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In order to solve the problems of difficult selection of carbon sources and high cost of dosage in advanced treatment of wastewater treatment plant, denitrification biological filter was used to explore the denitrification performance of different carbon sources. In this study, the denitrification performance of three carbon sources (sodium acetate, ethanol and methanol) at different hydraulic retention time (HRT), nitrogen ratio (C/N) and influent NH4+-N concentration and the microbial community structure at different heights of the reactor were investigated. The results showed that under the condition of low carbon nitrogen ratio, as the HRT increased, the removal efficiency of NH4+-N and NO3--N in the effluent of three systems with sodium acetate ethanol and methanol as carbon sources gradually increased, and the accumulation of NO2--N in methanol system was the lowest in the three systems. With the gradual increase of carbon to C/N, the concentration of NH4+-N and NO3--N in the three systems gradually decreased. The effluent TN concentration of sodium acetate and methanol system was less than 1.5 mg/L when C/N was 6 and 5, which met the Class W of Environmental Quality Standard for Surface Water. With the increase of influent NH4+-N concentration, it led to the increase of NO2--N accumulation degree, resulting in the increase of effluent TN concentration. Carbon sources led to significant differences in the abundance of the three systems at the phylum level. The differences at the genus level were more obvious, and the total relative abundance of denitrifying bacteria was in the order of sodium acetate system > ethanol system > methanol system. The results of this study can provide a theoretical reference for the selection of carbon source and the use of dosage in waste-water treatment plants. [ABSTRACT FROM AUTHOR]

In response to the problems of insufficient denitrification and poor denitrification effect of traditional constructed wetlands for the treatment of livestock biogas slurry, in this study Chlorella sorokiniana was used as an additional carbon source for the construction of C. sorokiniana - constructed wetland systems to treat piggery biogas slurry. The effect of the system on the removal of water quality of piggery biogas slurry and the change rule of the dissolved organic matters (DOMs) through the addition of C. sorokiniana under different concentrations (0, 0.25, 0.5 and 1.0 g/L) were investigated, and the mechanism of en- hanced nitrogen removal was explored from the perspective of microorganisms. The results showed that compared with the constructed wetland without the addition of C. sorokiniana, the removal of total nitrogen was obviously increased up to 70.24%, and the removal of nitrate nitrogen reached up to 93.45%. Based on the three-dimensional fluorescence parallel factor analysis, the three components in DOMs were fulvic acid/humic acid-like substances, polymer aromatic substances and humic acid-like substances, while the addition of C. sorokiniana enhanced the removal of DOMs from piggery biogas slurry and reduced the content of humic acid-like substances. The addition of C. sorokiniana evidently increased the Alpha diversity of microorganisms in the constructed wetland. Particularly, at the phylum level the relative abundance of dominant bacteria related to denitrification (Proteobacteria) increased obviously, while at the genus level the genera Nitrosomonas and Limnobacter played important roles in the ammonia oxidation and denitrification processes of the system. This study provides theoretical support for the use of C. sorokiniana as an additional carbon source to enhance nitrogen and phosphorus removal in constructed wetlands. [ABSTRACT FROM AUTHOR]

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Copyright of Industrial Water Treatment is the property of CNOOC Tianjin Chemical Research & Design Institute and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Environmental Science & Technology (10036504) is the property of Editorial Board of Environmental Science & Technology and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Tunnel Construction / Suidao Jianshe (Zhong-Yingwen Ban) is the property of Tunnel Construction Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)