Pumps are the most energy-intensive devices in water and wastewater treatment plants. If you want to control energy costs, then the effective management of the pump is crucial. Many ultrasound technologies are the tool of choice. In this article, David Hewitt, product manager for Siemens Automation and Drives Group, explains how advanced ultrasonic controllers give users the ability to control their pumps to increase profits. In water and wastewater treatment plants, the largest consumer of energy is the pump; in a typical treatment plant, pumps consume about 50% of the total energy bill. It is not hard to see that the key to energy management lies in the effective control of the pump. Water and wastewater treatment industries have traditionally used ultrasonic techniques for level measurement because of their low maintenance, ease of installation, reliability and low cost. The latest technological advances in ultrasound systems now provide promising solutions that intelligently manage energy because they provide users with the information they need to effectively monitor and control pumps, making them powerful tools for plant operators . These more sophisticated systems allow the user's plant to be effectively automated without the need for costly PLCs (Programmable Logic Controllers). Moreover, the plant can now reduce energy costs by implementing three pump control strategies: economic pumping to avoid peak cost periods; monitoring flow trends for efficient management; and monitoring pump performance to eliminate inefficient pumps. Ease of use should be one of your choices when comparing ultrasonic controls. The wall-mounted SITRANS LUCS500 controller can be programmed with a handheld keypad for economical pumping. Economic pumping is a valuable strategy as energy costs change over time at different times of the day. The ultrasound system allows users to configure individual pump operating points by region or time period, thus minimizing the well's water level before the high-cost time period comes. The wells can be flooded to higher water levels during peak cost periods. If this level is reached during the high-cost period, the pump will start pumping until it reaches a point above the minimum operating level, thus skipping the capture process and reducing the energy used to start the pump. In many cases, network traffic can be used to avoid pumping completely at high cost. Economic pumping can also be applied to reservoirs in water distribution control systems. The user programmed to pump the pump at night, the system not only met the requirements, but also used a lower cost of energy. Of course it is important that the system respond if a pump is needed. The point is to comply with the rules and prepare the fail-safe system. The user should ensure that the system is able to detect seasonal currents or storms and automatically switch back to normal pumping procedures in this case. Some systems also monitor for overflow emissions, recording dates, times, durations and volumes, which are valuable for periodic reports. Based on regional energy cost estimates, investing in a state-of-the-art controller with economic pumping capabilities that can perform these functions quickly pays for itself. The benefits are very real, as evidenced by South West Water, a British water supplier. Part of South West Water's motivation was to reduce total operating costs, Siemens ultrasonic controllers were installed at seven pumping stations. With its economic pumping strategy, the company reduced energy costs at some pumping stations by 10% and successfully avoided high-rate charges. Originally, each pumping station needed a water level measurement system, programmable logic controller and remote terminal equipment for telemetry. Advanced ultrasonic controllers eliminate the need for multiple systems because they provide all the features needed for pump control, data acquisition and communication over the network. As a result, South West Water's investment quickly reaped. The benefits of economic pumping are not limited to high rates, as changing pump control over time helps to balance the load on the entire network. This feature can be used in applications where there is a breakdown of the energy supply due to high loads, for example during periods of peak demand, causing the pumps in the network to work out of time. Monitoring Flow Trends Monitoring Flow Trends can also be the basis for effective management, with advanced systems that accurately measure and count the pumping volume without requiring raw equipment. The user must record the data or send the data to the central SCADA system via telemetry in order to obtain low-cost traffic trend data across the network. This enabled us to study atypical flows and identify the current and future problems. Permeation monitoring is one of them. In a closed sewer system, it is inefficient to pump rainwater that enters the network through an aged pipe. If traffic increases during heavy rains, the need to repair aged pipes to protect the integrity of the system reduces pumping and saves energy. Traffic trends also help users detect population growth and other signs so users can manage them effectively over the long term. One of the biggest challenges ahead is how to plan correctly to meet the needs of the future population. It is not uncommon for the pump to fail to meet or exceed the required targets. Infiltration monitoring enables users to store and predict traffic throughout the network, so that demand growth is clear