With an increased demand for package pumping stations thanks to their functionality and convenience, there are now greater variations in design and suitable applications for pumping stations than ever before. T-T Pumps looks at the options
Pumping stations, lift stations, pump houses. Despite the different names, they are all designed to remove waste and ‘nuisance waters’ from a site where gravity cannot be employed – be it for construction sites, highway drainage, flood protection schemes and more.
Package pumping stations
Designed as single, complete, preformed units, package pumping stations consist of the chamber, pumps, pipework, valves, control panel and level controls. The units are primarily deployed in the private sector where access to gravity drainage and connection to a site’s main sewage line is unattainable.
Because of the wide range of sizes available, package pumping stations are practical for small single dwellings up to larger multi-dwelling applications – effectively managing wastewater, drainage water, and sewage/treatment works across housing estates, schools, hospitals, hotels, and nursing homes.
Package pumping stations are conventionally installed below ground, but where this is not possible, there is the option of an above-ground station.
Above-ground pumping stations have the same suitability for surface water, sewage and drainage applications, but are more likely to be restricted in size due to land availability on the chosen site. Below-ground stations are less restricted in this sense.
A bespoke project is recommended for those who want a pumping station that can be adopted by a local water authority. This is because the station must meet stringent standards as set out in the Design and Construction Guidance (DCG). DCG replaced the previous guidelines, Sewers for Adoption, in 2020; setting out the provisions under which local water authorities can adopt a pumping station.
With package pumping stations being prebuilt, they will not meet DCG standards, despite undergoing testing for safety and durability. However, bespoke and adoption standard stations have their own drawbacks, with longer lead times on manufacturing/installation and additional fees associated with the adoption process. Package pumping stations have comparatively short lead times and can therefore be taken from initial order to commissioning within tight construction schedules.
Glass reinforced plastic (GRP) vs polyethylene
There are two main materials in the construction of pumping station chambers – glass reinforced plastic (GRP) and polyethylene. GRP was once the more popular material, but polyethylene has seen a gradual growth in the market. Both are durable; however, polyethylene is not only recyclable, but has additional benefits such as resistance to chemical corrosion, resilience to ground pressures, and strength against site abuse.
Differences in the manufacturing processes of GRP and polyethylene chambers also bring variations in product lead-times, repeatability and cost. GRP chambers are a manual and labour-intensive process with greater potential for human error, compared to the more automated process of polyethylene chamber construction that guarantees reliability through consistent manufacturing standards. Evidence of design integrity and certification by a recognised test house,
such as British Board of Agrément (BBA), can help in the search for high-quality pumping station providers. Finite Element Analysis (FEA) is also an important factor when choosing a manufacturer, providing evidence of a product’s ability to function over time and withstand a range of forces, such as hydrostatic ground pressures.
There are several factors to be considered when choosing a pumping station in each particular project’s case. These include the flow rate of the development being served; the distance the media must be pumped to the nearest sewage system; how high the pump can lift the medium (head lift); the potential loss of power and pressure needed for pump operation (‘rising main friction loss’), as well as power requirements and medium storage requirements.
Selecting a pumping station with maximum efficiency and operational life is a job for professionals who have experience in optimising the decision process. Take the time to select a company that offers a selection service that you can rely upon, providing support from concept to commission and beyond, with after sales and monitoring systems for long-term reliability.