Optimization of denitrification treatment process of fuel ethanol wastewater based on carbon source
NING Xingfang1,, CUI Haiwei2, DU Jinbao1, YANG Yang2,, 1.Guangdong Bio-Energy of SDIC Co.Ltd., Zhanjiang 524399, China 2.Beijing Guodian Longyuan Environmental Engineering Co.Ltd., Beijing 100039, China
Abstract:The C/N ratio in the A/O influent of the the rice fuel ethanol DDG wastewater treatment process in a plant was too low to meet the the discharge standard of total nitrogen for the effluent. In this study, the carbon sources in the denitrification system were screened, and a suitable carbon source was determined and the wastewater treatment process was adjusted for the increase of denitrification efficiency. The carbon source screening test was conducted among the three carbon sources of glucose, ethanol and clear liquid (raw wastewater). The changes of pH value and total nitrogen concentration in the the reaction system were invetigated, then the total nitrogen removal rates and operating costs were compared when different carbon sources are added to the denitrification system. The results showed that the when ethanol was taken as carbon source, the fastest removal rate of total nitrogen occurred with a value of 8.33 mg·(L·h)?1, which was 1.1 or 1.18 times of the carbon source of glucose or clear liquid (raw wastewater), respectively. The operating cost with the carbon source of raw wastewater was 9% of ethanol and 37% of glucose, respectively. Through the comprehensive analysis and comparison of denitrification reaction rate and operating cost among different carbon sources additions for denitrification, the best choice was to add raw wastewater to adjust A/O denitrification process in this wastewater treatment plant. After verification in field process, when the total nitrogen in the influentt of A/O system was about 300~600 mg·L?1 and the COD/TN ratio in the wastewater was above 12.1 by adding raw wastewater, the effluent total nitrogen concentration could be stablized lower than 50 mg·L?1. The research provides an economic and reasonable carbon supplement scheme for DDG wastewater treatment, and provides a reference for fermentation wastewater treatment with good biodegradability. Key words:rice fuel ethanol DDG wastewater/ total nitrogen/ denitrification/ carbon source.
图1某污水站工艺流程图 Figure1.Process diagram of wastewater treatment plant
AKUNNA J C, BIZEAU C, MOLETTA R. Nitrate reduction by anaerobic sludge using glucose at various nitrate concentrations: Ammonification, denitrification and methanogenic activities[J]. Environmental Technology, 1994, 15(1): 41-49. doi: 10.1080/09593339409385402
1.Guangdong Bio-Energy of SDIC Co.Ltd., Zhanjiang 524399, China 2.Beijing Guodian Longyuan Environmental Engineering Co.Ltd., Beijing 100039, China Received Date: 2020-03-09 Accepted Date: 2020-06-23 Available Online: 2021-01-13 Keywords:rice fuel ethanol DDG wastewater/ total nitrogen/ denitrification/ carbon source Abstract:The C/N ratio in the A/O influent of the the rice fuel ethanol DDG wastewater treatment process in a plant was too low to meet the the discharge standard of total nitrogen for the effluent. In this study, the carbon sources in the denitrification system were screened, and a suitable carbon source was determined and the wastewater treatment process was adjusted for the increase of denitrification efficiency. The carbon source screening test was conducted among the three carbon sources of glucose, ethanol and clear liquid (raw wastewater). The changes of pH value and total nitrogen concentration in the the reaction system were invetigated, then the total nitrogen removal rates and operating costs were compared when different carbon sources are added to the denitrification system. The results showed that the when ethanol was taken as carbon source, the fastest removal rate of total nitrogen occurred with a value of 8.33 mg·(L·h)?1, which was 1.1 or 1.18 times of the carbon source of glucose or clear liquid (raw wastewater), respectively. The operating cost with the carbon source of raw wastewater was 9% of ethanol and 37% of glucose, respectively. Through the comprehensive analysis and comparison of denitrification reaction rate and operating cost among different carbon sources additions for denitrification, the best choice was to add raw wastewater to adjust A/O denitrification process in this wastewater treatment plant. After verification in field process, when the total nitrogen in the influentt of A/O system was about 300~600 mg·L?1 and the COD/TN ratio in the wastewater was above 12.1 by adding raw wastewater, the effluent total nitrogen concentration could be stablized lower than 50 mg·L?1. The research provides an economic and reasonable carbon supplement scheme for DDG wastewater treatment, and provides a reference for fermentation wastewater treatment with good biodegradability.
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