Sewage pumping station (SPS): types, design, installation and maintenance

In situations where it is impossible to ensure the required slope of the sewer pipe, the gravity drainage scheme does not work.In these cases, a sewage pumping station is indispensable, ensuring unhindered outflow and recycling of waste.

There are two types of units: mini-stations and full-functional complexes for home maintenance. Let’s figure out which option is better to give preference to, what characteristics should be taken into account when choosing. In addition, we will describe step-by-step installation technology and operating rules for the sewer station.

Areas of application and purpose of CNS

A sewage pumping station (SPS) is an integral complex of hydraulic equipment, which is designed for pumping storm water, industrial and domestic wastewater when their gravity discharge is impossible.

Pumping stations can have an additional horizontal cavity to distribute sludge over a larger area, which allows for less sludge removal

CNS is used mainly in the following cases:

1. The geodetic level of the tanks and pipelines from which wastewater is discharged is located below the sewer or cesspool.
2. Lack of physical ability to organize straight-line gravity drainage or small sewer pipe slopethreatening its regular clogging.
3. The cesspool or central collector is located far from the source of wastewater.

Cottage villages, country houses, as well as industrial facilities located far outside the city and remote from the centralized sewer network are equipped with sewage pumping stations.

Classification of sewer stations

The sizes of domestic sewage pumping stations can be very different. They can fit directly behind the toilet and immediately pump wastewater from it in the required direction, or they can take the form of horizontal tanks with a volume of tens of cubic meters dug into the ground.

But it’s not just the size of the CNS that differs. Below are classifications of pumping stations for sewerage according to various parameters.

By installation type:

1. Vertical.
2. Horizontal.
3. With self-priming pumps.

The last type of pumping station involves the forced pumping of wastewater into the station body and its removal from it after treatment.

By type of location relative to the ground:

1. Recessed.
2. Ground.
3. Partially buried.

SPS tank with sensors, sewage pumps and shut-off valves can be located in the ground, and the automatic control system can be on the surface.

According to the equipment control scheme:

1. With manual control. Equipment modules are switched on and off as needed by maintenance personnel, who independently check the fullness of the sewer tank.
2. Remote. A tank condition monitoring system is used, the data of which is displayed on a remote control panel.
3. Automatic. Control is carried out automatically using sensors and relays located directly in the pumping station housing or next to it.

Manually controlled pumping stations are the cheapest, but require personal participation. They are used mainly in country houses and cottages with a small amount of water consumption.

According to the nature of sewerage:

1. For domestic wastewater. Designed for use under standard conditions.
2. For industrial purposes. Made from materials with increased resistance to chemically aggressive environments and thermal effects.
3. For storm networks. Equipped with additional cleaning systems.
4. For sludge water. They are most often used in industrial wastewater treatment plants. Equipped with additional devices for processing sediment.

When choosing a CNS model, it is better to focus not on the classification, but on the recommendations of specialists who will select the optimal system for a particular home.

Equipment selection rules

Next, the criteria will be analyzed, taking into account which it is necessary to select sewage pumping equipment for private use. Analysis of industrial installations is beyond the scope of this review.

The goal when purchasing a pumping station is to purchase equipment that is optimal in terms of power and other characteristics. There is no point in overpaying for systems that will operate at 10-20% of their designed capacity.

When choosing a CNS, the following parameters are taken into account:

1. Maximum flow of processed waste.
2. Transport distance.
3. The difference in geodetic levels between the inlet pipe and the outlet of the pressure hose.
4. Degree of pollution, fractional composition and structure of domestic wastewater. There are pumping stations that crush large fractions of inclusions, preventing blockages in pumping equipment.
5. Level of wastewater treatment required.
6. Equipment dimensions.

There is no single formula for calculating the performance of pumping equipment, therefore the calculation algorithm and the necessary indicators must be specified in the instructions for the purchased pumping station.

A typical project for calculating the performance of pumping equipment includes the following steps:

1. Determination of daily water consumption and wastewater volume.
2. Construction of an approximate schedule for the flow of sewage wastewater during the day.
3. Calculation of minimum and maximum sewer flow.
4. Determination of the required productivity of the pumping station, taking into account the contamination of wastewater.

After determining the above parameters, you can begin to select the appropriate equipment.

The price of a pumping station is influenced by the manufacturer’s brand, the maintainability of the product, and the possibility of service. It is especially not recommended to purchase cheap pumps if they are expected to be used daily, and there are no reserve tanks or an additional pump for drainage.

