Implementation of P-Reactive Layer for Improving Urban Water Quality: Kinetic Studies, Dimensioning and Economic Analysis

Urbanization and climate change affecting water quality are the most critical problems that humanity has to encounter globally. Undoubtedly, urban water bodies are heavily contaminated by phosphorus (P). This study aims to identify the mechanisms and efficiency of the P sorption process for selected reactive materials (Autoclaved Aerated Concrete (AAC), Filtralite® Nature P, lightweight expanded clay aggregate (Leca®), limestone, opoka, and zeolite) with surface water as adsorbate and dimension of P-reactive reactive layer supported with economic analysis. Four kinetic models were used to know the sorption mechanism: pseudo-first order, pseudo-second order, Elovich, and intra-particle diffusion model. Calculating the P-reactive layer was based on dimensioning rain retention spaces standards. The pseudo-second model provided the best description of the adsorption kinetics of most materials. The sorption properties obtained after 72 h showed the reduction of 83, 81, 59, 53, 37, and 36% for AAC, opoka, Filtralite® Nature P; limestone, Leca®, and zeolite, respectively. Depending on the volume, the P-reactive layer can remove 29–77 or 61–163 g of P-PO4. The unit cost of removing P-PO4 by the P-reactive layer range from 49.57 to 85.53 €/P-PO4 g. For these reasons, reactive materials seem to be an effective way of removing P from the urban water environment worldwide from both environmental and economic points of view