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Bid Number: 15-012
Bid Title: WWTP Oxidation Ditch Monitoring Equipment
Category: Construction and Design Services
Status: Closed


The City of Montrose Wastewater Treatment Plant operates three oxidation ditches. Each ditch is equipped with three 75 HP rotor motors. The rotors are used for mixing and adding oxygen to the water. WWTP staff is currently automating the process controls. Impending nutrient removal regulations will require real time monitoring of process control parameters, specifically ORP (oxygen reduction potential) sensors for oxygen depletion measurements, TSS (suspended solids) sensors for solids contents and mix quality, and DO sensors for oxygen levels. The monitoring system shall be a wireless, multi-parameter analyzer capable of communicating with up to sixteen sensors.

The analyzer must be compatible with PLCs and SCADA currently in use at the WWTP. The PLC is a Siemens 315-2PN/DP with Profinet and Profibus capabilities. The SCADA is a Siemens WINNCC Version 7.0. All equipment shall be delivered to the City of Montrose Wastewater Treatment Plant located at 3315 North Townsend Avenue, Montrose, Colorado 81402. The selected contractor is responsible for installation, programming, and integration with existing PLCs and SCADA systems.




  1. Measuring range of DO probe: 0 to 25 ppm
  2. Measuring range of TSS probe: 0 to 30,000 mg/l
  3. Measuring range of ORP probe: +/- 2000mv
  4. Sensor Check – Automatic self diagnostic
  5. Display – Backlit graphical display capable of continuously displaying all channels.
  6. Communication – compatible with Siemens PLC 315 – 2PN/DP with Profinet, Modbus RTU, or Profibus
  7. Output – 4 to 20 ma located at each sensor site and one setpoint relay located at each sensor site.
  8. Output – Data communication with PLC, Profinet, Profibus, or Modbus RTU.
  9. Input power – 115 volts AC
  10. Wireless Multi Parameter Analyzer capable of accepting up to sixteen channels.
  11. Range of analyzer to probe up to one mile.
  12. Self-contained air cleaning system for each probe.

 Cost For Services Not To Exceed:      $ ____________

Publication Date/Time:
3/9/2015 1:00 AM
Publication Information:
Montrose Daily Press
Closing Date/Time:
3/23/2015 2:00 PM
Bid Opening Information:
03/23/2015 @ 2:00
Pre-bid Meeting:
Not Provided
Contact Person:
John Harris
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