投加微米级磁性壳聚糖促进好氧颗粒污泥形成和稳定的机理研究

The rapid formation and long stability of aerobic granular sludge is still the difficulties and challenges for its full-scale application. Chitosan is a natural macromolecule polysaccharide, and has the advantages of biodegradability, bioactivity, etc. This study intends to prepare the micro-magnetic-chitosan powder using chitosan and nano-Fe3O4, and adopt the way of adding micro-magnetic-chitosan combined with a weak magnetic field to accelerate the formation of aerobic granular sludge, recover the stability of granule bulking, and enhance the denitrification of aerobic granular sludge as the nuclei and slow release carbon source. This study will systematically explore the effect mechanism of micro-magnetic-chitosan combined with a weak magnetic field on the formation, stability and denitrification enhancement of aerobic granular sludge by means of many analysis methods such as biological morphology, microbial signal, molecular biology and hydromechanics. The principles and influences of chitosan, nano-Fe3O4, weak magnetic field and micro-size scale on rapid formation of aerobic granular sludge, rapid stable recovery of granule bulking, and denitrification enhancement of granules will be elucidated. The preparation method of micro-magnetic-chitosan, adding way and adding dosage will be determined. This study will not only provide a new idea and theoretical foundation for the practical application of aerobic granule sludge, but also enrich the theoretical system of aerobic granule sludge technology.

好氧颗粒污泥的快速形成和长期稳定仍是该技术大规模应用的难题和挑战。壳聚糖是天然高分子多糖，具有生物可降解性和生物活性等优点。本项目拟采用壳聚糖和纳米Fe3O4制备微米级磁场壳聚糖粉末，通过投加微米级磁性壳聚糖协同弱磁场促进好氧颗粒污泥的快速形成、失稳颗粒的快速恢复和稳定运行，同时作为凝聚核和缓释碳源强化好氧颗粒污泥的生物脱氮。本课题将通过微生物形态学、微生物信号学、分子生物学和流体力学等多种分析手段，系统研究微米级磁性壳聚糖协同弱磁场促进好氧颗粒污泥形成、稳定和强化脱氮的作用机理，阐明壳聚糖、纳米Fe3O4、弱磁场和微米级粒径尺度等对好氧颗粒污泥快速形成，失稳颗粒快速恢复和强化好氧颗粒脱氮的影响和原理，并确定微米级磁性壳聚糖的制备方法、投加方式和投加量。本项目不仅能为好氧颗粒污泥的实际应用提供一种新的思路和理论依据，还能丰富好氧颗粒污泥技术的理论体系。

好氧颗粒污泥的快速形成和长期稳定是该技术应用的难题和挑战，同时好氧颗粒污泥的处理和处置也逐渐成为研究的热点。本研究主要开展了投加微米级磁性壳聚糖协同弱磁场促进好氧颗粒污泥的快速形成、失稳颗粒的快速恢复和稳定运行，同时研究了采用壳聚糖快速制备污泥聚集体并通过接种污泥聚集体促进好氧颗粒污泥系统的快速启动，最后初步探究了剩余好氧颗粒污泥通过厌氧发酵回收碳氮磷资源的潜力和优势。投加微米级磁性壳聚糖（M-CTS）或壳聚糖（CTS）（每天投加量：0.2g/gMLSS；pH：6.0）5天后，污泥容积指数（SVI30）从133.6mL/g迅速降低至55.3和59.2mL/g，运行13天后粒径分别增至255和204μm，基本实现好氧污泥的快速颗粒化。在膨胀失稳的颗粒中投加M-CTS或CTS（每天投加量：0.24g/gMLSS，投加3天；pH：6.0）运行5天后，SVI30快速下降至42.2和46.4mL/g，污泥粒径快速上升至422和424μm，失稳颗粒快快速恢复并稳定运行了50天。利用壳聚糖的阳离子和水不溶特性可以快速制备具有颗粒特性的污泥聚集体（SVI30=90.1mL/g；粒径：1300μm），接种污泥聚集体运行10天就能实现完全颗粒化，且脱氮除磷效果良好。好氧颗粒污泥厌氧发酵具有较好的碳氮磷释放潜力，碱性条件利于好氧颗粒污泥厌氧发酵产酸，而酸性发酵利于释磷。本项目研究的成果能为好氧颗粒污泥的应用和资源化提供可行的思路和数据依据。