碳化稻壳-铁锰氧化菌耦合净化严寒村镇高铁锰地下水效能与机制

针对严寒地区特有地理气候条件及制约当前村镇建设与发展的典型问题,以建设绿色低碳、节能环保村镇为目标,研发碳化稻壳-优势铁锰氧化菌耦合工艺净化严寒村镇高铁锰地下水,探究生物滤柱低温快速启动方式;基于接触氧化与生物法,对比分析不同滤速条件下滤柱沿程除铁效能与反应速率,研究生物滤层除铁机制;基于扫描电子显微镜(scanning electron microscope,SEM)、傅立叶红外线光谱(Fourier transform infrared spectroscopy,FTIR)、X射线光电子能谱(X-ray photoelectron spectroscopy,XPS)、拉曼光谱(Raman spectra)、电子顺磁共振(electron paramagnetic resonance,EPR)对运行不同阶段的滤料与反冲洗水泥样表征剖析生物滤层除锰机制.结果表明,优势菌液低滤速-全循环的运行方式使稻壳生物滤层成熟且稳定仅需15 d;稳定运行阶段出水铁、锰、细菌浓度分别低于0.3 mg·L~(-1)、0.1 mg·L~(-1)、100 CFU·m L~(-1),均满足国家生活饮用水卫生标准(GB 5749-2006);除铁机制主要依靠物化作用、辅以生物作用;在滤料成熟阶段与稳定运行初期除锰主要依靠生物作用,稳定运行后期物理化学作用占优势;该研究为严寒村镇Fe~(2+)、Mn~(2+)地下水集中处理应用提供了技术支撑.

Efficiency and Mechanism of Purifying High Iron-Manganese from Ground Water in the Cold Villages and Towns Based on The Coupling of Rice Husk and Iron-Manganese Oxidizing Bacteria

Aiming at the special geo-climatic conditions and typical problems constraining the development of villages and towns, making villages and towns have the following characteristics:green and low-carbon, energy saving and environmental friendly, the coupling process of adsorption by carbonized rice husk particles and biological oxidation using Bacillus megaterium bacteria was developed for purifying high iron-manganese from groundwater in the cold villages and towns. The quick start-up method of biological filter at low temperature was studied. Based on the contact oxidation and biological method, iron removal efficiency and reaction rate in different filtration layers under different filtration conditions were comparatively analyzed, and iron removal mechanism of biological filter was determined. Filter materials and the solid samples in backwash water at different stages were characterized and the manganese removal mechanism of biological filter was analyzed through SEM, FTIR, XPS, Raman spectra and EPR. The results showed that the active biological membrane reached mature and stable only after 15 d with the operation mode of bacteria liquid cycle and low filtration rate in the filter column. The effluent concentration met the requirements of drinking water quality (GB 5749-2006) in the stable operation process. Fe, Mn and bacteria were lower than 0.3 mg·L^-1, 0.1 mg·L^-1, 100 CFU·mL^-1, respectively. Iron removal mechanism relied mainly on the physical and chemical effects, supplemented by biological function. During the biofilm culturing stage and initial stable operation stage of filter column, manganese removal relied mainly on the biological effect. The physical chemistry was preferred at later stable operation stage. The study provides technical support for the applications of treating collectively Fe²⁺ and Mn²⁺ in groundwater.