How to choose the right wastewater pump?

Have you ever had water in your basement or are you considering a suitable pump for your septic tank, either at home or at the summer house? Wastewater pumps are among the most commonly used appliances for pumping water in or around the house.

What type of pump? Choose according to the type of water it will pump!

Wastewater pumps differ from conventional submersible pumps in that they are also capable of pumping liquids with a higher density and sludge content. These are solid, fibrous or abrasive contaminants and impurities including sand, clay or silt. A wastewater pump will also come in handy in other situations - for example, to pump out a flooded basement or rainwater containing leaves. What kind of water you're pumping is the most important information for choosing the right wastewater pump.

The most common types of "wastewater pumps" are:

Drainage pumps are designed to pump so-called light wastewater, such as rainwater, river water or wastewater free of fibrous dirt and abrasives (e.g., sand and rock). Typical applications are basement drainage or pumping from a river, stream, rainwater pumping or drainage. They are used specifically for low-polluted water and are not intended for sewage pumping. Typical design feature is a grate on the suction side that allows only such large impurities to pass through the pump at the same time as the pumped liquid.
A special category of drainage pumps are pumps designed for water with abrasives, which find application mainly in industry and construction.

Sewage pumps are used for pumping contaminated water, i.e., sewage and faeces. The most commonly used pumps are cast iron and stainless-steel pumps with a customized design, especially the impeller shape. In many cases, it is necessary to use a sewage grinder pump that first crushes the coarse dirt and then pumps it out. However, these pumps are not suitable for pumping water containing sand, stones or clay.
Logically, wastewater pumps for septic tanks are the most commonly used type of these pumps in homes that are not directly connected to a sewer. They are therefore used for septic tanks, sumps or sewage pits. Equipped with a float switch, they can be automatically switched on and off according to the level in the septic tank. With few exceptions, the pump can be permanently submerged in the septic tank. An example of a reliable septic tank pump is the stainless steel, Leo LKS. It is also ideal for retention tanks and basement drainage and can also handle impurities up to 3.5 centimetres in diameter.
Sewage lifting stations are used to pump waste from low-lying areas to the septic tank or sewer. They are used to drain toilets, showers, bidets and sinks and are suitable for pumping wastewater from places such as basement apartments where the wastewater cannot be fed directly into the sewer by gravity.

How to deal with a toilet below sewer level?

Pressure sewage pumps are used where height differences have to be overcome and a normal gravity sewer cannot be built. They are ideal for lower sumps and a pressure wastewater pump with the appropriate conveying height is used. These pumps are installed in so-called pumping sumps, which are fully equipped small pumping stations for wastewater. The sump is an ideal solution, especially for holiday homes such as summer houses and lodges, or even for permanently occupied properties if you have any problems connecting to the local sewerage system and obtaining the relevant permits.

An example of a powerful pumping sump pump is the PUMPA black line Box 1VE Morava Classic, which is equipped with a stainless-steel screw pump controlled by an automatic control system. The pump is also provided with a grinder and the whole assembly is designed for connection to the pressure sewer network. Relatively recently, GSM module is available, whereby key information about the operation of the pump is displayed directly to your phone and, where appropriate, sent to our service department. It can thus alert you to a potential problem and deal with the service straight away.

Key parameters for the selection process

Maximum immersion depth

If you've chosen a pump based on the water you'll be pumping, there are a few parameters to pay attention to. As the name implies, a submersible wastewater pump is designed to be submerged in the liquid being pumped, all the way to the bottom of the liquid without potential damage. An important parameter is therefore the maximum immersion depth, which determines the depth at which the pump is still able to operate without difficulty.

Flow rate

You must also select the pump flow rate, i.e., how much liquid the pump can pump in a given period of time. Most often you will see m3/hr or l/min. Manufacturers specify the maximum flow rate, i.e., the value that can be achieved at zero head. In normal operation, the pump flow will be lower due to the head and pressure losses. The higher the head, the lower the flow and vice versa.

Conveying height - head

Determine also required head. That is, from what depth and distance will you pump the water and what is the length of the supply pipe. This parameter is the conveying height, or head, of the pump. Add up all the heights from the water source to the outlet and add a loss of 1 m in height for every 10 m of pipe length.

Permeability

Another figure to be concerned with in a pump is the permeability. This indicates in millimetres the maximum diameter of coarse particles that can be present in the water. This is the dirt such as mud, sand, silt, pebbles that the pump is still able to pump out. Some pumps are provided with a grinder that first crushes the coarse dirt and then pumps it out.

Power and input

The power and input of the pump should also be taken into account. You will be interested in the energy consumption of your chosen pump.
Depending on where and how the pump is installed, choose whether you need a single-phase or three-phase pump.

Think about accessories

An important feature of the pump is an automatic shut-off system to prevent the possibility of dry running. Most often the float switch is used, but pumps are also available without one. Also check whether you need to purchase any other necessary accessories - most often a delivery hose or pipe, installation material for connecting the hose to the pump, connection fittings, a base for mounting the pump, a lowering rope or dry-running protection.
If you are unsure of your choice, use our enquiry form to guide you on the parameters without which the pump cannot be selected and on the basis of which we will suggest the optimum solution for your situation.