In the August 2015 issue of Utility, we took a closer look at the new Sewer Line Rapid Assessment Tool (SL-RAT) which adopts the innovative technology of using ‘sound’ rather than ‘sight’ to assess the condition of underground pipes. Now that testing of the new system has been carried out by major utilities over the past year, we thought it would be a good chance to touch base, and see how the SL-RAT is stacking up.
Utility spoke with Sydney Water’s Service Delivery Officer Steve Barclay, and Queensland Urban Utilities (QUU) Senior Engineer Bruce Thompson, to get the low-down.
Mr Barclay has worked in wastewater for over 30 years, is a Sydney Water expert condition assessor and has managed the sewer traverse program for almost 20 years. He commenced a trial of the SL-RAT in November 2014 and presented the results at the No-Dig Down Under conference on the Gold Coast in September 2015.
“The system has been very easy to use in the field, as there are only three buttons which prompt you for any information that the machine requires. Once the machine allocates a serviceability score, you can either record the result manually or download it via an easy-to-use website.
“Being able to evaluate the serviceability grading of reticulation sewers from the maintenance holes without the need to send any equipment through the pipe has continued to be a big bonus throughout our trials.
“It takes a fraction of the time in comparison to traditional CCTV inspections, and this adds to the system in terms of cost-effectiveness.
“A recent US EPA study has also shown that it can reduce inspection costs down to approximately $1 per metre,” says Mr Barclay.
Mr Barclay sees the SL-RAT benefitting Sydney Water in a number of ways in the future.
“The main benefit of the technology is that we can easily and quickly prioritise our choke reduction programs to better target chokes to reduce the impact on our customers and the environment.
“In my role, I am always looking for new ways to improve our system performance. When I learned about the SL-RAT I asked for a demonstration and it was soon decided to begin using it on trials. At the moment, Sydney Water is currently looking to include acoustic technology as part of its choke reduction strategy,” says Mr Barclay.
Queensland Urban Utilities
Mr Thompson is in charge of a small team who manages the infrastructure maintenance and servicing reliability of QUU’s sewage network assets. They analyse, monitor and report on planned maintenance, including budgets and compliance, as well as the annual performance of the sewers themselves.
QUU first began testing the SL-RAT in May 2015 in a joint trial with the Water Services Association of Australia (WSAA). According to Mr Thompson, a new set of trials will be underway over the next three months to further investigate the RAT’s potential.
“It’s early days just yet, but the effectiveness of the SL-RAT is looking positive. The system has the potential to reduce the number of chokes within our sewerage networks, by identifying partial blockages before they become a problem,” says Mr Thompson.
The new trials are being carried out in suburbs with particularly high choke rates, and in terms of accuracy, Mr Thompson is hoping that these upcoming tests will provide QUU with quantifiable data.
“Part of the reason why we are running these current full-scale tests is to compare the accuracy of the SL-RAT against traditional CCTV inspections. Once a blocked sewer is identified by the SL-RAT, we are going to use CCTV to confirm the system’s accuracy. Hopefully we will be able to see a correlation between the two methods and confirm that the SL-RAT is highly accurate.
“If the tests prove successful, we will hopefully be rolling out the technology across more suburbs in the next financial year,” says Mr Thompson.
Cost-effectiveness of the SL-RAT has also been a major selling point of the technology, as it has the potential to direct QUU’s cleaning program to target the sewers most in need, and leave those that don’t require cleaning.
“As well as pre-screening with the SL-RAT, post cleaning may also be possible. Once the blockage has been cleaned, we can run the device for confirmation. This will really help in providing us with a method of quality control for our cleaning program.
“Overall, the future of the SL-RAT is looking good. Chokes in sewers are not good for the customers nor the environment, and we really see this tool having the potential to help manage the inspection and cleaning process a lot better,” says Mr Thompson.