Reclamation facility uses online THM analyzer
Problem: The upgraded Tres Rios Water Reclamation Facility, operated by the Pima County (Arizona) Regional Wastewater Reclamation Department used a five-stage Bardenpho process for ammonia, nitrate and nitrite reduction. However, reduced effluent ammonia and the use of chlorine disinfectant increased potential for total trihalomethane formation in the effluent. Operations experimented with adding centrate as an ammonia source before chlorination to make chloramines, since that disinfectant produces lower THMs than chlorine.
Solution: The online THM-100 analyzer (Aqua Metrology Systems) was used to characterize and monitor THM formation. The device comes with a standard sampling schedule every four hours, but the sampling frequency can be changed to meet specific needs. Analytical results, system performance and analyzer health are remotely monitored 24/7 by AMS to ensure that the online THM instrument remains online and working under optimal conditions.
Result: The self-calibrating analyzer gave operators immediate and accurate daily reports on THM levels. By monitoring real-time THM formation after the addition of ammonia, operators were better equipped to control THM production and optimize the process. After successful testing, the instrument was placed into full-scale use. 408-523-1900; www.aquametrologysystems.com
Online turbidimeter delivers higher accuracy, easier maintenance
Problem: The MidAmerica water treatment plant provides drinking water for tenants of the 9,000-acre MidAmerica industrial park in Pryor Creek, Oklahoma. Most instrumentation in the plant was aging and obsolete. Turbidimeters were no longer supported by the manufacturer and required excessive maintenance.
Solution: The plant staff chose the MTOL+ Online Turbidimeter from HF scientific, a Watts brand. The instrument, which measures turbidity or presence of suspended particles, was installed as a trial. Plant instrument and maintenance staff found the unit much easier to calibrate and maintain than the previous instrumentation. The low-range three-point calibration also yielded higher accuracy at the very lower turbidities at which the plant operates.
Result: The plant replaced all turbidimeters with the HF MTOL+, Stagg has been happy with their reliability, support and ease of use. The team then evaluated the CLX chlorine analyzer from HF Scientific and found it superior to that of the existing device. 239-337-2116; www.hfscientific.com
Remote terminal units installed on lift station
Problem: The Gwinnett County Department of Water Resources, near Atlanta, Georgia, needed remote monitoring for the sewer lift stations.
Solution: All 211 lift stations have been equipped with Mission Communications remote terminal units, enabling the county to monitor the stations remotely, receive automated alarms, and integrate with the customized SCADA system. The department also upgraded all its lift stations to the newer MyDro series RTUs, which feature a boost-buck converter with a 12- or 24-volt DC selectable auxiliary output, removable terminal blocks, high-current onboard relays, increased memory, a backup battery charging unit and digital inputs.
Result: The upgrades took minimal time to install. “The LCD display is helpful for weekly and monthly inspections on every station,” says James Brannen of the pump stations group. Another benefit was over-the-air firmware updates: “We’ve saved incredible amounts of labor time, and it has led to less wear and tear on vehicles and increased fuel savings.” 877-993-1911; www.123mc.com
Sanitary sewer system updated with remote monitoring capabilities
Problem: The Minneapolis Public Works Department needed to modernize the sanitary sewer system. Nine wastewater lift stations and 23 storm sewer pump stations were spread throughout the city. None had remote monitoring capability.
Solution: PRIMEX was chosen to retrofit the stations with remote monitoring. The mandate was to develop and install a complete SCADA system, including digital cell routers on the Verizon network to improve monitoring. The upgraded system also incorporated local computer memory at each site, so that if the cell connection failed, data would not be lost. The local Wonderware Edge graphical operator interface has native capabilities to store and forward all data. When Verizon communications are lost, the system logs data to memory. On restoration of cellular communications, all historical information is backfilled to the historian.
Result: The system met the department’s goals. Remote monitoring added to all systems improved data analytics and enhanced the ability to manage storm sewers and sanitary sewers. 844-477-4639; www.primexcontrols.com
Laser technology allows for noncontact influent flow measurement at large treatment plant
Problem: The Ankara Central Wastewater Treatment Plant in Turkey serves a population of 4 million. The high concentration of solids in the plant inlet limited flow measurement options. AV contact sensors required time-consuming maintenance work and was rejected. AV radar for surface velocity measurement yielded unsatisfactory results.
Solution: Noncontact laser technology allowed for measuring velocity at multiple points in the flow profile below the water’s surface. A Teledyne ISCO LaserFlow sensor was mounted over a rectangular channel 15 feet wide and 13 feet deep. Two Teledyne ISCO Signature flowmeters were permanently installed at plant inlet and on the 20-foot wide overflow channel.
Result: The customer estimated that the noncontact laser technology provided significant savings over installing a traditional flume system. 800-228-4373; www.teledyneisco.com
Remote monitoring and control reduces false alarms
Problem: False alarms from lift station pumps required frequent evening and weekend operator attention at a California community services district. Seven lift stations had aging instrumentation comprised of auto-dialers with traditional SCADA, which required operators to respond in person to each alarm. Operators needed a reliable way to monitor wet well levels and pumps remotely.
Solution: The district installed XiO’s Lift Station Control System throughout the collections system. The cloud-based system allows operators to view status on sensors and pumps as well as wet well levels from any web-enabled device. They can receive alarms and control equipment, such as turning pumps on and off, via smartphones, greatly reducing the time required to respond to alarms.
Result: The system immediately reduced false alarms. Data collected gave operators insights to the health of the pumps, enabling a proactive maintenance schedule. 877-946-0101; www.xiowatersystems.com
