In the spring, when the groundwater level rises strongly, the snow melts and it rains, one problem appears in suburban areas. Wells, from which water is taken for domestic needs, are filled with dirty water almost to the neck. In this case, a strong silting of the bottom occurs. The owner of the hydraulic structure will have to clean it.
How to clean a well
The easiest way, which has been used for a long time: take a bucket, tie a rope to it and begin to scoop out the liquid until the well is completely free. After that, the bottom is cleaned with shovels - dirt is removed, which is loaded into the same buckets and raised to the surface. This process is laborious and takes a lot of time.
It is easier to pump out water from a well in early spring; for this, pumps (manual and electric) or motor pumps are used. But those units that are called "drainage" are suitable. This type of pumping equipment is specially made for pumping contaminated liquid.
Drainage pump selection criteria
Drainage pumping units are divided into two broad categories: surface and submersible. The first are devices that are placed on the surface near wells. A hose or pipe is lowered into the hydraulic structure itself, through which the dirty water will be pumped out.
The second are devices that are immersed in the liquid in the well. They are lowered almost to the very bottom (50 cm short). It is necessary to choose from the two proposed models taking into account the depth of the source. The former can pump water from a depth of up to 8 m, the latter can be lowered to 20 m. Submersible models are attached to the head of the well with a steel cable or polymer rope.
The second selection criterion is the operating conditions of the pumping unit, or rather, the degree of water pollution. This refers to the size of the impurities and in what quantity are present in the well fluid. This parameter must be indicated in the product passport.
- 10-20 mm - drainage pump for pumping water from a well of medium pollution.
- 20-35 mm - for highly polluted water, where there are impurities in the form of pebbles, various types of debris.
- З5-50 mm - for pumping out water in which there are stones, branches, household waste, etc.
If the contamination exceeds 50 mm, a fecal pump must be used to pump water out of the well, in the design of which a grinder in the form of steel knives is installed. The latter simply grind large impurities (even stones), turning them into a fine fraction.
The dimensions of the impurities are determined by the dimensions of a stainless steel mesh, which is installed on the suction pipe of the pump unit. It acts as a retaining element for debris.
The third criterion is the technical and operational characteristics of the drainage pump - capacity and head. The first indicator characterizes how much liquid the pump can pump over per unit of time. Usually this parameter is indicated either l / min, or m³ / hour. This is not the most important criterion if the task is to pump water out of the well. You can also use a low-power unit, it just takes more time to pump out.
It is imperative to pay attention to the pressure. First, everything will depend on the depth at which the bottom of the hydraulic structure is located.Secondly, at what distance it will be necessary to pump out the contaminated water. The more these two linear indicators are, the more the head of the pumping unit should be. For example, if the head according to the passport is 30 m, then it will be enough to pump out liquid from a depth of 20 m and pump it further to a distance of 100 m. Horizontal movement requires 10 times less head.
Water pumping technology
Knowing the depth of the hydraulic structure, it is necessary to select the required length of the cable for the submerged modification or the hose (pipe) for the surface modification. With the submersible option, do the following:
- a cable, hose and cable are attached to the pump, the latter two are connected to each other with plastic clamps every 1-2 m;
- lower the device into the well to the required depth;
- tie the free end of the cable to the head or any other fastener;
- the hose is laid to the place of disposal (usually a ditch, ravine, river or pond outside the suburban area), it can be drained into the garden;
- include a pump for pumping out.
In order to maximally clear the source from debris and silt at the bottom, it is necessary to pick up a long pole and stir up the sludge layer at the bottom.
Installation of a surface pump is easier. It is installed near the well, a hose with a length equal to the depth of the structure is connected to its suction nozzle, and a hose or pipe with a length equal to the distance to the disposal site to the outlet nozzle. Then turn on the pump to the outlet.
If the well is very dirty, it is better to use two pumps at once to clean it. One will pump clean water from some reservoir. For example, from a barrel next to it. This will erode bottom sediments and dilute contaminants with water. The second will simply pump out the water. It is better to use a surface drainage pump as the first device, and a submersible pump as the second.
This pumping and cleaning option is not economically viable. Too much electricity will be wasted. It's easier to hire workers who will lift up all the dirty water with buckets and clean the bottom. But if there are none, two pumps will be the best option. In addition, all this can be done by hand.
When pumping water out of the well is not recommended
Different situations need to be considered. As practice shows, they often face two problems:
- The well, which was recently dug, did not have time to be covered with a roof or a canopy, or to arrange a head. The passing downpour filled the structure with water, mixing it with mud. In this case, it is not worth pumping out, because the fragile walls of the structure, saturated with water, will collapse (partially or completely). It is recommended to wait until the walls of the well have completely shrunk.
- Water must not be pumped out while the snow is actively melting. The liquefied soil presses on the bottom from below, raising the water level. The latter, in turn, presses on the ground, preventing it from rising. If the liquid is pumped out at this time, the bottom will quickly rise, raising its level inside the well. On the one hand, this is not bad, but in this way you can lose access to the aquifer. We'll have to deepen the bottom, choosing the layer that has risen. And these are additional, rather serious financial expenses.
It is necessary to determine the exact time for pumping and cleaning. It is best to do this in summer, when the water level inside the well is at its lowest. There is not much liquid in the structure, it can be easily and quickly pumped out. The process will take a little time.
