Building Industrial Water Resiliency
Many industrial facilities in the United States rely on a single freshwater source, either surface or ground water, to provide water for production and utility needs. A sole-source approach may prove inadequate in times of water stress such as droughts, floods or other natural disasters or if water prices should increase. Due to a stressed water supply, production rates may need to be curtailed or even stopped to match the available water supply.
The goal of building water resiliency is to be able to consistently maintain production requirements despite adverse events. Whether driven by operational expenses, waste reduction goals, or both, building an industrial water resiliency program can only benefit a facility.
Source water options to consider
Much like diversifying investments can reduce risk to meet retirement goals, diversifying water sources can reduce the risk of meeting production goals. Depending on the location of a new or existing facility, a variety of water sources may be available to use directly as a water source or used after filtration and treatment (reverse osmosis, granular activated carbon, membrane biofiltration reactor, ultraviolet disinfection, etc.).
The requirements for water quality, such as total dissolved solids, to be used in an industrial application will be determined by site factors such as equipment tolerance, product specifications, and/or wastewater discharge requirements. For cooling towers and boilers, which are typically the largest water consumers on an industrial facility, the feed water quality must consider the cycles of concentration, which is the ratio of constituent concentration between the blowdown and feed streams.
External water sources to consider as a feed source include collected rainwater, tertiary treated wastewater from a local municipality, fresh water, ground water, brackish water or sea water. Reusing internal facility wastewater streams may also provide a reliable water source, and they have the added financial and eco-friendly benefit of reducing wastewater flows. Streams such as low conductivity rinses, condensate, boiler and cooling tower blowdown, process wastewater, and even reverse osmosis reject streams could be considered when building a water resiliency program.
Limitations to water sources
Each water source has advantages and disadvantages and there are circumstances that may limit source water options from use or limit the amount of water consumed. Site location, local regulations, site permits and operational variability must be considered when developing a water resiliency program.
Site location determines what water sources are available. A facility in a land-locked state will not be able to rely on seawater as a water source.
State, local or national regulations as well as permits can limit water sources. Some water sources may emit harmful vapors or create concentrated reject streams after treatment that may eliminate the water source from potential use or require additional treatment.
Water sources may vary in quality (such as municipal wastewater) or quantity (such as collected rainwater) that would require a facility to consider multiple sources to accommodate blending or supplementing certain streams. Likewise, the facility needs may fluctuate (such as cooling towers requiring less water in the winter and more in the summer) and source water options will need to modulate to meet plant demands.
Design can project costs
The desired water quality for use and available water source quality will dictate the infrastructure required for treatment. A front end engineering design (FEED) level study can determine an order of magnitude estimate for capital and operational expenses of different water sources or combinations of water sources. Design teams will be challenged to balance the cost of a reliable water source(s), the capital cost of required treatment and the cost of potential downtime if water becomes scarce.
Matrix Technologies is one of the largest independent process design, industrial automation engineering, and manufacturing operations management companies in North America. To learn more about our FEED services for water resiliency, contact Sarah Shank, PE, Project Engineer in the Process & Electrical Design Department.
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