氧化锌纳米颗粒对膜-生物反应器运行性能的影响

Impacts of ZnO nanoparticles on the performance of membrane bioreactors

考察了城市污水中典型浓度的氧化锌(ZnO)纳米颗粒对膜-生物反应器(MBR)运行、活性污泥性质以及膜污染的影响.结果表明,ZnO纳米颗粒不利于微生物对有机物的去除,但是不会影响微生物对氨氮的去除.由于微滤膜的截留作用,ZnO纳米颗粒对MBR的出水没有影响.ZnO纳米颗粒的投加导致溶解性微生物产物(SMP)浓度从17.9mg/gVSS上升到35.0mg/gVSS左右,污泥粒径由162.9μm下降到105.2μm,引起了外部阻力的上升,造成了膜污染的加剧.ZnO纳米颗粒会抑制微生物活性和改变活性污泥中微生物的种群结构,这主要与ZnO纳米颗粒释放的Zn2+有关.

The typical concentration of zinc oxide （ZnO） nanoparticles in municipal wastewater was used to investigate influences of ZnO nanoparticles on the performance of membrane bioreactors （MBRs）, sludge properties and membrane fouling. The results indicated that the ZnO nanoparticles had adverse effects on the removal of COD due to the microbial respiration, while they had little impact on the NH3-N removal of the microbial respiration. However, ZnO nanoparticles did not deteriorate the effluent quality of the MBRs at all due to the high retention of micro-filtration （MF） membrane. Meanwhile, the adding ZnO nanoparticles could lead to the increase of soluble microbial products （SMP） from 17.9mg/gVSS to approximately 35.0mg/gVSS and the reduction of sludge particle size from 162.9μm to 105.2μm, which caused the increase of the outer membrane resistance and the deterioration of membrane fouling. Moreover, the inhibition of microbial activity and the change of microbial communities in the activated sludge induced by the addition of ZnO nanoparticles could be attributed to the release of Zn^2＋ from the adding ZnO nanoparticles to the supernatant.