Ho Lionel, Hoefel Daniel, Bock Franziska, Saint Christopher P, Newcombe Gayle
Cooperative Research Centre for Water Quality and Treatment, Australian Water Quality Centre, SA Water Corporation, PMB 3, Salisbury SA 5108, Australia.
Chemosphere. 2007 Feb;66(11):2210-8. doi: 10.1016/j.chemosphere.2006.08.016. Epub 2006 Sep 26.
Taste and odour (T&O) causing compounds, in particular, 2-methylisoborneol (MIB) and geosmin, are a problem for water authorities as they are recalcitrant to conventional water treatment. In this study, biological sand filtration was shown to be an effective process for the complete removal of MIB and geosmin, with removal shown to be predominantly through biodegradation. In addition, MIB and geosmin were also effectively degraded in batch bioreactor experiments using biofilm sourced from one of the sand filters as the microbial inoculum. The biodegradation of MIB and geosmin was determined to be a pseudo-first-order reaction with rate constants ranging between 0.10 and 0.58 d(-1) in the bioreactor experiments. Rate constants were shown to be dependent upon the initial concentration of the microbial inoculum but not the initial concentration of MIB and geosmin when target concentrations of 200 and 50 ng l(-1) were used. Furthermore, rate constants were shown to increase upon re-exposure of the biofilm to both T&O compounds. Enrichment cultures with subsequent community profile analysis using 16S rRNA-directed PCR-DGGE identified four bacteria most likely involved in the biodegradation of geosmin within the sand filters and bioreactors. These included a Pseudomonas sp., Alphaproteobacterium, Sphingomonas sp. and an Acidobacteriaceae member.
产生味觉和嗅觉（T&O）的化合物，特别是2-甲基异莰醇（MIB）和土臭素，对供水部门来说是个问题，因为它们对传统的水处理方法具有抗性。在本研究中，生物砂滤被证明是一种有效去除MIB和土臭素的工艺，去除主要通过生物降解实现。此外，在使用来自其中一个砂滤器的生物膜作为微生物接种物的间歇式生物反应器实验中，MIB和土臭素也被有效降解。在生物反应器实验中，MIB和土臭素的生物降解被确定为伪一级反应，速率常数在0.10至0.58 d⁻¹之间。当使用200和50 ng l⁻¹的目标浓度时，速率常数显示取决于微生物接种物的初始浓度，而不是MIB和土臭素的初始浓度。此外，当生物膜再次接触这两种T&O化合物时，速率常数会增加。通过16S rRNA定向PCR-DGGE进行后续群落谱分析的富集培养，确定了砂滤器和生物反应器中最有可能参与土臭素生物降解的四种细菌。这些细菌包括假单胞菌属、α-变形杆菌、鞘氨醇单胞菌属和酸杆菌科成员。
