污泥基吸附剂强化MBR城市污水处理效能与膜污染控制机理研究

A large number of excess sludge from municipal wastewater treatment plant has posed a serious threat to the environment. Sludge resource utilization is one of the important means to solve the problem. Sludge is organic-rich carbonaceous material and can be prepared adsorbent which performance comparable to that of activated carbon. This study is to prepare inexpensive sludge-based adsorbent in place of powered activated carbon (PAC) for applying in membrane bioreactor (MBR) and compare the municipal wastewater treatment performance and membrane fouling among sludge-based adsorbent-MBR, MBR and PAC-MBR; Investigate the relationship between sludge-based adsorbent microstructure, surface characteristics and macro wastewater treatment effect and clarify the decontamination mechanism; Reveal the interaction law of sludge-based adsorbent and activated sludge and its effect on the characteristics of the activated sludge, which can illustrate the membrane fouling mechanism affected by sludge-based adsorbent. Furthermore, the economy and security of sludge-based adsorbent-MBR will be evaluated. In general, this study will reveal the decontamination mechanism of sludge-based adsorbent-MBR; Clear the influencing factors of membrane fouling in the craft; Supplement and develop the theory and technique of traditional MBR; Lay the foundation for the achievement of sludge resource and large-scale application of sludge-based adsorbent-MBR for municipal wastewater treatment.

城市污水处理厂产生的大量剩余污泥已对环境构成严重的威胁，污泥资源化利用是解决该问题的重要手段之一。污泥是富含有机物的碳质材料，可以制备成吸附性能比拟活性炭的吸附剂。本项目探索利用污泥制备成廉价吸附材料取代粉末活性炭（PAC）应用于膜生物反应器（MBR）工艺，并且对污泥基吸附剂-MBR工艺与MBR工艺、PAC-MBR工艺处理城市污水效能与膜污染状况进行比较研究；探讨污泥基吸附剂微观结构、表面特性与宏观污水处理效果之间的关系并阐明除污机理；揭示污泥基吸附剂与活性污泥相互作用规律及其对活性污泥特性影响，进而阐明污泥基吸附剂对膜污染的影响机理。此外，拟对污泥基吸附剂-MBR工艺进行经济性分析及使用安全性评价。此研究将揭示污泥基吸附剂-MBR工艺的除污机理，明确该工艺的膜污染影响因素，补充与发展传统MBR工艺的理论与技术，为实现污泥资源化与污泥基吸附剂-MBR工艺处理大规模城市污水的应用奠定基础。

本文对由城市污水厂污泥制备的吸附剂材料应用于MBR工艺进行去污效果的研究。以化学污泥为原材料，在无氧条件下以质量比1:1浸渍于3.0 M的ZnCl2中，在700 °C下活化1 h，可以制备出应用于MBR工艺的吸附剂。并对污泥基吸附剂进行物化性质表征。污泥基吸附剂-MBR工艺，并与不投加任何吸附剂的MBR工艺与投加商品活性炭的MBR（PAC-MBR）工艺对生活污水的去污效能情况进行了比较研究。研究结果表明，污泥基吸附剂-MBR工艺对生活污水中的浊度、NH3-N、优于MBR工艺，劣于PAC-MBR工艺，而对总磷去除效果最好；通过污泥基吸附剂吸附和生物降解的协同作用，污泥基吸附剂-MBR工艺对有机物（以UV254与DOC表征）的去除效率较高，并以膜作为最后屏障深度截留大分子胶体有机物。还考察了三种MBRs工艺的膜污染情况，并对其影响机理进行了系统的研究。研究发现， 污泥基吸附剂-MBR工艺膜总阻力最小，这有效减缓膜污染，降低膜压差的上升速度。通过检测并且对比了三种MBRs工艺的混合液的各种性质，包括悬浮液固体浓度、污泥体积指数、污泥颗粒粒径分布、胞外聚合酶、微生物溶解性产物等性质，分析了污泥基吸附剂-工艺对缓减膜污染优于其他工艺的原因。