- Requirements for water quality. Types of pollution
- Hardness of water
- Increased acidity
- Increased content of dissolved iron
- Iron bacteria in water
- Manganese contamination
- Hydrogen sulfide in water
- Water treatment stages
- The composition of the water treatment system
- Installation rules
- System maintenance
Autonomous water supply from a well or well should include the necessary equipment and routing. How to choose, install and maintain a water treatment system for drinking and household needs of a private household, we will talk in this article.
The water treatment system is an important part of the water supply of a country house. Depending on the composition of the water and the available impurities, it is necessary to use various cleaning and preparation devices, choose the right equipment and regularly monitor the correctness of their operation..
Requirements for water quality. Types of pollution
When receiving water from underground sources, which are wells and wells, hygiene standards distinguish the following categories according to GOST 2761-84:
Index Water quality indicator of underground water supply source 1st class 2nd grade 3rd grade Turbidity, mg / l, no more 1.5 1.5 ten Color, degrees, no more 20 20 50 Hydrogen exponent 6-9 6-9 6-9 Iron (Fe), mg / l, no more 0.3 ten 20 Manganese (Mn), mg / l, no more 0.1 1 2 Hydrogen sulfide (H2S), mg / l, no more Lack of 3 ten Fluorine (F), mg / l, no more 1.5-07 1.5-0.7 five Permanganate oxidation, no more 2 five 15 The number of bacteria of the group of E. coli (BGKP) in l, no more 3 one hundred 1000 Water treatment methods Not processed Aeration, filtration, disinfection Aeration, filtration with preliminary settling, reagent disinfection
According to SanPiN 126.96.36.1994-01, for safe consumption, it is necessary to control the quality of drinking water throughout the year, according to the given schedule.
Types of indicators Number of samples within one year, not less For underground sources For surface sources Microbiological 4 (according to seasons of the year) 12 (monthly) Parasitological Not held – Organoleptic 4 (according to seasons of the year) 12 (monthly) Generalized indicators – – Inorganic and organic substances 1 4 (according to seasons of the year) Radiological 1 1
Analysis of the water will provide accurate data for the inclusions that the water treatment system should help eliminate. But even without analysis, you can organoleptically judge the quality of water, and what filters and devices you need:
- brown water: manganese in a dissolved state;
- muddy water: excess of minerals, organics;
- the water is reddish: iron ions;
- the water smells like rotten eggs: dissolved hydrogen sulfide.
However, water analysis should be ordered to determine the content of substances that can significantly degrade water quality:
- calcium and magnesium salts create hardness;
- carbon and sulfur dioxide increase acidity;
- dissolved nitrates negatively affect health.
Hardness of water
Indirect signs by which you can judge the hardness of water:
- poor foaming and increased consumption of detergents;
- visible plaque when water settles;
- deposits in hot water pipes.
Hardness levels are defined differently in different countries and by different standards. For comparison, we present the parameters adopted in Russia and Germany:
Water hardness, mg-eq / l Hardness in terms of German degrees of hardness, ° dH Russia Germany 0-1.6 0-4.5 Soft Soft 1.6-2.4 4.5-6.7 Medium hardness 2.4-3.0 6.7-8.4 Moderately hard 3.0-3.6 8.4-10.0 3.6-4.0 10.0-11.2 Hard 4.0-6.0 11.2-16.8 Medium hardness 6.0-8.0 16.8-22.4 Very hard 8.0-9.0 22.4-25.2 Hard 9.0-12.0 25.2-33.6 Over 12.0 Over 33.6 Very hard
With medium hardness, softening of water for the operation of washing machines, dishwashers, boilers can be performed using neutralizing chemicals. Higher hardness forces the use of ion exchange units and reverse osmosis filters.
Increased acidity is observed in water, which is taken from a shallow depth and is explained by insufficient soil filtration of contaminated atmospheric precipitation, ingestion of organic decay products from nearby wetlands, and high soil acidity. Such water negatively affects the condition of human teeth, increases corrosion processes in plumbing equipment and utensils for cooking..
How to find out without analysis that the acidity of water is increased:
- steel products corrode faster in contact with water;
- the seams between the tiles in the bathroom are painted;
- red (steel corrosion) or green spots (copper alloy products corrosion) appear in the sink and toilet;
- the iron removal system is ineffective.
You can check the acidity with tests with reagents sold in aquarist stores or with a portable acidity analyzer. The latter is more accurate, but costs about 10 times more..
The easiest way to reduce acidity is to pass the flow through a container with a fine limestone packing, which must be replaced periodically. Limestone neutralizes acidity. To protect the metal equipment of the well, soda ash is used as an acidity regulator, the solution of which is dosed into the well shaft. But dosage errors can cause even more harm, so it is not recommended to do this on your own..
Increased content of dissolved iron
The increased iron content of water is manifested when washing with a reddish-yellowish color of linen, rust spots on the sink and toilet bowl, and a specific taste. To correctly accept the cleaning method, you need to know the number of ppm accurately, and for this you can order an analysis or use a special kit (it will cost much more, it makes sense for multiple analyzes).
If the analysis shows 0.3–1.5 ppm, it is enough to block the access of oxygen to the well by sealing the head, do not use a pressure tank with access to air (replace with a membrane one), and for greater purification include a polyphosphate filter-dispenser or an ion exchange unit in the water treatment.
If the iron content in the water exceeds 1.5 ppm, it is, on the contrary, subjected to aeration so that the ferrous dissolved iron passes into the solid phase – the trivalent salt – and precipitates in the form of flakes. For this, the water treatment system is equipped with an aerator and a filter tank, where the speed of the water decreases sharply and iron precipitates.
