Beenyup Wastewater Treatment Plants
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The Beenyup Wastewater Treatment Plant serves Perth's rapidly developing northern suburbs from Quinns Rock through to Scarborough and inland through Dianella and Bayswater to the foothills east of Midland.
It is an advanced secondary treatment plant.
Capacity is currently 120 megalitres per day but ultimately it will be developed to treat 150 megalitres per day, servicing a population of up to 750,000 people.
Odour Improvement Project
The Water Corporation has undertaken a series of major odour improvement initiatives since 2000.
Read about the Odour Improvement Project
History
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Early sub-divisions in the northern suburbs were served by small local wastewater treatment plants.
These were gradually closed down when a temporary plant was established at Beenyup in 1970.
In 1972 the first stage of the permanent plant was commissioned which catered for a flow of 3.6 megalitres per day.
This plant utilised the extended aeration process and provided for wastewater to be disposed of on-site by soakage.
By 1978 the plant had been expanded to treat 27 megalitres per day using the conventional activated sludge process.
At this time a gravity outfall was commissioned which enabled the treated wastewater to be discharged into the Indian Ocean off Ocean Reef.
Further facilities were commissioned in 1984 to enable the plant to treat 54 megalitres of wastewater per day.
The sludge digestion facilities were commissioned in 1990, replacing the sludge incineration process.
New secondary treatment facilities were opened in 1996
Treatment Process
Raw wastewater entering the plant passes through bar screens that remove materials such as paper, rags and other large objects from the flow and mechanically rake the material into a screw conveyor.
This material is then pressed and disposed to secure landfill.
After screening, the wastewater flows into circular grit removal tanks, aerated to allow the inorganic material (grit) to settle and the organic material to pass through.
Following removal of screenings and grit the wastewater passes very slowly through large, rectangular primary sedimentation tanks allowing about 50 per cent of the suspended solids to settle out as sludge.
The sludge is collected by a scraper mechanism and pumped to the solids handling area for thickening and digestion.
The treated liquid leaving the tanks is called "primary treated wastewater" and it passes to secondary treatment.
Secondary treatment is achieved in aeration tanks by the "activated sludge" process where ideal conditions are provided for microbiological life to grow rapidly and consume the organic material in the wastewater.
Microorganisms require oxygen to survive and this is provided by blowers which inject air through fine bubble dome diffusers on the floors of the tanks.
Following aeration, the treated wastewater passes slowly through circular clarifiers in which the activated sludge settles leaving a high quality secondary effluent.
The settled sludge containing active micro-organisms is rapidly removed using scrapers and is returned to the aeration tanks.
Solids removed from the primary sedimentation tanks and excess solids produced by the activated sludge process are thickened and fed to the anaerobic digesters.
Following digestion, the sludge is mechanically dewatered to produce a biosolid, suitable for use as a soil conditioner.
Secondary wastewater flows by gravity to the Indian Ocean in the vicinity of the Marmion Marine Park and is discharged into 10 metres of water via two outlets, one 1850 metres and the other 1650 metres offshore where it is rapidly diluted and dispersed.
Regular monitoring of ocean water quality is carried out to confirm that environmental and health standards are met.
Numerous analyses are regularly carried out to monitor the performance of the plant.
Regular tests are carried out to check compliance with the Department of Environment licence.
Monitoring for impacts on the marine environment
More information
Beenyup Wastewater Treatment Plant brochure
Beenyup Wastewater Treatment Plant
For more information about our Beenyup operation call 08 9306 7615.
For more monitoring information please call 08 9420 3710
For further information on metropolitan wastewater treatment plants email wastewater@watercorporation.com.au