Comparative analysis of phosphorus removal efficiency from water on selected filter beds for use in the natural swimming pond filtration systems

This study aimed to compare the adsorption efficiency of phosphorus and its possible removal using three types of filter materials: modified rock opoka (Rockfos ), iron grit (Sulfur E), and limestone, based on laboratory column studies.Adsorption studies of phosphorus were carried out in laboratory conditions at two concentration levels (2 mg P/L and 5 mg P/L), and phosphorus concentration analyses in eluate were conducted using a spectrophotometer.For the assessment of adsorption capacity and potential, changes in phosphorus concentrations in eluate (P tot ) per operating cycle of each filter were analyzed, including calculations of phosphorus adsorption efficiency and capacity.In case of possible eluate leaching from the bed, seven other parameters were additionally analyzed, including: pH, electrical conductivity (EC), water hardness (mval/L), ammonium ions (N-NH 4 ), nitrate ions (N-NO 3 ) iron ions (Fe), and manganese ions (Mn) in mg/L.Based on the results of eluate analysis, it was observed that the tested filtration materials were able to remove phosphorus from water.The highest and most stable adsorption efficiency was shown by the material Rockfos (90-99%), followed by Sulfur E (20-89%), and the lowest by limestone (24-70%).The tested granulate used in the study also showed very favorable parameters of sorption effectiveness and eluate leaching.The tested minerals were characterized by the release of various parameters from the deposit and/or change in their values to a minimal extent without exceeding the water quality standards for FLL eco-pools.The potential for use in filtration systems of natural swimming ponds applies in particular to modified rock (Rockfos ).The material Sulfur E, despite its lower adsorption effectiveness, was also highlighted due to its significant Fe content, which could be a phosphorus availability regulator for microorganisms in water and eco-pool systems.