Regional authorities, particularly in areas remote from major cities, often do not have readily available cost-effective rehabilitation solutions for their deteriorated sewers. Nevertheless, such authorities still experience similar problems as their major city counterparts.
Recognising their common inherent difficulties, three North Queensland authorities established a plan to release a combined tender to obtain the best value for their investment.
Fitzroy River Water (a commercial activity of Rockhampton City Council), Mackay Water and CitiWater – Townsville each had extensive programs for the rehabilitation of their sewer networks identified for the next five years. Funding had already been approved in the 2002/2003 budgets. A “Joint Tendering” process was suggested, offering the potential for a reputable service provider to provide the lowest available rates, thereby maximising the value of the service they could provide.
A report along these lines was presented to the respective Councils in September 2002, and approval to proceed with the negotiation was obtained. A project team with representatives from each of the three councils was formed and interviews with two of Australia’s major sewer rehabilitation contractors were conducted. Both companies expressed their support and provided valuable recommendations based on previous experiences on large scale contracts.
Due to the complexity and possible duration of the eventual contract, expert legal advice was sought regarding the tender documents. As a result, the AS2124 (1992) General Conditions of Contract were amended and additional clauses inserted.
At this point, CitiWater – Townsville withdrew, leaving Mackay and Fitzroy River Water to proceed with a combined tender. The works called for lining of trunk mains from 750 mm to 225 mm diameter and for minor works with 150 mm and 100 mm diameters.
Three tenders were received and the contract was awarded to Interflow Pty Limited, Australia’s largest sewer rehabilitation specialist. Conditions of Contract accepted by Interflow included:
• All works to be completed by 30 June 2003
• No time extensions due to inclement weather
• Each Council had the right to extend the contract for a further 12 months
• Each Council had the right to vary the extent and location of the work
• No provision in the Schedule of Rates for mobilisation
Solutions Offered
The expanded spirally wound Rib Loc Expanda Pipe structural lining system installed by Interflow has proven particularly suitable for a project of this nature as liners are formed on site to the actual host pipe diameter, rather than pre-manufactured to size in a factory. A range of five plastic profiles is all that is needed to make liners for pipes with diameters from 150 mm to over 750 mm. This versatility means that liners can be installed with minimal lead time as it is not necessary to wait for the correct line size to be manufactured, and sometimes shipped from overseas.
Other solutions provided by Interflow included the Epros DrainPlus epoxy cured-in-place liner for 100 mm and 150 m house service lines, and the Interflow Lateral Connection Repair (LCR) for making secure connections between laterals and lined sewer mains.
The project required an extension of the known capabilities of DrainPlus because of some particularly complex installations. House service lines are typically less than 10 metres in length, running from an inspection opening to the sewer main. However, in some of the steep parts of Rockhampton, combined house service lines collect wastewater from between two and five houses each and can be up to 50 metres in length. The 100 mm and 150 mm diameter house service lines often pass under houses and incorporate up to five square junctions in each as they “step” down the hill.
Inverting the liner over that distance and around such a series of bends was proof of the effectiveness of the DrainPlus liner and the installation process.
Conclusion
As a result of this initiative, the Councils have achieved cost reductions of between 12 per cent and 17 per cent compared to sewer rehabilitation contracts from previous years. This has been achieved through economies of scale offering increased buying and bargaining power, and the removal of high establishment costs for contractors located long distances away.
In addition to cost savings, other benefits have also been realised by the local authorities. For example, specialised resources are also locally available to carry out unplanned incident work.
The scope of the contract allowed Interflow to open a regional depot in Rockhampton, making a firm commitment to employ upwards of 20 people; mostly local residents.
Fitzroy River Water’s Capital Works Manager, Mr Neville L’Oste-Brown is enthusiastic about the outcome. “My
experience has been that by combining the talents of two or more local authorities, significant additional advantages have been gained through networking and personal development. The additional costs (if any) are completely offset by the exposure to a fresh approach to the tendering process.”
“In this particular case, not only have savings been achieved, but also a new local business has been established with flow on benefits for Rockhampton and the Central Queensland region.”
