噻虫嗪对活性污泥颗粒化影响的数学模型

Study of the effect of thiamethoxam on activated sludge granulation by mathematical model

文章在活性污泥1号模型（ASM1）的基础上加入抑制动力学模型,建立活性污泥颗粒化过程数学模型,模拟噻虫嗪（thiamethoxam,TMX）抑制和非抑制2种条件下,序批式反应器（sequencing batch reactor,SBR）中颗粒的生长及有机底物的去除、微生物总量的生长、TMX和溶解氧（dissolved oxygen,DO）在颗粒内部分布趋势以及自养菌、异养菌和TMX降解菌颗粒内部的空间分布。结果表明,TMX对自养菌和异养菌产生非竞争性抑制,同时对TMX降解菌产生底物抑制。DO对好氧颗粒内的微生物种群空间分布具有重要影响,DO在颗粒内部的传质深度为200~600μm,所以基于氧气生长的自养菌和TMX降解菌在颗粒外层分布较多。不添加TMX时,异养菌均匀分布于整个颗粒;而添加TMX时,由于对异养菌的生长造成非竞争性抑制,故其空间分布变为内部多外层少。

Based on the activated sludge model 1 （ASM1）, the mathematical model of aerobic granule was established with inhibition kinetics with AquaSim software. The model was used to simulate the sequencing batch reactor（SBR） operation with and without inhibition of thiamethoxam（TMX） respectively. The aerobic granule process such as the growth of the particles, the nutrients removal, the growth of microorganism, the distribution profiles of TMX and dissolved oxygen（DO） as well as the spatial distribution of autotrophic bacteria, heterotrophic bacteria and TMX degrading bacteria in aer- obic granular sludge（AGS） were simulated well by this model. The results showed that TMX had noncompetitive inhibitory effect on the autotrophic bacteria and heterotrophic bacteria, and had sub- strate inhibitory effect on TMX degrading bacteria. And DO had important influence on the spatial distribution of aerobic microbial population. The depth of the mass transfer of DO was 200-600μm in aerobic granular sludge. Hence, autotrophic bacteria and TMX degrading bacteria based on oxygen lo- cated primarily in the outer space of particles. Heterotrophic bacteria distributed uniformly in the whole particles without TMX. When TMX was added to the SBR, the heterotrophic bacteria spatial distribution shows more in the inside of the particles but less in the outer space owing to TMX non- competitive inhibition of heterotrophic bacteria.