In coming years, power companies will need to become more strategic and aware of water usage, writes Jan Bultiauw

Water has long been a crucial aspect of industrial manufacturing and production processes.

Mounting water shortages and resulting regulations across the globe are increasingly calling on industrial companies to evaluate water sources and technologies that more efficiently use – and reuse – the growing limited supply of freshwater.

Given the immense use of water in a variety of power production processes, rising regulations surrounding industrial water use can have a real impact on environmental and water preservation.

As such, it’s becoming all the more challenging to produce high quality water for industrial use given mounting regulations surrounding water quality, limiting usage and environmental discharge. Therefore, water – an already imperative piece of the power production process – is becoming increasingly important.

Water treatment plants can supply process, cooling,
Water treatment plants can supply process, cooling, boiler and HP boiler water

Having a true impact on the production output, it’s crucial to ensure that power plants use the purest water in order to produce the highest quality products. If water quality is low, it compromises everything that follows.

Low water quality, whether caused by a variety of factors including contamination, turbidity, algal bloom or season/flow peaks, can damage equipment at a faster rate and/or increase the need for more routine maintenance – already an often expensive, time-consuming process – which can slow down or halt production altogether.

Additionally, if not addressed, poor water quality can also affect the life expectancy of a plant’s water systems and overall infrastructure.

Additionally, power plants require water treatment systems capable of meeting a wide variety of water quality demands and requirements for process, cooling, boiler and HP boiler water. Each of those specific processes also has its own set of water quality requirements and specifications, creating a need for a seamless water treatment management method to meet the many aspects of industrial water needs.

These growing regulations around water quality, water usage and environmental discharge continue to plague power plant operators who must not only understand the changing, complex landscape, but also devise a path forward that meets regulatory compliance.

Maintaining a healthy supply

As water quite literally fuels the production of power, these plants must ensure that they are prepared to keep the water flowing should they face any equipment challenges or regulatory issues.

As technology and design have vastly improved in the past decade, innovative solutions such as self-contained, mobile membrane filtration systems have emerged as capable and viable options that can provide high quality water during planned or unplanned instances.

These units are particularly valuable during periods of maintenance and repairs, when power plants must quickly meet regulatory deadlines, and in response to emergency situations where water production is unavailable.

The Induss II water production
The Induss II water production plant at the port of Ghent

Capable of producing large water quantities with a very small footprint, mobile membranes are ideal solutions for maintaining efficient water production in both the short and long term. These automated, self-contained units can be rapidly deployed and able to produce water within hours of installation.

They can also be operated remotely to limit the amount of downtime and lost production. As such, high capacity mobile membrane solutions are the ideal state-of-the-art technology to debottleneck and relieve old, conventional water treatment systems, while reducing operating and maintenance costs.

Time-sensitive regulations

Faced with meeting stringent water quality requirements, a large European power plant was in need of identifying a reliable and more abundant source of water to feed its existing demineralization unit.

As the plant’s original water supply, conventionally treated groundwater, could no longer provide a stable and high quality treated water source, it had to quickly implement a solution in order to meet the impending water quality regulations and avoid plant shutdown.

Due to the short supply of water, the resolution was made to utilize water from the adjacent La Meuse river. To provide stable, high quality treated water, the source water, characterized as having variable organic load and suspended solids due to seasonal variation, required two mobile integrated membrane systems consisting of low pressure membranes and one reverse osmosis unit.

Ultimately, the membrane system produced a reliable source of water and exceeded the requirements of the pre-existing demineralization plant without interrupting productivity. Three years later, the fully integrated membrane systems are used for treatment of biological and organic control and the removal of all particulate matter from the river water. The speedy deployment of this membrane solution, which was operational within two months of delivery, saved the power plant from a potential costly shutdown procedure.

The nature of these mobile, containerized units allowed for fast deployment and significantly minimized installation time along with infrastructure costs.

Fully-integrated production site

Seeing a market opportunity surrounding industrial water, Induss, a Belgian water supplier, decided to create a fully integrated water production site to serve surrounding industrial customers with water to meet a variety of production qualities and needs.

Thus Induss II, a fully integrated water watproduction site in the port of Ghent, was formed to serve surrounding industrial customers with water. In order to successfully infiltrate this new market, the plant operators needed to identify and implement a water treatment system capable of meeting the wide variety of water quality demands and requirements for process, cooling, boiler and HP boiler water.

Complicating matters, the solution needed to comply with local regulations regarding the amount of water the plant could extract from the local river, which serves as the main water source.

This water also posed a unique challenge as the river quality is highly variable with the seasons and has high salinity due to its close proximity to the sea, and high levels of conductivity are faced in the summer months. Due to footprint restrictions and discharge limits capping a maximum daily flow and limiting hours for peak flow rates, as well as the fact that there was no sewerage or waste water treatment plant available, the new water system needed to have a wide capacity range to provide consistent water quality, requiring the RO system to be able to handle a varied range of salinity to maintain high recovery without sacrificing production and quality.

Ultimately, Induss selected and implemented a fully integrated membrane system with advanced pressurized membrane filtration capable of successfully meeting the four different water quality requirements.

The original water treatment design scheme included automatic cleaning strainers (300 μm) to remove larger solids and out-to-in with air scrub reverse flow-operated hollow fibre filtration membranes to remove suspended solids and micro-organisms, preventing the reverse osmosis from fouling. It also incorporated first pass reverse osmosis (RO1) to (partially) desalinate the water, second pass reverse osmosis (RO2) as polisher for desalination and electrodeionization (EDI) as final polisher to reach high purity water.

As such, the system is capable of producing process water, cooling water, boiling water and HP boiler feed water. The system’s flexibility met the feed water conditions of the operating window.

Following the implementation of the filtration system, the plant was able to meet all four feedwater demands for each unique process and comply with necessary water quality and environmental discharge regulations.

As regulations are rapidly enacted due to the intensifying global water crisis, power production facilities are increasingly facing new challenges related to water quality. In the coming years, companies will need to become more strategic and aware of water usage and treatment to ensure compliance and the production of the highest quality sources of power.

Jan Bultiauw is Manager Applications Engineering at Pall Water. www.pallwater.com