Accurate Flow Monitoring Aids Billing Process
When a new regional wastewater treatment facility opened in north Kern County, Calif., the nearby city of Shafter closed its own facility and began piping its residential wastewater to the new plant. Shafter, located 17 miles northwest of Bakersfield, Calif., has 12,000 residents. For billing purposes, the city needed to precisely monitor daily flow to the plant. The operators needed to remotely monitor flow between the city’s collection system and the regional treatment facility.
The project integrator, Bob Witcher, initially assumed he would need four separate products for the project including a PLC, an open channel flowmeter, a chart recorder and a remote telemetry unit.
But in a conversation with David Ehret at RMB Engineering and Sales, he learned about the Siemens-Milltronics EnviroRanger as a solution for monitoring and control in water distribution and wastewater collection systems.
EnviroRanger uses ultrasonic technology, patented Sonic Intelligence echo-processing techniques, and application software to provide accurate level monitoring in liquids up to 50 ft. Five relays control any combination of pumps, gates and alarms. It effectively monitors flow in flumes, weirs and open channels, and its patented pumped volume algorithm offers accuracy within ±5%.
Features include report by exception and data logging for trend analysis. It will log up to 20 occurrences of combined sewer overflows. Its built-in telemetry interface allows remote monitoring in real time. A 30-in. Palmer-Bowlus flume had been installed on the line carrying flow from the city to the treatment plant.
Witcher installed an ultrasonic transducer above the flume, wiring the transducer to the EnviroRanger located in an aboveground enclosure. EnviroRanger is preprogrammed to work with Palmer-Bowlus and other standard flume types, so Witcher simply had to input the flume size and tell the unit what types of data to collect.
He set the on-board totalizer to monitor accumulated flow and daily highs and lows. Witcher also attached a modem to the built-in RTU to send instantaneous flow and accumulated flow readings to the treatment plant.
In May 2002, the plant discontinued the unreliable phone line connection and switched to radio communications for increased reliability of connection. EnviroRanger required no additional hardware to implement this change.
The city of Shafter and the regional treatment facility both rely on the flow data from EnviroRanger to process billing. The system’s reliability has given them confidence in the accuracy of the readings. EnviroRanger is designed to monitor level, control lift station pumps and measure flow. This broad functionality makes it a cost-effective solution because it can replace a number of devices. This means a lower initial cost of ownership and faster payback. It also simplifies purchasing, installation and service.
“This application wasn’t complicated, but it was going to require a lot of hardware to collect the data, store it and transmit it back to the plant,” said Witcher. “By handling all of those tasks, the EnviroRanger made my job much easier.”
EnviroRanger requires no regular reclaibration, saving on service fees. Its ability to serve up data by phone line, radio or satellite meant a cost-free change when the plant decided to switch to radio. With its built-in communications, EnviroRanger enables remote monitoring, saving the cost of daily manual inspections.