Located in North-eastern Barcelona on the Mediterranean Sea, the recently renovated Besos Wastewater Treatment Plant (WWTP) is a new solution for more than two million inhabitants. The new 84,000 m2 (900,000 ft2), underground facility is the last stage in the city's water cycle and it now treats more than 70% of the city of Barcelona's wastewater and its surrounding towns: Sent Adrian de Besos, Santa Coloma de Gramanet, Badalona, Montage and Tiana.
 

The problem

Barcelona, the capital of Catalonia, is the second largest city in Spain. With a thriving population, the city also has a bustling tourist industry. In fact, the city's 74-acre Forum, which is also located on the Mediterranean Sea just north of downtown, is a main attraction for residents and tourists alike. The Forum consists of plazas, parks, ports, luxury hotels, a concert arena, a convention centre and a public square complete with an amusement park.

While the population and the tourist traffic in Barcelona have continued to grow to overwhelming proportions, odours from the cities' increasing wastewater also grew. Specifically, odours from existing concentrations of H2S and NH3 in the wastewater were very prevalent. Both gases emit pungent, irritating odours if left untreated.

In order to eliminate the poignant odours, as well as achieving a visually pleasing atmosphere, the Ministry of Environment sought to enlarge and update the Besos WWTP. Due to the area's growth, the space was limited. Therefore, the proposed solution for the necessary wastewater treatment plant was to construct the plant completely underground. The renovated Besos WWTP was constructed beneath the Barcelona Forum's premium accommodations, which intensified the primary requirement for guaranteed odour control.
 

The solution

Purafil was suggested to provide odour control for the Besos WWTP because the products and equipment can be customised to specifically eliminate the odourous gases found in wastewater while providing 100% odour removal for the heavily populated area. Initially, nearly 100 Purafil ESD drum-scrubber odour control systems complete with Purafil's Odoroxidant™ and Odormix™ dry-scrubbing media were selected to remove the odours and ventilate the densely populated area's WWTP.

MediaSAKs™ containing Purafil Odoroxidant™ and Odormix™ media sit inside the drum scrubbers located at the Besos WWTP. Once the air enters the scrubbers, the odourous gases are trapped within the media and the clean air is discharged out of the scrubbers' centrifugal air ventilator.

Once the facility's spacing and the end-user's overall goal were reassessed, 16 Purafil Side Access Units (PSAs) were also added to several rooms of the Besos WWTP.

Although PSAs are typically used in either industrial or commercial environments, the systems' versatile ability to remove both particulate and gaseous pollutants was a good addition to the Besos WWTP. The systems are individually engineered to the customers' size parameters and to meet the customers' specific odour needs.

Each PSA contains MediaPAK modules filled with the users' choice of Purafil media for an engineered solution that will permanently eliminate the largest percentage of the odourous gases through chemisorption. The Purafil units are filled with various media to eliminate the prevalent gases specific to their location within the wastewater treatment plant. For instance, 0.2 ppm of H2S and 0.3 ppm of Mercaptans were detected at the plant's inlet. To eliminate these odourous gases, a PSA filled with Purafil Select and Purafil CP Blend Select media was used.

The clean air solutions that Purafil provided were ultimately successful in removing the odourous gases from the air. The Forum is a premier tourist attraction located directly above the Besos WWTP, but the visitors can no longer detect the once stifling scents.

In fact, once the Besos WWTP facility engineers realised the Purafil drum scrubbers, PSAs and media were successful in removing the prevalent odours, they placed an order for additional units. For the facility engineers, a Besos WWTP expansion indicated a larger need for odour removal and Purafil products proved to be the primary gas-phase filtration solution to meet the plant's needs.