The Cleveland Bay Purification Plant (CBPP) was first commissioned in 1988 as an activated sludge plant with a nominal design capacity of 126,000 EP. A sludge digestion train was later added and commissioned in 1994.
The introduction of a load based licence from the regulators, now Department of Environment Heritage and Protection (DEHP), in September 2005 necessitated a further technology upgrade to meet licensed conditions and to provide effluent re-use capability.
The load based licence led to the plant being upgraded to a membrane bioreactor (MBR) plant in 2008, resulting in the retrofitting of an ultrafiltration system (immersed membrane cassettes) into two existing clarifiers, including supporting infrastructure. However, for various historical reasons and government level decisions of the time, the upgraded plant was not able to meet the licensed conditions under all scenarios.
The plant's current ability to meet the licensed conditions is limited as follows:
- The licence requires the plant to fully treat sewage inflows up to 1,007 litres per second (L/s), equivalent to 3 times design average dry weather flows (3ADWF); the plant capacity is limited to 530L/s (1.58ADWF) due to the insufficient volume of the installed membrane system, resulting in sewage bypassing the ultrafiltration system; and
- The licence requires the plant to screen all inflows above 1,007L/s before discharging to receiving environment; the plant can receive flows as high as 2,014L/s and the current configuration of the plant can give rise to unintended bypasses of unscreened sewage to the receiving environment; and
- The plant's configuration lacks redundant capabilities conceivably giving rise to plant failure and breach of licence conditions; the conduct of planned repairs and maintenance activities requires detailed planning prior to implementation and the occurrence of component failures increases the risks to personnel and chance of licence breach during reactive repair and maintenance activities.
The consequence of these limitations is that the plant, in wet periods (i.e. when inflow is greater than 530L/s) cannot meet the licence requirements to fully treat all flow up to 1,007L/s and meet the prescribed concentration limits in the licence for full treatment. Also, the plant currently cannot fully screen all flows above 1,007L/s and modifications to the screens are required to ensure licence compliance.
Council has, in two separate planning reports, explored numerous options to economically resolve the non-compliance at the CBPP. At its 22 September 2015 meeting, Council resolved to proceed with an upgrade to the CBPP to address the items identified above.
The approved work is focused on the liquid stream and includes constructing a new membrane (ultrafiltration) tank, carrying out upstream and downstream upgrades for hydraulic flow and screening, upgrading the hydraulic capacity of the outfall pipeline to meet full flows, and consequential modifications to odour, noise and solids stream assets to ensure the plant maintains regulatory compliance in all regards.
The project is jointly funded by the State Government and the Townsville City Council. For more information on the project please go through the 'TCC Wastewater Treatment Cleveland Bay' page under 'Project Documents' or visit the Townsville City Council website: www.townsville.qld.gov.au
Opportunities on the Project will be released soon.SHOW LESS