高铁粉煤灰强化厌氧生物法处理造纸废水

Enhanced anaerobic biological treatment of paper wastewater with high iron fly ash

粉煤灰是煤粉在悬浮燃烧条件下经受热面吸热后冷却形成的微小颗粒,是一种重要的大宗工业固体废物。以粉煤灰为原料,通过磁选法制备高铁粉煤灰,用于强化厌氧生物处理造纸废水的效能。SEM、XPS、XRD、XRF和BET表征结果显示,与普通粉煤灰相比,高铁粉煤灰具有更加优越的理化性质,比表面积和中大孔体积分别达到11.51 m^(2)/g和0.073 cm^(3)/g,分别为普通粉煤灰的6.5、9.1倍。高铁粉煤灰中的Fe_(3)O_(4)质量分数达41.35%,为普通粉煤灰的11.1倍。实验结果表明,添加高铁粉煤灰后,厌氧反应器处理出水的COD平均去除率较未添加时的增加22.3%,甲烷产量提高145%,B/C由进水的0.07提高至0.42,为后续好氧工艺提供了良好的可生化性。此外,高铁粉煤灰的添加有利于厌氧活性污泥辅酶F_(420)和EPS的产生,促进厌氧活性污泥的团聚,同时显著提高活性污泥的导电活性和电导率,有效强化了造纸废水中污染物向甲烷的转化程度,提升厌氧工艺的降解性能。高铁粉煤灰原料来源丰富,制备工艺简单,具有良好的工程应用前景。

Fly ash is an important industrial solid waste formed from small particles of pulverized coal after cooling under suspended combustion conditions by heat absorption from the heated surface.High iron fly ash was prepared from fly ash by magnetic separation method and used to enhance the effectiveness of anaerobic biological treatment of paper wastewater.SEM,XPS,XRD,XRF and BET characterization results showed that compared with ordinary fly ash,high iron fly ash had better physicochemical properties,with specific surface area and mesoporous(microporous)pore volume reaching 11.51 m^(2)/g and 0.073 cm^(3)/g,respectively,which were 6.5 and 9.1 times higher than those of ordinary fly ash.The mass fraction of Fe_(3)O_(4) in the high iron fly ash reached 41.35%,which was 11.1 times of the ordinary fly ash.The experimental results showed that average COD removal rate of effluent treated by anaerobic reactor increased by 22.3%,methane production increased by 145%and B/C increased from 0.07 to 0.42 after adding high iron fly ash,which provided good biodegradability for the subsequent aerobic process.In addition,the addition of high iron fly ash facilitated the production of anaerobic activated sludge coenzymes F_(420) and EPS,promoted the agglomeration of anaerobic activated sludge,as well as significantly improved the conductive activity and conductivity of activated sludge,effectively enhanced the conversion of pollutants to methane in paper wastewater and improved the degradation performance of anaerobic process.The raw materials of high iron fly ash are abundant and the preparation process is simple,which has good prospects for engineering applications.