Université de Toulouse, INPT, UPS, Laboratoire de Génie Chimique, 4 Allée Emile Monso, F31432 Toulouse, France.
Université de Toulouse, INPT, UPS, Laboratoire de Génie Chimique, 4 Allée Emile Monso, F31432 Toulouse, France.
Sci Total Environ. 2018 Dec 1;643:1464-1480. doi: 10.1016/j.scitotenv.2018.06.303. Epub 2018 Jul 4.
The performance of tertiary moving bed biofilm reactors (MBBRs) was evaluated in terms of micropollutants (MPs) removal from secondary-treated municipal wastewater. After stepwise establishment of a mature biofilm, monitored by scanning electron and confocal microscopies, abiotic and biotic removals of MPs were deeply studied. Since no MPs reduction was observed by the both photodegradation and volatilization, abiotic removal of MPs was ascribed to the sorption onto the biomass. Target MPs i.e. Naproxen, Diclofenac, 17β-Estradiol and 4n-Nonylphenol, arranged in the ascending order of hydrophobicity, abiotically declined up to 2.8%, 4%, 9.5% and 15%, respectively. MPs sorption onto the suspended biomass was found around two times more than the biofilm, in line with MPs' higher sorption kinetic constants (k) found for the suspended biomass. When comparing abiotic and biotic aspects, we found that biotic removal outperformed its counterpart for all compounds as Diclofenac, Naproxen, 17β-Estradiol and 4n-Nonylphenol were biodegraded by 72.8, 80.6, 84.7 and 84.4%, respectively. The effect of the changes in organic loading rates (OLRs) was investigated on the pseudo-first order degradation constants (k), revealing the dominant biodegradation mechanism of co-metabolism for the removal of Diclofenac, Naproxen, and 4n-Nonylphenol, while 17β-Estradiol obeyed the biodegradation mechanism of competitive inhibition. Biotic removals and k values of all MPs were also seen higher in the biofilm as compared to the suspended biomass. To draw a conclusion, a quite high removal of recalcitrant MPs is achievable in tertiary MBBRs, making them a promising technology that supports both pathways of co-metabolism and competitive inhibition, next to the abiotic attenuation of MPs.
采用逐步建立成熟生物膜的方法，通过扫描电子显微镜和共聚焦显微镜进行监测，评估了三级移动床生物膜反应器（MBBR）对二级处理城市废水中微污染物（MPs）的去除效果。深入研究了非生物和生物去除 MPs 的情况。由于光降解和挥发都没有观察到 MPs 的减少，因此将 MPs 的非生物去除归因于生物量的吸附。目标 MPs 即萘普生、双氯芬酸、17β-雌二醇和 4n-壬基酚，按疏水性顺序排列，非生物去除率分别下降了 2.8%、4%、9.5%和 15%。发现悬浮生物量对 MPs 的吸附量是生物膜的两倍左右，这与悬浮生物量对 MPs 更高的吸附动力学常数（k）一致。在比较非生物和生物方面时，我们发现对于所有化合物，生物去除都优于其非生物去除，因为双氯芬酸、萘普生、17β-雌二醇和 4n-壬基酚的生物降解率分别为 72.8%、80.6%、84.7%和 84.4%。还研究了有机负荷率（OLR）变化对伪一级降解常数（k）的影响，揭示了共代谢是去除双氯芬酸、萘普生和 4n-壬基酚的主要生物降解机制，而 17β-雌二醇则遵循竞争抑制的生物降解机制。与悬浮生物量相比，生物膜中所有 MPs 的生物去除率和 k 值也更高。总之，在三级 MBBR 中可以实现对难降解 MPs 的相当高的去除率，使其成为一种很有前途的技术，除了 MPs 的非生物衰减外，还支持共代谢和竞争抑制这两种途径。
