aerators.


Bioreactor

We add a high concentration of micro-organisms (activated sludge) to the wastewater. We use small diffusers at the bottom of the tank to introduce air into zones in the tank. By varying the amount of air in different parts of the tank, we ensure different types of micro-organisms are able to break down nutrients (like nitrogen and phosphorous).

Bioreactor at Wollongong.

Micro-organisms break down nutrients in the wastewater.


Secondary clarifiers

The activated sludge settles to the bottom of the clarifier where scrapers remove it. We recycle some of this sludge back into the bioreactor and treat the rest to produce biosolids.
 
The treated water from the top of the tank flows to tertiary treatment. 

A clarifier at Wollonong

We use clarifiers to separate the activated sludge from the treated wastewater.


Tertiary treatment

Tertiary treatment uses chemical and physical processes to remove very fine solids and disinfect the treated wastewater.
 

Filtration

Filters made of layers of sand and coal trap remove any remaining fine particles. 

Filter tanks

Filters made of layers of sand and crushed coal trap very fine solids.


Disinfection

Wollongong uses two types of disinfection:

  • ultraviolet light
  • chlorine.

For recycled water that will be used on site, at the golf course, sports fields and coal terminal, we use both ultraviolet light and chlorine to kill any micro-organisms that can make us sick.

For recycled water that will be discharged to the ocean, we use ultraviolet light only.


Advanced water recycling

Advanced water recycling uses membranes to remove extremely fine particles, including dissolved salts, from the water.

Microfiltration

We pass the water through a hollow fibre membrane that has a pore size of 0.05-2.0 micron (µm). Particles larger than the pore size are trapped on the membrane and the water passes through.

Microfiltration membrane

A microfiltration membrane.


Reverse osmosis

We push the water through a flat sheet, spiral-wound membrane known as a reverse osmosis membrane. The membrane pore size is 0.0005 micron (µm). The pore size is so small that it can remove nutrients, chemicals, bacteria, viruses and dissolved salts from the water.

This very high quality water is used by BlueScope Steel. 

We use recycled water for a number of different things.

On site re-use

On our plants, we use recycled water instead of drinking water wherever we can. Hoses, sprays and filter backwashes all use recycled water.

Local sports fields

Wollongong City Council uses recycled water to irrigate JJ Kelly Park soccer fields and Vikings Rugby field.

The sports fields are within one kilometre of the Wollongong Water Recycling Plant. We pump recycled water to the council's 120,000 litre storage tank, which is used to irrigate 22 hectares of sports fields.

The council uses about 5 million litres of recycled water each year. The council generally irrigates the sports fields at night to help reduce water loss from evaporation.
 

Local golf course

We supply Wollongong Golf Club with as much recycled water as they need to irrigate the greens and fairways.

The golf club is next door to the Wollongong Water Recycling Plant. We pump recycled water to the club's 2.8 million litre storage dam, which is used to irrigate 25 hectares of the 45 hectare site.

They use about 50 million litres of recycled water each year. The amount of recycled water used varies, depending on the weather and other factors.

The club generally irrigates the course at night to help reduce water loss from evaporation.

Wollongong golf course waters the greens with recycled water.

Wollongong Golf Club uses recycled water to irrigate.


Dust suppression

Port Kembla Coal Terminal uses recycled water for dust suppression. They spray recycled water on the coal to keep it damp and reduce dust as it's moved around. They've been using recycled water since 2008.

Wollongong dust suppresion

Port Kembla Coal Terminal uses recycled water for dust suppression. 


Steel manufacturing

BlueScope Steel uses high quality recycled water for steel manufacturing. 99% of the water they use comes from either recycled water or salt water. They use recycled water for cooling, dust suppression, descaling and scrubbing. Learn more about BlueScope's environmental improvement initiatives.

BlueScope uses recycled water when it makes steel.

BlueScope Steel uses recycled water for cooling steel.

Running the plant

Eight staff manage, operate and maintain the plant. They collect and analyse water samples, do laboratory testing and manage special projects to keep the plant running safely and efficiently.

Worker at a plant

Staff monitor the plant to make sure it's working at its best.


Maintaining the plant

There are three types of maintenance required to keep the plant operating: preventative, planned and reactive.

Maintenance type Description Example
Preventative Prevents a break down Oiling a motor
Planned Replacing equipment as it reaches the end of its useful life, before a break down Replacing a worn motor
Reactive Fixing equipment that has unexpectedly broken down Repairing a motor