Nitrogen and Phosphorus Recovery from Chicken Manure Biogas Slurry via Magnesium-Modified Zeolite Coupled with Electrochemical Precipitation Crystallization

• • MgCl2-modified zeolite (MgCl2-ZO) achieved the highest coupling precipitation efficiency among tested modifications, with optimal conditions at N/P ratio 3.78, pH 8.43, and current density 13.11 A·m−2, yielding removal rates of 54.84% TN, 62.93% TAN, 82.02% TP, and 77.72% TPS. • • The coupled electrochemical system enables in-situ Mg2+ supply and pH regulation, significantly enhancing struvite crystallization efficiency compared to conventional chemical dosing. • • Response surface methodology identified precise operational windows, demonstrating that current density and pH are critical factors controlling nitrogen and phosphorus removal, with a synergistic effect between electrochemical field and zeolite adsorption. • • The process achieves high phosphorus recovery (82.02% TP) from chicken manure biogas slurry, addressing the bottleneck of phosphorus pollution and offering a scalable approach for nutrient recycling in intensive livestock operations.