Design and principle of operation of the CNS

The design of modern pumping stations should be considered in two main versions:

• sololift;
• sewer station for home or cottage.

There are no fundamental differences between these devices.But sololifts are a single ready-made piece of equipment that you can buy on the Internet and connect yourself, and sewer stations are formed from separately sold parts for a specific external sewerage project.

Compact mini-stations

Portable pump stations of the Sololift type have a compact appearance and are installed near plumbing equipment. It is installed either in the basement of the house or in the bathroom itself.

Sololift ensures the removal of sewage as it enters the device body (+)

The main structural components of the sololift are:

• sealed housing with pipes and holes;
• engine;
• impeller with cutting edge;
• automation.

When water enters the device, the automation is triggered and the engine is turned on. As a result, liquid is pumped from the internal reservoir into the pressure pipe. The impeller additionally crushes large fragments to effectively remove suspended particles and prevent clogging.

When connecting a large number of sewer connections to a mini-sewage station using tees, it is necessary to take into account that the pump capacity may not be sufficient to pump the incoming liquid (+)

The sololift body may have 2-5 holes for connecting plumbing fixtures. There is an air valve on top of the device, which allows air to be drawn in from outside when the pump is running. This prevents breakdown water seal in siphons home equipment.

Performance portable mini-KNS is standard and theoretically calculated based on the number of supply pipes.After purchasing the equipment, it is enough to connect the pressure hose and sewer pipes to the solofit body, and then plug it into a power outlet.

KNS for a country house

A pumping station for a private home usually has impressive dimensions and is dug into the ground. It will not be possible to find ready-made design solutions of this type on the Internet, and to determine the approximate cost of the equipment, you need to call store managers or leave a request on the sellers’ websites.

Containers made of fiberglass and plastic are more durable. They do not require any maintenance and will last at least 50 years. The station is a sealed container with pumps inside.

The main elements of CNS for the home are:

1. Plastic storage tank, fiberglass, concrete or metal with a volume of several cubic meters.
2. Fecal pump. In daily operating stations, two pumps are installed: a working one and a reserve one, the task of which is to raise wastewater to a certain level for its further movement through the pipes by gravity.
3. Gravity water supply system (supply and pressure discharge), combining the internal sewerage system, water pumping station and subsequent collector. The system is equipped with valves and check valve, which allow fluid to flow in only one direction.
4. Automation with float switches. It is recommended to install 3-4 floats at the same time, each of which is capable of turning on a pump. They are inexpensive, so there is no need to skimp on them.

Large home pumping stations have an operating principle that is somewhat different from a sololift. The wastewater reservoir is buried in the ground and connected to the drain internal sewer pipe. When the level of sewage wastewater reaches the level set by regulation, the float mechanism closes the network and turns on the pump.

Pumping of water stops only when the float reaches a level much lower than the one that led to its activation. This scheme allows you to turn on pumping equipment less frequently, reducing operating loads.

Additional floats are designed to activate a backup pump. The water level for starting them is set slightly higher than for the main pump.

This allows you to play it safe and turn on backup equipment only in the event of a malfunction of the main one.

Additionally, the KNS can be equipped with the following devices:

• flow meter;
• lattice containers for filtering large debris;
• control and adjustment cabinets;
• ladder for descending into the container;
• vortex flow regulator;
• sorption filters.

The selection of a set of equipment should be carried out only under the supervision of specialists. This will allow you to select components with the most consistent characteristics and productivity.

Installation instructions for pump station

Installation of household pumping stations is carried out exclusively by qualified workers, due to the high requirements for the accuracy of work and compliance with the sequence of actions.

Failure to comply may result in damage to the tank or associated pipes. Next, we will consider step-by-step instructions for installing the CNS for people who want to do it themselves.

Step #1. The location for installation of the pumping station is being selected. SNiPs require digging a tank at least 20 m from the walls of a residential building. If geodetic levels allow, then it is advisable to choose a higher site so that a lot of groundwater does not accumulate under the station.

KNS should not be installed on the front side of the house, near children's playgrounds and near picnic areas

Step #2. A hole is dug taking into account the diameter of the container and the location for convenient installation work. If the soil is obtained by an excavator, then work must be stopped 20-30 cm above the design level. Next, the soil must be removed manually with a shovel to maintain the integrity of the soil.

When digging a hole for a sewer tank, you do not need to make it huge. A diameter 1.5-2 meters larger than the size of the container itself will be sufficient.

Step #3. The type of foundation for installing the water pumping station is selected and installed. To do this, after digging a hole, the soil water content is assessed. If the soil is dry, then you can make formwork and fill it with a 30-centimeter layer of concrete.

