Key Laboratory of Integrated Regulation and Resource Development on Shallow Lakes, Ministry of Education, Hohai University, Nanjing 210098, China.
CAS Key Laboratory of Urban Pollutant Conversion, Department of Chemistry, University of Science &Technology of China, Hefei 230026, China.
Sci Rep. 2017 Feb 17;7:42910. doi: 10.1038/srep42910.
Activated sludge granules and flocs have their inherent advantages and disadvantages for wastewater treatment due to their different characteristics. So far quantitative information on their evaluation is still lacking. This work provides a quantitative and comparative evaluation on the characteristics and pollutant removal capacity of granules and flocs by using a new methodology through integrating fuzzy analytic hierarchy process, accelerating genetic algorithm and entropy weight method. Evaluation results show a higher overall score of granules, indicating that granules had more favorable characteristics than flocs. Although large sized granules might suffer from more mass transfer limitation and is prone to operating instability, they also enable a higher level of biomass retention, greater settling velocity and lower sludge volume index compared to flocs. Thus, optimized control of granule size is essential for achieving good pollutant removal performance and simultaneously sustaining long-term stable operation of granule-based reactors. This new integrated approach is effective to quantify and differentiate the characteristics of activated sludge granules and flocs. The evaluation results also provide useful information for the application of activated sludge granules in full-scale wastewater treatment plants.
由于其不同的特性，活性污泥颗粒和絮体在废水处理方面都有其固有优势和劣势。到目前为止，对于它们的评价还缺乏定量信息。本工作通过整合模糊层次分析法、加速遗传算法和熵权法，为颗粒和絮体的特性和污染物去除能力提供了一种新的定量和比较评价方法。评价结果表明颗粒的总评分较高，表明颗粒比絮体具有更有利的特性。虽然大粒径的颗粒可能会受到更大的传质限制，并且容易出现运行不稳定的情况，但与絮体相比，它们还能够实现更高水平的生物量保留、更大的沉降速度和更低的污泥体积指数。因此，优化颗粒粒径的控制对于实现良好的污染物去除性能和同时维持基于颗粒的反应器的长期稳定运行至关重要。这种新的综合方法可有效量化和区分活性污泥颗粒和絮体的特性。评价结果还为活性污泥颗粒在实际规模的污水处理厂中的应用提供了有用信息。
