When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products （SAP） should be paid much attention, as they are important precursors for formation of disinfection by...When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products （SAP） should be paid much attention, as they are important precursors for formation of disinfection byproducts （DBPs）, which have potential risks for human health. Chlorella sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from Chlorella sp. HQ to DBP formation after chlorination.The predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows： chloroform〉dichloroacetic acid〉trichloroacetic acid.展开更多
The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlor...The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U（RCS） and hydroxyl radicals（HO） in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine（TOCl）, respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.展开更多
基金Acknowledgements The authors gratefully acknowledge the assistance of Prof. Hongying Hu and Prof. Zhimin Qiang in designing the experiments. Besides, we are thankful to doctor candidates Ke XU （in Prof. Zhimin Qiang＇s laboratory） and Peirui Liu （in Prof. Yu Hong＇s laboratory） for polishing the article. This research project was financially supported by National Natural Science Foundation （Grant No. 51571034） and the Beijing Nova and Leading Talents Cultivation Program （No. Z1511000003150147）.
文摘When microalgae are simultaneously applied for wastewater treatment and lipid production, soluble algal products （SAP） should be paid much attention, as they are important precursors for formation of disinfection byproducts （DBPs）, which have potential risks for human health. Chlorella sp. HQ is an oleaginous microalga that can generate SAP during growth, especially in the exponential phase. This study investigated the contribution of SAP from Chlorella sp. HQ to DBP formation after chlorination.The predominant DBP precursors from SAP were identified with the 3D excitation-emission matrix fluorescence. After chlorination, a significant reduction was observed in the fluorescence intensity of five specific fluorescence regions, particularly aromatic proteins and soluble microbial by-product-like regions, accompanied with slight shifting of the peak. The produced DBPs were demonstrated to include trihalomethanes and haloacetic acids. As the algal cultivation time was extended in wastewater, the accumulated SAP strengthened the formation of DBPs. The trend for DBP formation was as follows： chloroform〉dichloroacetic acid〉trichloroacetic acid.
基金supported by the Hong Kong Research Grant Council (grant number 16208914)
文摘The formation of disinfection by-products（DBPs） from the degradation of N,N-diethyl-3-methyl benzoyl amide（DEET） and ibuprofen（IBP） by the ultraviolet irradiation（UV）/chlorine process and subsequent post-chlorination was investigated and compared with the UV/H_2O_2 process.The pseudo first-order rate constants of the degradation of DEET and IBP by the UV/chlorine process were 2 and 3.1 times higher than those by the UV/H_2O_2 process, respectively, under the tested conditions. This was due to the significant contributions of both reactive chlorine species U（RCS） and hydroxyl radicals（HO） in the UV/chlorine process. Trichloromethane, 1,1,1-trichloro-2-propanone and dichloroacetic acid were the major known DBPs formed after 90% of both DEET and IBP that were degraded by the UV/chlorine process. Their yields increased by over 50%after subsequent 1-day post-chlorination. The detected DBPs after the degradation of DEET and IBP comprised 13.5% and 19.8% of total organic chlorine（TOCl）, respectively, and the proportions increased to 19.8% and 33.9% after subsequent chlorination, respectively. In comparison to the UV/H_2O_2 process accompanied with post-chlorination, the formation of DBPs and TOCl in the UV/chlorine process together with post-chlorination was 5%–63% higher,Ulikely due to the generation of more DBP precursors from the attack of RCS, in addition to HO.
