MULTI-STAGE OPTIMIZATION OF LIQUID ORGANOMINERAL FERTILIZER PRODUCTION FROM POULTRY MANURE AND PHOSPHORITE SLUDGE: CHEMICAL SYNERGY AND EXTRACTION MECHANISMS

Abstract

The sustainable management of agricultural and industrial wastes is a cornerstone of the modern circular economy. This study provides a comprehensive analysis of the production of liquid organomineral fertilizers using poultry manure (PM) and low-grade phosphorite sludge (PS) via alkaline extraction. By varying the component ratios (95:5 to 65:35) and solid-to-liquid (S:L) ratios (1:1 to 1:3), we identified the critical parameters governing nutrient recovery. Experimental data show that P2O5 and CaO concentrations are maximized in mineral-rich blends, while the preservation of bio-active humic and fulvic acids requires a manure-dominant matrix. The study also discusses the chemical mechanism of phosphorus solubilization by organic ligands in an alkaline medium. The optimized formulation (PM:PS = 75:25, S:L = 1:2) yields a balanced nutrient profile suitable for high-yield sustainable agriculture.