Cleaning and disinfection of water

The main objective of water treatment - exemption from suspension particles to improve the physical properties (transparency, color and others). In practice, this is achieved by defending and coagulation.
When you are simply defending delayed mainly large particles, and small colloidal not deposited. The process of settling water lasts 4-8 hours or more. To accelerate the process of sedimentation of suspended solids and increase its effectiveness is coagulation of water.
For this purpose in the water add a chemical reagent - coagulant, often aluminium sulphate, which is in the water reacts with bicarbonate salts of calcium and magnesium, resulting in the hydroxide of aluminum, which falls in the form of flakes. Tiny particles suspended stick to the surface flakes coagulant and settle.
Coagulation significantly speeds up the settling of suspended particles, but a number of small particles still remains. So after settling and coagulation further purification of water - filtration. The filtering process consists of passing water through finely porous material (sand).
There are slow and fast filters. Currently used high-rate trickling filters. Filtering rate reaches 5-7 m/H. these filters water goes through the filter layer (quartz river sand and supporting gravel layer laid on perforated bottom. Filtered water enters podarennoe space and then the pipe in the reservoir with clear water.
In decentralized water sedimentation, coagulation and filtration of water can be produced in barrels or other tanks. As filtering materials used powdered charcoal or river sand.
The use of different methods of purification allows to get water, released from suspended particles, however, such water is not completely free from microorganisms. Therefore, additional treatment is disinfection. This is most often used chlorination, irradiation with ultraviolet rays and boiling. Chlorination of water to produce gaseous chlorine and chlorine solution.
Gaseous chlorine use in large water treatment plant, where chlorine is stored in cylinders under pressure 6-7 at. At smaller stations and in decentralized water for disinfecting solution using bleach. Fresh bleach contains 28-38% active chlorine. Bleach - matter is unstable and collapses. It should be stored in sealed barrels in a cool, dry and dark place.
The effectiveness of water disinfecting bleach depends on several conditions:
1) careful release of water from turbidity and suspended solids;
2) introduction of a sufficient amount (dosage) of chlorine;
3) thorough rapid mixing;
3 Hygiene with the basics of health
4) sufficient exposure of the water with chlorine (30 min to 2 h);
5) check the quality of chlorination.
At chlorination coming into the water, hydrolyzed chlorine, and products of hydrolysis exert a bactericidal effect on the microbial cell. To be sure that the microbes were exposed chlorine, you must enter it in quantities exceeding harpagoxenus water (the difference between the amount of added chlorine and left after a certain exposure). The chlorine dose is sufficient if after disinfection of water in it remained 0,3-0,5 mg/l of the so-called residual chlorine. In such quantities of residual chlorine does not affect the organoleptic properties of water and harmless to the body.
Studies have shown that chlorine bactericidal activity is most pronounced within the first 30 minutes (depends on the dose and temperature). In winter time the contact is prolonged up to 2 h quality Control chlorination is carried out by determining the residual chlorine in the water and bacteriological analysis.
Depending on the magnitude of the applied dose distinguish regular chlorination considering the magnitude of harpagoside water and pereplanirovana, when the water is treated with high doses of chlorine. The last method is used at chlorination of water suspicious sanitary condition. The excess of residual chlorine in this case, connect a hyposulphite. Excess chlorine is removed (dechlorination) by filtering water through activated carbon. Further to determine the dose of chlorine necessary for the chlorination of the water of the well, determine the volume of water. To find out the amount of water in the well, with the help of a rope with a weight at the end determine the height of the water column, and then - sectional area of the framework. Multiplying the height of the water column (in metres) in the well-sectional area (in square metres), will learn the volume of water in the well (in cubic metres). The chlorine dose of 1 m3 of water obtained is multiplied by the volume.
To determine the chlorine dose for chlorination of conduct trial chlorination (three glasses). Can the dose of chlorine to choose approximately: for transparent water - 6 - 8 g on 1 m3, for muddy - 10-12 g on 1 m3 (the content of chlorine bleach should not be less than 25-27%). After the establishment of the necessary quantity of chlorinated lime begin to chlorination of water in the well.
Pre-prepared bleach solution (1% or 3-5%) poured into the well, carefully mix the water sixth and leave for 1-2 hours After 2 h water should have a faint smell of chlorine; if the smell of chlorine, you need to increase the dose. When there is strong smell of water dechlorinate.
Disinfection of individual stocks. For disinfection of individual supplies of water can be used by boiling, and the tablets of pantied, which include chloramine. One tablet of pantied contains 3 mg of active chlorine. If the water is clear, that in the container {700 ml) dissolved one tablet, and if the water is turbid, you should add 2 tablets. The duration of the contact 30 minutes.