Disinfection and disinfection of water is one and the same process. It is aimed at the complete or partial destruction of viruses, bacteria contained in a liquid, its purification from dust, debris, etc. The purpose of the event is to protect people from viral and infectious diseases, food poisoning, helminthic invasion. In the article we will introduce you to several methods of water disinfection - traditional and innovative, industrial and suitable for use in the field.
Cleaning methods
First of all, we note the fact that the complete cleansing of all the elements contained in it (including bacteria) will make the liquid completely unsuitable for drinking and cooking. Therefore, you need to properly choose a method of disinfecting water, to be sure of its high-quality implementation.
Disinfection should always be preceded by a chemical-biological study of the fluid. Already on the basis of its results, one of the methods of disinfection is chosen:
- Chemical, reagent.
- Combined.
- Reagent-free, physical.
Each of them is a way of disinfecting water, but according to its own specific technique. For example, a chemical is an effect with the help of coagulant reagents, physical methods are a reagent-free effect. Innovative ones are also highlighted, which we will definitely analyze throughout the material.
The use of combined methods is interesting - this is the application of both physical and chemical purification alternately. It is considered today the most effective in disinfection - it not only allows you to get rid of bacteria, but also helps to prevent their repeated visit. The use of several methods of water disinfection is also a guarantee of its purification from the maximum amount of pollutants.
Chemical methods
In particular, this is the treatment of liquids with various substances - chemical coagulants. The most common are:
- chlorine;
- ozone;
- sodium hypochlorite;
- metal ions and so on.
The effectiveness of these methods of disinfecting drinking water depends on the most accurately determined dose of the reactant, on the proper time of its contact with the liquid being cleaned.
The appropriate dosage is determined by both a calculation system and a test disinfection, after which water is taken for analysis. It is important not to miscalculate in the sense that a small dose of chemical reagents is not only powerless against viruses and infections, but can also increase their activity. For example, the same ozone in small quantities kills only part of the bacteria, secreting special compounds that awaken sleeping microorganisms, stimulating them to accelerate reproduction.
From here, the dose is always calculated in excess. But one thing is how to disinfect wastewater, and another is drinking. In the latter case, the excess should be such as not to cause poisoning with disinfectants in people who use liquid.
We suggest that you familiarize yourself with the chemical procedure in more detail.
Chlorination
If you ask the townsfolk: “Indicate the easiest way to disinfect water,” many will immediately notice chlorination. And for good reason - as a method of disinfection, it is very common in Russia. This is explained by the undoubted advantages of chlorination:
- Easy to use and maintain.
- Low price of the active substance.
- High efficiency.
- The subsequent effect after application - the secondary growth of microorganisms does not occur even with a minimal excess dose of chlorine.
- Control of smell, taste of water.
- Clean filter support.
- Obstruction to the formation of algae.
- The destruction of hydrogen sulfide, the removal of iron and manganese.
However, the tool has its drawbacks:
- When oxidized, it has a high degree of toxicity, mutagenicity, carcinogenicity.
- Subsequent purification of the liquid after chlorine with activated carbon does not save it completely from compounds formed by chlorination. Highly resistant, they can make drinking water unsuitable for drinking, clog rivers and other natural bodies of water along the course of drains.
- The formation of trihalomethanes, which have a carcinogenic effect on the human body. They contribute to the growth of cancer cells. And boiling, the easiest way to disinfect water, exacerbates the situation. In chlorinated liquid, dioxin is formed after it - a dangerous toxic substance.
- Studies show that chlorinated water also contributes to the development of diseases of blood vessels, gastrointestinal tract, liver, heart, hypertension, atherosclerosis. Negatively affects the condition of the skin, hair and nails. Destroys protein in the body.
Today, modern replacement is chlorine dioxide, which is more effective in disinfection. But a significant minus - it must be applied immediately at the place of production.
Ozonation
Many consider ozonation to be the most reliable way of disinfecting water. Ozone gas is capable of destroying the enzyme system of a microbial, viral cell, oxidizing some compounds that give an unpleasant odor to liquids.
The advantages of the method are as follows:
- Fast disinfection.
- The most safe disinfection for humans and the environment.
At the same time, ozonation has a number of disadvantages:
- If the dosage is incorrect, the water smells unpleasant.
- Excess ozone contributes to increased corrosion of the metal. This also applies to water pipes, and household appliances, utensils. It is necessary to wait for the period of gas decay before letting water through the pipes.
- A rather expensive method to use - large waste of electricity, sophisticated equipment, highly qualified staff are needed.
- Gas during the production process is toxic and explosive. Belongs to the first class of danger.
- After ozonation, bacteria may multiply again. There is no guarantee of 100% water purification.
Polymer Antiseptics
Another popular chemical method is the use of polymer reagents. The most famous today is the Biopag. Most often it is used in public pools, water parks.
The advantages of this method of cleaning and disinfecting water:
- It does not harm human and animal health.
- Does not give water a specific smell, taste or color.
- Pretty easy to use.
- It has no corrosive effect on the metal.
- It does not cause allergic reactions.
Disadvantages - may irritate the skin, mucous membrane.
