Secondly, pipe areas targeted through the camera investigation are repaired using innovative trenchless relining techniques to correct faults, rather than being replaced. This is a ‘no-dig’ and cost-effective way of renewing the pipe. In most cases, the new pipes are formed on site by taking a continuous strip of profile and spirally winding it inside the damaged pipe, forming a new, water-tight structural pipe within the host pipe (see Figure 2.4). “Using Trenchless Technology, this no-dig, cost-saving pipe renewal process will help prolong the life of our sewer network, defer the need for expensive infrastructure upgrades and minimise any inconvenience to our customers. “Relining pipes and rehabilitating manholes also helps protect the environment and public health by reducing the amount of groundwater infiltration entering the sewer via pipeline cracks or faulty joints, allowing us to better manage sewage flows, especially in times of extreme wet weather.” – Unitywater Manager Network Projects, Ashley Massie. Case Study 3 – South East Water Overview
Figure 6.1 includes the area serviced by Central Highlands Water. Figure 6.1: Central Highlands Water location and boundaries Asbestos Cement Pipe Maintenance at Central Highlands Previous approach Prior to its current approach to pipe removal, Central Highlands Water was replacing asbestos cement pipes using the ‘pipe bursting’ technique and leaving fragments in the ground. However, in 2015, the Victorian Government clarified that asbestos fragments left in the ground after pipe bursting classified as asbestos waste and as a result these required removal and disposal. Based on this clarification, Central Highlands Water transitioned to its current asbestos removal methods. Current approaches Central Highlands Water currently has two approaches for removing asbestos pipes. Both methods follow the ‘excavate and remove’ strategy, but the specific approach depends on the nature of the pipe. If an AC pipe cracks, Central Highlands Water assumes that the removal process will involve friable asbestos. In response, a Class A licenced contractor is engaged to remove the pipe. If the AC pipe is not cracked, the asbestos is bonded (or non-friable) and can be managed internally by the appropriately trained and licenced Central Highlands Water staff. Further details on these two approaches are provided below. Approach One – A non-cracked AC pipe Appropriately trained Central Highlands Water staff undertake the removal of a non-cracked AC pipe. Training covers the hazards associated with asbestos in accordance with the Regulations, and for a staff member to conduct the removal, training must have occurred within the past two years. Mandatory requirements for the removal of non-cracked AC pipe includes: Completion of a job safety and environment analysis (JSEA), includes an outline of the necessary Personal Protective Equipment (PPE); Handling, transport and disposal carried out in accordance with EP regulations; Notifying adjoining commercial businesses (including schools, retail etc) immediately it is determined necessary to cut and or remove AC pipe; If cutting is required, Central Highlands Water will remove an entire section of pipe (6 metres), rather than limiting the removal to the damaged area; Completion of an Asbestos Removal Control Plan. The procedure for removing non-cracked AC pipe at Central Highlands Water is outlined overleaf, followed by a real-life example of this removal process.