Vilagarcía, Spain, optimizes sewage network with new pumps

In the City of Vilagarcía de Arousa in Spain, problems with the sewage network were leading to pollution events and a $231,000 USD annual maintenance bill. To resolve these issues, the city council partnered with experts from Sulzer’s service center in nearby Vigo.

The whole process was initiated by a free audit, which was offered by Sulzer to establish the full scale of improvements that could be achieved. The Sulzer team spent more than two weeks in Vilagarcía, inspecting the town’s network of 52 pumping stations. The engineers evaluated the condition of the pumps and ancillary equipment installed at the stations. They then made detailed calculations of the pressures as well as flow rates required for optimum performance across the network.

A Build-Up of Issues

Their report identified multiple root-causes for the city’s sewage pollution problems. Some pumps were old, worn out and in need of replacement. Others were in good condition but were the wrong size or specification to cope with the demands placed upon them. In addition, primary screens installed before the inlets of many pumps were becoming blocked with sanitary wipes.

Most network pumping stations contain two or three pumps, and the prospect of replacing hundreds of pieces of equipment was unpalatable for the city council. Sulzer’s team, however, was able to recommend an alternative approach that could address the problems while keeping the capital costs of the project under tight control.

The proposal involved a systematic reconfiguration of the network’s equipment. Some pumps would be replaced with new high-efficiency designs, sized to meet the foreseeable needs of the pumping station. However, where assets were undersized but still in good working order, they would be moved to stations that experienced lower levels of demand.

Lino Mouriño, infrastructure town councilor, and Ramón Caldas, council technical manager, explain: “Our planners worked closely with Sulzer’s team to define a program of improvements that would upgrade the performance of the sewage system while also meeting our financial and environmental goals. The supply of equipment for the project has been coordinated by Sulzer from the local service center in Vigo.

Selective Changes, Comprehensive Improvements

As part of this project, at least 10 pumps had been moved to different stations, enabling the performance of these sites to be optimized at the earliest opportunity. In addition, more than 20 pumps had been specified in such a way that they were interchangeable between several pumping stations. These actions reduced the number of pumps required to support the network, making the project more cost-effective and sustainable.

In some cases, the pumping stations had been equipped with controllers, which could provide feedback on performance and also take pre-emptive action when a pump became blocked by running backwards and then returning to normal operation. This could significantly reduce the number of maintenance visits required for each station, reducing costs for the municipality.

Sulzer installed 47 of its pumps, most of which were its XFP CB Plus units. These use the company’s Contrablock impeller, a design that coped with high concentrations of solid material. The new pumps eliminated the need for primary screens, and consequently the expensive and unpleasant task of cleaning those screens to remove obstructions.

The partnership between Sulzer and Vilagarcía city council is ongoing, with further upgrades and improvements planned over the coming years. In the meantime, Sulzer engineers continue to provide maintenance and operational support to maximize the performance and reliability of the city’s wastewater network.

SOURCE: DMA Europa Group, for Sulver