Case Study

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Monterey Regional Water Pollution Control Agency Saves Millions Turning Wastewater into Safe Water

PlantPAx DCS from Rockwell Automation helps water treatment facility improve control over process and data

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  • Aging, high-risk SCADA system was nearing obsolescence and becoming difficult to maintain


  • Installed Base Evaluation Assessment - Initial assessment helped determine assets most in need of update
  • PlantPAx Distributed Control System
  • Single, scalable system integrates all operations to help increase productivity
  • Virtualized control system with high-availability; redundancy helps reduce risk of system failure
  • Information-enabled system helps improve reporting procedures through production intelligence software


  • Improved Control Over Chemical Use - Improved visibility into process led to tighter control over chlorine use and reduced costs by $25,000 in the first year
  • Automated Regulatory Reporting - Data collection and trending capabilities helped ease regulatory reporting

A Water-Dependent Industry

The central California city of Monterey is located along the state’s rugged coastline, with expansive views of the Monterey Bay. The area’s moderate climate makes it ideal for agriculture, earning it the nickname the “Salad Bowl of the Nation,” with major farming productions providing a wide range of fruits, vegetables, and even grapes for wine production.

In order to provide clean and safe water for the region’s nine cities and outlying farms, the Monterey Regional Water Pollution Control Agency (MRWPCA) processes over 18.5 million gallons of wastewater each day.

After completing an extensive research project in 1998, the agency determined that reclaimed water was safe for use on various crops, and may even increase crop yield and quality. As a result, the area decided to implement wastewater recycling programs to help support the local crop irrigation needs.

Recycling Wastewater

The programs would recycle wastewater pulled in from over 10 different collection points for fresh, edible food crops, including artichokes, celery, broccoli, lettuce and cauliflower. This extensive system includes the Salinas Valley Reclamation Project (SVRP) water recycling plant and the Castroville Seawater Intrusion Project (CSIP) distribution system. The gathered wastewater is cleaned through an extensive process control system, which required tight control over water-quality analysis, level control, chemical additions and distribution.

After nearly 15 years in operation, the control system running the process was nearing obsolescence. The dated Windows® XP-based human machine interface (HMI) software had no backup power in case of a shutdown or emergency. Communications from the various, disparate collection points were often delayed and irregular – leading to falsified communication status. Additionally, production data was logged manually, a time-sensitive and error-prone process that also made data transfer unreliable. The system operators were unable to quickly gather data and trend reports critical for good decision-making. For example, if an engineer put in a request for flow estimates, the data may not be available for weeks.

After a review of the entire supervisory control and data acquisition (SCADA) and IT systems’ master plan with Kennedy Jenks Consultants, the agency decided it was time to upgrade its control and information system to help keep up with demand and reduce risk.

Refreshing the System

The agency wanted a thorough understanding of the current SCADA system’s operational performance, and turned to Rockwell Automation for a complete, Installed Base Evaluation assessment. This process provided MRWPCA with a baseline understanding of its most critical assets and obsolescence risks.

The agency decided to rebuild the network and control infrastructure, and implement a PlantPAx® distributed control system (DCS) from Rockwell Automation.

Starting from the ground up at the SVRP facility, MRWPCA needed to lay new fiber optic runs to help support the newly virtualized system. The old programmable logic controller (PLC) code was easily converted to the new PlantPAx system, helping to ease setup and programming during commissioning. The virtualized system would also allow staff to start operations with a backup server in case the primary server failed, reducing the risk of water treatment interruption.

The system was built using network communications standards based on EtherNet/IP to help streamline control and information flow, and enable real-time diagnostics and electronic documentation for the water treatment process.

Conversion to nine Ethernet I/O modules reduced installed I/O by an entire rack, and increased the speed of the system. This enabled MRWPCA to physically move the PLC off the plant floor and into an administrative building.

A Rockwell Automation field service engineer came on-site to help install the software and provide hands-on training for the agency staff.

Improving the information-enabled functionalities of the new DCS included redundant historian capabilities to provide real-time and historical water trends, such as system demands, levels and storage. The system collects, tracks and records key process data from approximately 2,300 historian tags to pinpoint water trends.

The new HMI was converted directly from the old software and implemented on redundant virtual servers, which has increased reliability and speed – all with improved screen aesthetics.

To ease process and regulatory reporting, MRWPCA also implemented a FactoryTalk® VantagePoint® enterprise manufacturing intelligence (EMI) system from Rockwell Automation, which aggregates water treatment information from the historian and other assets. Operators can use the new EMI system to access various instrument and report tags in real time and generate specific reports for process management and regulatory purposes.

Improvements Across the Board

The new information-enabled DCS has helped MRWPCA collect and access data that is crucial to the water treatment process. Now operators can reliably access data from any of the disparate locations in real time.

The improved visibility and access to data has helped improve control over chemical usage. Because the treatment processes use upward of 5,000 pounds of chlorine each day, achieving tighter control meant major cost savings. MRWPCA has since been able to save $25,000 per year in chemical costs. These cost savings were not initially anticipated, but were an added benefit, that in turn provided a full ROI on the HMI upgrade in just five years.

An energy audit yielded no further energy-saving suggestions – drives were running more efficiently, and the system was fully optimized for energy savings. This was a huge win for the agency, as energy consumption is often one of the highest operating costs associated with water treatment.

MRWPCA was also operating a booster station affected with a pressure problem, leading to multiple burst pipes, breaking valves and several other unresolved issues. Prior to the new DCS system, the county was unable to determine the root cause of the issue, but the data collection and trending capabilities helped enable operators to pinpoint and resolve the issue. The DCS system prevented the county from having to modify the booster system by putting in variable frequency drives, saving almost $3 million.

The agency also partnered with OSIsoft to use its open data infrastructure PI System to build dashboards of publicly facing data. The data is migrated from the SCADA system up to the enterprise system. Then, it is pushed up to Microsoft® Azure cloud, where dashboards are available for constituents to see water quality in real time.

Advanced reporting capabilities within the new DCS also allowed for easy regulatory reporting. The process, which used to take up to three days, is now done through the click of a button.

MRWPCA is taking the lessons learned from the SVRP and CSIP projects, and applying them to a critical new initiative for residents of the Salinas Valley. The Pure Water Monterey project will leverage a PlantPAx system, and aims to provide safe, reliable and sustainable drinking water.

The results mentioned above are specific to Monterey Regional Water Pollution Control Agency’s use of Rockwell Automation products and services in conjunction with other products. Specific results may vary for other customers.

FactoryTalk, Installed Base Evaluation, PlantPAx and VantagePoint are trademarks of Rockwell Automation Inc.

EtherNet/IP is a trademark of ODVA Inc.

PI System is a trademark of OSIsoft.

Azure and Windows are trademarks of Microsoft Corporation.


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