More often, for the arrangement of autonomous water supply on the site, they mount their own source - a well or a well. Their depth varies from 15 to 25 meters (per sand layer). The flow rate of such hydraulic structures is relatively constant. But sometimes it happens that water comes from wells with fine sand. This indicates a source problem. They need to be eliminated, otherwise in the future the mine will become completely silted up and become unproductive.
Causes of sand in well water
Experienced specialists identify several reasons for the appearance of sand in the water from the well. Each of them has its own location relative to the length of the casing.
Filter mesh issues
When installing the casing pipe, its lower segment must be perforated and fitted with a special fine mesh. It serves as a filter. Here the following malfunctions may occur:
- Grid break when installing the bottom of the column. In this case, sand will appear in the water almost immediately after the buildup of the well. Its volumes will gradually increase in direct proportion to the flow rate of the source. Signs of a rupture of the filter mesh are particles of sand in water of different sizes - from the smallest to almost pebbles.
- Incorrectly selected mesh cells. If they are too large, and the grains of sand have a very small caliber, they will freely penetrate into the casing space and mix with the supplied water.
If there are problems with the filter, two options for changing the well performance are possible:
- Too small particles of sand pass through large filter cells into the source shaft and settle to its bottom. Gradually increasing its layers, such a layer will completely fill the lower part of the sump and completely cover the filtering area. The master will note a gradual, and then a complete decrease in the productivity of the hydraulic structure.
- At a high aquifer, water will continue to ooze into the mine even with sand, but the owner of the source will detect large volumes of extraneous impurities in the liquid.
Due to heavily polluted water, the working units of pumping equipment, automation, and pipeline elements can fail. Therefore, do not let such a problem drift.
Casing leak
This happens more often for the following reasons:
- Corrosion of the metal under the condition of incomplete make-up of pipe sections. If there are open areas of the thread when the two elements are improperly joined, under the constant influence of water they rust and give a fistula. From this, the well can sand in any part of the pipe. On average, properly screwed columns last up to 50 years.
- Incorrect, incomplete welding of joints. Here, over time, holes also appear through which groundwater and sand ooze into the source. Such phenomena are also bad in that not quite pure water resources (mixed with nitrates, acids, atmospheric precipitation, absorbed into the soil) are mixed with particles of earth in the casing string. The average service life of welded columns is 20 years.
- Displacement of the casing relative to the limestone formation at artesian sources. This occurs in violation of the technology of drilling and installation of the column. Only experienced professionals should drill and equip such deep hydraulic structures.
When the pipe is depressurized, it will be necessary to carry out complex repair work that is best trusted by professionals.But if the casing has shifted about its axis in one of its sections, in most cases it will not be possible to save such a shaft.
Gravel Backfill Problems
If previously the dummy brewing of its bottom was considered to be the correct technology for installing the casing, today instead of this the lower part of the pipe is covered with a layer of different-gravel gravel. Then the following may happen:
- The filter mesh first fully performs its function.
- Later, its colmatage occurs (dense filling of cells with grains of sand of various calibers). The filter is just clogged.
- Since water needs to find the entrance to the casing string, it begins to wash gravel backfill with its pressure, swells it up and opens up grit of different calibres to the string.
Another cause of gravel backfill problems is an overly powerful pump, located very close to the bottom. Such equipment draws in not only water, but also overcomes the resistance of gravel stones, gradually raising them. As a result, over time, sand opens up from the bottom of the mine. The layer can reach a level of several tens of centimeters, which will reduce the productivity of the well and lead to the appearance of dirty water.
Is it possible to use liquid with sand
Theoretically, such water is allowed to be used for economic purposes - watering garden gardens, washing a car, etc., but only after its high-quality mechanical cleaning. However, it is worth remembering that the complete disposal of liquid from sand is the high cost of installing filtration systems, the need to use a drainage pump for pumping and lifting dirty water. Such costs can be considered inappropriate. It is better to completely get rid of sand in the well by taking appropriate measures.
Effective Cleaning Methods
The easiest way to deal with a silty bottom is to use a bailer: cut a steel pipe with teeth on one side and special sashes in the same place. The principle of its work is that when it falls freely from a height of 0.6-0.8 meters, it crashes with its weight into a layer of sand deposits. At this point, the flap openings, and the sludge enters the cavity of the pipe. When it rises, the blades close, preventing the return of dirt into the casing space.
As soon as the volumes of sludge to be raised are very low, a stream of water should be applied to the bottom of the shaft under high pressure. This will help wash away dirt in the filter area. Dirty liquid is pumped out with a powerful pump until a clean water resource appears.
Wells up to 15 meters deep can be cleaned with the help of a chute. With its greater length, the master will no longer cope with the problem.
Mechanical flushing
Here you need to use two pumps - one powerful for supplying pressurized water to the siltation zone, the second drainage pump for pumping dirty liquid up. Both units must work simultaneously.
The supply hose is equipped with a special load so that it does not rise upward under the pressure of the incoming water. It is lowered by about 20-25 cm from the sludge layer. A sampling hose is located a little higher (30-40 cm from the bottom). Turn on both pumps and start work. The incoming liquid will break down the sludge, and the drainage pump will pump them up.
Under dirty water, it is advisable to prepare a special barrel or other tank. A bucket without a bottom is fastened to its upper edge; it is covered by a fine-mesh net from below. Water will pass through such a home-made coarse filter and be cleaned of sand grains.
Periodically, the drain pump must be turned off and flushed away from accumulated dirt.
Use of special equipment
If a well drives sand, a special technique may come to the rescue - a fire truck. Equipment rental will cost a pretty penny. But the work can be done in half an hour.
The principle of operation is that the operator delivers large volumes of water into the well through a fire hose, and with its help pumps out liquid contaminated with sludge.
Preventative measures
So that the well does not give sand over time and does not cause trouble to its owner, it is important to take a number of preventive measures.
- Fully swing (rinse) the source after drilling it. It is important to do this until the water goes completely clean.
- Correctly calculate the fraction of the cells of the filter mesh according to the size of grains of sand. This can be done by experienced professionals.
- Monitor the strength and reliability of all casing joints during installation.
- Use the pump that according to the technical characteristics corresponds to the performance of the source. Too powerful a unit will either deplete the well or drive sand.
- Regularly operate the hydraulic structure (even in winter). Seasonal downtime leads to siltation of the filter. If it is impossible to avoid seasonal operation of the well, it is advisable to come to the site once a month and pump out at least 100-150 liters of water.
A problem is always easier to prevent than to solve it later.
