In a water scarce country like South Africa, handling wastewater correctly is not a luxury but an essential service. Due to rapid urbanization and resource-heavy lifestyle changes, our wastewater system is under severe pressure. This pressure is compounded exponentially by an aging wastewater infrastructure that is not quite capable of handling increased volumes of wastewater.
Aging infrastructure also implies aging rotating equipment. In the case of water treatment these rotating machines are typically motors, pumps, blowers, and compressors. Higher demand requires these machines to be available and to run reliably for longer periods between extended maintenance intervals. There is a growing need for maintenance related outages to be shorter and subsequently maintenance efforts need to be focused and problem oriented.
In a nutshell, the key factor to getting ahead of our growing wastewater problem is a maintenance planning process driven by excellent condition monitoring and machine status data. So, the question is, how do we achieve this?
1. Continuous condition monitoring
A properly implemented vibration condition monitoring strategy has been proven in practice to increase the reliability and reduce the maintenance costs of machines by preventing “run-to-failure” use cases. Traditionally, a walk-around vibration condition monitoring program would be perfect for wastewater machines, although there is always the risk of missing problems that develop in-between surveys. With the advent of new monitoring technologies, it’s becoming more cost effective to monitor these types of machines around the clock, making it possible to detect problems early and plan for maintenance interventions.
2. Sensors that can withstand harsh environmental conditions
It is essential to implement rugged sensors that can withstand the corrosive wastewater environment and can be used in applications where the sensor might be occasionally or continuously submerged. Typically, these sensors are stainless-steel with integrated cables that are hermetically sealed to withstand submersion. Using sensors that are appropriate for these conditions can also make it possible to monitor bearings that are inaccessible during normal operating conditions, such as submersible pumps.
3. Integration of measurements
Over the years vibration transmitters have become “smart” and can differentiate between the most prevalent vibration problems faced by wastewater operators. Transmitters can provide a vibration level output indicating misalignment, looseness and un-balance conditions, as well as a signal indicating the condition of the rolling element bearing. These vibration levels, and the corresponding alarm status, provide valuable information for planning maintenance requirements and should be visible to operators and engineers. This is easily achieved by integration with existing PLC/ SCADA and data historian infrastructure. This also allows for the automatic shutting down of these machines in the event that vibration levels exceed pre-defined safety limits, protecting machines from running to complete failure.
4. Going wireless
In many plants, wireless condition monitoring strategies are also becoming a viable solution. Wireless monitoring systems allow for all the functionality of traditional systems, with the benefit of mitigating cable costs. This not only reduces the costs of copper wire, but also allows for an easier and often quicker installation. Wireless technology is proving to be the right solution when there is a requirement not to disrupt operations during installation. Battery life and battery maintenance of wireless sensors are big factors to consider, but as technology continually evolves and improves, a sensor battery life of several years is becoming a reality.
5. Staying within the budget
Continuous monitoring requires a significant up-front investment to establish the monitoring infrastructure. Therefore, it is essential identify the correct solution before spending money on it. Cost-effective condition monitoring solutions are available to put the power in your hands. The key is to utilize sensors, record the signals of interest, make the measurement data available to the right maintenance personnel, and to integrate this information into the existing maintenance planning process. The investment in continuous measurements and condition monitoring can realize real savings for your business by applying a data-driven predictive maintenance approach.