Spotlight on Sewage Pumping Stations Spotlight on Sewage Pumping Stations

Spotlight on Sewage Pumping Stations

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24 May 2018

Pumping stations come in a variety of shapes and sizes and can be located in driveways, gardens, roadside verges and other areas. CSC Services specialise in the refurbishment of sewer system structures. Mick Flounders, CSC Services’ Contracts  Director looks at what they do and why do they need to be protected.

Sewer networks rely on gravity to transport wastewater from a property to its nearest main sewer. If a property sits on lower ground than the nearest mains sewer, a sewage pumping station is often used.

A sewage pumping station consists of a wet well which collects wastewater from a property. The wastewater will collect in the well until it reaches a predetermined level at which point a pump activates. The pump will pressurise sewage out of the wet well to the main sewer or to a point where it can then travel into the main sewer under the force of gravity.

Private sewer transfer

In October 2016, water companies became responsible for all eligible sewage pumping stations, in their area. Water companies are now in charge of servicing, maintenance and all associated running costs for these stations. This applies to all pumping stations built before July 2011, that drain to the water company sewer and aren’t part of a private treatment works, such as a cesspit or septic tank. The pumping station must serve more than one property, or, sit outside the curtilage (similar to boundary) of the property it serves.

Hydrogen Sulphide

The interior of a sewage pump station is a hazardous environment. Poisonous gases, such hydrogen sulphide can accumulate in the wet well. Hydrogen sulphide results from septic conditions during the collection and treatment of wastewater. This colourless gas, known for its rotten egg smell, is produced by the biological reduction of sulphates and the decomposition of organic material. In confined spaces, hydrogen sulphide gas will dissolve in the condensation on surfaces to form sulphuric acid which is highly corrosive and attacks concrete. It is therefore important that wet wells are protected against such chemical attack.

Repair and Protection

CSC Services have many years of experience in reinstating the concrete surfaces of such structures. Waterproof fairing coats are used to fill defects and repairs surface cavities. Specialist repair mortars are specified for this type of environment with enhanced chemical resistance, offering excellent protection from acid gases and chlorides.

An overcoat of a specialist cementitious coating can then be installed. This will protect existing concrete from further deterioration offering chemical, abrasion and impact resistance.

A cementitious coating system can be installed quickly causing minimum disruption. Unlike polyurethanes which require adequate drying and dehumidification to prevent ‘bagging’ and ‘debonding’ of the structure, cementitious coating systems are water based so can be installed in damp conditions removing the requirement for costly heating and dehumidification equipment. This is a key consideration where access to the pumping station site is restricted.

Refurbishing and protecting a structure in this way is significantly cheaper that replacing. Using the correct coating system can significantly increase the life-span of the asset.  Call 0191 410 3444 today for more information about the refurbishment of wet wells, pumping stations and all other sewer related structures.