Monitoring and Instrumentation

Monitoring and Instrumentation
Flow monitor provides accurate reports

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Flow monitor provides accurate reports

Problem

Dry-weather influent at the 4 mgd Sandy Beach Treatment Plant on Oahu, Hawaii, fluctuated from 0.2 to 10 mgd with velocity from less than 0.10 to 3.5 feet per second. Flow monitors just downstream from a rectangular channel feeding a 36-inch concrete pipe produced unreliable readings, resulting in excessive explanatory reporting to the state Department of Health.

 

Solution

The plant superintendent looked for a reliable unit that would require little operator attention, integrate with the SCADA system, and trigger the wastewater sampler on accurate flow-weighted intervals to meet regulatory obligations. Plant staff did comparative testing that included a FlowShark Pulse cross correlation flow monitor from ADS Environmental Services.

 

Result

“The FlowShark Pulse provided stable data even during low-flow periods,” says Robert Cuevas, operations manager. “For the first time, our influent flowmeter tracked our effluent flowmeter so well that we couldn’t believe our eyes. This will make my life much easier when it comes to future reports.” 800/633-7246; www.adsenv.com.

 

Alarm monitors use cell phone interface

Problem

Douglasville-Douglas County (Ga.) Water and Sewer Authority needed a backup for the SCADA system at two 3 mgd treatment facilities. They searched for alarm monitors that were affordable, easy to use, and had the necessary functionality.

 

Solution

Officials bought nine Viper Kits from OmniSite with five universal voltage inputs, one analog option, NEMA 4X enclosure with locking hasp, a pre-connected wiring harness, and two current switches. Installation hardware, access key, high-level float, and conduit with fitting were included. Configuration changes, sent over the cellular network, are backed up with alarm notifications via text SMS messages.

 

Result

The equipment monitors floats, relays, and pump-run alarms. “Installation was easy and the quality is very good,” says supervisor Charles Butts. 317/885-6330; www.omnisite.com.

 

Plug-and-play gas sensors cut changeout time

Problem

Every year, operators at a 30 mgd wastewater treatment plant in Minneapolis, Minn., changed out multiple gas detector sensors. Swapping each unit took almost 30 minutes, plus time to check and calibrate them.

 

Solution

Looking for alternatives, the staff selected SEC 3000 sensor modules and SEC 3100 universal transmitters from Sensor Electronics Corp. that take less than two minutes per unit to change out. The sensors, factory-calibrated for hydrogen sulfide, methane, chlorine, sulfur dioxide and 20 more gases, plug into the gas detector, then automatically upload operating parameters and calibration settings to the control board in the module. The control board also enables operators to change easily to a different gas sensor.

A backlit digital liquid crystal display on the transmitter shows gas concentrations, while LEDs change from green to amber to red as levels increase. An isolated RS485 Modbus interface provides reliable communication in noisy environments and eliminates ground loop problems.

 

Result

Changing sensors now takes a little more than two man-days per year, helping the plant reduce labor costs and stay within budget. 800/285-3651; www.sensorelectronics.com.

 

Software modernizes treatment plant

Problem

One of Austria’s largest wastewater treatment plants needed to upgrade its control system while in operation and against a tight deadline.

 

Solution

Vienna-based Internationale Automationssysteme (IAS) upgraded more than 30 pump stations by replacing star delta starters and contactors with Allen-Bradley control and display systems from Rockwell Automation. Besides soft starters and components, IAS equipped each station with PanelView Plus 400 displays and wireless modems to monitor assets and energy use remotely.

ControlLogix controllers managed process control while visualization operated with FactoryTalk View SE software and restructured three-tiered network architecture. Using a virtual private network, IAS engineers can access the system from anywhere in the world to help operators troubleshoot errors.

 

Result

The project, completed in 18 months, allows for future expansion and changes to the system. 414/382-2000; www.rockwellautomation.com.

 

Telemetry panels integrate with SCADA systems

Problem

The Cow Creek Band of the Umpqua Tribe in Canyonville, Ore., owns the Seven Feathers casino, hotels, a recreational vehicle park, and other businesses. As the facilities expanded, the tribe needed monitoring equipment for its water, graywater, and wastewater treatment systems.

 

Solution

Engineers at Orenco Controls designed seven custom TeleComm (TCOM) Affordable SCADA control panels programmed for peer-to-peer networking via a fiber and Ethernet network with operator control and monitoring via TELNET. Once the expansion was completed, the panels were reprogrammed to work with a SCADA system using RSView software from Allen Bradley. No new hardware was required.

 

Result

The panels communicate seamlessly with various programmable logic controllers and other devices under RSView supervision. 877/488-3594; www.orenco.com/controls.



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