Sydney Water recently invited tenders for the SRP 2009-12 (Sewer/Stormwater Rehabilitation Program 2009-12) to procure delivery of the rehabilitation work over a three year period.

The activities involved in this tender include the design, manufacture, supply, installation and testing of structural liner for 150–900 mm diameter sewer and stormwater pipes over a three-year period at different locations across Sydney Water’s wastewater and stormwater areas.

The SRP 2009-12 tender consists of six packages as follows:

Packages 1 & 2 reticulation: planned and reactive reticulation sewer rehabilitation (150–300 mm diameter) in all wastewater areas.

Package 3 carrier: planned and reactive sewer carrier rehabilitation (375–900 mm diameter) in all wastewater areas.

Package 4 salt-water: investigation and possible rehabilitation of sewers affected by tidal ingress (150–900 mm diameter) in all wastewater areas. Package 5 stormwater pipes: investigation and rehabilitation in all stormwater areas. Package 6 oviform: sewer carrier rehabilitation in all wastewater areas.

Kembla Watertech Pty Ltd has been carrying out pipeline rehabilitation for over 15 years using a combination of the following specialised Trenchless Technology:

• Ex method (‘fold and form’) PVC pipe lining: this system involves the expansion of a continuous coil of specially formulated PVC pipe to form a tight fitting liner in the existing host pipe.
• Enviroliner CIPP (cured-in-place pipe) system: renovation of pipelines using resin impregnated felt tubes which are cured in place to form a structural pipe in the host pipe.
• FlexiLiner: a small bore lining system capable of lining house service lines down to 100 mm diameter, including 90 degree bends.
• Tiger T: a resin impregnated T section for structural repair and sealing of pipe connections.
• Tiger Patch: a fibre reinforced plastic (FRP) patch is remotely positioned to structurally repair localised pipe defects.
• Kemseal: chemical grout sealing system for pipelines, house service lines and maintenance holes.
• Internal robotic repairs and junction reinstatement: robotic cutting equipment is coupled with various CCTV cameras to enable internal repairs and junction reinstatement after lining.
• Beaver H Expander: hydraulically powered machine for re-rounding deformed pipe sections remotely from within the pipe.
• Pipe bursting: pipe bursting employs a high-powered hydraulic static force head to crack through existing pipes while pulling into place behind it a new pipe, usually polyethylene.
• Amex 10 Seals: an internal joint sealing system used for over 25 years for the sealing of leaks in pressure pipes.

Sydney Water has completed its detailed tender review process and has awarded a contract to Kembla Watertech for Packages 1, 4 and 6 of the SRP 2009-2012 three-year program.

These three packages of work represent a major portion of the total contracts awarded worth $A83 million and continues the long term trusted relationship Kembla has with this major authority. Details of these packages are:

Package 1 consists of 30 kilometres a year of reticulation sewer relining and associated works similar to that delivered by Kembla over the past three years.

Kembla’s Ex system will be the predominant lining technique employed for Package 1. Kembla first introduced its Ex fold and formed system back in 1993 and the system has been in continual use ever since.

The liner is produced in Australia by Vinidex Pty Ltd as a circular PVC pipe that is coiled straight from the extruder onto a spool. The spool is then transported to site where it is heated by steam to soften the Ex material so that it can then be easily and quickly winched into the sewer from one access point to the next.

Steam circulation is continued for a short time to ensure the entire length is completely flexible and then the internal pressure is increased in a controlled manner until the reversion process is complete. The line is then cooled under pressure and finally the ends are trimmed to complete the installation. Ex method is offered in 150 mm, 225 mm and 300 mm diameters and because of the short installation period involved it is not uncommon to finish three linings in a single day.

PVC is the material of choice for new sewer pipes and the Ex method simply provides the same strength and durability of a new PVC pipe without the need for excavation.

Ex pipe ‘formed’ to shape of sewer by steam and pressure

Package 4 represents a continuation of the current tidal ingress catchments program and the addition of a further 30 catchments.

Gravity sewers by their nature flow towards the lowest point on a system, and for a city like Sydney this means harbour and river foreshores. Many of the sewer pipes that have had to be laid close to these tidal areas have saltwater ingress. In fact, many of the sewer pipes are located underwater. The saltwater infiltration results in sewer asset deterioration (corrosion) and unnecessary operating costs in the transporting, treating, and disposal of the additional flows.

The tender specification requires that flow/salinity readings be taken in maintenance holes upstream of each sewage pumping station (SPS) catchment where the likelihood of inflow/salinity is highest. The inflow/salinity sampling and CCTV surveys are used to narrow down the source of tidal ingress. Rehabilitation of areas affected by tidal ingress will include design, manufacture, supply, installation and testing of structural liners. Other activities will include inspection and sealing of maintenance holes.

Package 6 consists of a twelve month contract to line 3,529 metres of oviform sewers in sizes ranging from 381 mm x 254 mm to 990 mm x 660 mm.

As mentioned above, Kembla’s Enviroliner system is a process to renovate pipelines by installing a resin impregnated flexible tube, which is inverted into the existing conduit using hydrostatic pressure.

The tube is cured to a hardened state while held in intimate contact with the conduit.

Enviroliner is tailor-made to suit the circumference of the pipe being repaired and because it is inserted in a softened state it will take the shape of the host pipe. This makes it ideal for non-circular shapes such as oviform.