Upgrading a Wastewater SCADA System

The City of Yuma installed a SCADA system to control and monitor its water and wastewater distribution system remotely. But as the city expanded, the existing SCADA system lacked the needed support, performance and diagnostic capabilities.

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The new networked system also helped eliminate proprietary system troubleshooting expenses. Access to parts and service was improved because the new system is based on open standards with local support.

“The old system required personnel to frequently be on-site monitoring the pumps,” observes Ritter. “Now that the system is completely networked, we receive an alarm in the main control room if amperage in one pump controller is too high, and we can go directly to the problem and fix it. In some instances, the system’s predictive monitoring helps us address over-amperage problems before faults occur.”

Predictive maintenance is implemented by monitoring pump starts, pump stops and pump motor amperage. After a preset number of starts, an operator is alerted to write up a work order for an electrician to perform a field inspection. After the field inspection, the operator resets the pump start counter at the HMI.

The system also alerts operators after a certain number of runtime hours for each pump motor. A work order is then written for the mechanical staff to pull the pump for cleaning and inspection. Run-time hours are reset after inspection.

The HMI is used to create a history for each remote site. This lets us see variations in flows and pump failures and correlate this data against pump starts, pump run-time hours and pump motor high-amperage alarms. Data analysis lets us set pump monitoring parameters accordingly to prevent failures.

Monitoring discrete parameters also aids field personnel. “Monitoring pump on/off status along with pump hand-off-auto status can prevent potential problems if someone working at the site accidentally leaves the pump in manual,” according to Ritter.

The new MCCs performed so well in the wastewater pumping stations that they are now standard in our wastewater system design specifications. Smart MCCs are ideal for the city’s wastewater treatment system because they provide the diagnostic information that we need to keep the system running.

We saved at least $12,000 annually due to the local support provided by the distributor. Local distribution can deliver replacement parts in one or two days as opposed to several weeks with the old system. This has significantly increased uptime.

“When a station goes down, we need it fixed as soon as possible,” stresses Ritter. “We can’t tell someone not to use his or her water for a few weeks because we’re waiting on a new part.”

Perhaps the greatest savings has been in avoiding unnecessary costs. When the networked system sounds an alarm to indicate that a station is operating outside of its parameters, it alerts operators who can send out a mechanical or electrical staff member to repair potential problems before a station shuts down.

This networked alarming capability helps us comply with environmental regulations because we can identify and prevent pump malfunctions that might cause wastewater to be accidentally released into a residential or environmentally restricted area. Such offenses could cost us up to several hundred thousand dollars per offense. “The new system gives us confidence that we’ll never have to deal with environmental offenses,” says Ritter. “Its networked design keeps us informed of potential problems so we can fix them before anything severe happens.”

“We view the installation as a complete success,” concludes Ritter. “We’ve cut costs, have a more reliable system, and we can do the majority of work ourselves.”

 


 

Problems with Old Proprietary SCADA System

  • Outside contractor needed for routine repairs and maintenance
  • Spare parts not readily available
  • Difficulty effectively monitoring remote sites
  • Upgrades difficult and costly
  • Difficulty meeting environmental requirements

 

Table 1: Problems with Old Proprietary SCADA System

1) Outside contractors needed for routine repairs and maintenance
2) Spare parts not readily available
3) Remote sites could not be effectively monitored
4) Upgrades difficult and costly
5) Difficult to meet environmental requirements

 

 

Table 2: Advantages of New SCADA System

1) System uptime increased by real-time monitoring and control
2) System can be supported with in-house personnel
3) Site visits much less frequent because of remote monitoring
4) Spare parts stocked by local distributor
5) Extensive diagnostic information allows predictive maintenance

 

Advantages of New SCADA System

  • System uptime increased by real-time monitoring and control
  • System supported by in-house personnel
  • Less frequent site visits because of remote monitoring 
  • Spare parts stocked by local distributor
  • Extensive diagnostic information enables predictive maintenance
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