Sustainable water management in the pulp and paper industry

The ABB Ability™ Smart Solution for Wastewater addresses the unprecedented challenges faced by wastewater treatment plant operators. The solution uses advanced process control (APC) to reduce water use and process variability, and stabilize operations through continuous monitoring and automation.

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_{Abhay Anand, ABB Process Automation, Västerås, Sweden, abhay.anand@se.abb.com}

Water scarcity is an increasingly pressing global issue, with projections indicating that by 2030, 1.6 billion people will lack access to safe drinking water. Despite covering over two-thirds of the Earth’s surface, less than 1 percent of the planet’s water is available as fresh water. This limited resource is crucial for various industries, including the pulp and paper industry, which is responsible for 12 percent of global water consumption. As the industry heavily depends on fresh water, its need to advance water and wastewater management is paramount.

ABB Ability Smart Solution for Wastewater

To help the operators of all types of wastewater plants – including those in pulp and paper mills – reduce water and energy use and optimize operations, ABB recently introduced the digital ABB Ability Smart Solution for Wastewater. This solution leverages continuous monitoring and automation to reduce water and energy usage. Because it is platform-agnostic, the ABB Ability Smart Solution for Wastewater can be layered onto any automation package.

One of the main technologies that underpins the ABB Ability Smart Solution for Wastewater is APC. APC is increasingly pivotal in optimizing the complex and dynamic processes found in pulp and paper mills.

ABB Ability Smart Solution for Wastewater exploits the power of APC to provide a reliable forecast of future operational needs. The provision of forward-looking data allows treatment plants to reduce water use and reach optimal operating conditions by reducing process variability and stabilizing operations and enabling constant, incremental operational adjustments and gains.

What is advanced process control?

Energy savings too

As well as water scarcity, energy consumption is also a significant issue in the industry: According to the International Energy Agency, global electricity consumption in wastewater treatment reached 222 TWh in 2020, with electricity usage across the sector predicted to increase by 80 percent by 2040¹. This is partly due to the increasing demand for treated wastewater, now considered a valuable potential resource.

ABB Ability Smart Solution for Wastewater leverages ABB’s long-standing expertise in advanced process control, performance optimization and digital twin technology. With the demand for treated wastewater rapidly growing worldwide, the goal is to continue developing sustainable solutions that reduce energy use while improving water quality and operational efficiency.

Developed with hydraulic modeling intelligence from the Danish water environment specialists, DHI Group, the ABB Ability Smart Solution for Wastewater creates a more stable treatment process by predicting wastewater inflow together with environmental factors such as weather patterns, reducing the risk of overflow and fines. ABB Ability Smart Solution for Wastewater is the first in a family of smart solutions for the water industry. The application of the solution in the pulp and paper industry to achieve sustainable water management makes use of sophisticated APC techniques.

APC to optimize water use in pulp mills

The water circuit in pulp mills involves a complex, integrated process with multiple intakes and effluent generation points. The main stages include wood handling, cooking, screening, washing, oxygen delignification, bleaching and paper machine operations »02. Each of these stages requires fresh water and generates effluents that must be treated and managed efficiently.

Throughout the pulp mill, there are multiple locations that present opportunities for APC to optimize the process »03:

• Debarking wash water: Reducing the water used in debarking can significantly decrease the mill’s water footprint.
• Boiler feed water: Maximizing boiler efficiency helps minimize water usage and enhance overall operational efficiency.
• Wastewater reuse and sludge management: Reusing wastewater and effectively managing sludge can reduce freshwater consumption and improve discharge water quality.
• Black liquor treatment: Stabilizing black liquor concentration and managing condensate production are critical for efficient chemical recovery and reduced water use and environmental impact.

Optimization of water usage in paper machines

In the paper industry, optimizing water usage is vital not only for reducing freshwater consumption but also for increasing process efficiency, reducing costs and improving product quality. The water circuit in paper machines involves various stages where water is used and treated, but these are different from those in a pulp facility »04.

Again, several locations in the machine come up as APC optimization opportunities:

• Implement tight APC control in the section from the ABB SteamPlus xP steambox to the continuously rotating wire mesh that initially forms the paper by sucking out water. This control minimizes profile variability and reduces dryer section steam usage.
• Exploit data from the ABB Network Platform scanners and High-Performance Infrared Moisture Sensor to reduce variability, ensuring optimal dryer operation and saving energy.
• Improve wet-end stability to reduce product variability, chemical usage and sheet breaks, and enhance machine runnability. This aspect is covered by the ABB Wet-End Control of white water package (see below).

To demonstrate how APC can enhance efficiency, product quality and sustainability while reducing costs and environmental impact in real-life situations, it is instructive to examine some case studies

Optimizing water treatment at an integrated pulp and paper mill

An integrated pulp and paper mill sought to improve water management across the entire water cycle by handling natural variances in influent disturbances and ensuring effluent quality with minimal operating costs »05. The APC for influent and effluent management exploited a wide variety of inputs and outputs – such as intelligent weather forecasts, upstream sensors and adaptive controls – to manage chemical, energy and water use »06:

APC for influent management:

• Use smart weather forecast and existing upstream sensors to estimate future influent flow/biological oxygen demand (BOD)
• Anticipate setpoint changes to smooth out events
• Manage inventory to create a control margin ahead of events

APC for effluent management:

• Control dissolved oxygen/ammonia for each zone in bioreactors via air flow
• Control NO₃ in anoxic reactor via recycle 
• Maximize valve average opening (MOVP) for aeration
• Balance load considering residual NH₃ (NH₄-N) in bioreactor

The APC reduced chemical dosing by 5 to 10 percent, increased energy efficiency by 10 to 15 percent and significantly decreased untreated water offload.

Bringing the water industry into the digital era

The ABB Ability Smart Solution for Wastewater represents ABB’s offer to collect, gather and analyze data and explore patterns from a water plant or network to enable next-level performance efficiency. The APC systems can also integrate with advanced analytics and machine learning to improve maintenance strategies. For example, predictive maintenance models can proactively analyze process data to predict equipment failures and schedule maintenance activities, reducing downtime and extending equipment life. The ABB Ability Smart Solution for Wastewater can work with any automation package to achieve energy savings of up to 25 percent and a 10 percent decrease in chemical usage on top of significant water usage reductions.

All ABB’s digital solutions are connected through ABB Ability™, enabling real-time monitoring and optimization of operations and water usage. This holistic approach delivers intelligence to unlock new sources of productivity and efficiency over time, keeping pace as businesses change and enabling a sustainable society.

References
[1] International Energy Authority, “Introduction to the water-energy nexus.” Available: https://www.iea.org/articles/introduction-to-the-water-energy-nexus. [Accessed February 5, 2025.]

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