固定化菌诱导矿化脱氮除磷及养猪粪水的资源化利用

Immobilized bacteria-induced mineralization for nitrogen and phosphorus removal and utilization of swine manure wastewater resources

摘要:

目的 探究地衣芽孢杆菌(Bacillus licheniformis) ZXT的不同固定化策略及矿化方式对高氮磷废水的脱氮除磷效能，明确最优矿化条件与载体作用机制，为养猪废水等复杂高氮磷废水的绿色处理与资源回收提供技术支撑。方法 对比游离菌、化学沉淀、活性炭纤维(activated carbon fiber, ACF)固定化、聚乙烯醇-海藻酸钠-炭粉(polyvinyl alcohol-sodium alginate-carbon powder, PVA-SA-CP)固定化4种体系在Mg:N:P为0.6:1:1、1:1:1、1.4:1:1比例下的矿化效果，结合X射线衍射、扫描电子显微镜、傅里叶变换红外光谱等表征手段解析矿物特性，通过实际养猪废水验证体系应用潜力。结果 ACF固定化体系效能最优，在Mg:N:P=1:1:1比例下培养7 d，NH₄⁺终浓度仅0.59 mg/L (去除率99.81%)，PO₄^3-终浓度低至0.03 mg/L (去除率99.99%)，均满足国标GB 8978—1996排放标准，且生成结晶规整的长板状鸟粪石(即磷酸铵镁，magnesium ammonium phosphate, MAP)；PVA-SA-CP固定化体系同比例下NH₄⁺、PO₄^3-终浓度分别为5.07 mg/L、0.45 mg/L，去除效果显著较弱；化学沉淀法24 h内NH₄⁺终浓度为38.90-48.01 mg/L (去除率84.70%-87.61%)，未达标。游离菌处理实际养猪废水时，培养8 d NH₄⁺、PO₄^3-去除率分别达99.97%、99.92%，终浓度为0.15 mg/L、0.05 mg/L，符合排放要求。结论 ACF凭借发达的微孔结构与良好的生物相容性，可高效富集菌体并促进胞外聚合物规整组装，其固定化地衣芽孢杆菌ZXT的矿化技术为最优选择，Mg:N:P=1:1:1为最佳矿化比例，该技术可实现高氮磷废水的高效净化与氮磷资源回收，在实际废水处理中具有重要应用价值。

Abstract:

Objective To explore the nitrogen and phosphorus removal efficiency of different immobilization strategies and mineralization methods of Bacillus licheniformis ZXT for high nitrogen-phosphorus wastewater, clarify the optimal mineralization conditions and carrier mechanism of action, and provide technical support for the green treatment and recovery of complex high nitrogen-phosphorus wastewater resources such as swine manure wastewater.Methods Four systems—free bacteria, chemical precipitation, activated carbon fiber (ACF) immobilization, and polyvinyl alcohol-sodium alginate-carbon powder (PVA-SA-CP) immobilization—were compared for their mineralization effects under Mg:N:P molar ratios of 0.6:1:1, 1:1:1, and 1.4:1:1. Characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FT-IR) were employed to analyze mineral properties. The application potential of the systems was verified with actual swine manure wastewater.Results The ACF immobilization system exhibited the optimal efficiency. Under the Mg:N:P ratio of 1:1:1, after seven days of cultivation, the final concentration of NH₄⁺ was only 0.59 mg/L (removal rate: 99.81%) and the final concentration of PO₄^3- was as low as 0.03 mg/L (removal rate: 99.99%), both meeting the national discharge standards (GB 8978—1996), with the formation of regular crystalline long plate-like struvite (i.e., magnesium ammonium phosphate, MAP). The PVA-SA-CP immobilization system showed significantly weaker removal effects under the same ratio, with final concentrations of NH₄⁺ and PO₄^3- being 5.07 mg/L and 0.45 mg/L, respectively. The chemical precipitation method failed to meet the standards, as the final concentration of NH₄⁺ ranged from 38.90 to 48.01 mg/L (removal rate: 84.70%-87.61%) within 24 h. Free bacteria achieved the removal rates of 99.97% for NH₄⁺ and 99.92% for PO₄^3- in actual swine manure wastewater after eight days of cultivation, with final NH₄⁺ and PO₄^3- concentrations of 0.15 mg/L and 0.05 mg/L, respectively, which complied with the discharge requirements.Conclusion Due to its developed microporous structure and good biocompatibility, ACF can efficiently enrich bacteria and promote the regular assembly of extracellular polymeric substances. The mineralization with ACF-immobilized B. licheniformis ZXT is the optimal choice, with Mg:N:P=1:1:1 as the best mineralization ratio. This technology can achieve efficient purification of high nitrogen-phosphorus wastewater and recovery of nitrogen and phosphorus resources, thus having important application value in actual wastewater treatment.