低强度超声波强化SBR处理生活污水

通过设置超声波(ultrasound,US)的SBR反应器(sequence batch reactor,SBR)与对照反应器的对比试验,研究了超声波对SBR处理生活污水的强化效果.结果表明,采用强度0.3 W·cm^-2的超声波,每隔8h取SBR反应器中10%的污泥进行10min辐射处理,对COD的总去除率提高3%～6%,其出水COD与对照反应器的出水相比降低了40%～53%,通过该辐射处理有效提高了SBR反应器对模拟生活污水的高负荷冲击和有毒物质冲击的耐受能力.对于实际生活污水,设置超声强化使污泥耗氧呼吸速率(oxygen uptake rate,OUR)增加14%左右,有效提高了微生物对难降解有机物质的分解能力.对污泥沉降性能的研究表明,超声波强化会引起污泥的SVI值升高,但升高的幅度仅为5%左右,不会对系统的沉降性能造成显著影响.根据电镜观测以及种群结构分析发现,超声波对细胞产生了损伤作用,其表面出现了明显的皱褶,但是活性污泥种群结构并未发生显著变化.通过对2个反应器中活性污泥的呼吸动力学分析表明,设置US反应器中活性污泥对底物具有更高的利用率.

Treatment of Domestic Wastewater Using Sequence Batch Reactor Enhanced by Low Intensity Ultrasound

Enhancement effect of ultrasound (US) on the bio-treatment of domestic wastewater was studied through contrast experiments between two sequence batch reactors (SBR) with and without US. The results showed that when US with intensity of 0.3 W x cm(-2) was employed to irradiate 10% of the activated sludge in the SBR for 10 minutes every 8 hours, the removal rate of COD was improved by 3% - 6%, and the effluent COD of US-SBR was lower than that of the control SBR by 40% - 53%. Moreover, the tolerance of SBR to high concentration and toxicity impact was improved effectively. For the practical domestic wastewater, the sludge activity was 14% higher in the US-SBR than that in the control SBR, increasing the capacity of microorganism to degrade the refractory compounds. The settleability of activated sludge in the US-SBR descended slightly and 5% increase of SVI (sludge volume index) was observed during the experiment, but it had little influence on the system since the increment was very small. According to the results of scan electro-microscope (SEM) and microbial community structures analysis, the microorganism in the US-SBR was damaged by US and compared with the control, the cell wall was ruffled obviously, but it didn't change the community structures of activated sludge. Kinetics analysis of microbial respiration in the two SBRs showed that the activated sludge in the US-assisted SBR could make better use of substrate.