Enhancing denitrification efficiency for nitrogen removal using waste sludge alkaline fermentation liquid as external carbon source
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External carbon source was usually added to enhance denitrification efficiency for nitrogen removal in wastewater treatment. In this study, waster sludge alkaline fermentation liquid was successfully employed as an alternative carbon source for biological denitrification. The denitrification performance was studied at different C/Ns (carbon-to-nitrogen ratios) and HRTs (hydraulic retention times). A C/N of 7 and an HRT of 8 h were the optimal conditions for denitrification. The nitrate removal efficiency of 96.4% and no obvious nitrite accumulation in the effluent were achieved under the optimal conditions with a low soluble chemical oxygen demand (SCOD) level. The sludge carbon source utilization was analyzed and showed that the volatile fatty acids (VFAs) were prior utilized than proteins and carbohydrates. The excitation-emission matrix (EEM) spectroscopy with fluorescence regional integration (FRI) was adopted to analyze the compositional and variations of dissolved organic matters (DOM). Moreover, a high denitrification rate (VDN) and potential (PDN) with low heterotroph anoxic yield (YH) was exhibited at the optimal C/N and HRT condition, indicating the better denitrification ability and organic matter utilization efficiencies.
KeywordsDenitrification Carbon source Sludge alkaline fermentation C/N HRT Kinetics analysis
The study was supported by the Natural Science Foundation of Shandong (Grant Number: ZR2017MEE067), Sciences and Technology Project of Qingdao (Grant Number:16-5-1-20-jch), Open Fund of Laboratory for Marine Ecology and Environmental Science, Qingdao National Laboratory for Marine Science and Technology (LMEES201805), China Scholarship Council-International Clean Energy Innovation Talent (iCET) program, and the Ocean University of China-Auburn University (OUC-AU) grants program.
- APHA (1998) Standard methods for the examination of water and wastewater. APHA, Washington, DCGoogle Scholar
- Guo L, Lu MM, Li QQ, Zhang JW, Zong Y, She ZL (2014) Three-dimensional fluorescence excitation-emission matrix (EEM) spectroscopy with regional integration analysis for assessing waste sludge hydrolysis treated with multi-enzyme and thermophilic bacteria. Bioresour Technol 171:22–28CrossRefGoogle Scholar
- Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275Google Scholar