{"id":3309,"date":"2021-10-15T12:06:28","date_gmt":"2021-10-15T09:06:28","guid":{"rendered":"https:\/\/hydravgis.gr\/?page_id=3309"},"modified":"2021-10-18T13:42:42","modified_gmt":"2021-10-18T10:42:42","slug":"questions-worth-answering","status":"publish","type":"page","link":"https:\/\/www.hydravgis.gr\/en\/questions-worth-answering\/","title":{"rendered":"Questions worth answering"},"content":{"rendered":"

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<\/span><\/span>Why do I have to use a filter for drinking water? The Municipality or the Community is not responsible for taking care of its suitability?<\/h5>
[vc_column_text]<\/p>\n

Municipalities and Communities make significant efforts to provide clean and potable water, free of particulate suspended matter and undesirable substances, chlorinated to destroy bacteria and viruses. After the purification and quality control of the water by the Municipality \/ Community, the water travels through piping networks where it is not possible to control its contamination by dirt, rust, or dangerous metals such as lead, from the old networks. Moreover, testing for insecticides and pesticides in water sources may not be continuous due to the complexity of these analyzes.<\/p>\n

Therefore there is a need to purify the water at the point of use for the following reasons:<\/p>\n

    \n
  • aesthetic reasons<\/u>, with the removal of rust, dirt and other suspended solids, the removal of the unpleasant odor and taste of chlorine<\/li>\n
  • hygiene reasons<\/u>, by removing organic substances (insecticides, pesticides), hazardous metals (lead), derivatives of the reaction of chlorine with organic compounds (halogenated hydrocarbons), microbes, viruses, possibly even radioactive substances.<\/li>\n<\/ul>\n

    [\/vc_column_text]<\/div><\/div>

    <\/span><\/span>How many categories of filters are there?<\/h5>
    [vc_column_text]The filters are divided into: a.<\/strong>\u00a0central supply filters\u00a0b.<\/strong>\u00a0drinking water filters<\/p>\n

    More specifically :<\/p>\n

    A1<\/sub>. Filters for dirt \/ rust filters, suspended particles<\/p>\n

    A2<\/sub>. Filters for dirt \/ rust, suspended particles \u2013 chlorine, organic substances<\/p>\n

    B1<\/sub>. Filters for dirt \/ rust \u2013 chlorine, organic substances (below or on top of the kitchen counter)<\/p>\n

    B2<\/sub>. Filters for dirt \/ rust – chlorine \u2013 organic substances – microbes – lead – chemicals (below or on top of the kitchen counter)<\/p>\n

    B3<\/sub>. Reverse Osmosis system with retention of more than 97% of all harmful substances (under or on top of the kitchen counter).[\/vc_column_text]<\/div><\/div>

    <\/span><\/span>How expensive is a water filter?<\/h5>
    [vc_column_text]There are products in the market with large differences in quality and different origins. Therefore there are many “prices”. A careful market research will prove that “cheap” products without support and guarantees are always “expensive”. When it comes to products that protect our health, what matters is quality. To the extent that we now pay close attention to “what we eat” we should also focus on “what we drink”. Therefore the installation of a water filtration system is necessary.<\/p>\n

    The efficiency of each filter and especially of the filter that contains activated carbon depends mainly on 2 factors:<\/p>\n

      \n
    • water flow through the filter, i.e. how fast the water passes through the filter<\/li>\n
    • size of the filter, i.e. available surface for retention.<\/li>\n<\/ul>\n

      The small filters that are placed on the faucet have a very small surface for retention and therefore in order to be effective the water flow must be small so that there is enough contact time for cleaning.[\/vc_column_text]<\/div><\/div>

      <\/span><\/span>What should I pay attention to, when choosing a filter or water purifier?<\/h5>
      [vc_column_text]We must ask the supplier and carefully read the manufacturer’s technical specifications which refers to the operation of the filter or purification device and its recommended conditions of use, i.e.<\/p>\n
        \n
      • what it removes from the water<\/li>\n
      • the size of the pore<\/li>\n
      • if it contains activated carbon<\/li>\n
      • the capacity of the replacement cartridge<\/li>\n
      • water flow during use<\/li>\n
      • location of installation<\/li>\n
      • maximum and minimum operating pressure<\/li>\n
      • maximum and minimum operating temperature<\/li>\n
      • certificates from international or national organizations<\/li>\n<\/ul>\n

