Towards sustainable and regenerative territories: ecological restructuring of phosphorus retention and mobilization based on substance flow analysis (sfa) in Quirino Province

Phosphorus (P) is an essential and finite nutrient element that cannot be substituted by any other substance. To overcome limited supply of mineral Phosphate rocks (PR) deposits and to contribute to its sustainable management, a better knowledge on P flows is needed. In this study, a Substance Flow Analysis (SFA) for P was conducted for the Quirino Province. Different subsystems were investigated such as forestry, agriculture, anthropogenic consumption, organic wastes, and wastewater management. The researcher found that within the system under study, there is an excess total P inflow into the three (3) major river watersheds system in Quirino Province. The aim of the study was to analyze the flow of Phosphorus that enter, transform, pass through, and leave the territorial subsystems in order to create a knowledge bank that will aid in the transition of Quirino Province from linear to circular metabolism.

Phosphorus removal in a vertical upflow constructed wetland system

Mechanisms for P removal in a vertical upflow macrophyte system were studied in controlled laboratory columns filled with sand and planted with Phragmites australis. Substrate P removal was shown to increase with flow rate, a parameter which can be enhanced through effluent recirculation. An alternative substrate (leca, light expanded clay aggregate) provided improved equilibrium adsorption characteristics, but uncrushed and within the kinetic constraints of a macrophyte system gave no improvement for P adsorption over sand. Intermittent loading of the sand based macrophyte system permitted control of the P concentration, with lower effluent peak concentrations for increased resting interval (no P inflow). Where P loading was targeted, continuous flow provided the optimum mass removal conditions.