Mg2+、Ca2+对厌氧消化系统中CO2的捕获和营养盐的回收

为探究矿物碳酸化与污泥厌氧消化耦合过程中实现CO₂捕获和N/P营养盐协同回收的可行性，在污泥水解液为底物的厌氧消化系统中，研究不同比例Mg²⁺/Ca²⁺离子添加对厌氧消化系统中CO₂捕获和营养盐的协同回收效果的影响.结果表明，添加Mg²⁺/Ca²⁺离子为（20mmol/L）/（0mmol/L）、（10mmol/L）/（10mmol/L）和（0mmol/L）/（20mmol/L）均可促进有机质降解，使沼气产量分别提升16.97%、21.56%和23.99%，并使CO₂含量由27.27%分别下降至24.81%，22.06%和21.98%.不同比例Mg²⁺/Ca²⁺离子添加可使磷酸根浓度下降63.46%~66.47%，但仅Mg²⁺/Ca²⁺离子以（20mmol/L）/（0mmol/L）和（10mmol/L）/（10mmol/L）添加的实验组中氨氮浓度得到下降.XRD分析揭示，Mg²⁺/Ca²⁺离子以（20mmol/L）/（0mmol/L）、（10mmol/L）/（10mmol/L）和（0mmol/L）/（20mmol/L）添加时分别使厌氧消化系统中形成鸟粪石和碳酸镁、鸟粪石和方解石、方解石和三斜磷钙石.Mg²⁺、Ca²⁺离子等摩尔量联合添加可实现最优的CO₂捕获和营养盐协同回收效果.

CO2 sequestration and nutrients recovery in anaerobic digestion with Mg2+ and Ca2+ addition

In order to explore the feasibility of simultaneous CO₂ sequestration and N/P nutrients recovery in sludge anaerobic digestion coupled with mineral carbonation, different ratios of Mg²⁺/Ca²⁺ were added in the anaerobic digestion systems with sludge hydrolysate as substrate, to investigate the performance of simultaneous CO₂ sequestration and nutrients removal. The results showed that the addition of Mg²⁺/Ca²⁺ of (20mmol/L)/(0mmol/L), (10mmol/L)/(10mmol/L) and (0mmol/L)/(20mmol/L) could promote the degradation of organic matters, so that the biogas production increased by 16.97%, 21.56% and 23.99%, and the CO₂ content was reduced from 27.27% to 24.81%, 22.06% and 21.98%, respectively. The phosphate concentration was reduced by 63.46%~66.47% with Mg²⁺/Ca²⁺ addition of different ratios. However, ammonia nitrogen concentration was reduced only in the digesters with Mg²⁺/Ca²⁺ added at (20mmol/L)/(0mmol/L) and (10mmol/L)/(10mmol/L). XRD analysis revealed that struvite and magnesium carbonate, struvite and calcite, calcite and monetite were respectively formed in the digesters with Mg²⁺/Ca²⁺ added at (20mmol/L)/(0mmol/L), (10mmol/L)/(10mmol/L) and (0mmol/L)/(20mmol/L). The combined addition of Mg²⁺/Ca²⁺ in equimolar amount achieved the best simultaneous CO₂ sequestration and N/P nutrients recovery.