From food and beverage centers to manufacturing plants, water quality is essential in industrial settings. Many manufacturing and production processes require pure water that’s nearly free of contaminants. If the water is contaminated, the final product may not meet the necessary quality.
Industrial facilities can obtain water from a variety of sources, which include everything from municipal water to surface water. Once it gets to the facility, it must be treated with everything from heat to chemicals. Most industrial facilities use chlorine to perform a deep-cleaning process known as free chlorination.
While free chlorination is a highly effective option for eliminating contaminants, it has a few downsides that every industrial facility should consider. In this guide, we’ll delve into disinfection in industrial settings to determine which technique is right for your facility.
Understanding Disinfection
Water disinfection is a process that involves removing or eliminating harmful microorganisms. Once these contaminants are deactivated or filtered out of the water, they will no longer be able to grow and reproduce. If the contaminants remain in the water, they could make people sick and damage the quality of the products that are made at your facility.
There’s a major difference between disinfecting water and sterilizing it. When water is disinfected, only harmful microorganisms are eliminated. In comparison, sterilization kills all microorganisms, even harmless ones.
When it comes to water quality, the disinfection process is necessary to protect people from bacteria, viruses, and other pathogens. Over the years, disinfectants have proven to be highly effective at decreasing the rate of diseases like cholera and typhoid fever. When water isn’t properly disinfected, there’s a higher chance that outbreaks of illnesses will occur. For example, Walkerton, Canada experienced a severe outbreak of E. Coli because of a contaminated drinking water supply.
Public water systems are responsible for disinfecting water before it’s distributed to consumers and industrial facilities. Most public water systems are tasked with maintaining a small amount of disinfectant in the water to limit the growth of microorganisms. In industrial settings, it’s possible to use a wide range of different disinfectant methods, which include chlorine, heat, and filtration.
Heat is a common disinfectant that can be applied in industrial settings. Microorganisms can be killed when the water reaches a high temperature. For example, the pasteurization process that can be used with wine or milk is able to destroy pathogens and spoilage-causing organisms by heating the water to a range of 140-160 degrees Fahrenheit. The water doesn’t need to get close to the boiling point of 212 degrees Fahrenheit to eliminate most harmful microorganisms.
Even though boiling isn’t necessary, it’s important to understand that all organisms are destroyed within seconds when water reaches 212 degrees Fahrenheit. When water is heated from 140 degrees Fahrenheit to the boiling point, it continues to be disinfected.
It’s also possible to eliminate contaminants in water with clarification. This process is regularly used to reduce turbidity in water. When water has high turbidity, it will appear cloudy, which results from the presence of inorganic and organic substances. Clarification is able to improve the taste and appearance of water by decreasing microbial contamination. However, this process isn’t powerful enough to make the water potable. Chemical treatment or filtration is needed.
Filtration is a process that can be done with many different systems, which include everything from activated carbon to reverse osmosis. All filtration systems are made with at least one filter. Each filter comes with a specific pore size. When water gets pushed through a filter, most contaminants should be left behind. Reverse osmosis systems are often equipped with several different types of filters.
When looking at chemical options, water can be disinfected with electrolytic solutions or chlorine dioxide. Electrolytic solutions and halogens offer the following benefits:
- Affordable
- Available in tablet form
- Allow for flexible dosing
- Can treat small or large volumes of water
- Residual protection
- Possible to remove the bad taste of water
However, there are some drawbacks to this approach, the primary of which is that proper dosing requires an in-depth understanding of how to chemically disinfect water. As for chlorine dioxide, it’s easy to use and more powerful than other disinfectants. It’s also effective at removing all types of waterborne pathogens.
Free Chlorination
Free chlorination is a highly effective technique that can keep water clean and potable. Utility companies are tasked with distributing drinkable water to residential customers every day. This water is sent through drinking water distribution systems (DWDSs). While the water is disinfected before it gets sent to homes, it’s possible that new contaminants and microorganisms will be picked up as it’s traveling through pipes. Free chlorination is a process that allows utilities to meet federal water quality standards and keep the water clean.
A DWDS fosters an environment where algae, fungi, bacteria, and other types of microorganisms can grow. If these microbes get into the water, there’s a chance that waterborne diseases will spread. However, free chlorination mitigates this possibility. This process is a temporary one that effectively involves replacing combined chlorine with free chlorine when performing distribution system maintenance. This procedure is typically performed once every two years.
How Free Chlorination Works
There are several chlorination methods that can be used in industrial facilities. In most cases, the chlorine is flushed into a water main. While chloramines can be sent into distribution pipes, chlorine is more effective. Chloramines consist of ammonia and chlorine. Some water systems will use a combination of the two.
