Location	Castlereagh Road, Penrith
Population served	100,000 people
Area serviced	63 km2 Including the suburbs of Castlereagh, Cranebrook, Mt Pleasant, Penrith, Glenmore Park, Glenbrook, Blaxland, Warrimoo and Mt Riverview.
Amount of wastewater treated each day	24 million litres
Treatment level	Tertiary
Recycled water applications	We reuse some water on site for industrial purposes like washing down equipment and filter backwashes. Penrith Council uses up to 18 million litres of our recycled water a year to water nearby sportsfields.
Environmental discharge	We send the remainder to the St Marys Advanced Water Recycling Plant for advanced treatment. The water is returned to Penrith and released into Boundary Creek. It flows to the Nepean River.
Amount of biosolids produced each year	20,000 tonnes.
Operating license and regulation	We operate the plant under three sets of rules: Environmental protection license issued by NSW Environmental Protection Authority (EPA). View the licence limits. Recycled water produced by the plant must meet the Australian guidelines for water recycling. Biosolids produced by the plant must meet the Environmental guidelines: Use and disposal of biosolids products.

Primary Treatment

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.
 

Grit removal

We stir the wastewater rapidly, forcing the water to spiral and create a vortex. The vortex causes grit to spiral to the centre of the tank, separating it from the water.

We split the wastewater into two streams. One stream flows to the sedimentation tank and bioreactor and the other flows to the Intermittently Decanted Aerated Lagoons (IDAL).

Sedimentation

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.

Secondary treatment

Secondary treatment removes nutrients such as phosphorous and nitrogen using physical, biological and chemical processes.

Bioreactor and clarifier

We add a high concentration of micro-organisms (activated sludge) to the wastewater. 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).

We pump the wastewater to a clarifier. 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.
 

IDAL

We add a high concentration of micro-organisms (activated sludge) to the wastewater.

Like in the bioreactor, varying the amount of air ensures different types of micro-organisms are able to break down nutrients (like nitrogen and phosphorous). In the IDAL, wastewater goes through three stages - aeration, settling and decanting - in one tank, rather than passing through separate tanks.
 

Tertiary treatment

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

Chemical mixing

We add chemicals that make the smallest particles ‘stick’ together forming larger ‘flocs’. This process is called flocculation.

Filtration

Filters made of sand trap remove any remaining floc and fine solids.
 

Disinfection

We add chlorine to kill any micro-organisms that can make us sick. We remove any residual chlorine before discharging the treated wastewater to the environment or recycling it.

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 where ever we can. Hoses, sprays and filter backwashes all use recycled water.

Local sports fields

We supply Penrith Council with as much recycled water as they need to irrigate the local sports fields.

Environmental flow

We release some water into the local creek to help keep the creek alive and healthy.

Advanced treatment

The rest of the water is sent to the St Marys Advanced Water Recycling Plant for further treatment using membrane technology. This water is released into the Hawkesbury Nepean river for environmental flow.

Discharge at Penrith

We release high quality recycled water for environmental flow at Penrith.

Running the plant

A small team 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.

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