The ongoing challenge of all industrial cooling water programs is to provide chemical programs that will maintain clean heat transfer surfaces. This means providing protection against corrosion, scale and biological fouling that will ensure continuous operation of equipment with minimal downtime. RMC offers sustainable programs like solid treatment for convenience and ease in placement and ozone for biological control that will ensure that your employees work safer; your operational costs are reduced and minimize impact on the environment.
cooling tower chemical treatment pdf free
Cooling tower water must be properly treated for safety, performance, and equipment longevity. Traditional chemical water treatment has been the standard for many years and is now joined by ozone water treatment. Stand-alone ozone water treatment uses only the addition of environmentally friendly ozone gas to cooling water to provide excellent results. Ozone water treatment often outperforms traditional chemicals in many ways in addition to environmental responsibility. Information from the Federal Government on ozone water treatment for cooling towers can be found in our resources page. TRS can provide equipment, service, and consultation for successful application of a chemical-free ozone water treatment program assuring excellent, reliable and environmentally responsible results.
If you are in charge of managing a cooling tower, you may find that determining which water treatment methods work best is challenging. If you should be aware that your water needs chemicals in order to help your cooling towers function at peak performance, you have a number of options to choose from. An experienced water treatment expert can analyze your specific water situation and advise you on which chemicals would be needed most, but going into the conversation with basic knowledge of your choices will make the process simpler.
Nearly all cooling towers and HVAC systems benefit from using chemicals in their water. These chemicals, which vary in both function and type, serve a number of purposes; primarily, they are meant to increase the longevity of the cooling tower and prevent issues like fouling, corrosion, and Legionella over time.
One of the primary issues that cooling towers face is corrosion and degradation of metal parts due to the natural breakdown forming rust and compounds that break down metal. Over time, corrosion will weaken the mechanical parts of a water tower and cause malfunctions, contamination of the water used in the tower.
Another common issue that cooling towers face is the development of organic material. This may include anything from algae and biofilms to organic contaminants that have crept into the water due to leaks. Because these materials are actually alive, they can proliferate and overtake a cooling tower in a surprisingly short time. For this reason, most cooling towers are treated with some sort of biocide (anti-biotic) to prevent a sudden bloom or burst of organic life that fouls components in the system and can also cause health concerns.
Algaecides, as their name might suggest, is intended to kill algae and other related plant-like microbes in the water. Biocides can reduce other living matter that remains, improving the system and keeping clean and efficient water usage in a cooling tower. One of the most common options when it comes to biocides for your water is bromine.
Regardless of whether you rely on water treatment in your cooling tower, you should consider evaluating your current water usage and locating improvements to extend the life and effectiveness of your cooling tower. The experienced technicians at Tower Water set the standard in water treatment and would be happy to review your current situation and offer personalized suggestions for your cooling tower-based specifically on your local water conditions and the type of equipment that you use.
5. Do it properly. Check with organizations such as the Cooling Tower Institute and the American Society of Heating, Refrigerating and Air-Conditioning Engineers for their latest recommendations. Follow instructions on chemical product labels. Keep records of the procedure, including the chemicals used, the time the chemicals were added to the system, and chlorine and pH test results. Be sure to follow all EPA and other applicable regulations and observe safety precautions. Utilizing a highly qualified and experienced water treatment specialist is the best way to ensure proper protocol is followed.
Update: In 2016, both New York City and New York State established permanent laws for registering and maintaining cooling towers to reduce the risk of Legionella. New York State requires hospitals and nursing homes to maintain all water systems, not just cooling towers, to minimize Legionella.
Disinfectant must be flushed through dead legs so they do not reinoculate the system. Common examples include equalizer piping and free cooling coils which are temporarily valved off.The standard maintenance protocol should include flushing of dead legs. This can be automated in most cases.
Adherent scale or other deposits on the tower and distribution system that have not been removed by the above method can be dissolved using chemical descalants carefully chosen to avoid damage to the fabric of the system. If this is not possible, routine inspection and testing of water quality should be particularly thorough.