Iron bacteria in water
If the grids and filters are constantly clogged with silty rust, then the aquifer is saturated with iron bacteria – bacteria that oxidize ferrous iron to ferric. Aquifer contamination can occur when using contaminated drilling equipment. High-quality deferrization of water is impossible without sanitation of the source, which is carried out by chlorination right in the well (shock chlorination). To do this, the chlorine content is brought to 25 ppm, after which the water with dead bacteria must be pumped out (passing through filters, settling and pouring out) until the chlorine content reaches 0.5 ppm. It is better to order this work from a specialized company..
Contamination of a surface or underground source with iron bacteria is a very serious problem requiring urgent action and solutions.
If there is an increased content of manganese in the water in the well, health problems are possible: disruption of the nervous system, liver function, and respiratory organs. Urolithiasis, hormonal problems, allergic reactions, weakening of memory, tone may occur. After washing, clothes take on a brownish tint, plumbing fixtures cover brown spots, scale in the teapot can turn black or dark brown. Drinking water should not contain more than 0.1 mg / l manganese.
Manganese removal from water is carried out in the same way as iron removal.
Hydrogen sulfide in water
It is impossible not to detect the presence of hydrogen sulfide by its characteristic smell. Food cooked in this water acquires the same smell, pipes corrode rapidly. This compound is toxic and can harm humans and animals. The presence of hydrogen sulfide can be due to the vital activity of sulfuric or sulfate-reduced bacteria or contamination of the source with decaying organic matter.
Hydrogen sulfide has a pungent odor and is completely colorless. Its presence in tap water causes a lot of trouble.
As in the case of iron bacteria, one of the methods of control is the chlorination of the well; the method that we recommended for removing iron when its content is more than 1.5 ppm can also help. Aeration helps a lot. The best results will be obtained by membrane devices, in particular – reverse osmosis.
Water treatment stages
In order to choose the right set of filtering, disinfecting, purification devices in the water treatment system, it is necessary to determine the content of harmful impurities in the water from the well.
As a rule, in addition to shock downhole chlorination or acidity reduction with soda ash directly in the well, the first stage of cleaning is getting rid of mechanical impurities – clarification. For this, one or more coarse filters are installed. Filters are bottom, borehole and surface filters, they have a different design and retain a different fraction of solid particles. Their choice depends on the degree of water pollution.
Then they put a washing sump, one- and two-stage purification from iron, manganese, hydrogen sulphide, water softener. This is achieved by a cascade of filters and installations, adopted depending on the content of substances and financial capabilities: tank equipment (with or without reagents), ion exchange installations (good for softening), reverse osmosis (pure H2ABOUT). If there are harmful microorganisms in the water, a UV disinfection device is installed on the water supply.
Further, if necessary, you can put a fine filter – on the entire line or only on taps with drinking water. As a result, all stages of water treatment are combined into a single complex.
Water treatment. 1. Coarse filter 100 microns. 2. Aerator. 3. Iron removal filter. 4. Softener filter. 5. Recovery tank with salt concentrate. 6. Fine filter. 7. UV sterilizer. 8. Compressor of the aerator. 9. Bypass
The composition of the water treatment system
Focusing on the analysis of water from a well, you can select ready-made solutions aimed at eliminating this or that pollution.
With normal acidity and the absence of hydrogen sulfide, iron and manganese, to improve transparency, taste and reduce water hardness, the water treatment complex can include sequentially located filters: mechanical, softening with an automatic valve and with a carbon cartridge.
Water treatment. 1. Coarse filter 100 microns. 2. Softener filter. 3. Fine filter. 4. Recovery tank with salt concentrate
If the water contains hydrogen sulfide, iron and manganese in concentrations above the MPC, water treatment includes aeration and deferrization.
- coarse filter;
- aeration column;
- iron removal filter;
- carbon cartridge filter.
Water treatment. 1. Coarse filter 100 microns. 2. Aerator. 3. Softener filter. 4. Regeneration tank with salt concentrate. 5. Fine filter. 6. UV sterilizer. 7. Aerator compressor
If softening and removal of iron, manganese, hydrogen sulfide is required, the complex includes aeration, deferrization, softening and fine cleaning filters.
Water treatment equipment, except for the downhole filter for sand removal, is installed on the surface after the pumping equipment, in a caisson or in a house. When choosing a pump, it is necessary to take into account the number of cleaning stages and their hydraulic resistance. A fine filter can be installed in the kitchen, for example, under the sink. Sometimes a separate tap is organized for drinking water – so the filter will last longer.
The diameter of the pipes for distribution is taken based on the maximum water consumption. In this case, the speed of water in the pipe should not exceed 1.5–2 m / s, in rare cases with a high-pressure pumping station – up to 3 m / s, if required for a hot water or heating boiler. If the pipes do not carry an aesthetic load, it is advisable to take lightweight HDPE pipes that are not prone to corrosion..
System maintenance consists in water quality control, filter cleaning, and system pressure control – as an indicator of the cleanliness of filter elements and cartridges.
If the water pressure drops, the coarse filters are most likely clogged. They need to be cleaned and, if necessary, replaced. If a leak is found, it is necessary to replace the damaged pipe section and seal the system.
If the analysis shows increased hardness, then you need to clean the water softeners..
Reagent-free softeners periodically require flushing or replacement of the nozzle, while reagent softeners, in addition, require replenishing the reagent in the regeneration tank. Magnetic softeners need to be cleaned and flushed from time to time to remove iron deposits.
In ion exchange units, the resin must be changed periodically.
Practical advice and guidance on refilling the iron remover and softener is provided in the helpful video. We recommend that you watch it.