Force Main Pressure Monitoring Technology Provides Cost-Saving Data to Extend Asset Life at Western Lake Superior Sanitary District

This presentation will detail how the investment in new monitoring technology gave Minnesota Utility Western Lake Superior Sanitary District data and analysis to allow them to make informed decisions concerning capital planning, plus the confidence to plan specific asset repairs amid wastewater network vulnerability. Background to the Problem Western Lake Superior Sanitary District (WLSSD) provides wastewater treatment for seventeen communities and three large industrial facilities in a 530 square mile region in the Duluth-Cloquet (MN) area. While treating about 14 billion gallons of municipal and industrial sewage annually, WLSSD is committed to protecting the environment, including the region's most precious resource -- Lake Superior. Preventing sewer overflows and leaks into the watershed is a top priority; pump stations and force mains serve as an effective way to control sewer overflows. The Challenge Force mains by their nature are not accessible by camera and therefore they can be notoriously difficult to evaluate. It was necessary for the utility to hire an external consulting firm to help overcome this, to spot and discover where network frailty lay and make suggestions to ultimately formulate an all encompassing asset management plan. Once appointed, the external consultants conducted measurements and modeling on three force mains with the sole purpose of identifying locations of greatest risk and making recommended improvements to reduce that risk. Based on this analysis, this presentation will detail the consultant-provided recommendations (which were very much) based on worst-case scenarios, ranging in cost from $185,000 to a $1 million in capital improvements. Obviously with a vast differentiation in the amount of capital spend required and looking down the barrel at significantly increasing costs, WLSSD wished to obtain additional data to verify the model results prior to making any decisions about planning capital improvements. The Technology Solution WLSSD came to Syrinix and specifically adopted their relatively new solution for Wastewater monitoring, which had seen excellent results and significant adoption at UK Utility - Anglian Water. PIPEMINDER-C (now known as PIPEMINDER ONE EXTERNAL) and it's analysis platform RADAR provides pressure transient detection, burst alarming and intelligent asset performance analysis to alert scenarios such as high/low delivery pressures, blocked pipes, trapped air and failing pumps or valves. This presentation will detail how in wastewater, unlike potable water, the impetus stops being on transient detection so much, and more on trend spotting. Subtle changes in the size or shape of transients, or the mean pressure being higher, lower or changing over time can be symptoms of an ongoing maintenance requirement or a break. RADAR has systems built in to automatically alert on these symptoms, especially when spotting a break, or analysts can use more subtle and complex knowledge and understanding to tease out the cause of these symptoms. Breaks, on rising mains, can go for months without being known about, due to their remoteness and that their effectiveness is measured by how well the main manages to shift it's wet well's contents. A break makes the main less restrictive to flow and so the main will often appear to be operating better than usual. Due to the nature of what they are moving however, this can cause untold damage to wildlife and habitats and the water companies will be expected to clean up the affected area. This presentation concentrates on maintenance events. Pumps operating poorly and NRV/Check Valves passing will cost the water company huge amount in energy costs alone, since every litre of water is now taking so much more energy to get from point A to B. Spotting entrapped air or the effects of poorly performing air-valves also can lead to a reduction in breaks throughout an asset's life. To summarize, pressure logging provides critical burst alarms on pumped mains alongside invaluable asset performance analysis and alerting, to prevent breaks and increase asset lifetimes. Results WLSSD installed the PIPEMINDER technology system in January 2020. Analyzing multiple locations, it was found that the data generated during normal operations lined up reasonably well with the models but in addition, the technology and analysis enabled the WLSSD team to verify or identify specific problem areas. This presentation will detail three examples of discoveries via the data that informed capital decision making. 1. A Welded Air Release Valve Wasn't Demonstrating Benefit. The modelled data revealed a specific valve was providing limited air transfer to and from the pipe. The installed technology allowed WLSSD to confirm that this component was not critical to force main operation and the risk of an emergency repair from this connection could be eliminated without detriment to the operation of the system. 2. An Ineffective Air Release Valve Manhole. At one station, WLSSD had planned to vent an air release valve manhole to improve conditions. Data revealed that this change would not benefit pressures at the station or in the pipeline. This finding surprised the WLSSD team. Additional work took place to evaluate whether reinstating a former air release valve location would improve pressures. 3. Transient Events Due To Power Outages. The devices captured four significant transient events when pumps shut down due to power failure. Transients were documented and showed significant additional pressure on the pipes that could cause a failure if they were not addressed. This data enabled the analysis team to highlight the importance of determining the cause of the outages and to work with the utility to identify the cause and mitigate the problem Cost Savings Data provided by PIPEMINDER now informs capital planning work to improve conditions of WLSSD's force mains. While modelling is important, the results may not reflect actual conditions. The utility has learnt that modelling that is too conservative can lead to unnecessary capital expenditures. Having accurate monitoring data helps WLSSD identify smaller capital projects that extend pipeline life-and to see where additional protection is warranted. Improved System Availability Industrial and residential customers rely on WLSSD's systems 24/7. Shutting down a pipeline due to transient events or component failures is not an option. By proactively identifying potential problem areas using data generated, WLSSD can take steps to reduce the risk of operational interruptions. Informed Decisions WLSSD improved its ability to make decisions regarding capital investments and operations backed by accurate data. They now have the information needed to invest resources where there is the greatest risk and the greatest potential benefit.