The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic proc...The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic process of the petrochemical refinery. The method involved the biological shortcut nitrification and denitrification lab-scale’s sequencing batch reactor (SBR) process based on intermittent aerations and aeration patterns. All the operations were carried out in a 20 L working volume SBR bioreactor, and the influent synthetic wastewater’s concentration was always 1000 mg/L ammonia-nitrogen NH<sub>4</sub>-N concentration at a C/N (carbon/nitrogen) ratio of 2.5:1. Effective shortcut nitrification to nitrite was registered at 1.1 mg-O<sub>2</sub>/L (i.e. 9 L-air/min) with 99.1% nitrification efficiency, 99.0% nitritation rate and 2.6 mg-NO<sub>3</sub>-</sup>-N/L nitrate concentration. The best results with 99.3% nitrification efficiency were recorded when operating at 1.4 mg-O<sub>2</sub>/L (i.e. 12 L-air/min). According to these experiments, it results that the nitrite accumulation rate was related to aeration rate and cycle’s duration. However, at 1.7 mg-O<sub>2</sub>/L (i.e. 15 L-air/min), the system was limited by an increase in nitrate concentration with more than 5 mg/L which could be a point of reverse to conventional nitrification. The best total nitrogen (TN) removal was about 71.5%.展开更多
The main purpose of this work is to investigate the characteristics of night soil and leaf co-composting using aerobic static composting method. Three influencing factors, including proportion of night soil and leaf, ...The main purpose of this work is to investigate the characteristics of night soil and leaf co-composting using aerobic static composting method. Three influencing factors, including proportion of night soil and leaf, aeration rate and aeration pattern, were investigated through the evolution of the principal physicochemical properties, i.e., temperature, oxygen consumption rate, organic matters, moisture content, carbon, nitrogen, carbon-to-nitrogen ratio and Germination index （GI）. It was found that the 3：1 （w：w） mixture of night soil and leaf was capable of achieving the highest composting temperature, longest retention time of high temperature （55℃）, and fastest organic matter degradation. The 0.14 m3. min-1. m-3 aeration rate was most beneficial to composting, and the mixture of night soil and leaf maintained the highest temperature for the longest duration and achieved the highest CO2 content and GI. The continuous aeration pattern during composting was superior to an intermittent aeration pattern, since the latter delayed the composting process.展开更多
文摘The effects of aeration rates and aeration patterns on the oxidation of ammonia-nitrogen into nitrite were investigated. The influent high ammonia-nitrogen synthetic wastewater resembled to those of the catalytic process of the petrochemical refinery. The method involved the biological shortcut nitrification and denitrification lab-scale’s sequencing batch reactor (SBR) process based on intermittent aerations and aeration patterns. All the operations were carried out in a 20 L working volume SBR bioreactor, and the influent synthetic wastewater’s concentration was always 1000 mg/L ammonia-nitrogen NH<sub>4</sub>-N concentration at a C/N (carbon/nitrogen) ratio of 2.5:1. Effective shortcut nitrification to nitrite was registered at 1.1 mg-O<sub>2</sub>/L (i.e. 9 L-air/min) with 99.1% nitrification efficiency, 99.0% nitritation rate and 2.6 mg-NO<sub>3</sub>-</sup>-N/L nitrate concentration. The best results with 99.3% nitrification efficiency were recorded when operating at 1.4 mg-O<sub>2</sub>/L (i.e. 12 L-air/min). According to these experiments, it results that the nitrite accumulation rate was related to aeration rate and cycle’s duration. However, at 1.7 mg-O<sub>2</sub>/L (i.e. 15 L-air/min), the system was limited by an increase in nitrate concentration with more than 5 mg/L which could be a point of reverse to conventional nitrification. The best total nitrogen (TN) removal was about 71.5%.
文摘The main purpose of this work is to investigate the characteristics of night soil and leaf co-composting using aerobic static composting method. Three influencing factors, including proportion of night soil and leaf, aeration rate and aeration pattern, were investigated through the evolution of the principal physicochemical properties, i.e., temperature, oxygen consumption rate, organic matters, moisture content, carbon, nitrogen, carbon-to-nitrogen ratio and Germination index （GI）. It was found that the 3：1 （w：w） mixture of night soil and leaf was capable of achieving the highest composting temperature, longest retention time of high temperature （55℃）, and fastest organic matter degradation. The 0.14 m3. min-1. m-3 aeration rate was most beneficial to composting, and the mixture of night soil and leaf maintained the highest temperature for the longest duration and achieved the highest CO2 content and GI. The continuous aeration pattern during composting was superior to an intermittent aeration pattern, since the latter delayed the composting process.