        [\/vc_column_text]<\/div><\/div>

        <\/span><\/span>What does a graded density filter mean?<\/h5>
        [vc_column_text]The graded density filter means that the water is filtered throughout the depth of the filter, i.e. the filter pore size is reduced as the water goes deeper inside the filter. This technology utilizers the use of all the filter material for filtration (all the depth of the filter) and thus increases the filtration efficiency and the life of the filter.[\/vc_column_text]<\/div><\/div>
        <\/span><\/span>Why are the melt blown graded density polypropylene cartridges better than the string wound cartridges?<\/h5>
        [vc_column_text]The water filters for the removal of dirt, rust and other suspended particles use filtering media such as:<\/p>\n

        \u03b1) metal sieve<\/p>\n

        \u03b2) woven string<\/p>\n

        \u03b3) material in compact block (eg ceramic, polypropylene)<\/p>\n

        \u03b4) graded density polypropylene<\/p>\n

        More specifically:<\/strong><\/p>\n

        a) The metal sieve filters the water on the surface of the filter (sieve) and has relatively large pores (80microns).<\/p>\n

        b) The woven string filters the water mainly on the surface of the filter (woven string) and less on the inside of the woven material.<\/p>\n

        c) Compact material block (such as ceramic or polypropylene) filters the water mainly on the surface and less inside.<\/p>\n

        d) Polypropylene of graded density has pores that progressively become smaller (for example down to 5microns) and it filters water both on the surface and inside the cartridge.[\/vc_column_text]<\/div><\/div>

        <\/span><\/span>Why do filters not retain dirt and rust and allow them to escape?<\/h5>
        [vc_column_text]When a filter allows dirt or rust to pass, then one of the following may occur :<\/p>\n
          \n
        • the cartridge has a very large pore size while the dirt and rust are smaller in size.<\/li>\n
        • the cartridge is not installed correctly and some of the water passes through the filter without passing through the cartridge (partial by-pass of the cartridge).<\/li>\n
        • the cartridge is not of good quality and either allows the water to pass through without being filtered or changes shape (deforms) with the pressure fluctuations of the network \u2013 common in the spiral wound type – and releases the already retained dirt.<\/li>\n<\/ul>\n

          [\/vc_column_text]<\/div><\/div>

          <\/span><\/span>What does ``micron`` mean when we talk about ``pore`` size of the filter cartridge, ie retention size?<\/h5>
          [vc_column_text]”Micron” is a unit of length: 1 micron is depicted with the Greek letter “\u03bcm”, i.e. 1 micron is 1\u03bcm.<\/p>\n

          1m is equivalent to one millimeter of a millimeter, ie one millionth of a meter.<\/p>\n

          That is: 1 meter = 1000 mm (1m = 1000 mm)<\/p>\n

          1 mm = 1000 microns (1mm = 1000\u03bcm)<\/p>\n

          therefore: 1 meter = 1,000,000 microns (1m = 1,000,000 \u03bcm)<\/p>\n

          When the spare part of a filter has a pore:<\/p>\n

          1 micron <\/u>\u00a0can hold solids larger than 1 micron<\/u><\/p>\n

          10 microns <\/u>\u00a0can hold solids larger than 10 microns\/u><\/u><\/p>\n

          25 microns<\/u>\u00a0can hold solids larger than 25 microns<\/u><\/p>\n

          Examples :\u00a0<\/strong><\/p>\n

          Human hair size (diameter) = Over 20\u03bcm<\/p>\n

          Flour = more than 1\u03bcm<\/p>\n

          Cigarette smoke = over 1 \u03bcm<\/p>\n

          Bacteria = more than 0.1 \u03bcm[\/vc_column_text]<\/div><\/div>

          <\/span><\/span>Filter cartridges have many grades of ``pores`` (1 micron, 5 microns, 25 microns, etc.). How do I choose the right cartridge?<\/h5>
          [vc_column_text]The service life of cartridge depends mainly on:<\/p>\n
            \n
          • the water quantity, ie how much water passes through the filter daily<\/li>\n
          • the degree of purity of the water, ie if the water contains a lot of dirt, rust and other suspended particles<\/li>\n
          • the pore size of the filter<\/li>\n<\/ul>\n

