Packaged Pump Stations in Residential Properties

Thousands of homes in the UK use gravity drainage to carry wastewater from their bathrooms and kitchens to nearby sewer systems, but this method relies on a downhill gradient that can carry waste at the speed required to prevent solids from settling within the pipe (this is known as self-cleaning velocity)

In instances where wastewater is generated below the main sewer line, a packaged pumping station is needed to pump wastewater under pressure to an appropriate drainage outlet. 

For architects and residential property developers working on a site where the topography doesn’t facilitate gravity drainage, or for homeowners looking to expand with a basement conversion or annexe, packaged pumping stations offer a flexible drainage solution for managing wastewater generated by fixtures like toilets, sinks, showers and white goods. 

This article will cover packaged pump station design and use in domestic settings, including: 

1. Types of Domestic Wastewater 
2. What is a Packaged Pump Station?  
3. Design & Installation Considerations 
4. Packaged Pump Station Maintenance 

Types of Domestic Wastewater 

All residential buildings generate two kinds of wastewater, both of which can be managed by a packaged pump station: 

Sewage 
Also known as foul water, sewage comes from toilets and contains high amounts of human waste. It is important that sewage is moved away from its source, either via gravity or mechanical means, such as a pumping station, to remove the risk of odours or septicity.  

Greywater 
Generated by showers, washing machines, dishwashers and sinks – greywater contains washing chemicals and small traces of human waste and is therefore not safe for consumption.  

What is a Packaged Pump Station? 

Packaged pumping stations are systems designed to sit above or below ground, collecting and pumping wastewater up to the main sewer system/outfall manhole. Unlike adoptable pumping stations, packaged stations are privately owned and all operational and maintenance costs are the responsibility of the site owner or established management company.  

Components include: 

• Chamber – Collates wastewater and contains pumps, valves, level control and pipework. Our Planet® Range pumping station chambers are made of virgin grade polyethylene that is strong and corrosion resistant, ideal for long-term handling of wastewater, with guaranteed product repeatability. 
• Pump/s – One or more pumps sits within the pump station chamber, transporting wastewater under pressure to the nearest sewer system/outfall manhole. 
• Valves – Isolation valves and check valves (also known as non-return valves) provide pipeline isolation for maintenance works and prevent pumped flows from returning into the pumping station post transfer.  
• Level Control – Different kinds of level control can be found in packaged pumping stations; float switches are the most common for domestic wastewater.  As the name suggests, they float within the pumping station chamber, sending a signal to a control panel when they reach a pre-set high or low level, calling either the pumps or the alarm features into operation.  
• Control Panel – Automatically controls the operation of the pumps and the alarm system triggered by the position of the system’s float switches (as above). They also provide audio/visual alarms for system status that require attention, such as high level or a tripped pump motor. 
• Rising main – This is a length of pressure-rated pipework that carries wastewater from the pump outlet up to the main sewer network/ outfall manhole. 
   

All pumping stations, packaged or adoptable, work in the same basic way: 

1. Collection – Sewage and waste/surface waters are collected in the chamber via gravity. 
2. Level monitoring – The wastewater level in the chamber rises, triggering a float switch as explained previously. Once the waste reaches a pre-determined level the float switch sends a signal to the control panel. 
3. Pump activation – When the control panel receives the high-level signal from the float switch it begins pump operation. 
4. Rising main – The wastewater is transferred under pressure up through the rising main to the main sewer network, where gravity directs the pump flows to an alternative location (sewer system, receiving treatment system). 
5. Pump deactivation – The pump runs until the float switch reaches a pre-set low level and sends a signal to the control panel which then stops pump operation to prevent dry running.

Packaged pump stations are available in above or below-ground designs; both designs have the same main components, just arranged differently to suit the application.  Browse our Planet® Range of packaged pump stations. 

Design & Installation Considerations 

There are different kinds of packaged pumping stations available that have been designed to serve various applications. It is important to select the correct product for the application with key considerations as follows:  

Pump Type 
Characteristics of the wastewater that is likely to enter the station will determine the kind of pump you need. For domestic applications that generate sewage and greywater, solids-handling sewage pumps are the correct choice. They are constructed from strong corrosion-resistant materials like cast iron and feature sufficient free passage to allow suspended solids to pass through the pump uninhibited. 

Today’s wastewater is more difficult to pump than the same sewage, a decade ago.  With the introduction of water-saving utilities, cleaning products such as wipes, cooking fats entering our systems, a pump selection to cater for such wastewater is a vital consideration.  

Flow rate 
A pump’s flow rate refers to how fast a specified volume of liquid moves through the outlet. This is usually measured in l/s (litres per second) or m³/h (metres cubed per hour). 

A pump’s flow rate must exceed the inflow rate where permissible and the wastewater pumped at the correct speed to prevent solids within the pipe work from settling.  

Chamber size 
According to Building Regulations 2010, Drainage and Waste Disposal: Approved Document H, your chamber must be big enough to hold 24 hours of inflow to allow for safe storage in case of a disruption in regular service (such as a power outage). 

Document H also advises that we should assume 150 litres of foul drainage per person each day, for domestic sewage. To calculate the size of the chamber you need, multiply 150 litres by the number of residents the pump station will serve. For example, a four-person home will need a chamber that can hold up to 600 litres. 

Installation 
The space you have to work with, excavation restrictions and the level of incoming and discharge pipe work in the area will determine whether you need a below or above-ground packaged pumping station. 

Above-ground drainage systems generally have a less invasive installation process than below-ground systems and are easily accessed for visual inspection and maintenance purposes, however, they traditionally contain less storage within the body of the system, due to their compact design. 

Below-ground systems have less of an aesthetic impact and make up most product selection, as traditionally, drainage pipe work is maintained underground. However, a suitable manhole is required for maintenance operative access.  

Installation and commissioning of both options should only be carried out by qualified professionals, this will ensure that it works as intended and meets relevant safety standards, such as 18th Edition Wiring Regulations and BS761:2018. 

Packaged Pump Station Maintenance 

Regularly scheduled maintenance and service visits will ensure your pumping station operates efficiently long term. We recommend that sewage pumping stations are serviced every 6 months to so that any maintenance works, such as replacing worn or damaged components, can take place before leading to a larger issue like a breakdown. 

Checks commonly made during a packaged pump station service include: 

• Pumps and level control cleaned 
• Visual inspection of cable condition and wear components (wear ring, wear plate, impeller), replaced if necessary 
• Operational check of pump/s, valves, high-level alarm and control panel sequencing 
• Mechanical seal oil checked and renewed if contaminated 
• Motor insulation check 
• Operational simulation checks

You can maintain the reliability of your pumping station between scheduled services by ensuring solid matter such as FOG (fat, oils and grease) or foreign objects (e.g. sanitary products, razors, medication) are not disposed of in your sinks, showers or toilets. 

Improper disposal of these items leads to pipe blockages and can damage equipment in your pump station. Learn more in our guide, How-To: Protect Your Pump Station from Blockages & Breakdowns.

Due to health and safety risks, all maintenance works should be carried out by appropriately trained engineers. T-T Service® offers three levels of pump maintenance packages, including bi-annual service visits, monitoring, equipment replacements and priority breakdown services. Learn more about our maintenance packages.

Contact the Experts 

Our engineers in T-T Pumping Stations® are ready to help you find the best packaged pump station for your application. Both our above and below-ground stations are available in various designs and can be customised to suit your site. 

See our packaged pump stations online today or speak with a member of the team for expert support – call 01630 647200, email pumpingstations@ttpumps.com or complete our online enquiry form and a member of the team will be in touch.