The impact of preozonation on the coagulation of cellular organic matter produced by Microcystis aeruginosa and its toxin degradation  

作　　者：Magdalena Barešová Jana Naceradská Katerina Novotná LenkaCermáková Martin Pivokonský 

机构地区：[1]Institute of Hydrodynamics of the Czech Academy of Sciences,Pod Patankou 5,16612 Prague 6,Czech Republic

出　　处：《Journal of Environmental Sciences》2020年第12期124-133,共10页环境科学学报（英文版）

基　　金：supported by the Czech Science Foundation (No. GA18-14445S);by the institutional support of the Czech Academy of Sciences (RVO 67985874)。

摘　　要：Ozonation pretreatment is typically implemented to improve algal cell coagulation. However, knowledge on the effect of ozonation on the characteristics and coagulation of associated algal organic matter, particularly cellular organic matter(COM), which is extensively released during algal bloom decay, is limited. Hence, this study aimed to elucidate the impact of ozonation applied before the coagulation of dissolved COM from the cyanobacteria Microcystis aeruginosa. Additionally, the degradation of microcystins(MCs) naturally present in the COM matrix was investigated. A range of ozone doses(0.1–1.0 mg O3/mg of dissolved organic carbon – DOC) and ozonation pH values(pH 5, 7 and 9) were tested, while aluminium and ferric sulphate coagulants were used for subsequent coagulation. Despite negligible COM removal, ozonation itself eliminated MCs, and a lower ozone dose was required when performing ozonation at acidic or neutral pH(0.4 mg O3/mg DOC at pH 5 and 7 compared to 0.8 mg O3/mg DOC at pH 9). Enhanced MC degradation and a similar pattern of pH dependence were observed after preozonation-coagulation, whereas coagulation alone did not sufficiently remove MCs. In contrast to the benefits of MC depletion, preozonation using ≥0.4 mg O3/mg DOC decreased the coagulation efficiency(from 42%/48% to 28%–38%/41%–44% using Al/Fe-based coagulants), which was more severe with increasing ozone dosage. Coagulation was also influenced by the preozonation pH, where pH 9 caused the lowest reduction in COM removal. The results indicate that ozonation efficiently removes MCs, but its employment before COM coagulation is disputable due to the deterioration of coagulation.

关 键 词：Algal organic matter Coagulation MICROCYSTINS Microcystis aeruginosa Ozonation 

分 类 号：TU991.2[建筑科学—市政工程]