Wastewater pumping system at airport solves clogging and halves energy usage

London’s Heathrow Airport is one of Europe’s busiest airports, catering for more than 200,000 passengers each day with an average of 1200 flights arriving and departing from the airport daily. Heathrow Airport Water Services Department has an extensive network of 120 pumping stations to manage.

Heathrow Airport Water Services Department recently installed and trialled Xylem’s latest Flygt wastewater pumping system in an effort to solve chronic clogging issues at one of the airport’s wastewater pumping stations. As well as delivering consistently clog-free pumping, Xylem’s Flygt Concertor reduced energy consumption by 53% at the pumping station.

The challenge

To deliver clog-free pumping of aircraft wastewater — some of the most challenging wastewater to pump.

The Central Area Sanitation Unit adjacent to Terminal 1 is a receiving station for aircraft toilet waste, which contains a high level of non-biological solids including various plastic material, wipes, nappies and clothing. This stringy material can be difficult to pump, since it can easily get caught on the impeller and partially block the pump — leading to increased energy consumption and, in the worst case, a full blockage of the pump.

This challenging wastewater application led to regular clogging and to the sump requiring significant operational activity to try to keep it clean.

“We would usually have to deal with two or three clogging issues during a three-month period,” said Ian Jolly, systems specialist for water, Heathrow Airport Water Services Department. “We also used to see a shelf of fat and material deposits build up on the walls of the sump, as well as floating debris. This presented a very tough challenge to our existing wastewater pumps, which we frequently had to de-clog.”

The solution

Heathrow Airport required a solution that would solve the operational costs and environmental problems caused by:

• high levels of floating debris on the surface of the wet well;
• higher than normal percentages of rag/non-biological solids in the wastewater.

Flygt’s new wastewater pumping system combines built-in sump and pipe-cleaning functionalities in a single integrated solution, capable of tackling sump floating debris as well as pipe sedimentation. Furthermore, the pump-cleaning function, together with Adaptive N-hydraulics, effectively detects and solves clogging from large debris.

One of Heathrow’s aircraft wastewater vehicles, transporting sludge to the Central Area Sanitation Unit.

Since its installation at the Heathrow Central Area Sanitation Unit in November 2015, the system has provided clog-free operation, along with an improvement in the wet well environment. “Since installing Concertor, we have had absolutely no clogging and the sump remains clean with no fat build-up,” said Jolly. “As well as peace of mind — which really is priceless — the cost savings are significant at approximately 87.5% of the annual costs in cleaning and servicing.”

Clog-free operations and a clean wastewater pumping station are, however, not the only ways that the system improves wastewater operations. It also aims to deliver reliability at the lowest total cost of ownership and to achieve this it also, among other benefits, drastically reduces energy consumption.

Ian Jolly, system specialist for water services at Heathrow Airport, was pleased with Flygt Concertor’s trial results.

In the case of the once-troublesome Central Area Sanitation Unit pumping station, energy savings are up to 53%, which again is a result of both sophisticated software and cutting-edge components.

The Energy Minimizer function, together with the Adaptive-N hydraulics and the IE4 efficiency motor, automatically ensures that all the pumps run at their most efficient duty point. Additionally, since there is no need for ventilation, cooling or heating of cabinets, customers benefit from substantial energy savings over the system’s total life cycle.

The new system uses sophisticated technology but is still compact, user-friendly and simple to install, commission and operate.

“Concertor’s compact design allowed it to fit into the existing position within the pump station, without any extra investment required to enlarge the cabinet. From an aesthetic and practical consideration, the reduced panel requirement size will be of great benefit,” said Jolly. “It was simple to install and very user-friendly. Actually, the trial pump was installed by one of the airport’s water services mechanical technicians, who was not experienced in the commissioning of wastewater pumping systems and quickly gained confidence in the ease of installation and operation.”

For more information, visit flygt.com/one-ultimate-system.