Installation of a pumping station at the entrance: solution of interruptions in water supply

Recommendation points

• Legal status and preparation of the pumping room
• Booster complex equipment
• Solving the problem of hourly water supply
• Optional: filtration, automation, noise isolation
• The question of a construction contract
• Ladder logic

Sadly, the problem of hourly water supply may be relevant in the 21st century. In small settlements, the stations of the second rise of water often fail, which causes consumers to suffer. However, there is a whole arsenal of tools that help deliver water to the right floor at any time in the right amount..

A pumping and filtering station (NFS) is a complex of equipment that includes a group of pressure boosting pumps (booster), a storage tank, a filtering unit and a reserve source of water. Also, the FTS includes a diagram of electrical connections and devices that provide continuous and fully automatic operation. Ideally, in practice, the layout of the complex may vary, depending on the needs of consumers..

Legal status and preparation of the pumping room

According to current legislation, technical basements are in the common shared use of residents. Such objects include basements, in which there are risers of water supply, heating and sewerage, communication inputs and metering devices.

Execution of all the necessary documentation is the prerogative of the instance that owns real estate, in particular – housing and communal services or the owner of the house. The participation of the average person in resolving these issues is minimized; all bureaucratic frictions are taken over by the consumer relations department. In other words, it is enough for a person authorized by the tenants’ cooperative to contact the reception with the appropriate requirement.

For the needs of the pumping station, a place of the required area will be allocated in the technical underground, which must be properly prepared:

1. Enclose with a lattice fence, excluding the possibility of unauthorized access. As an option – rectangular sections made of professional pipes, tightened with a netting and rigidly attached to the concrete floor and ceiling.
2. Restore the floor in proper condition, fill in a cement screed if necessary.
3. Whitewash or paint the walls and ceiling.
4. Install a door with a padlock, distribute the keys to the communications and supervision services.

Booster complex equipment

The basis of the LFS is a booster that provides a consistently high water pressure in the system. There are two basic versions of the booster system: a turnkey solution and an individual layout..

Complete pumping station	Individual assembly
Quick and easy to install	Exactly meets the design parameters
Easy to maintain	The total cost is less than the turnkey solution
Replacement parts only from the manufacturer	Difficult to design and implement

When combining pumps into a common network, a number of rules must be observed:

1. Pumps must have the same performance and pressure.
2. The connecting intake manifold must have a larger cross-section of pipes to normalize hydraulic losses.
3. The pumps should be installed as close as possible to each other and to the point of connection to the house riser.
4. Avoid a lot of bends in pipes and connections before entering the mains.

The operating mode of the supplied object can be different and, depending on it, the most acceptable method of water intake from the supply network is selected. The intake can be carried out directly, there is also the option of including a damper tank in the system. It is filled with water from the system by gravity and feeds the pump. The advantages of such a system:

• constant booster power;
• there is no need to take into account pressure fluctuations in the supply network;
• the container serves as a source of water during the absence of supply;
• no dry running protection required.

The accumulator also eliminates the very specific problem where, due to the pressure drop in the supply line, the pumps create a vacuum, which causes overlaps to fly off the pipe walls, which degrades the water quality. The main drawback of the fence through the container is the bulkiness of the complex. In general, this option is more than justified if the price of the container is comparable to the cost of the second pump..

Solving the problem of hourly water supply

The storage capacity plays a very important role in the hourly operation of the supply network, which is observed on the periphery of large cities or in small settlements. The calculation of the volume of the tank is done simply – this is the maximum total water consumption at all outlet points at the time of the availability of water supply from the city network. The value must be recalculated based on the time when there is no feed.

For example, tenants of a three-story building consume 0.8 m per day³. For the whole house, this indicator must be multiplied by the number of apartments: 0.8 x 27 = 21.6 m³. It turns out that in the absence of water supply (residents, while maintaining the rate of consumption, spend 22 m³ water) just such a volume needs a container. Of course, the consumption schedule at night differs from the daytime one, but having such a reserve, the building will remain completely autonomous even in the event of an accident in the city water supply system, and at the time of chlorination, residents will continue to use “safe” water.

A container of this size cannot be placed in the basement, so it will have to be dug into the ground next to the house or several smaller containers installed. Capron tanks for burial into the ground have a volume of up to 10 m³, their cost ranges from 6 to 15 thousand rubles. per thousand liters. You can make a sheet metal container on site. It will be cheaper, but the water quality will be worse.

The installation of the tank can be replaced by drilling a well. In terms of cost, both events are almost equivalent. In implementation, the well is somewhat simpler, but a number of difficulties may arise:

1. Approval for drilling a well near a multi-storey building.
2. The well will not supply water without electricity.
3. Complicated recalculation of payments for city water and sewage.

When taking water from a well, you can completely abandon the city water supply: this is rational, and the quality of well water cannot be compared with the central water supply. But it is more difficult to refuse from city sewage services, therefore, payment for sewage will still be recorded according to installed water meters.

Optional: filtration, automation, noise isolation

If it is necessary to improve the quality of drinking water, it is reasonable to supply the pumping unit with filtering devices. This will have a positive effect not only on the health of residents, but also on the durability of washing and dishwashing equipment..

