Cooling towers are used by industries to keep heat transfer surfaces clean, permit process heat removal, and increase product throughput. These are generally used for comfort cooling in commercial or building applications.
Water used in cooling tower applications continuously draws impurities from the air and absorbs them, which contributes to the excessive build-up of deposits (scale, corrosion, fouling and biological activity). These build-ups result in lower heat transfer efficiency and higher operating and maintenance expenses.
In this blog, we will discuss about the treatment of cooling tower water, with the process flow diagram and the working in detail.
Why is water treatment in cooling towers required?
Industries use cooling towers to remove process heat, maintain clean heat transfer surfaces, and boost product throughput. In commercial or building applications, comfort cooling is provided via cooling towers.
The excessive development of deposits is as a result of the water used in cooling tower applications, which continuously remove contaminants from the air and absorbs them. It results in the lower heat transfer efficiency and greater operation and maintenance costs.
Additionally, the contaminated water might reduce the effectiveness of your chiller, which can raise your energy expenditures. The best outcomes come from cooling towers that operate at their peak capacity. Minor flaws or damage, though, can place a strain on a project and, if left unattended, result in costly repairs and high operating costs.
Finally, slime, and algae can all collect on the basin bottom of dirty cooling tower water, which can serve as a breeding habitat for Legionella bacteria. Your cooling towers' safety can be created and this can be avoided, with proper cooling tower cleaning.
Which contaminants are present in the water of cooling towers?
· Legionella
Freshwater habitats are home to a type of bacteria called legionella, which is the cause of legionnaire’s disease. Once legionella gets into an enclosed area, like the cooling tower system of a building, it can grow and spread throughout the water system of the building.
· Fouling
Scale, algae, suspended particles, and insoluble salts that accumulate on a surface, are together referred to cause fouling. It is commonly found on heat exchangers and process equipment’s. Similar to scale, fouling will quickly lower heat exchanger efficiency levels, lowering the effectiveness of your HVAC system.
· Scale
Calcium, magnesium, and other metals can be found in hard water in dissolved form. These substances build up on different surfaces over time, and eventually harden to form scale. The efficiency of your HVAC system declines when the scale layer thickens, and lowers the effective transmission of heat from the heat exchangers.
Additionally, these contaminants are present in cooling tower water:
· Calcium carbonate scale,
· Chlorides,
· Organic matter which encourages the growth of microorganisms, and can cause fouling, corrosion, and other system problems,
· Iron when mixed with phosphate can cause equipment to become contaminated,
· Silica which leads to hard scale deposits,
· Sulphates which can be very corrosive to metals,
· Total dissolved solids (TDS) and total suspended solids (TSS) are undissolved pollutants, which can form biofilms, or induce corrosion.
What components make up a fundamental cooling tower water treatment system?
According to the manufacturer's recommendations, the precise components of a cooling tower water treatment system depend on, the feed water quality and circulatory water chemistry, in relation to the water quality required for the particular cooling tower and associated equipment.
Basic cooling tower water treatment system consists of:
· Clarification equipment’s
· Filtration,
· Reverse osmosis plant, or ultrafiltration, or ion exchange, and automated monitoring of chemical feed.
Any combination of these treatments may work best for your facility, and make up your treatment system depending on the contaminants in your water, so it's crucial to speak with your water treatment specialist like Netsol Water Solutions, to make sure the proper system for your particular tower is being taken into consideration.
How does a water treatment system for cooling towers operate? How to treat cooling tower water?
Treating the blowdown water from cooling towers presents a number of difficulties, due to the high salt concentrations and chemicals placed in the cooling tower. Every source of water contains varying amounts of suspended and dissolved particles. The water still in the cooling tower becomes concentrated, because the evaporative loss is water with little to no particulates.
To keep the equilibrium, fresh water must be introduced. However, the levels of dissolved solids will rise when the mass balance of water in the system is balanced. Numerous issues, including corrosion, scaling, fouling, and microbial development, may arise as a result in the cooling tower.
Depending on the needs of the cooling tower and the quality/chemistry of the feed and circulation water, several treatment methods are used, however the following steps are typically included, in a cooling tower water treatment system:
· Input of makeup water for cooling towers
First, makeup water is pulled from its source, which could be well water, city water, treated effluent from the city, in-plant wastewater recycling, or any other surface water source. Makeup water is used to replace bled, evaporated, and leaked water from cooling towers.
You could or might not need treatment in this location, depending on the quality of the water. When water treatment system is needed at this stage of the process, it consists of equipment’s that eliminate silica, as well as hardness, or stabilises and modifies the pH value.
