污泥原位侧流减量工艺强化技术研究及其机理模型构建

The sludge in situ reduction strategy with a side-stream reactor (SSR) inserting in the returned activated sludge line is considered as a promising way potentially employed in wastewater treatment plants owing to its advantages of low operation cost and adverse effects on biomass. In the SSR, sludge hydrolysis and biomass lysis process are the rate-limiting step and resulted in a longer hydraulic retention time comparable to the biological wastewater treatment process; therefore, regulation of dissolved oxygen (DO) and application of carriers in the SSR will be investigated to accelerate the hydrolysis/lysis process. The SSR coupled membrane bioreactor (SSR-MBR) will be constructed to investigate the fluctuation of suspended solids in the effluent owing to the mismatching of sludge production and reduction rate in the sludge in situ reduction process. Effects of DO level and carriers on the pollutants removal, sludge reduction, and membrane fouling will be studied by long-term operation of SSR-MBR systems. The sludge reduction mechanisms of these SSR systems will be elucidated by analyzing microbial structure, secondary substrate release and utilization, sludge characteristics and membrane foulants. The sludge reduction kinetic model will be constructed and calibrated for parameter estimation, and then correlated with physiological and ecological indices of biomass to determine the contribution of cell lysis, particles hydrolysis and metabolic uncoupling to sludge reduction. The regulation mechanisms and crucial parameters of the SSR sludge reduction process will be advanced to provide theoretical support for its applications.

由于运行成本低、对微生物影响小等优点，在污泥回流管线中设置侧流反应器（SSR）是最有潜力在污水处理厂中应用的污泥原位减量技术。针对SSR水力停留时间过长的问题和减量机制解析的需求，拟开展溶解氧水平调控和填料投加强化污泥减量技术研究，并构建SSR耦合膜-生物反应器（SSR-MBR）解决污泥产生与减量速率不匹配时的出水悬浮物波动问题。本申请项目将通过长期运行实验考察溶解氧水平、填料投加对SSR-MBR工艺污染物去除、污泥减量和膜污染的影响，通过微生物种群、元素迁移转化、污泥性质和膜污染物分析阐明SSR工艺的污泥减量机制；构建SSR污泥减量动力学模型并进行参数优化估计，通过数学模型与微生物生理生态学指标的关联分析，测算微生物溶胞、颗粒物水解和代谢解偶联等过程对污泥减量的贡献，明确污泥减量的主导途径；最终提出SSR污泥减量技术的调控机制与关键参数，为其实际应用提供基础理论支撑。

侧流反应器（SSR）技术是污水处理厂实现污泥原位减量的优选工艺。针对传统SSR水力停留时间（HRT）长、出水悬浮物偏高等问题，通过研究不同强化技术与SSR有效耦合的方法，开发填料强化侧流减量技术和双污泥构型微氧强化减量技术，阐明污泥减量强化机制与主导途径，并建立工程示范，同步实现污染物高效去除与污泥产量削减。.超声处理、投加填料强化SSR污泥减量效果对比表明，两者可通过刺激水解酶活性提高污泥减量效率（SRE）。超声处理能破坏污泥絮体和细胞，强化减量效果，但能耗过高且会恶化污泥沉降脱水性能，影响微生物种群稳定性和出水水质。投加填料能促进解偶联代谢，富集水解发酵菌，延长微生物食物链并改善污泥性质，是一种经济高效的强化策略。.对填料强化侧流减量技术的关键工艺参数优化发现，填料填充率25%和SSR池HRT为6.7 h时，SRE最高达50.5%，较传统SSR提高约30%。微生物机制深入解析表明，填料会增加与细胞运动性和信号机制相关的功能基因，有利于微生物在不良生境条件下的快速响应，形成群落保护机制；填料会富集剑水蚤、红斑顠体虫等大型后生动物，强化捕食减量效应。通过污泥回流系统重构，开发基于进水强化污泥减量的水解酸化功能提升技术并建立工程示范，实现污泥减量40.5%，总氮去除率提升13.7%.厌氧、微氧和好氧强化技术对比发现，微氧可充分刺激水解菌和发酵菌活性，强化效果最佳。在此基础上，针对长泥龄下单污泥系统污泥易老化的问题，提出双污泥构型微氧强化原位减量SPRAS工艺。关键参数优化发现，污泥过程减量（SPR）模块回流比50%和沉淀池HRT为6.0 h时，SRE最高达62.7%。插入SPR强化了糖酵解途径，诱导解偶联和维持代谢以减少污泥产量。.构建基于污泥组分划分的原位减量数学模型，分析发现维持代谢是SSR的主导减量途径，而SPRAS可显著加速污泥衰减并强化代谢解偶联途径，较SSR在减量率提升81.9%的同时降低反应器容积32.8%。污水与污泥全流程碳排放分析表明，SPRAS和填料强化SSR较传统AAO可减少碳排放14.1%和5.4%。说明两种强化方式均是绿色低碳的污染控制技术，而SPRAS是最佳可行技术。