and future plans and projects can be identified. In a comfortable control room, operators can remotely manage pumps and other plant equipment using an ultrasonic level controller integrated into a SCADA or other control system. Monitoring pump performance Pumps running at less than rated flow waste energy and money. As the pump is worn or clogged with material, their performance can deteriorate. The advanced ultrasound system enables users to monitor the performance of each pump, including pump status, efficiency and total pump volume. It will record pump run-time and pump start-up times, and integrate the pump with other components for effective monitoring and control. It also automatically removes a poorly performing pump and starts a more efficient pump. The user will receive an anomaly report or alarm alerting him or her that it is time to repair or replace a failed pump or a low performance pump. Recovering the pump to its original high performance state is also conducive to energy efficiency improvements; however, pump performance monitoring also shows when the pump is in good working order, reducing on-site inspections or unnecessary repairs. If the pump station includes pumps of different flow rates, the user can program the controller to start or stop the appropriate pump based on the flow rate. This allows the user to start high-flow, high-energy pumps when needed. Advanced controllers provide a variety of pump control programs and subroutines, such as fixed task aids and fixed task backups, alternative task aids and replaceable task backups, service rate task aids and service rate task backups, and first and foremost task aids . These programs effectively manage the pump and save energy. With this information, users have the opportunity to use pump control to optimize their work, balance pump operation with rate of change in liquid level, service rate, reduce power pulsation with pump start-up delay, or flush valve to clear deposits. The scumming line reduction feature allows the user to automatically change the pump start-up level within specified limits, thus reducing scum lines and reducing the need for regular cleaning and maintenance of the sink. The controller monitors two types of pump failure (high temperature and seal failure) and removes the failed pump from the system. It also monitors the power of the pump and does not attempt to start the pump if the power is interrupted. The controller uses Modbus RTU protocol to send data to the remote SCADA system in the control room via the modem. In the event of an exception, such as a pump fault, it dials out to warn the operator. Choosing a system There are many systems on the market today and their benefits are obvious. When evaluating a pump controller for a plant, users should first make a detailed list of all the pumps, their locations and functions, and then compare the needs of the plant with the specifications of the different products to get the best fit for the user. Ease of use is important, and users should look for controllers with a wide range of functions, but with control algorithms and pre-programmed subroutines so that they can be installed and configured without the need for complicated programming. Users should be able to make changes quickly and simply in the field. Wetwell Sensors Regardless of how advanced the controller is and the system's measurement accuracy is very much dependent on the performance of the sensor, it is important to choose the best sensor and to ensure that the supplier has a wide range of sensors for different distances (ranges) and needs . The user should also look for products with high output efficiency, high performance, suitable for the working environment and with safety certification and check the accuracy of the product under working conditions. If there is a harsh environment of dust, moisture, corrosion, vibration, flooding or extreme temperatures, make sure that the user-selected sensor is able to handle these conditions and that the sensor specifications should be checked to ensure that it is suitable for the user's application needs and requirements Compatible with the transceiver used. Depending on the plant's installation, the user needs a bracket, panel or wall mounting. The controller should be easy to integrate with existing SCADA, DCS or PLC systems to enable remote monitoring of all process variables, instrument diagnostics, status and programming parameters. More data at your fingertips means better monitoring, maintenance scheduling, staffing information and asset management capabilities. If a user has multiple or remote workplaces, he or she needs to ensure that the controller has built-in communications capabilities or can be connected to the fieldbus over the phone, leased line, wireless modem, satellite, or direct PC connection. The advantages of energy saving and maintenance reduction make advanced ultrasonic controllers an extremely economical asset management tool. With advanced pump control features, users can really increase profits. The key points to evaluate a pump controller are: â—† Maximum distance between controller and sensor â—† Number of pumps, gates, and alarms that it will control â—† Pump monitoring capability â—† Pump control programs and subroutines â—† Data logging and reporting â—† Accuracy and Reliability â—† Supplier reputation and industry experience â—† Modularity - Scalability â—† Integration with SCADA, DCS or PLC systems â—† Remote communication capabilities â—† Easy installation and use