            When the water is very dirty, that is, it contains a lot of dirt, rust and other suspended matter and the cartridge we use has a small pore, then the cartridge will clog quickly. Of course for the same water quality and the same cartridge, the more water passes through the filter per day, the faster it will clog.<\/p>\n

            The service life of cartridge decreases when :<\/p>\n

              \n
            • the water quantity passing through the filter per day is high<\/li>\n
            • the water is dirty<\/li>\n
            • the pore of the cartridge is small<\/li>\n<\/ul>\n

              It is therefore recommended:<\/p>\n

                \n
              • for central water supply filters (large water flow and water quantity) and relatively clean water to use cartridges of 5\u03bcm or 25\u03bcm<\/li>\n
              • for central supply filters and relatively dirty water to use cartridges 25\u03bcm<\/li>\n
              • for drinking water filters and relatively dirty water to use cartridges 5\u03bcm<\/li>\n
              • for drinking water filters and relatively clean water to use cartridges 1\u03bcm<\/li>\n<\/ul>\n

                The ideal solution is to install a cartridge 5 to 25\u03bcm in the central supply and a cartridge 1 to 5\u03bcm in the drinking water faucet.[\/vc_column_text]<\/div><\/div>

                <\/span><\/span>How do I understand that the useful life of the cartridge has come to an end?<\/h5>
                [vc_column_text]As the cartridge accumulates the dirt it cleans from the water, its pores fill up and the water finds it difficult to pass through. This difficulty causes the pressure and water supply to gradually decrease when we turn on the faucet.[\/vc_column_text]<\/div><\/div>
                <\/span><\/span>What is activated carbon, in what forms is it and how does it purify water?<\/h5>
                [vc_column_text]Carbon is the key element of organic matter. The carbon used in water filters can be of inorganic (mineral rock) or organic (eg coconut) origin. The carbon is subjected to a suitable cleaning treatment so that its surface area increases in relation to its volume and this is how activated carbon is obtained. It is typical that 1 gr of activated carbon has an area of 1000 m2. Activated carbon has the property, with a natural process called adsorption, to attract and retain on its surface various chemical compounds such as chlorine, its derivatives and organic compounds such as insecticides and pesticides. Thus the water that passes through a layer of activated carbon is freed from its unwanted components. Activated carbon is used in two forms:<\/p>\n
                  \n
                • granular form, is in the form of \u2018powder\u2019<\/li>\n
                • solid form, is in the form of a compact piece (block) with a fixed shape<\/li>\n<\/ul>\n

                  This second form of activated carbon also achieves the filtration of suspended particles (dirt, rust)[\/vc_column_text]<\/div><\/div>

                  <\/span><\/span>Does the water filter remove inorganic salts?<\/h5>
                  [vc_column_text]The only water filters that remove inorganic salts (i.e. hardness salts) are those that contain a special resin and the reverse osmosis system. Some special filter cartridges contain polyphosphate crystals that prevent the deposition of salts in pipes and appliances. Another technology that prevents the deposition of salts is magnetic softeners.[\/vc_column_text]<\/div><\/div>
                  <\/span><\/span>Why does the filter cartridge often turns green?<\/h5>
                  [vc_column_text]The filter retains dirt and rust and other suspended particles that can carry various microorganisms. Some microorganisms (eg algae) when they grow, they produce plant like material, i.e. “greenery”. These microorganisms need food and sunlight to grow. The food comes from the materials that have been retained on the filter.[\/vc_column_text]<\/div><\/div>
                  <\/span><\/span>Could the carbon filter used for drinking water and where bacteria and chemicals accumulate, become a breeding ground for microorganisms and a source of infection?<\/h5>
                  [vc_column_text]The carbon filter could become a source of infection. For this reason it is recommended that the water does not stand still in the filter for more than a few hours. Otherwise it is recommended to let the faucet run for 1-2 liters before taking water for drinking and other uses.[\/vc_column_text]<\/div><\/div>
                  <\/span><\/span>How good (effective) is a small filter placed on the faucet?<\/h5>
                  [vc_column_text]The efficiency of each filter and especially of the activated carbon filter depends mainly on 2 factors:<\/p>\n