Switch helps prevent arc-flash exposure in high-voltage applications

Problem: The Los Angeles County Sanitation District conducted an arc-flash study on its high-voltage switchgear and concluded that the best protection for maintenance personnel was not to be present in the area when the trip or close occurs. The facility needed to find a way to remotely control the process.

Solution: The Electroswitch TD-CSR enables service technicians to remove themselves from harm’s way by initiating a time delay through a push-button sequence available in the lighted nameplate of the switch, providing 10 seconds to clear the area before the switch changes position. The switch was a direct replacement of the existing breaker control switch, requiring no panel modification or changes in existing drawings.

Result: “The TD-CSR is an easy-to-implement and very cost-efficient option for providing a level of protection from arc flash,” says John Shay, director of electrical maintenance with LACSD. “We have deployed this solution in multiple locations within our network and are pleased with the results and reliability.” 781/335-5200; www.electroswitch.com.

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Calibration capabilities enable low-conductivity water measurement

Problem: In 2011, a water and wastewater authority in western Canada added a UV disinfection plant. For part of the year, the water supplied was too low in conductivity to use electromagnetic flowmeters. Because the plant was designed with a small footprint, the minimum straight-run inlet section for the KROHNE UFM 3300 ultrasonic flowmeter could not be met. The plant team had to keep optimal accuracy to ensure adequate dwell time for the UV treatment.

Solution: To achieve the accuracy with the reduced straight run, the on-site piping configuration was duplicated at the KROHNE calibration facility in Dordrecht, Netherlands, and all eight flowmeters were calibrated using this special piping configuration.

Result: The meter calibrations were successfully completed and the required accuracy was achieved. Because the meters could be fabricated and calibrated to unusual piping configurations, the customer was able to achieve the desired accuracy to run the process successfully. 800/356-9464; www.krohne.com.

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Ultrasonic flowmeters measure biogas from digesters

Problem: The City of Charlotte, North Carolina, wanted to generate biogas at its wastewater treatment plants and burn it to generate electric power. The city needed to know the quantity and quality of biogas that could be reliably produced from its anaerobic digesters to determine the economic viability of the process.

Solution: The city installed Proline Prosonic Flow B200 ultrasonic flowmeters from Endress+Hauser. Similar technology is often used to measure the flow of wet, dirty, low-pressure and variable-composition refinery flare gas, making it an effective solution for biogas measurement. With its integrally mounted PT1000 temperature sensor, the unit uses sound velocity to calculate the methane fraction of the gas. Further calculations determine net and gross heating values, energy flow and Wobbe Index.

Result: The city purchased, installed and started up its first B200 in March 2013. Expected readings for both flow rate and methane content were immediately seen. There have been no requirements for maintenance of the device since installation. 888/363-7377; www.us.endress.com.

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Subscription-based monitoring system helps city simplify monitoring

Problem: The City of Kimberley, British Columbia, made significant investments in monitoring instruments for its water and wastewater systems and was seeking a data management solution to provide leakage-control flow monitoring and to monitor and alarm other processes.

Solution: In October 2013, the city implemented FlowWorks subscription-based monitoring solution. Previously, data had been collected manually, and alarm notifications were done through a third-party auto-dialer system.

Result: FlowWorks enabled the city to control monthly expenses. “With FlowWorks, we know what’s actually going on in the field,” says Chris Mummery, utilities supervisor. “We have been able to pick up on leaks and issues at PRV stations much, much faster than in the past.” The city no longer needs to manually record compliance monitoring data, and performance reporting is easier. This frees up time for operations and management personnel. 206/859-6999; www.flowworks.com.

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Plant uses dynamic imaging to improve digester performance

Problem: Team members at a wastewater treatment plant in Augusta, Georgia, wanted to monitor the condition and presence of methanogens in the anaerobic digestion process to find a potential correlation with methane production. They wanted to optimize anaerobic digestion and ultimately improve digester performance using dynamic imaging particle analysis.

Solution: After running samples on the Fluid Imaging Technologies FlowCAM to determine particle shape, they found some were rod-shaped bacillus they believed to be Archaea. With its VisualSpreadsheet software, the instrument can record over 30 different measurements per particle and capture particle images at up to 22 frames per second, allowing for high sampling efficiency and fast analysis times.

Result: The data collected trended closely to some of the performance parameters the staff normally tested for in the analytic digestion strains. Future studies need to be conducted, but the basic morphology and frequency of testing available enables effective population dynamics studies. 207/289-3200; www.fluidimaging.com.

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District relies on flowmeter to comply with allocation quota

Problem: The Ashley Valley Water and Sewer Improvement District in Vernal, Utah, shares its water source, a year-round spring, with several other water entities. The spring’s output can vary with weather and the seasons, making accurate tracking of water use for allocation and conservation critical. To better meet performance objectives for a new pilot plant application, the district needed to replace the flowmeter on the raw waterline while minimizing operational interruptions and reducing labor needed to bring the flowmeter into service.

Solution: McCrometer’s application team recommended the FPI Mag flowmeter for its consistent, accurate performance, easy hot-tap installation, low maintenance and versatility. The meter allowed simple installation and easy connection to the district’s SCADA system without outside contractors. 

Result: The meter provides reliable flow readings to ensure that the district remains within its share allocations and avoids costly overage rates. Based on the results, the district plans to purchase two more meters for a new treatment plant under construction. 800/220-2279; www.mccrometer.com.

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Analysis of frequent water pump motor failure points to resonance

Problem: A large Florida water treatment plant employed a mixed flow pump producing 113,750 gpm at 76 feet of head. The pump was direct-coupled to a 3,000 hp, 514 rpm induction motor. Since installation 30 years ago, the system had experienced elevated vibration of the above-ground structure as well as frequent motor and pump failures, including contacting of the motor rotor and stator, motor bottom bearing failure and pump impeller vane breakage.

Solution: After a catastrophic motor failure, the plant commissioned a system analysis from WEG Electric Corp. to determine root cause. The analysis concluded that discharge piping support grouting was fractured and unable to provide sufficient support. The existing motor was beyond repair.

Result: Vibration at the pump was due to system resonance as well as poor hydraulic impeller design. Review of maintenance records revealed the original impeller had been replaced with a third-party design. System resonance was corrected using column stiffeners. Additional investigation determined system resonance to be a common issue in the model pump when operating above 350 rpm. 800/275-4934; www.weg.net/us.

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Facility meets minimum staffing requirement with continuous online monitoring

Problem: New discharge permit requirements for nutrient removal required the water resource recovery facility in South Charleston, Ohio, to double staff hours. The facility was previously staffed by a part-time contract operator.

Solution: Instead of increasing the number of hours the facility is staffed, the municipality installed a continuous monitoring system, an exception allowed by Ohio EPA. The IQ SensorNet system from YSI, a Xylem brand, uses an online sensor network for continuous water-quality monitoring and process control. Measured values are sent to a third-party cellular telemetry unit that allows real-time measurements to be viewed online. Alarms are programmed into the telemetry unit to notify of potential problems so that staff can take corrective action when necessary.

Result: “The purpose for the installation was to maintain the same amount of hours required for the plant operator to be on site,” says Steve Canter, the South Charleston project consultant. “The YSI IQ SensorNet system provides continuous monitoring of effluent DO, pH and turbidity, in addition to influent and effluent flow monitoring that can be remotely monitored to activate predefined alarm and relay setpoints.” 800/765-4974; www.ysi.com.