Urban waste water treatment plants produce water of acceptable quality at the outlet, its pollution occurs already in the water supply system, where the water is saturated with particles of rust and salt deposits, bacteriological pollution can occur. For complete cleaning, the filter station must have three stages of cleaning:

• mechanical cleaning (cartridge filters, reverse osmosis);
• sorption filter (carbon or reverse osmosis);
• disinfection (ultraviolet light, ozonation).

Keep in mind that the installation of LFS can cause a number of minor troubles: from breakdowns and the need for regular maintenance, to an increase in noise levels in apartments on the first floor.

The last problem is solved by pasting the pumping room with sound-absorbing materials. The way out in solving the issue of the autonomy of the installation and its uninterrupted operation will be the acquisition and installation of a reliable imported instrumentation and automation complex for pumping stations. Installation of frequency converters for modulating pressure control will extend the service life of the equipment and, as an additional plus, will significantly reduce energy consumption.

The question of a construction contract

Design and installation can be entrusted to contractors, in this case the degree of participation of the residents of the cooperative will remain minimal, but the budget will grow by 30-60%. If you have basic manual skills and a careful study of the issue, you can do it yourself.

For clarity, we can consider a case of medium complexity. Entrance to a nine-storey building, each floor has four apartments. During peak hours, the pressure drops so much that the water does not rise above the fifth floor. Having handed over the water for analysis at the SES, the residents received an answer about the increased content of iron oxides, chlorates, and the mass fraction of dissolved dry particles was more than 1500 mg / l. In addition, on weekdays, the water supply is periodically lost. Residents sent a letter to the Ministry of Natural Resources, it was reviewed and approved, a package of accompanying documents and approvals for drilling a well was collected.

The calculation of the average daily water consumption was carried out by taking meter readings in each of the apartments. It ranged from 0.5 to 1.2 m³ per apartment and 32 m³ daily consumption for the whole house.

The well drilling contractor performed the calculation. Based on it, the design debit was 2 m³ per hour at a well depth of 118 m, the diameters of the production pipe and casing string are 110 and 133 mm, respectively. The NOCCHI SCM 4 Plus submersible pump with a capacity of 3 m was taken into operation³/ hour for 47 thousand rubles. A 32 mm polyethylene pipe (30 rubles / m) and a copper cable VVG 2×2.5 (24 rubles / m), both 160 m long, were laid from it into the basement of the house. The total cost of the well was:

• 118 x 1500 + 47000 + 160 x (30 + 24) = 232 640 rubles.

A tank with a volume of 6 m is installed in the basement³ (10,000 rubles), which receives water from the city network under natural pressure, the pipe is closed by an electric valve Tork 1 1/4 “(3,000 rubles). The water level sensor ERSU-3M (3,000 rubles) is installed in the tank. from the tank has a diameter of 40 mm.Together with the pipe from the borehole pump, it is connected to a common collector from a pipe of 50 mm.On the other hand, two Pedrollo PK-65 centrifugal pumps (2 x 8000 rubles) are fed from the collector, which are included in the outlet with four outputs to a 25 mm plastic pipe for supplying apartment risers.Installed three NOCCHI PT 6 pressure switches (3 x 1300 rubles): two on the outlet manifold and one on the city water supply pipe.

For maintenance and repair, 32 mm ball valves were installed on pumps, riser inlets, city pipe and at the point where the borehole pump is connected to the collector, 10 pcs. (10 x 300 rubles). Also, the system uses six brass check valves (6 x 750 rubles), which are installed on risers, a city pipe and a pipe of a well pump.

1 – borehole pump NOCCHI SCM 4 Plus; 2 – well caisson; 3 – check valve; 4 – inlet manifold; 5 – ball valve; 6 – electric valve Tork 1 1/4 “; 7 – pressure switch NOCCHI PT 6; 8 – centrifugal pump Pedrollo PK-65; 9 – storage tank; 10 – water level sensor ERSU-3M; 11 – outlet collector; 12 – apartment risers

The electrical part of the installation includes:

1. Two IEK KMI-10960 starters in an IP54 case (2 х 1600 rubles).
2. MKI-10610 starter (450 rubles).
3. Relay group REK77 (1400 rubles).
4. Metal box IP54 (2000 rubles).

Ladder logic

Normal condition: admissible pressure in the city network, tank full, maximum pressure at the outlet manifold. The manifold pressure drops, the first pressure switch activates and the first pump turns on.

If the pressure falls below the threshold for the first pump, the second relay is activated and the second pump is turned on. The liquid level in the tank falls, the solenoid valve on the city pipe opens. If there is no pressure in the city network, activation of the valve is blocked through the intermediate relay, but the borehole pump is started, which supplies water to the inlet manifold.

The total project budget is about 280 thousand rubles, excluding the cost of installing the Federal Tax Service and laying a pipe into the basement of the building. The equity participation of one apartment in the project will be up to 8,000 rubles, which is quite a lifting amount, especially considering the prospect of a complete rejection of tap water, using the natural resources of the well.