Other chemical methods
What methods of water disinfection can be called in this case? These are a few options:
- Disinfection with heavy metal ions, iodine, bromine.
- Disinfection using noble metal ions. The most commonly used silver.
- Use of strong oxidizing agents. A common example here is sodium hypochlorite.
Physical methods
This will include non-chemical methods of exposure to microorganisms in a liquid. Their use is most often preceded by filtration and coagulation of water. This removes suspended particles, worm eggs, an impressive portion of the microbes in the liquid.
The most common ways:
- Exposure to ultraviolet radiation.
- The impact of ultrasound.
- Boiling. An effective way to disinfect water in natural conditions.
Let's look at each of them in more detail.
UV exposure
It is important to calculate the necessary share of the acting energy on a certain volume of water. To do this, multiply the radiation power and contact time with the liquid. It is important to first determine the concentration of microorganisms in 1 ml of water, the number of indicator bacteria (in particular, E. coli).
Note that UV rays will adversely affect microorganisms better than chlorine. According to the results of purification, ozone will be equal in radiation efficiency. UV rays affect both enzyme metabolism and the cellular structures of bacteria and viruses. What is important, they destroy vegetative, spore forms.
The advantages of the method are:
- There is no upper dose threshold, since such irradiation does not form toxic compounds in water. By increasing it, you can gradually achieve the best results.
- Great for individual use.
- Long UV lamp life - several thousand hours.
But there are also disadvantages:
- There is no consequence of the event - in order to prevent the return of microorganisms, the water should be decontaminated periodically and systematically, without turning off the unit.
- Quartz lamps are sometimes contaminated with deposits of mineral salts. However, this is easily prevented by using conventional dietary acid.
- Preliminary purification of water from particles suspended in it is mandatory - by screening the rays, they nullify the whole process.
The method of water disinfection in the field using UV radiation is shown in the picture.
Ultrasound
The action here is based on cavitation. This is called the ability of a number of sound frequencies to form voids that create a big difference in pressure. This dissonance leads to the rupture of the cell walls of viruses and bacteria, which leads to the death of microorganisms. Efficiency depends on the intensity of sound vibrations.
This method is not very common primarily because of its high cost. It requires certain equipment, specially trained personnel. It is important to remember that ultrasound is dangerous for bacteria only at certain frequencies. Low waves, in contrast, can accelerate the growth of the number of microorganisms in water.
Boiling
The simplest and most common way of disinfecting water in the field is, of course, boiling. Its popularity and recognition is based on many factors:
- Destruction of almost all harmful microorganisms in a liquid - viruses, bacteria and bacteriophages, antibiotics, etc.
- Accessibility - you need a heat source that can heat water to 100 degrees Celsius, and a heat-resistant tank.
- Does not affect the taste of the liquid, its color and smell.
- Eliminates gases dissolved in water.
- It fights well with fluid hardness and softens it.
Complex cleaning methods
From simple methods of water disinfection, we turn to complex ones, which are the most effective in some cases. For example, this is a combination of UV radiation and chlorination, ozonation and chlorination (an obstacle to secondary infection), reagentless and reagent methods.
Filtration is often referred to the same category. But with the peculiarity that each filter cell must be smaller in size than the screened microorganisms. And this means that its diameter should not exceed 1 micron. But in this way, you can only fight bacteria. Against viruses, more microscopic pores are used - with a diameter of less than 0.1-0.2 microns.
In today's market, a filtration system called Purifayer is popular. The device is characterized in that it uses several systems of water filtration, its disinfection. Some models can additionally cool water to 4 degrees and heat up to 95 degrees.
Installation is applicable both on an industrial, and office, home scale. It is quite simple to connect it to a water pipe with a plastic adapter. Manufacturers claim that the acquisition, connection and operation of Purifayer will cost the owner less than the delivery of bottled water.
Innovative disinfection methods
The newest methods for disinfecting water today are electrochemical and electro-pulse. In the domestic market, they are used in devices such as Emerald, Sapphire, Aquamarine.
Their functioning is based on the operation of a special electrochemical diaphragm reactor through which water is passed. It, in turn, is separated by a cermet membrane, which is capable of ultrafiltration into cathode and anode zones.
At the moment when current is supplied to the anode and cathode chambers, solutions — alkaline and acid — begin to form in them. Then - an electrolytic formation (its other name is active chlorine). This whole environment is distinguished by the fact that an overwhelming number of species of harmful microorganisms are actively dying in it. It is also capable of destroying certain compounds dissolved in a liquid.
The performance of the presented devices mainly depends on two factors: the number of working elements and their design. In some aggregates, catholytes and anolytes are used (mainly in the medical field). This disinfection is called ECA technology.
By the way, many misconceptions are connected with it. Some device manufacturers claim that the water treated in their unit becomes healing and even miraculous. However, in reality, it is only cleaned and disinfected.
Electropulse cleaning is the transmission of electric discharge through the water column. The shock wave of ultrahigh pressure, light radiation, ozone formation are the result of exposure. All this is detrimental to microorganisms suspended in a liquid.
We got acquainted with different methods of water disinfection - simple and complex, traditional and innovative, effective and safe for humans. Each of them has its own advantages and disadvantages. However, the leading factor is harmlessness to the human body and the environment.