To stop the spread of diseases and damaging effects on the body, there must be an appropriate supply of water for human consumption and use. It is required to set acceptable boundaries for its bacteriological, physical, organoleptic, chemical, and radioactive features, in order to do this. The water must go through a process of water purification treatments, in order to ensure and maintain its quality until it is delivered to the user.
Physical and chemical treatments are used in the water purification process, to get rid of impurities that can be dangerous. Microorganisms, inorganic chemicals (salts, minerals, metals), and organic compounds (fats, oils, petroleum derivatives, pesticides, detergents, medicines), are some of the pollutants that can be found.
7 common water purification techniques
The normal procedure for making water fit for human consumption, consists of seven phases. Thus, the steps in the water purification procedure that must be followed, if the water is to be utilized for human consumption are listed below:
The most popular disinfectant for reducing or getting rid of bacteria and viruses, which might be in water is chlorine. The risk of waterborne illnesses like diphtheria, typhoid, and cholera has significantly decreased, as a result of the addition of chlorine to drinking water. Water is somewhat purified by chlorination but is not entirely cleansed.
2: Using granular media for filtering
The purifying procedure that eliminates suspended particles from water is called filtration. Deep-bed filters are another name for granular media filters. They can retain particles with diameters larger than 1 micron, depending on the type of media, but usually they only keep those larger than 5 to 10 microns, such as dirt, sand, silt, and other particles that may be present in the water.
To avoid contaminating or obstructing equipment used in later stages of the purification process, sediments must be filtered at one of the early stages of the purification process. The most popular granular media include garnet, silica sand, zeolite, anthracite, and combinations of these materials, in a substance known as a media bed. When the pressure differential between the inlet and output reaches 10 psi, granular media filters need to be backwashed.
3: Granular activated carbon (GAC)
GAC works well as an adsorbent for organic substances that can be poisonous, or give water a bad taste, odour, or colour. Additionally, GAC functions as a reducing agent at this point, converting free chlorine into chloride ions (Cl–).
GAC is a favourable environment for bacterial development. The majority of the organic compounds it catches are biodegradable, and serve as food for these creatures. Additionally, they are resistant to being washed away by water due to their rough surface, which enables contaminants to adhere well.
Bacterial control in activated carbon beds requires a number of sanitization procedures, which must be repeated on a regular basis. The efficiency of the process, the working environment, and the positioning of the equipment will all affect the periodicity. The GAC should be changed once a year, as advised.
4: Water Softening
When water is to be osmotized and its hardness is greater than 170 mg/L, softening the water is advised. Additionally, it is advised when the product won't be osmotized and its value results in an unpleasant taste, or incrustation in following equipment. Water's ability to foul depend on indices, like the Langelier index, whose value depends on hardness, pH, total dissolved solids, and other factors.
The concentration of different divalent metal ions in the water that can form scale, is what determines the overall hardness of the water. Normally, Ca+2 and Mg+2 make up almost all of it. Only these two cations are taken into consideration for practical reasons.
An ion exchange resin that is negatively charged is utilized to soften water. These are artificial, polymeric-matrixed spheres that may exchange ions in a liquid, based on their charge and intensity. The softening procedure makes use of strong cationic resins. The more positively charged Ca+2 and Mg+2 ions replace the less positively charged Na+ ions, as water passes through the resin. The ions that lead to hardness are kept in the resin spheres in this way.
The exchange capacity of ion exchange resins is often expressed in grains per cubic foot (gr/ft3). The resin needs to be replenished when this threshold is reached. A 10% solution of sodium chloride (NaCl) serves as the regenerant.
5: Reverse Osmosis
When enough pressure is applied to the water in reverse osmosis apparatus, the water is forced across a porous membrane that rejects more than 99% of the salts. Because of this technique, some of the water that is fed into the system is utilized to reject the salts.
Rejection or concentrate are two terms for this flow. The quality of the water that needs to be treated determines the percentage of water that is rejected.
Membranes for reverse osmosis
There are many various membrane types available, including brackish water, high productivity, and high rejection, to name a few. They have variable capacity in terms of operation flow and salt rejection % because, to variances in their design and manufacturing materials.
Membranes may contain carbonates, silica, organic material, or microbes embedded within them. When this occurs, items can either be treated locally or sent to have the appropriate chemicals, used to descale them.
In order to capture solid particles larger than 1 micron, which would not have been captured in the prior equipment or from the same, a cartridge filter is added before entering the RO. This serves as the RO's last line of defence.
The water has already undergone purification at this stage of a treatment train, making it safe to consume. After the RO, it is vital to utilize disinfection techniques to keep the water from becoming contaminated, with microorganisms from outside sources.
In order to create ozone, molecular oxygen (O2) must first pass through a specific chamber where it is subjected to an electrical charge, strong enough to rupture O2's covalent bond and recombine it into triatomic oxygen molecules (O3 or Ozone). Ozone production is known as the Corona discharge.
To get the O3 to the treated water, it is either suctioned directly into the product water pipe using a venturi, or injected as bubbles into a resident tank. When water is packaged in recyclable barrels that may have retained some bacterial contamination following cleaning, it leaves a residue that is helpful.
7: UV disinfectant
The use of an ultraviolet (UV) light lamp, which passes the water through a chamber that, integrates a source of UV light of the right wavelength, to prevent bacterial or viral reproduction and proliferation if present, serves as the final stage of sterilization and a second protective barrier before bottling.
Manufacturer of water purification plants/water treatment plants
A wide range of industrial and commercial water filters are available from Netsol Water, and they may be customised to meet the demands and requirements of any particular project. In addition, we provide top-notch RO plants, water softeners and activated carbon filters that can be used for any tertiary water treatment, or water purification application.