Groundwater replenishment scheme

This webpage provides information on the history and Department of Health’s (“the Department”) regulatory role on the Water Corporation (“the Corporation”) Groundwater Replenishment Scheme (GWRS).

What is the GWRS?

The GWRS is a climate independent water source for Perth. The GWRS is designed to treat recycled water from the Beenyup Wastewater Treatment Plant. Recycled water is further treated by two Advanced Water Treatment Plants to achieve drinking water quality before being injected into the Leederville and Yarragadee aquifers for later abstraction for drinking water use.

When did the GWRS start and how much water will be injected?

The commissioning of Stage 1: GWRS 14 GL/year capacity was approved by the Western Australia State Government in August 2014 after successful completion of the three-year Beenyup Groundwater Replenishment Trial (GWRT). Stage 1 approval to recharge was granted by the Chief Health Officer in August 2017

GWRS Stage 2 expansion to build a second Advanced Water Recycling Plant to treat additional 14 GL/year was approved in November 2017 and approval to recharge the Leederville and Yarragadee aquifers was granted by the Chief Health Officer on 21 May 2020.

Is the treatment process of the GWRS the same as the one used in the trial?

Yes, the process for the GWRS is the same as the one used in the GWRT and a summary of the key process is presented below:

• Secondary treated wastewater from the Beenyup Wastewater Treatment Plant is pumped to an Advanced Water Recycling Plant where it is further treated. 
• Water that enters the Advanced Water Recycling Plant is treated by passing through three barriers: ultra-filtration, reverse osmosis and disinfection with ultra-violet light.
• Once water has passed through the three barriers it is as pure as drinking water and it is injected into groundwater for storage.
• Through a series of monitoring bores, the stored water in the groundwater is then pumped out for sampling and testing.

What are the treatment barriers for the GWRS?

Multiple barriers are used during the treatment process to generate recycled water suitable for drinking water purposes.

• The first barrier within the waste water catchment area is the trade waste control system applied by the Water Corporation onto industry and other waste water producers.
• Once waste water enters the Beenyup Wastewater Treatment Plant it passes through a primary and secondary treatment process (barriers) designed to remove and reduce biological and chemical contaminants. 
• The treated wastewater is then passed through three additional treatment barriers ultra-filtration, reverse osmosis and disinfection with ultra-violet light within the Advanced Water Recycling Plant to achieve drinking water standards before injection into the groundwater.
• After injection protected recharge areas has been created and water treatment occurs after abstraction before it is supplied to the community

What are the Department of Health requirements for the GWRS?

The Department is responsible for public health in Western Australia and has directed the Corporation to establish a compliance program that ensures that each treatment barrier is effectively applied at ‘control points’, so that the quality of the water is within the required standard before it enters the next stage of treatment. If water quality is below the required standard at the ‘control point’, an alarm is generated to correct the problem. A response to an alarm may include, for example, calibration of monitoring devices or diversion of the water back to early stages of the treatment train.

All treatment barriers and control points within the Advanced Water Recycling Plant are designed to be “fail safe”. This means that if any quality or barrier failure occurs the water is diverted or the plant is shut down.

The Department of Health requires any failures within the whole treatment barrier system to be notified within 24 hours and the cause of each failure is closely examined.

What has the Department done before the GWRS?

Before the GWRS the Department has been actively involved in groundwater replenishment since early stages as summarised below: 

• The research conducted from a three-year feasibility study entitled “Characterising Treated Wastewater for Drinking Purposes Following Reverse Osmosis Treatment” (2005-2008). The Department was the leading agency of this research and the results indicated that microfiltration and reverse osmosis treatment were able to achieve drinking water quality standards in a reliable and consistent manner.
• The feasibility study also provided the Department with valuable information for setting monitoring requirements through the identification of recycled water quality indicators. The 18 microbial and chemical indicators are monitored more frequent and are used to verify all treatment barriers are performing as expected. 
• The Department also reviewed all Beenyup Advanced Water Recycling Plant reports for the GWRT to demonstrate that the plant was capable of producing water as pure as drinking water (i.e. suitable for recharge) prior to giving the go ahead to recharge. For example, more than 15 reports were submitted by the Corporation for assessment over a two-year period (2009 and 2010). 
• The Department regulate the GWRT during the years of operation through a Memorandum of Understanding for the GWRT between the Department and the Corporation (July 2010). Monthly audit meetings were conducted to oversight the recycled water quality and Advanced Recycled Plant Performance. 

What is the Department’s role in the GWRS?

The Department has identified the knowledge and competencies required to safely manage a recycled water system where recycled/replenished water become a drinking water source.

Information and experience gathered during the GWRT has been used by the Department to develop a strong management system to closely monitor and regulate the GWRS though a Memorandum of Understanding between the Department  and the Water Corporation for wastewater Services and Groundwater Replenishment.

The primary role of the Department is to:

• Assess all reports presented during commissioning of the GWRS and ensure water quality before approval to recharge is granted.
• Ensure the quality and safety of recycled water produced is maintained during the operation of the GWRS.
• Endorse the quality management system designed to protect public health

Other roles include:

• Provide advice to the Corporation on matters regarding the production and quality of recycled water.
• Audit the Corporation’s systems and databases used to manage and report on the GWRS.
• Provide comment and advice to the community with respect to recycled water quality.

What has the Department done to ensure the safety of the recycled water?

The Department has:

• Closely monitored compliance of all sampling activities and assessed the competency of the Corporation to manage the treatment processes required to produce water as pure as drinking water. To do this a Memorandum of Understanding (MoU) has been developed and updated over the years to provide clear guidelines for the Corporation to follow during the GWRS
• Required the Corporation to notify the Department of events that may effect any part of the Advanced Water Recycling Plant and its capacity to produce high quality water.
• Required all treatment systems used in the Advanced Water Recycling Plant to “fail safe”. This means that if at any stage water treatment does not meet the required standard water does not proceed to the next stage of treatment.
• Conducted monthly reviews of the Corporations performance by checking the sampling results, monitoring frequency and treatment/ barrier performance. To do this the Department and Corporation have established a Health Advisory Committee for GWRS since recharge started.
• Review findings of the GWRS monthly governance report and asses the Corporation’s skills and competencies to operate the scheme. 
• Site visits to the Beenyup Advanced Treatment Plants during commissioning of the GWRS.
• Requested and assessed external audit reports

What other Government organisations are involved in the GWRS?

The GWRS is also regulated by the Department of Water and Environmental Regulation.

Where can I found more information about the GWRS?

For more information please visit the Water Corporation GWRS website (external site).