Water loss in swimming pool filter backwashing processes in the Balearic Islands (Spain)

Abstract

Swimming pools are a major contributor to water consumption in our community. However, the high water loss associated with filter cleaning is unknown. In this work, we investigate the current procedures for filter backwashing in public swimming pools by questionnaires to owners and managers. Then, we use the collected data to estimate their environmental and economic costs. Besides, we measure several parameters in the field during the process performed in four representative swimming pools. The investigation revealed that the water loss associated with filter cleaning in public swimming pools arises to 5.5 million m3 water per year, which represents an expense of 13.96 million €. Based on our results, the followed protocols were inappropriate in most cases, indicating that even the required water amount would be higher. The most suitable parameters for filter backwashing monitoring were combined chlorine, ammonium, turbidity and chemical oxygen demand (COD). The necessity for specific strategies and legislation for the management of these installations, the treatment of the generated wastewater, as the implementation of different technological solutions to reduce water loss are discussed.

Water Reuse in a Municipal Sports Center

“…Therefore, in the future, filter backwashing could be fully reused for this purpose. Nevertheless, the treated backwashing could also be used in the flushing cisterns or, after a broader treatment, reintroduced back into the swimming pool [20]. However, due to the lack of specific legislation for backwashing monitoring and quality control, other indicators such as DOI 10.18502/kms.v7i1.11624 nutrients, micropollutants, and other chlorine forms [11,20] should be determined and monitored before deciding on the best reuse for the water from the filter backwashing.…”

“…Indeed, this process is required to remove contaminants accumulated during the pool filtration process. The filters are cleaned by flushing them with water in the reverse direction to normal flow (backwashing) [9]. The resulting backwash water is characterized by high contents of suspension and dissolved substances and, depending on the future application, requires differentiated treatment before being reused [8,[10][11].…”

Improving Water Efficiency in a Municipal Indoor Swimming-Pool Complex: A Case Study

“…Regular swimming pool filter backwashing is unavoidable due to the need to remove the contaminants accumulated during the filtration process and to condition the filter beds for continued efficient operation [41]. Nevertheless, this process generates large amounts of water, which may constitute 20% to 70% of the total facility wastewater volume discharged into the sewage contributing to water (and energy) use inefficiencies and environmental contamination [24].…”

“…Furthermore, considering that the annual amount of water necessary for irrigating the lawn of the local football stadium, located in the surroundings of the swimming pool complex, is around 7200 m 3 (data provided by municipality), the backwashed water could be fully reused for this purpose. Nevertheless, the treated filter backwashing could also be used in the flushing cisterns or, after a broader treatment, reintroduced back into the swimming pool [41]. However, due to the lack of specific legislation for backwashing monitoring and quality control, other indicators such as nutrients, micropollutants, and other chlorine forms [41,42] should be determined in future approaches.…”

“…Nevertheless, the treated filter backwashing could also be used in the flushing cisterns or, after a broader treatment, reintroduced back into the swimming pool [41]. However, due to the lack of specific legislation for backwashing monitoring and quality control, other indicators such as nutrients, micropollutants, and other chlorine forms [41,42] should be determined in future approaches.…”