If you’re building a dream home away from it all in a beautiful countryside location, it may mean no access to the mains sewer; Dan Berry from Harlequin Manufacturing explains why packaged pump stations are a simple answer
If a pumping solution is needed on a property, due to it having no mains sewer connection, normal practice in recent years has been to build a chamber made from concrete rings, fitted with equipment including pumps, pipes, and valves. But this is very time consuming, and can create several challenges.
You can now get the same solution built and ready to be installed, in the form of a packaged pump station, which presents a much more efficient, cost-effective, and long-lasting solution. They save significant time and cost, being able to be installed very quickly.
A pump station is effectively a collection tank designed to transfer sewage, effluent or surface water to a local drain, private manhole or mains sewer when they are located higher than the domestic sewage plant. Pump stations are also used to remove wastewater from residential properties that do not have access to the main sewer; some homes are already connected to a private pump station before they connect to the main sewer.
HOW IT WORKS
A pump station comprises a large tank – also known as a wet well – that acts as the receiver for sewage from a house or a group of houses, until it reaches a predetermined level. The pump is located in the bottom of the chamber, activated by a float switch when liquid waste reaches a certain level. The waste is pumped through an MDPE pipe up to the outlet connected to the mains sewer. Once the liquid waste level has dropped below the float switch threshold, the pump stops. A non-return valve is built in to ensure that the liquid waste cannot return to the chamber once pumped up to the higher level.
TYPES OF PUMP STATIONS
Single effluent pump stations comprise a single pump, designed for liquid effluent only. They are often placed after a domestic sewage treatment plant to pump the treated effluent to a watercourse or field drainage.
Twin effluent pump stations consist of two pumps and a control panel. Twin pumps can cope with much bigger amounts of liquid. They are often used for surface water on sites where ground conditions aren’t suitable for soakaways, or for larger commercial treatment plant to pump the treated effluent to a watercourse or field drainage.
Single sewage pump stations comprise a single vortex pump, designed for solid and liquid waste. They are mostly used on a single dwelling or an extension, to pump sewage to a private manhole cover.
Twin sewage – Twin sewage pump stations use two vortex pumps designed to cope with solid and liquid waste. They also include a control panel. Twin pumps are mostly used on larger domestic dwellings or multiple dwellings that are discharging to the mains sewer.
Single grinder – Single grinder pump stations use a single pump, designed for heavy solids and liquid waste. They are often used to reduce the amount of liquid entering a mains sewer as the water authorities in certain areas are very strict about the quantity of liquid entering the mains sewer system.
SELECTING THE RIGHT PUMP STATION
There are a few key criteria that need to be considered while selecting a pump station that meets your requirements:
- Distance the pump/s need to travel in metres
- Uphill lift in metres
- Capacity of pump stations required
- Requirement of 24-hour storage to comply with Building Regulations.
PART H BUILDING REGULATION – 24-HOUR STORAGE
Part H of Building Regulation offers guidance on drainage including foul and surface water and rainwater, and sanitary waste disposal, including sewage structures and their upkeep. Approved Document H1 2.39 states that, “Where foul water drainage from a building is to be pumped, the effluent receiving chamber should be sized to contain 24-hour inflow to allow for disruption to service. The minimum daily discharge of foul drainage should be taken as 150 litres per head per day for domestic use.
“For other types of building, the capacity of the receiving chamber should be based on the calculated daily demand of the water intake for the building. Where only a proportion of foul sewage is to be pumped, then the capacity should be based pro-rata. In all pumped systems the controls should be so arranged to optimise pump operation.”
GRP VS POLYETHENE
GRP tanks are manufactured by hand or in a semi-automated process. Anything made by hand is subject to human error and discrepancies. GRP tanks are effectively a skin and do not have any structural stability until encased in concrete. The concrete is what gives the chamber its strength.
Polyethene tanks on the other hand are made using a fully automated process. This results in a consistent product thickness throughout a chamber which is free of defects. This means a much stronger and durable finish, and a life over 20 years.
Dan Berry is area sales manager at Harlequin Manufacturing