And if groundwater constantly seeps into the pit, then only a ready-made reinforced concrete slab with a thickness of at least 30 cm is suitable for the foundation.

The concrete base must be strictly horizontal, so when laying the finished concrete slab you need to take care of this in advance.

KNS containers have a skirt or legs for attaching to the foundation. Anchor bolts are used as fasteners, although when pouring concrete onto the ground, metal rods can also be built into the mixture, onto which the container can then be attached.

You should not skimp on the size of the anchor bolts. Their optimal length is 200 mm and diameter is 20 mm. And before laying in liquid concrete, metal rods must be bent with a hook or the letter G (+)

Step #4. The water pumping station tank is installed on the foundation, secured and connected to the drain pipe of the internal sewer system of the house. With a vertical type of station and a large amount of groundwater, it is necessary to load the container with concrete. To do this, concrete is poured around the tank 20 cm above the level of the first stiffener of the station.

It should be borne in mind that after pouring concrete it will be impossible to change the tank, so it is necessary to calculate its volume taking into account the expansion of the house and the increase in the number of its residents

Step #5. The station is backfilled with fine soil, the maximum grain size of which is 32 mm. Each layer of earth should be no more than 50 cm. After filling the next belt, it is filled with water for shrinkage and compacted.

This completes the external installation of the pump station. After being fixed in the ground, pumps, sensors, check valves and other auxiliary equipment are installed inside the station.

For safety reasons, it is recommended to close the hatches of sewer tanks with locks, because while playing, children can hide in them and lose consciousness

It would not be superfluous to install an emergency warning system in the house about the critical level of domestic wastewater in the tank, which will warn about malfunctions in the operation of the station.

Typical installation errors

Damage to tank walls, connections or associated pipes can occur if the tank is not installed correctly, tilted or backfilled incorrectly. Such problems threaten manual excavation of the container and considerable financial costs.

Therefore, you should sort out typical mistakes in advance so as not to repeat them when installing your own pump station.

1. Incorrect soil filling. Possible mistakes: filling with frozen soil or large stones, lack of layer-by-layer compaction. The consequence may be subsidence of the earth with damage or displacement of the internal pipeline.
2. Different type of backfill from different sides. If you poured sand into the pit on one side and earth on the other, then over time the container may become distorted, causing damage to the external pipes or the tank itself.
3. Incorrect estimate of groundwater quantity, due to which there is a strong subsidence of the entire pumping station with rupture of pipes and damage to the tank.
4. Using Wedges to Level Foundation Slabs. The consequence may be a gradual displacement of the tank to the side with rupture of pipes.

Only people with geodetic education and experience in installing similar structures can evaluate the correct installation of the SPS. Therefore, you should not trust the installation of this expensive equipment to non-specialized organizations.

Maintenance of external pump stations

A sewage pumping station is not equipment that you can install and simply be content with its operation. The tank and pumps require regular inspection.

It is strictly prohibited to go down into the tank or carry out cleaning work on your own!

Inhalation of sewer gases can cause sudden loss of consciousness and death if the person is not removed to clean air within a few minutes.

The most profitable option for regular cleaning of a sewer tank is to purchase a gas mask with forced air supply from the surface

When purchasing a water pumping station, it is advisable to immediately sign a contract for its maintenance.

To access the tank and check the equipment, the stations have a hatch, and deep tanks also have a ladder for descent.

Monthly or quarterly, the service department must:

• check the automation;
• diagnose the operation of the main and backup pumps, check the oil levels in them;
• remove stuck debris from filters;
• remove silt deposits from the bottom.

In case of urgent emergency situations, an independent inspection of the tank is possible, but it must be carried out in the presence of assistants, with a rope harness and wearing a respirator.

Conclusions and useful video on the topic

To fully understand the installation process of sewerage stations and the hydrodynamic processes occurring in them, it is recommended that you familiarize yourself with the videos presented below.

Operating principle of the CNS:

The operating principle of an in-house mini-station for pumping sewage:

Installation of a medium-sized domestic sewer station:

The pumping equipment of sewerage pumping stations is designed for trouble-free operation for 8-10 years, and the system of tanks and pipelines can last up to half a century.

Therefore, by purchasing and installing a sewer pump system once during the construction of a house, you can ensure the comfortable functioning of the sewer system for decades.

Do you have experience operating a sewage pumping station? Please share information with our readers, tell us about the features of installation and use of the SPS. You can leave comments in the form below.