镁钙比对有机废物厌氧消化液中生物矿化产物的制约OA

Anaerobic digestate from organic waste typically exhibits high concentrations of chemical oxygen demand(COD),phosphate and ammonia nitrogen,classifying it as recalcitrant high-strength organic wastewater.This study proposes supplementing digestate with sulfate as an electron acceptor for sulfate-reducing bacteria,aiming to rapidly degrade organic matter while inducing biomineralization to fix carbon,nitrogen,and phosphorus.To investigate the influence of magnesium and calcium ions on COD removal,biomineralization products,and carbon fixation in anae-robic digestate,batch biomineralization experiments were conducted using anaerobic systems with varying magnesi-um and calcium ion concentrations.The results show that under a total salinity of 10 g/L and a Mg2+/Ca2+molar ra-tio ranging from 0.5 to 10,increasing the Mg2+concentration from 0.12 g/L to 2.4 g/L boosted total organic car-bon(TOC)degradation rates initially,but then caused them to decline.The optimal degradation rate was achieved at a Mg2+/Ca2+molar ratio of 5,corresponding to 1.2 g/L of Mg2+.Furthermore,when the Mg2+/Ca2+molar ratio was less than 1,calcite and struvite were the primary mineralization products,whereas monohydrocalcite and stru-vite prevailed for ratios above 1.These findings suggest that Ca2+mainly facilitates carbon capture,while Mg2+is crucial for immobilizing nitrogen and phosphorus.Consequently,the Mg2+/Ca2+molar ratio serves as a key regula-tor of controlling both the types and proportions of carbonate and phosphate phases.