Public water suppliers and city governments often notify the public before they perform the free chlorination process. These notices usually detail where the process will occur, the potential for disruptions, the date of the chlorination, and the duration. As touched upon previously, the chlorination process usually takes place once every two years.
The two main chlorination methods include a “slug-in” technique and a high-pressure metering pump injection. Both types of shock chlorination use chlorine. Once the chlorine is introduced to the water, it will dissolve and create radicals that eliminate nearby pathogens like viruses and bacteria.
The “slug-in” method of shock chlorination is mainly paired with large-diameter water mains. When using this method, you’ll need to place a slug of chlorine into one area of the pipeline before moving it into the pipe interior. The solution must have a contact time of three or more hours to ensure the pipe walls are properly sanitized. The chlorine can be applied to the water in the form of liquid chlorine, a sodium hypochlorite solution, or calcium hypochlorite granules.
Calcium hypochlorite granules are mainly used when disinfecting mains with 12-inch diameters that only extend for 2,500 feet or less. Once the tablets are placed in the water, the main will be filled at a rate of less than one foot per second. The water will be kept in the main for 24-48 hours before being flushed.
The operators will then gather chlorine residuals to make sure that the water has the right concentration of the substance. Once the water is flushed, it should still contain at least 25 mg/L of chlorine. If the measurement verifies that there’s enough chlorine in the water, a final flushing can occur. The operators can then check to make sure that all chlorinated water has been taken out of the pipeline.
While the “slug-in” method has some advantages, it’s considered to be unreliable. This chlorination technique doesn’t evenly distribute chlorine residuals to all parts of the system. The water becomes diluted with differing residual levels, which can lead to issues like fixture damage and stainless-steel corrosion.
The other chlorination method involves using a high-pressure metering pump injection. In this scenario, pipes and water lines can be properly disinfected. The pipeline or water system will be kept at a consistent pressure. During this process, a low-volume metering pump will inject a potent chlorine solution into the water while it flows at a specific rate. The solution will stay in the pipes for at least 12 hours once the operators measure chlorine residuals that range from 50-100 ppm.
Benefits of Free Chlorination
There are many notable advantages of using free chlorination, which include everything from being able to get rid of pathogens to removing mineral buildup. Municipalities can use free chlorination to provide their customers with clean water that’s free of most contaminants. While biofilm will develop on the pipe walls over time and negatively impact the taste of the water, this issue can be mitigated by regularly flushing the hydrants and mains.
Free chlorination is capable of eliminating pathogens and microbes throughout miles of water lines. There’s a much smaller chance that harmful microorganisms will grow within the DWDS. Without this form of chlorination, the organisms that grow within the pipes could lead to corrosion, water discoloration, health issues, and nitrification.
Free chlorination also helps municipalities maintain DWDSs by requiring consistent flushing. Since the flush occurs system-wide, the bacteria along the pipe walls won’t be able to form a resistance to the disinfectant.
When performed properly, free chlorination can also remove sediment and mineral buildup within the water main. Keep in mind that water mains often contain high concentrations of mineral deposits and loose sediment. These issues can lead to reduced efficiency, clogging, and discolored water. By flushing the mains, you can effectively enhance the taste, smell, and color of water.
Potential Downsides of Free Chlorination
While free chlorination offers many advantages, there are some potential downsides that you’ll need to consider. For example, free chlorination can sometimes harm the quality of the water even though it eliminates most contaminants. Some amount of biofilm, sludge, and trihalomethanes can remain in the water even after free chlorination is applied.
The chlorine that’s introduced into the water with free chlorination reacts with the surrounding organic compounds. This reaction creates disinfection byproducts (DBPs), the most harmful of which are trihalomethanes (THMs) and haloacetic acids (HAAs). If someone drinks water that contains high levels of THMs and HAAs, they could develop severe health issues, which include the following:
- Rectal and bladder cancer
- Stillbirths
- Increased risk of liver and kidney cancer
- Congenital disabilities
- Heart problems
- Liver damage
- Issues with the central nervous system
Keep in mind that free chlorination can also introduce a bad taste and odor to the water. As touched upon previously, small amounts of chlorine are designed to remain in the water until it’s distributed through the pipes and into nearby homes. If, however, the concentration of chlorine is too high, the water might taste or smell bad.
At low levels, chlorine can alter the taste of water. People who consume chlorinated water are more likely to replace it with soft drinks, ice teas, and other beverages that contain too much sugar. A reduction in water intake can lead to numerous health problems, which include everything from kidney damage to diabetes. The suspended solids from the piping system can also get into your home’s supply of water, which might cause a further reduction in the smell and taste of the water.