The right treatment at this stage of the procedure maximises the tower evaporation cycles, and reduces the water leak rate to drain more effectively than could be achieved with just chemicals.
· RO/Ultrafiltration and filtration
The next step usually involves filtering the cooling tower water to get rid of any suspended particles like silt, turbidity, and specific kinds of organic materials.
The removal of suspended solids upstream helps prevent membranes and ion exchange resins, from fouling later in the pretreatment process, hence it is frequently advantageous to perform this early in the process. Suspended particles as small as one micron can be removed, depending on the filtration method utilised.
· Filtration in the side-stream
A side-stream filtration will be useful in removing any troublesome contaminants that have entered by drift contamination, leak, etc., if the cooling tower water is going to be re-circulated throughout the system. A fair rule of thumb is that 10% or less of the circulating water will filter through, if your cooling tower water treatment system calls for side-stream filtering. Usually, it includes a high-end multimedia filtration system.
· Water softening/ion exchange
If your source or makeup water has a high level of hardness, the hardness is treated. In place of lime, a softening resin can be used; this resin is charged with a sodium ion, and as the hardness develops, it has a higher affinity for magnesium, calcium, and iron, therefore, it will grab that molecule and later, release the sodium molecule into water. This process is known as a strong acid cation exchange. If these pollutants are present, scale deposits and rust will result.
· Treatment of Blowdown for cooling tower
A portion of the concentrated water must be discarded in order to preserve the effectiveness and lifespan of components. Here, blowing down or bleeding off refers to the purged water.
The make-up water pretreatment process and the number of concentration cycles affect the qualities of blowdown water. The water may also have pathogens, bacteria, or algae in addition to minerals (high TSS, TDS, Hardness, and alkalinity values). Chemical additives are frequently added to water in order to prevent scaling, lower pH, prevent corrosion, and eliminate biological contaminants (biocides).
Reuse and blowdown treatment
When cooling towers are in use, a lot of blowdown water is produced. One of the most important aspects of running a plant is managing this blowdown.
The following are typical options for blowdown management:
Discharge to wastewater treatment facilities: Pre-treatment may be necessary.
Treatment and reuse: The types of applications for water, as well as a wide range of other factors, such as water reuse legislation and water availability, affect the alternatives for reusing water.
Zero liquid discharge (ZLD): This option entails thorough blowdown treatment to enable reuse along with volume reduction, to reduce or completely remove the need for liquid discharge.
Flow chart for the treatment of cooling tower water
Water treatment solutions for Cooling Tower Water
Netsol Water provides the most cutting-edge cooling tower water treatment options, all of which are created to improve and maximise the productivity of your business and the effectiveness of heat transfer. Our skilled, knowledgeable engineering and technical service experts are committed, to assisting you in finding the ideal solution to your operational problems.
With the use of cooling tower water treatment to maintain clean heat transfer surfaces, which enable optimal process heat removal and product throughput, industrial facilities look on us to help them meet and maximise production goals. Our cooling tower water treatment is used by commercial and institutional buildings, to enhance and maximise chiller efficiency, while lowering water and energy costs and usage.
How are our cooling tower water treatment solutions different?
Every programme for treating cooling tower water is different. The relative concentrations of ions and microbial populations in cooling tower waters, as well as the increased utilisation of contaminated and recycled water sources, vary greatly across the globe.
Every customer has various cooling tower operation conditions, such as temperature, sizes, flows, building materials, and process variation. Our team of skilled technicians and industry experts will work with you, to build a solution that meets your demands. We have spent decades leading the industry in engineering the most reliable, and efficient systems for cooling tower water treatment.
Benefits of cooling tower water treatment systems
· System performance: increased efficiency of heat transfer in key operational equipment,
· Ecological profile: consumption of water, treatment costs, and blowdown/discharge volume all improved or decreased,
· Operating expenses: reduced maintenance requirements, downtime, and turnaround times.
How we can assist?
Netsol offers a wide range of solutions to remove suspended solids and regulate biological growth, in the recirculating water stream to ensure effective operation and extended life, which can:
· Boost system performance
· Cut back on annual cleanings
· Maximise the efficiency of the chemical programme
· Encourage efficient microbial control
· Lower your overall operating costs
Understanding your alternatives for cooling tower water treatment can be confusing, especially as the majority of cooling tower systems are distinctive, or particular to their particular locations and uses. This is why it's crucial to contact a knowledgeable water treatment specialist, who can examine your cooling tower and offer suggestions that are tailored to your specific needs. Netsol Water Solutions is the industry leader in cooling tower treatment, and we would be pleased to help you choose the solution that will work best, and last the longest for your cooling tower. Call us at +91 9650608473 or email at enquiry@netsolwater.com for further information.
