When installing filters of softeners and iron removers, it is always necessary to consult a specialist and conduct a water analysis in order to correctly calculate the required volume of filter material and, accordingly, the size of the filter housing. If you need a water filtration system installation, it is important to learn more about the operation of different types of filters.
Reagent water softener
The reagent method of water softening involves the addition of specific safe chemicals to the water, which form compounds with hardness salts that are not able to precipitate and thus prevent the deposition of scale. This method of softening can only be used for industrial water (washing machine, boiler, heating system), since the substances that make up the softening mixtures are harmful to humans when consumed in food.
Typically, reagent softening of water in the home takes place on special filters that are filled with salt crystals of the emollient components. When water passes through such a filter, the crystals partially dissolve and saturate the water with the required amount of softening additives. Such filters are enough for 15 – 20 m 3 of water or 300-400 cycles of operation of the washing machine.
The main disadvantage of most such devices is that their main component is polyphosphates. These substances can cause allergies, skin irritations in humans and adversely affect the operation of centralized biological treatment facilities. For this reason, the use of phosphates in the home (powders, water softeners) is prohibited in many countries of the world. But not everything is as sad as it seems at first glance, there are environmentally friendly and safe phosphate-free water softeners.
Adsorption water treatment
Adsorption filters are designed to remove from water:
- chlorine and organochlorine compounds. (In addition to the disinfecting properties, chlorine has a number of disadvantages, the main of which is a pungent odor even at low residual concentrations in water and the formation of carcinogenic organochlorine compounds);
- hydrogen sulfide and other sulfur compounds. (They are the cause of the unpleasant smell of “rotten eggs”, which makes the water unsuitable for domestic use);
- organic compounds of natural (fulvic acid) and technogenic nature (pesticides, phenols, etc.), which can be toxic, and also cause unpleasant marsh odors and tastes of water.
Adsorption is a spontaneous process of increasing the concentration of solute at the interface between two phases due to uncompensated forces of intermolecular interaction. In simple terms, in the context of water purification, this is the process of concentrating certain pollutants on the pore surface of special substances – sorbents. In water treatment technologies, the products of combustion of natural raw materials, such as wood, seeds of various fruits, etc., have long been used.
Today activated carbon (treated in a special way) is the most common and sufficiently effective sorbent for purifying water from chlorine, malodorous and toxic macromolecular substances of natural and industrial origin. The main characteristic of activated carbon is the surface area, in simple words, this is the internal area of all available pores of the adsorbent, which can be occupied by particles of contaminants.
Also, due to the high active surface, coals can serve as a carrier of catalysts (accelerators) for the oxidation of water impurities such as hydrogen sulfide. There are several types of filters based on activated carbon, namely charge filters, cartridge filters made of granular or compressed material.