Long-term exposure to free chlorination may also damage the quality of your hair and skin. If you regularly shower with chlorinated water, your hair and skin could become itchy, dry, and flaky. Your hair might feel dry and frizzy to the touch. If you often dye your hair, chlorine can cause the color to fade quickly.
Exposure to chlorine is most harmful to people who have sensitive hair or skin. Your body invariably produces oils and proteins that create a thin coating around your hair and skin. In turn, your epidermis will remain soft and healthy. However, chlorinated water can damage this layer and eventually wash it away completely.
This substance can impact aquatic life as well. Even though chlorine is a necessary component of plant growth, the plants can get too much of this substance. When a high amount of chlorine accumulates on leaf tissues, the plant can take on a burned or scorched appearance. These leaves might also shrink and fall off too soon.
As for aquatic life, chlorine is highly corrosive to fish and marine invertebrates. The substance causes chemical burns on the gills of fish. It can also enter the bloodstream, which may lead to burns throughout the entire body.
Chlorine Dioxide as an Alternative
This form of chlorine is a strong oxidizing agent that can disinfect water by eliminating most of the harmful microorganisms within it. Unlike free chlorine, it’s extremely effective at killing protozoa. Once it enters the cell walls of a microorganism, it will disrupt the metabolic processes, which means that it will become inactivated in an instant.
The main difference between free chlorine and chlorine dioxide is that the latter doesn’t leave behind a notable amount of residuals. On the other hand, free chlorine is known to leave these residuals behind, which is why this solution is regularly used in distribution pipes for residential drinking water.
A significant advantage of using chlorine dioxide is that it’s able to control the formation of biofilm while also reducing DPBs. It should mitigate odor and taste issues in the water as well. Industrial water disinfection processes regularly use this form of chlorine to instantly remove viruses, bacteria, and other pathogens.
In desalination plants, this substance is commonly used because it’s a more potent disinfectant. However, the choice between these two types of chlorine depends on factors like regulatory requirements, treatment objectives, and water quality.
Relevance to Industrial Water Settings
Industrial water treatment can be challenging. Some of the effluents that are created at industrial facilities occur as a result of complex processes. These processes form wastewater streams that contain high concentrations of numerous contaminants, which is why the water can be more difficult to treat. For example, a single wastewater stream can consist of high concentrations of corrosive chemicals, heavy metals, and oil. Each contaminant requires a different treatment.
Complex effluents can also have ample amounts of suspended solids and high biological oxygen demand. An integrated treatment system may be needed to ensure that all types of contaminants can be destroyed.
Keep in mind that industrial facilities can also be tasked with scaling their water treatment operations, which takes a considerable amount of time and money. The water treatment process can involve everything from automation and logistics to advanced controls and wet lab testing, all of which must be implemented correctly.
It’s also important that you choose the right disinfectants and treatments for your industrial water. While chlorination and chlorine dioxide are effective at killing viruses and bacteria, they both have drawbacks. You’ll need to select the method that’s most suitable for your facility as well as the application.
Best Practices for Water Disinfection in Industry
When you’re attempting to disinfect the water in your home or industrial facility, there are some best practices you should consider implementing. If you only need to treat a small amount of water, consider heating it to a temperature range of 140-160 degrees Fahrenheit.
While sterilization is arguably more effective than using a disinfectant, it can’t be maintained in a distribution system, which makes it the least practical method of eliminating contaminants in water.
If you’re disinfecting industrial water, you must regularly monitor and maintain the strategies you use. While chlorination is effective, it’s important that the water doesn’t contain too many chlorine byproducts after it’s treated.
It’s also a good idea to use filtration systems after disinfecting the water. Reverse osmosis and other filtration techniques can remove chemicals, particulate matter, heavy metals, dissolved salts, and pesticides. Once you screen these particles out of your water, you can be confident that nearly all harmful contaminants have been removed.
Conclusion
Disinfection in industrial settings is crucial to limit the spread of harmful microorganisms while also maintaining the quality of various manufacturing and production processes. While there are numerous substances and methods that an industrial facility can use to remove contaminants from the water, free chlorine and chlorine dioxide are among the most effective.
When you’re choosing between these solutions, free chlorine is a potent oxidizer that can eliminate, viruses, bacteria, and other pathogens. However, it leaves behind a residual concentration that’s not suitable for every application. In comparison, chlorine dioxide has even stronger disinfecting properties. Since it doesn’t leave behind residual concentrations, it’s ideal for applications that require precise water chemistry.
Source link: https://sensorex.com/disinfection-industrial-water/ by Joshua Samp at sensorex.com