On completion of the cleaning operation, the system should be refilled and chlorinated to maintain a minimum level of 5 mg/l of free residual chlorine for a period of 5 hours with the fan off. This needs to be checked hourly to ensure that a concentration of 5 mg/l is present for the total period. Again, the use of a biodispersant will enhance the effectiveness of this chlorination. If the system volume is greater than 5 m3, the water should be de-chlorinated, drained, flushed and refilled with fresh water and dosed with the appropriate start-up level of treatment chemicals, including the biocides.
While the maintenance of a continuous minimum residual of 5 mg/l of free chlorine for a minimum period of 5 hours is considered the best practice, if the downtime to conduct such a lengthy operation is not available, some compromise may be necessary. Under such circumstances it may be acceptable to shorten the pre- and post-chlorination times and to increase the free chlorine level, e.g. 50mg/l for 1 hour or 25 mg/l for 2 hours. This should only be done if the operators are trained in this process because, at these levels, there is a greater risk of damaging the fabric of the system. The system should then be de-chlorinated, drained, flushed and refilled with fresh water and dosed with the appropriate start-up level of treatment chemicals, including the biocides.
To minimise any aerosol creation all surfaces will be scraped and washed down by hand with a disinfectant solution containing free residual chlorine at a level of at least 30 mg/l. Particular attention should be paid to the surfaces of the fill pack, within the pond, balance pipes, filters, drift eliminators and spray bars / water distribution system. Blocked spray nozzles should be removed and cleaned. The pond may be cleaned using a wet vacuum cleaner. The cooling tower may be hosed down to remove the smaller remnants in the tower. This should be continued until the water going to drain is clear and the sediment in the sump has been removed.
a) The area will be isolated and consideration also given to other occupied premises in the immediate areas as well as members of the public who may be in the vicinity during cleaning.b)Water jetting using high pressure hoses will not be used.c) Personnel involved in cleaning will be protected by the use of fully pressurised respirators.d) No persons other than those wearing fully pressurised respirators will be allowed in the immediate vicinity of the cooling towers.
On completion of the cleaning operation, the system should be refilled and chlorinated to maintain a minimum level of 20 mg/l of free residual chlorine for a period of 6 hours with the fan off. This needs to be checked hourly to ensure that a concentration of 5 mg/l is present for the total period. Again, the use of a biodispersant will enhance the effectiveness of this chlorination. The water should be de-chlorinated, drained, flushed and refilled with fresh water and dosed with the appropriate start-up level of treatment chemicals, including the biocides.
The reason one would not use swimming pool standards are several. First, no one is going to be immersed in the cooling tower water. Second, most pools are tested and treated more than once a day for safety purposes. This is not going to happen with a tower. Third, the level of chlorine set in a pool would be very corrosive in a tower system. Forth, pool testing does not look at the actual count of bacteria, as suggested by CTI.
A long term regular water treatment, maintenance, and inspections program is definitely necessary for Legionella control in cooling tower in the long run. Keep in mind, concentrations of the disinfectant and contact time are the two factors for effective disinfection. For Emergency Disinfection after a outbreak, achieving 25 to 50 ppm offree residual halogen for shock treatment and maintaining 10 ppm free residual halogen for 24 hours is recommended by OSHA guideline.
The NYC law and NY state regulation requires that biofilm be controlled.The new NYC law states:28-317.2 of this code.1. Each inspection shall include an evaluation of the cooling tower and associatedequipment for the presence of organic material, biofilm, algae and other visible contaminants.
New York State Regulations:4.5 Inspection and Certification(1) Each inspection shall include an evaluation of:(i) the cooling tower and associated equipment for the presence of organic material, biofilm, algae, and other visible contaminants;Chlorine dioxide is the only biocide that will effectively remove biofilm. Chlorine will not. A use of both should be considered in order not to miss this critical area. Legionella hides out in the biofilm. 2ff7e9595c
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