South West Water supplies around 1.7 million residents in Cornwall, Devon, the Isles of Scilly and parts of Somerset and Dorset reliably and efficiently with high-quality drinking water and is also responsible for waste water treatment. To meet the needs of its customers, the company holds water in more than 20 reservoirs and treats it into drinking water in around 40 plants.
South West Water operates another 650 plants to recycle waste water, including a plant at Marsh Mills on the outskirts of the major city of Plymouth. Around one third of the wastewater from the city of 230,000 inhabitants is treated here in several stages before being fed back into the water cycle.
Treatment consists of mechanical cleaning followed by biological cleaning. In the process, microorganisms break down the organic substances dissolved in the water. Here it is crucial that sufficient oxygen is permanently added to the water so that the decomposition process can take place in the required quality. This task is performed by nine blowers, which pump up to 390 cubic liters of air per minute into the pools with a total output of 615 kW.
The challenge: Keeping an eye on the health of all assets
Despite regular maintenance, however, it happened time and again that a plant failed due to unexpected bearing damage. This is because, due to the fully insulated construction of the plants, it was not possible to detect the typical noises that could have indicated a deterioration of the condition.
Downtimes and unplanned work were the result, along with the corresponding costs. It was therefore not a surprising but a logical step that South West Water decided to equip the blower units at Marsh Mills with ifm ‘s vibration diagnostics system as a first step.
The solution: Condition monitoring using vibration analysis
The vibration analysis system consists of acceleration sensors and an evaluation unit. The sensors are positioned at the relevant positions of the plant and transmit the data to the evaluation unit. The unit continuously analyzes the information and sends appropriate signals to the control system when limit values are exceeded. Data and alarms can then be transmitted to a central control room via Ethernet interface.
Thanks to the monitoring of the occurring vibrations in the time and frequency range, any incipient damage is registered at an early stage and can be analyzed in real time by ifm’s own software in a more detailed FFT analysis (Fast Fourier Transformation). Since an exact frequency can be assigned to the individual system components or damage patterns, the sometimes time-consuming on-site troubleshooting is no longer necessary, and maintenance work can be prepared effectively, even remotely. The Maintenance Manager can get a picture of the situation at short notice, assess the need for action and, in an emergency, inform the maintenance team on site.
The result: Achieving corporate goals through condition monitoring
Over 200 evaluation units have been installed at South West Water’s facilities along with the accelerometers connected to them.
By detecting damage at an early stage, it was possible to react in time and thus avoid downtimes and cost-intensive repairs. The introduction of condition monitoring has reduced the cost of maintaining and replacing damaged assets by a total of £100,000 to £150,000 per year on average.
Condition monitoring helps to achieve the company’s goals with regard to environmentally friendly handling of water and waste water.
In order to benefit more comprehensively from the advantages of condition monitoring in the future, South West Water has defined condition monitoring on pumps and blowers as a technical standard. Each new plant must be equipped accordingly with sensor and evaluation technology that can be integrated into the existing structure. This helps to efficiently and effectively keep the quality in perfect condition even at smaller processing plants in rural areas.
The future: Collaboration via IoT platform
South West Water has been able to effectively prevent serious failures of critical water supply and waste water treatment equipment with a comprehensive condition monitoring program. This saves the company significant costs for repairing or replacing equipment. At the same time, plant monitoring supports the company’s goals with regard to the responsible use of water as a resource.
As a further development step, South West Water can very well imagine switching to the new IoT platform ifm moneo, because on the one hand it allows even complex sensor infrastructures to be easily mastered, and on the other hand it offers far-reaching possibilities for even more comprehensive vibration analysis. The relevant data would then be available in a cloud environment and could be shared even more effectively with maintenance colleagues in the supply area, so that the quality of maintenance and the speed of response in the event of an alarm would again increase significantly.
