Reuse – Reduce – Recycle: water and wastewater management in swimming pool facilities

The main objective of the study is to analyze the quality of washings resulting from backwashing of filter beds in a selected swimming pool facility from the point of view of their possible discharge into surface waters, their use for utility purposes within the pool facility or their return to the pool water circulation, and thus rationalize water and wastewater management in the swimming pool under consideration. The quality of the washings samples was tested under laboratory conditions in three stages (stage 1 – sedimentation, stage 2 – jar coagulation, stage 3 – ultrafiltration). After each stage, based on physicochemical and bacteriological analysis of washings samples, the degree of their contamination was determined and compared with the conditions to be met when waste-water is discharged into surface waters and with the guidelines of the regulation on the quality of swimming pool water. The discharge of raw washings into surface water is not possible, mainly due to the total suspended solids (TSS) content above 35 mg/L and the free chlorine concentration above 0.2 mg Cl₂ /L. As a result of stage 1, TSS decreased by about 67% and free chlorine by about 28%. After stage 2, TSS decreased to 11.7 mg/L and free chlorine to 0.09 mg Cl₂ /L. After stage 3, TSS was reduced to 5.3–7.8 mg/L and free chlorine to 0.01–0.03 mg Cl₂ /L (depending on the type of membrane). The total number of mesophilic bacteria >100 CFU/1 mL was not found in the superna-tant after stages 1, 2 and in the permeate after stage 3. The use of a three-stage washings treatment process makes it possible to use permeate from the washings to replenish losses in the swimming pool water circuit. In laboratory tests, about 65% of the washings volume was recovered for use.