BREWARRINA SHIRE COUNCIL

Agenda Submission for Council Meeting held on 16 December 2011

TITLE:

Sand Filter Report

DOC REF: Item 12

REPORT BY:

Siew Neale Assets and Contracts Manager

DATE: 9 Sept 2011

IPR / MANAGEMENT PLAN REFERENCE: Services- Water Supply PURPOSE: To inform Council on the current condition of the Water Treatment Plant and required maintenance. CONTENT: The Lower Macquarie Water Utilities Alliance commissioned NSW Public Works to prepare a Regional Water Quality Management Plan in line with the Australian Drinking Water Guidelines in November 2010. Brewarrina Shire Council’s Water Quality Management Plan’s Executive Summary (Attachment 1) contains a number of recommendations including the rectification of issues at the filter. Appendix E of the Water Quality Management Plan - System Inspection Report (Attachment 2) details the filter inspection on 5 August 2010 and recommendations for remedial works to be undertaken were considered imperative in order to ensure that the filter would operate satisfactorily for the next 15 to 20 years and to produce filtered water of the quality that meets the Australian Drinking Water Guidelines of 2004. NSW Office of Water inspected Council’s Water Treatment Plant on 22 June 2011 and in a letter dated 11 July 2011 raised a number of concerns regarding the Water Treatment Plant and its operations (Attachment 3). The NSW Office of Water stated in their letter dated 11 July 2011 that:

”the issue of the filter maintenance is becoming urgent due to aluminium and turbidity breakthrough. This could lead to more serious health issues if not addressed”.

Brewarrina Shire Council requested a Filter Inspection Report and a Proposal for Filter Upgrade at the Brewarrina Water Treatment Plant in August 2010. The filter upgrade proposed to:

• Remove and dispose of the existing filter media • Remove the existing nozzles domes, stems and undercaps and replace with

new units. • Repair the filter false bottom if required; • Remove the existing filter inlet/outlet and backwash launder and replace with

new units; • Place new dual media filters as appropriate with supporting material; • Install a new backwash pump to meet current design practices; • Increase the capacity of the existing air blower or replace with a bigger unit or

install a second unit to be operated in parallel with the existing unit; • Install a bigger diameter backwash wastewater outlet pipe;

• Replace the filter valves; • Convert operating mode to a constant level filer; • Provide automatic backwash; • Install a control panel for the filter valves; and • Install an on-lone filtered water turbidity meter.

A detailed cost estimate had not been undertaken, however an initial preliminary assessment was in the order of $300,000. In addition, NSW Public Works fee to undertake the works was $33,500 (ex GST) at the time the proposal was written (August 2010). Council had contacted the original supplier of the sand filter for advice and pricing on refurbishment or replacement options. Water Treatment Australia inspected the Water Treatment Plant on 25 July 2011 and considered the options available to Council and recommended to install a smaller second filter rather than refurbishment of the existing sand filter. Refurbishment of the existing filter would require it to be taken from service for a number of weeks whilst the media and filter nozzles are removed and replaced. Due to the limited storage space in the reservoir, the short period of time that the plant was able to be shut down and the costs associated with installing a temporary filter, an additional filter was recommended. Water Treatment Australia’s proposal based on the installation being undertaken by one of their working supervisors with assistance from Brewarrina Shire Council was $197,450 excl. GST. A concrete base to be designed, constructed and paid for by Brewarrina Shire Council. The filtration rate would increase to approximately 10 cubic metres per square metre per hour from approximately 5 cubic metres per square metre per hour. This would significantly improve existing rates and negate the requirement to replace the backwashing equipment. Daryl McGregor, Project Officer of the Lower Macquarie Water Utilities Alliances has reviewed the proposals from NSW Public Works and Water Treatment Australia and the letter from NSW Office of Water. An email with his comments on the proposal is included at Attachment 6. Council currently has $705,290 in the Water Fund Restricted Assets with $498,084 unallocated.

CONSULTATION: Nil GOVERNANCE IMPLICATIONS: Allocation of $210,000 excl. GST from the Water Fund Restricted Assets. CONCLUSION: The installation of a new filter would not only improve the treatment of our water and, therefore, water quality in Brewarrina, but also enable Council to refurbish the existing filter when and if funds allow. This would then provide Council with the opportunity to service and maintain the filter without interruption to supply. RECOMMENDATION:

That Council: 1. Upgrade the sand filter at the Brewarrina Water Treatment Plant in this

financial year;

2. Call tenders to carry out the works; and 3. Allocate from the Water Fund Restricted Assets, based on a

successful tender being received, the required allocation as listed in the report.

_____________________

Rod Shaw General Manager

ATTACHMENTS: Attachment 1 - LMWUA Water Quality Management Plan – Executive Summary Attachment 2 - LMWUA Water Quality Management Plan - Appendix E Attachment 3 - NSW Office of Water letter dated 11 July 2011. Attachment 4 - NSW Public Works Filter Upgrade Proposal dated August 2010. Attachment 5 - Water Treatment Australia Proposal. Attachment 6 - Email from Daryl McGregor, Project Officer LMWUA. Attachment 7 - Water and Sewer Schedule of Restricted Assets.