Grit
Small insoluble particles in wastewater such as sand, coffee grounds gravel, glass and food particles.
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Recycling water
Wollongong Water Resource Recovery Facility is one of about 30 water resource recovery facilities in Sydney, the Blue Mountains and the Illawarra. It serves Wollongong and surrounding suburbs.
Facts and figures
Location: Port Kembla Road, Wollongong
Population served: 200,000 people
Area served: 71 square kilometres, including Port Kembla, Bellambi, Wollongong and surrounding suburbs
Wastewater treated: 49.8 million litres each day
Treatment level: Tertiary
Recycled water applications:
- We reuse 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 kilometre offshore.
Biosolids produced: 11,000 tonnes each year
Operating licence and regulation: We operate the plant under 3 sets of rules.
- Environmental protection licence issued by NSW Environmental Protection Authority (EPA) – find out more about our EPA licences and limits.
- Recycled water the facility produces must meet the Australian guidelines for water recycling.
- Biosolids the facility produces must meet the EPA's Environmental guidelines: Use and disposal of biosolids products.
Flow chart
Primary treatment
Primary wastewater treatment removes large solids using physical separation processes.
Screening
Screens trap and remove large solids as wastewater flows through.
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.
The grit and screenings captured are sent to landfill.
Large solids like wipes, food scraps, rubbish, cotton buds and plastic are caught on the screens.
Sedimentation
Wollongong uses 2 different types of sedimentation processes.
Traditional sedimentation allows 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 treated to produce biosolids.
A multi-flow tank (sometimes called a lamella plate) uses a set of stacked inclined plates. Water travels up and over the inclined plate. The heavy solids are captured on the plate. Mechanical scrapers remove the solids, which are treated to produce biosolids.
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 nutrients in wastewater.
Wollongong uses 2 types of secondary processes that work in a similar way:
- a Conventional Activated Sludge system (CONVAS)
- a bioreactor.
CONVAS and bioreactor
We add a high concentration of microorganisms (activated sludge) to the wastewater. In the CONVAS, we use large mechanical aerators to introduce air into zones of the tank. In the bioreactor, we introduce the air using small diffusers at the bottom of the tank. By varying the amount of air in different parts of the tank, we ensure different types of microorganisms can break down nutrients like nitrogen and phosphorus.
The bioreactor uses diffuser aerators.
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.
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.
Disinfection
Wollongong uses 2 types of disinfection:
- ultraviolet light
- chlorine.
For recycled water that will be used on-site, and at the golf course, sports fields and coal terminal, we use both ultraviolet light and chlorine to kill any microorganisms that can make people sick.
For recycled water that will be discharged to the ocean, we use ultraviolet light only.
Filters made of layers of sand and crushed coal trap very fine solids.
Advanced treatment
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 a size of 0.05–2.0 micron (µm). Particles larger than the pore size are trapped on the membrane and the water passes through.
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 microns. 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.
A microfiltration membrane.
Reusing the water
On our plants, we use recycled water instead of drinking water wherever we can. Hoses, sprays and filter backwashes all use recycled water We use the remaining recycled water for a number of different things.
Local sports fields
Wollongong City Council uses recycled water to irrigate JJ Kelly Park soccer fields and Vikings Rugby Club field.
The sports fields are within one kilometre of the Wollongong Water Resource Recovery Facility. 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 it needs to irrigate the greens and fairways.
The golf club is next door to the Wollongong Water Resource Recovery Facility. 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. It uses 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.
Dust suppression
Port Kembla Coal Terminal uses recycled water for dust suppression. It sprays recycled water on the coal to keep it damp and reduce dust as it's moved around. It has been using recycled water since 2008.
Steel manufacturing
BlueScope Steel uses high-quality recycled water for steel manufacturing. Of the water it uses, 99% comes from either recycled water or salt water. It uses recycled water for cooling, dust suppression, descaling and scrubbing. Learn more about BlueScope's environmental improvement initiatives.
Wollongong Golf Club uses recycled water to irrigate.
Port Kembla Coal Terminal uses recycled water for dust suppression.
BlueScope Steel uses recycled water for cooling steel.
Operations and maintenance
Running the facility
Eight staff manage, operate and maintain the facility. They collect and analyse water samples, do laboratory testing and manage special projects to keep it running safely and efficiently.
Maintaining the facility
Three types of maintenance are required to keep the facility operating: preventative, planned and reactive.
See the table below for examples.
A small team make sure the plant runs efficiently.
Maintenance type |
Description |
Example |
|---|---|---|
Preventative |
Prevents a breakdown |
Oiling a motor |
Planned |
Replacing equipment as it reaches the end of its useful life, before a breakdown |
Replacing a worn motor |
Reactive |
Fixing equipment that has unexpectedly broken down |
Repairing a motor |