Providing SA Water with a Trenchless Solution

PPS Inflatable liner technology is helping SA Water protect significant trees from damage, as well as ensure our sewer networks remain structurally sound free of blockages that impact our customers and the environment.

Tree root intrusion is the leading cause of blockages at customers’ wastewater connection points, especially when cooking fats and other foreign objects are flushed down the toilet and get tangled in roots that have made their way into our pipes.

Most sewer blockages can be cleared by cleaning the inside of the pipe, without the need for excavation. However, in some cases, tree roots continue to grow, causing further blockages of pipes. To improve service to customers experiencing repeat blockages, SA Water has an annual capital program is underway to replace these troublesome connections.

The Production & Treatment Alliance Projects team typically replaces connections using either traditional excavation or hydro-excavation (using water to remove soil from around the roots) when working in a tree protection zone. This approach, while effective, is time-consuming and can cause additional disruption for our customers. Looking for a better solution, the team engaged Plumbing and Pipeline Solutions (PPS) to participate in a trial involving the installation of a structural cured in place (CIPP) liner. The resin-impregnated liner is inserted through the customer’s inspection point avoiding the need for excavation. Once inserted, the CIPP liner is inverted and inflated while the resin cures and hardens in place rehabilitating the pipe resulting in a structural liner. PPS had developed the service internally, trialling in their Marleston workshop prior to partnering with SA Water where trials we conducted on several properties to prove the required outcome was achievable.

A recent job to replace two neighbouring connections on Glynburn Road in Kensington Park provided the perfect challenge for PPS to put the CIPP technology into action. The particular challenge on this job was persistent root ingress from an approximately 300-year-old, State Heritage-listed river red gum. Given the location, significant traffic interruption would result if excavation was required.

Production & Treatment Alliance Project Manager engaged PPS to clean and inspect (via CCTV) the two connections, confirming they were suitable for lining, before the CIPP liners were installed providing a structural liner between the GIO and sewer main.

“Having a range of pipe replacement options at our disposal allows us to tailor solutions to best meet the specific challenges of individual sites,” said the Production & Treatment Alliance Project Manager.

“The CIPP lining technology allowed us to replace the Glynburn Road connections without impacting the root zone of this important tree, with the added benefit of avoiding traffic disruptions that excavation would have brought.”

This project was completed over 2 days onsite without any excavation and now provides these SA Water owned assets with a life extension of 50 years.