How can water companies reduce storm overflow discharges? (Part 2)
Table of contents
Part 2: Improving asset maintenance and changing consumer behavior.
In part 1 of this series, we discussed the benefits of using low-CAPEX solutions as part of a combined strategy to help water companies eliminate storm overflow discharges. By implementing low-CAPEX solutions early on, the scope for a selected high-CAPEX option could be recalculated and reduced. This would allow water companies to achieve significant reductions in capital expenditure, environmental impact, lead times and public disruption. That’s not to mention that existing low-CAPEX solutions could help in meeting combined storm overflow targets quicker and in addressing factors such as pump clogging that high-CAPEX options don’t usually address. In part 2 of this series, we will dive into details of specific low-CAPEX solutions that are available today and what benefits they provide as part of a proposed combined strategy approach.
The downside of high-CAPEX options
The high-CAPEX options covered in part 1 of this article were outlined in a UK government report1 though these options have global applicability. These included separation of the combined sewer network, construction of additional storage and Sustainable Drainage Systems (SuDS). In addition to high capital expenditure levels, all high-CAPEX options were calculated to have long lead times, high levels of embedded carbon2 and a negative impact on consumer bills. The non-SuDS options also have a high risk of environmental harm, and would cause years of disruption to public life.
The upside to low-CAPEX options
Low-CAPEX/OPEX solutions would by comparison be quick to implement and do not have the significant carbon footprint as the high-CAPEX options. They also avoid the associated public disruption and would have a negligible effect on end consumer bills. A prime focus of these solutions revolves around improving consumer habits and reducing current inefficiencies in the wastewater network3. Below we discuss two frequently used strategies:
Changing consumer behavior
Changing consumer behavior could significantly influence sewer networks. In the UK for example 93% of materials causing clogged pumps in the sewer network are baby wipes flushed down toilets. By reducing consumption and waste of water, storm overflow discharges could be improved by 69% in terms of volume and cause a 39% reduction in duration4. Some methods to achieve this include reducing shower duration, using water meters, using low water-use equipment, and implementing more water retentive gardens. Such measures could also improve climate change resilience and reduce energy costs and associated emissions for consumers and producers.
Public awareness campaigns, which are comparatively low cost, could be used to positively influence customer behavior. Many successful campaigns have been produced globally covering a variety of different issues to change public perception and gain public support. Water companies themselves always have public awareness as part of their overall strategy, though there are no guarantees on campaign success. Care has to be taken to use the right channels and level of engagement to have a positive impact. The 2019 ‘Love Water’ campaign for example was aimed at convincing the British public to help protect water resources for the future. However, research (Savanta ComRes polling) in 2020 still revealed that most people significantly underestimated their water use. To compound the effectiveness of public awareness campaigns, legislative measures could be introduced such as placing warnings on packages to reduce disposal of inappropriate materials such as fats, oils and wipes down sinks and toilets.
Improving performance and efficiency through condition monitoring
Apart from improving consumer behavior, water companies can implement strategies that reduce operational inefficiencies and in turn pollution events. Asset failure in the industry has a high criticality due to the high costs this can incur, financially and environmentally. One strategy offering numerous benefits to avoid critical failure is condition monitoring. Condition monitoring is the name for a class of tools that measure one or more physical features to identify changes in a machine’s behavior that signal a developing fault. With the rise of artificial intelligence and the industrial internet of things, modern condition monitoring techniques can make maintenance strategy more data-driven, more effective and more efficient. Depending on the operating environment, it can enable round-the-clock data collection and real-time analysis to provide better results at a lower cost. Repairs can also be performed when they are cheaper and faster. Such a strategy could therefore hold many benefits for reducing storm overflow discharges on the path to 2050:
An optimal condition monitoring maintenance strategy could help to meet early storm overflow reduction targets, reducing the targets associated with the high-CAPEX options.
A condition monitoring strategy doesn’t incur the high environmental impact or cost of implementation as the high-CAPEX options.
A condition monitoring strategy could help reduce the scope and requirements for the high-CAPEX options. As a result, it will reduce the overall capital expenditure and environmental impact of a combined strategy.
A condition monitoring strategy could be used to deal with certain factors that can cause pollution events which the high-CAPEX options can’t. For example, it could be used to detect and resolve upcoming failures or potentially even pump clogging at an early stage.
Implementation of a condition monitoring strategy will not cause the disruption to public life that the high CAPEX options would.
Upscaling condition monitoring in the wastewater industry with remote data collection
There are numerous techniques which fall under the umbrella of condition monitoring. These include oil analysis, infrared thermography, acoustic emission analysis, vibration analysis and electrical signature analysis. Choosing the optimal condition monitoring strategy means understanding the operating environment. A wastewater network is very dispersed geographically with equipment operating in a challenging environment. This creates hurdles for many condition monitoring techniques which require performance of analytics at the equipment itself or the need for sensors to be located on the equipment. Having a technique that could monitor remotely would be a game changer for the wastewater industry, providing for continuous data gathering and real-time analysis. This would allow for faults to be detected at an early stage and maintenance activities to be performed before pollution events could occur.
One technique which is highly applicable to remote monitoring is electrical signature analysis (ESA). For this technique, data could be gathered remotely via sensors located in the motor control cabinet, which would make it comparatively quick to implement. This would enable continuous and real-time monitoring, data processing and fault detection. Such a technique would improve maintenance planning and operational efficiency. It would also mitigate the need for preventive inspections. This would save on significant financial and environmental costs, especially since most pumps inspected during such visits are in a healthy operating condition.
The benefits of such a low-CAPEX condition monitoring technique with remote capabilities would make it an ideal candidate to be used as part of a joint strategy to reduce storm overflow discharges.
Reducing discharges from storm overflows is a major focus of wastewater companies in order to protect the environment and reduce the financial impact associated with pollution incidents. The optimal solution will undoubtedly be a combined strategy incorporating multiple low-/high-CAPEX options.
An up-front low-CAPEX option based on condition monitoring would be a very cost-effective method, especially if a remote monitoring capability allowed for continuous and real-time data collection, processing and fault detection. This would enable improved maintenance planning and greater efficiency across wastewater networks. A knock-on effect would be to reduce the scope of high-CAPEX options of a combined strategy. As a result, this would reduce overall capital expenditure, lead times, environmental impact and disruption to society. It would further help to achieve early targets set by regulators in reducing storm overflow use. Utilizing public awareness campaigns would also be a beneficial low-cost method to try to positively influence consumers. Such campaigns could be used to help reduce consumption and waste of water and behavior which causes pump clogging in the sewer network.
In the final article in this series we will look into more detail at the benefits that electrical signature analysis offers within a joint strategy to reduce storm overflow use. This will include how ESA techniques are already successfully implemented in the water industry.
Storm Overflows Discharge Reduction Plan. UK Dept. for Environment, Food and Rural Affairs. (August 2022).
Total CO2 emissions associated with the construction of a project.
Not all options in the government report are covered in this article such as reducing groundwater infiltration and reducing misconnections.
‘Quantifying the Impact of Water Habits’. UK Dept. for Environment, Food and Rural Affairs bespoke analysis.
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