Outside The Box

Nov. 8, 2018

Wastewater authority streamlines process monitoring

About the author:

Steven London is president of Steven London Associates. London can be reached at [email protected].

Cherokee County Water and Sewerage Authority (CCWSA) provides high-quality water and sewer service to more than 170,000 residents in Cherokee County, Ga. CCWSA was established as a subdivision of the government of the State of Georgia by an act of the Georgia Legislature in 1955. It was created for the express purpose of providing public drinking water and sanitary sewer services to the citizens of Cherokee County. CCWSA has performed this mission since establishment, adding infrastructure and treatment systems over the years in response to growing demands for services.

The authority has no taxation powers, is not part of Cherokee County government, and does not receive any tax revenue from county or city governments. CCWSA sells high-quality drinking water and efficient sewage conveyance and treatment services, the charges for which go to pay ongoing operations and maintenance costs. New customer connection fees are designed to repay any money the authority borrows for capital improvement projects, such as new or expanded water and sewer lines, or new or expanded treatment facilities.

CCWSA maintains and operates two wastewater facilities, and a third plant came online in June 2018. 

Rose Creek Treatment Facility

The Rose Creek facility went onstream in 1987. The plant is permitted to discharge flows of up to 6 million gal per day (mgd) of treated waters to Allatoona Lake. Rose Creek incorporates sequencing batch reactor technology to meet wastewater discharges at a quality higher than the permit limitations. Treated effluent from the Rose Creek facility is pumped through a 24-in. force main from the plant site to Allatoona Lake and discharged at the bottom of the lake into an arm of the Etowah River. Rose Creek holds a 4-mgd permit to supply reuse water from the facility to the Towne Lake Hills Golf Course for irrigation purposes. 

Fitzgerald Creek Wastewater Facility

The Fitzgerald Creek Wastewater Facility became operational in 1988 and was given an upgrade in 2008. CCWSA is permitted to discharge flows of up to 5 mgd of treated water to Little River from this facility. Fitzgerald Creek incorporates new technology in sequencing batch reactors to meet wastewater discharges, and it produces an effluent quality higher than state permit limitations. It was at Fitzgerald Creek that Xylem stepped in to help a valued long-term customer improve remote accessibility and simply make the plant easier to operate.

Riverbend Treatment Facility

The Riverbend wastewater facility began operations in June 2018. The authority chose the Xylem solution for the new facility. CCWSA was seeking increased control of its Sanitaire ICEAS advanced sequencing batch reactor basins directly from its offices at Fitzgerald Creek for two primary reasons. First, it was interested in advanced features that allowed it to easily make changes to its process compared to the original control package. Secondly, plant personnel were forced to navigate a lengthy walk between their offices, the laboratory and the room where the control panel was mounted. They wanted easy access to the control panel human machine interfacing (HMI) without having to constantly walk to the panel room every time an adjustment was required. CCWSA contacted Xylem distributor The TDH Co. TDH had a lengthy pre-existing relationship with CCWSA.

CCWSA was already operating its own SCADA system. However, TDH offered an enticing alternative solution: Sanitaire’s customizable Oscar process performance optimizer control system. Sanitaire would replace the existing programmable logic controller (PLC) and HMI hardware and software to enable remote connectivity.

An Oscar Winner

The Oscar control system is a customizable, integrated biological process control software and hardware system that is used with Xylem’s treatment equipment to help plants meet their desired performance and operating budget. The system provides:

• Dynamic adaptability to changing conditions to optimize contaminant removal for the best effluent quality possible;

• Energy savings and reduced chemical consumption resulting from optimized equipment operation; and

• An operator-friendly intuitive user interface and remote accessibility bolstered by transparent real-time monitoring and quickly available electronic help features built into the HMI.

It is standard practice for an industrial control panel system to provide an HMI for access to critical parameters inside an industrial controller. It is typical for HMIs to be included as a package for the control system, but their functionality is limited relative to a SCADA system. It is for this reason SCADA systems are more popular to provide continuous monitoring via remote connections that can use TCP/IP by monitoring facilities via wireless radio modems, point-to-point networks or even satellite connections. The Oscar solution enhances standard features of an HMI to provide remote monitoring with software that keeps CCWSA workers efficient. This allows them to send information to a facility where a secure viewer program provides users access to adjust process control set points and monitor tank levels, oxygen levels, flow rates, alarms and more.

By March 2017, CCWSA had already provided a PC for the office, which was quickly set up with the new secure viewer program. Replacement of the previous HMI with the new industrial computer, which features a much larger screen,  took only two hours. The previous PLC processor was replaced with a newer model that included the Oscar system software logic. A highly secure industrial web port was installed, which enables rapid response from Xylem’s support staff engineers. All critical features typically provided by SCADA were offered with this upgrade.

Training of two staff members took about two hours. Ongoing training is not required due to the nature of hardware and software upgrades. Once upgrades are installed, they do not require maintenance unless a hardware failure occurs. If the plant requires additional assistance, 24-hour support is provided. 

Following training, the main goal—remote control of the ICEAS basins—was met. There was more to come in the form of additional trending data, set-point saving, priority alarming, local storage of help documents, equipment maintenance reminders and updated graphics with intuitive navigation. These features allow for some personalizing of the plant’s HMI, creating a friendly graphical user interface (GUI). The HMI includes many features, all accessible directly in the GUI and available remotely, including:

• Documentation and manuals for troubleshooting and optimization;

• Set-point restore, which allows an operator to save up to four groups of set points that can be reloaded at any time. This was a particularly appealing feature to CCWSA, which is trying to optimize its ICEAS process by adjusting current set points. Because set points can now be saved, operators are more comfortable making these changes;

• Alarm troubleshooting guides for each alarm directly in the HMI to ensure alarms can be solved quickly and easily;

•Trending capability to simplify process overview and troubleshooting; and

•Maintenance health dashboards that track core equipment and ensure timely maintenance.

Oscar has quickly become a critical partner in optimization of the CCWSA plant. Plant personnel now are able to remotely monitor and adjust plant operation when not at the plant through the use of a computer, tablet or mobile phone. Operators have begun testing experimental process methods to increase flexibility, confident that no issues with the new system will occur.

CCWSA was confronted with the challenge of bringing greater efficiency to its wastewater treatment operations. It selected a flexible and highly satisfactory solution: Oscar. The control system, working hand-in-hand with SCADA, is a combination that has delivered everything it was seeking, and even more. CCWSA is so satisfied with its decision that the new Riverbend treatment facility will feature the Oscar control system. 

About the Author

Steve London

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