Water treatment plant operators face daily challenges meeting drinking water demand, managing scheduled and unscheduled maintenance, ensuring regulatory compliance, monitoring and troubleshooting to optimize performance, reporting to management and stakeholders, and more.

Digital technology can transform the role of operators and the operations management team, and the ways in which they manage smarter plants. Digitization doesn’t have to be a complex and costly venture — it can be deployed on a plant’s existing automation framework. 

Diverse duties

Water plant operators are charged with making sure that critical processes like coagulation, sand filter backwashing, fail-safe filter ripening and disinfection are operating at or near their optimum.

Historically, operators have monitored and managed plant operations mainly by interacting with the process control system through the human-machine interface component of the SCADA system. In recent years, digital transformation technologies have been introduced to facilitate plant operations.

A paradigm shift is occurring with this technology infusion. Plants are transitioning from reactive to proactive (or predictive) maintenance — in other words, toward a “smart water plant” paradigm.

In an April 2020 white paper, COVID-19 Water Industry Impact: Navigating toward Resiliency, Bluefield Research contends that digitization of water treatment is needed, but that “It is too late for most utilities to rapidly transition to significant remote operational control of their assets in the next three months.”

The paper continues, “Only those utilities that have already invested heavily in remote monitoring and digital asset management will likely see more immediate benefits from a resiliency perspective. Those that have not will be more challenged in the foreseeable future. Seventy-nine percent of U.S. community water systems have SCADA systems fully implemented, while just 21% have network optimization solutions in place that facilitate remote management.”

This presents a partially correct picture, based on the notion that digitization is a massive undertaking, requiring significant investment in infrastructure. However, retrofit digitization of a water treatment plant can be surprisingly straightforward if the plant already has a SCADA system and parts of its operations are already automated.

Broad benefits

Digitization disconnects water plant performance information from the SCADA historian and HMIs and delivers it encrypted over the internet outside the plant to any computer or mobile device anywhere in the world.

This enables operators to track what is happening at the plant with near-real-time fidelity. Moreover, the information can be delivered to multiple experts at the same time, allowing a team of experts to troubleshoot an event. This can help prevent the recurring anxiety that a lonely operator in the graveyard shift may feel when an excursion happens.

Any intervention decision can be collective and collaborative, capturing the knowledge and experience of the operations team, based on objective data and evidence collected directly from the plant.

It is entirely feasible to add digitization components that provide decision support and even elements of remote decision automation to water treatment plants, using existing technologies that are primarily software- and cloud-based.

The technology requires no additions to plant hardware and causes no disruption to operations. It can be deployed on any water plant automation platform distributed control system/SCADA to monitor, control and optimize critical water processes.

If the unit operation has already been modelled — for example, coagulation, multimedia filtration, and low- and high-pressure membrane filtration — optimization of these processes can be completed in about two weeks, after all necessary information is provided.

From a process control perspective, digital transformation allows operators to monitor the plant remotely, reducing time required on site — important during the COVID-19 pandemic — without losing any control or insight to the plant’s performance

Putting it to work

The digitization technology, once deployed, has a wide range of practical applications.

Operational monitoring

Dashboards and reports give process engineers a thorough overview and detailed understanding of the plant. The overview screen provides the operational details, while various drill-down menus deliver details about the individual process component behaviors.

The reporting tool allows the plant engineers to track plant behavior in response to fluctuations of influent quality or operating conditions. It is customized for every plant and is developed in consultation with the plant designer, operator and process engineering team. The reporting tool also provides a dynamic view of how the plant is optimized. It can provide estimates of savings, waste and energy reduction, and increases in production, with resolution to the level of individual processes.

Coagulant dosing

Coagulation dosing can be optimized essentially with an “inline jar tester” to reduce chemical consumption and subsequent residuals handling. It also helps ensures the best floc for the filter and ties in with filter operation.

Filtration

Surface water multimedia filtration. Media filters including rapid sand, dual-media and multimedia beds treating for microbial removal can be optimized by controlling filtration rate changes, reducing backwash and optimizing filter ripening to reduce the volume of backwash water. Other benefits include reducing or eliminating manganese release by minimizing offline time and minimizing the volume of backwash wastewater requiring further treatment.

Low-pressure hollow-fiber and ceramic membrane filtration. Self-adaptive flux optimization can be used to optimize low-pressure membrane filtration processes where the fast (seconds to minutes) kinetics of fouling outpace human operators’ and engineers’ ability to make adjustments. It automatically and directly adapts and adjusts flux optimization cleaning actions in real time to mitigate irreversible fouling, maintain optimum water production, and extend filter life.

GAC/BAC filters. Self-adaptive flux optimization can be used to adapt artificial-intelligence-controlled air-water scour and water filter backwash to suit feedwater conditions.

Time to get onboard?

By embracing digitization technologies, water treatment plant operators can gain additional capabilities. They can dynamically optimize the plant, prepare for and respond to sudden excursions in raw-water quality or operating conditions, and schedule maintenance of critical components.

They can also remotely modify or change plant operating conditions, automate routine tasks such as report preparation, and automatically manage consumables inventory and delivery. It all can happen on the existing plant automation platform, and without disruptive and major capital investments.

About the author

Tony Wachinski (tony@wisewaterglobal.com) is a civil engineer and the CEO of Wisewater Global, a consultancy specializing in process water treatment technology for municipal and industrial markets.