Biogas purification via water scrubbing produces effluent containing dissolved CH4, H2S,and CO2, which should be removed to reduce greenhouse gas emissions and increase its potential for water regeneration. In this st...Biogas purification via water scrubbing produces effluent containing dissolved CH4, H2S,and CO2, which should be removed to reduce greenhouse gas emissions and increase its potential for water regeneration. In this study, a reactor built with air supplies at the top and bottom was utilized for the treatment of biogas purification effluent through biological oxidation and physical stripping processes. Up to 98% of CH4 was removed through biological treatment at a hydraulic retention time of 2 hr and an upper airflow rate of 2.02 L/day. Additionally, a minimum CH4 concentration of 0.04% with no trace of H2S gas was detected in the off gas. Meanwhile, a white precipitate was captured on the carrier showing the formation of sulfur. According to the developed mathematical model, an upper airflow rate of greater than 2.02 L/day showed a small deterioration in CH4 removal performance after reaching the maximum value, whereas a 50 L/day bottom airflow rate was required to strip the CO2 efficiently and raise the effluent p H from 5.64 to 7.3. Microbiological analysis confirmed the presence of type 1 methanotroph communities dominated by Methylobacter and Methylocaldum. However, bacterial communities promoting sulfide oxidation were dominated by Hyphomicrobium.展开更多
To understand the change regions of pH and the effect on phytoplankton while the acidic effluent of desulfuration from power plants drai- ning into seawater, the changing modes of phytoplankton species and quantity to...To understand the change regions of pH and the effect on phytoplankton while the acidic effluent of desulfuration from power plants drai- ning into seawater, the changing modes of phytoplankton species and quantity to pH were established in seawater through laboratory survey in this work. Then, the ECOMSED model was applied to predict the change scope of pH and the ecological influences on phytoplankton due to the acidic effluent from a programming power plant in Zhanjiang Bay. The experimental results in laboratory showed that the species of phytoplankton changed with pH in a rule of convex parabola, and the quantity of phytoplankton decreased linearly with the fall of pH. The results of pH numerical simulation indicated that the acidic effluent from the power plant flowed zonally with tide. When the pH value of surface seawater decreased from the back- ground value of 8.0 to 7.8, the extreme area influenced harmfully by the acidic effluent was near 30.70 km2, accounting for about 16.2% of the to- tal area of Zhanjiang Bay （190 km2）. The predict results of ecological impact showed that if the species and quantity of phytoplankton decreased by 5% in surface seawater, the corresponding extreme areas influenced harmfully by the acidic effluent were 0.40 and 10.81 km2, accounting respec- tively for 0.21% and 0.53% of the total area of Zhanjiang Bay. Moreover, around the outlet of the power plant where the pH value of seawater was near to 6.8, the species and quantity of phytoplankton decreased most. However, the corresponding influenced area was rather small, just about 0.15 km2, accounting for 0.08% of the total area of Zhanjiang Bay.展开更多
Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidat...Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidation technology to eliminate micropollutants in water treatment.Due to the complexity of the wastewater matrix,orthogonal experiments and single factor experiments were conducted to study the influence of operational parameters on the degradation of 17α-ethinylestradiol（EE2） in the synthetic secondary effluent.The results of the orthogonal experiments indicated that the initial ozone and natural organic matter（NOM） concentration significantly affected EE2 degradation efficiency,which was further validated by the single factor confirmation experiments.EE2 was shown to be effectively degraded by ozonation in the conditions of low pH（6）,NOM（10 mg/L）,carbonate（50 mg/L）,but high suspended solid（20 mg/L） and initial ozone concentration（9 mg/L）.The study firstly revealed that the lower pH resulted in higher degradation of EE2 in the synthetic secondary effluent,which differed from EDCs ozonation behavior in pure water.EE2 degradation by ozone molecule instead of hydroxyl radical was proposed to play a key role in the degradation of EDCs by ozonation in the secondary effluent.The ratio between O3 and TOC was identified as an appropriate index to assess the degradation of EE2 by ozonation in the synthetic secondary effluent.展开更多
基金supported by the Japan Society for the Promotion of Sciences as a Grant-in-Aid for Scientific Research(A)(grant number JP23241029)
文摘Biogas purification via water scrubbing produces effluent containing dissolved CH4, H2S,and CO2, which should be removed to reduce greenhouse gas emissions and increase its potential for water regeneration. In this study, a reactor built with air supplies at the top and bottom was utilized for the treatment of biogas purification effluent through biological oxidation and physical stripping processes. Up to 98% of CH4 was removed through biological treatment at a hydraulic retention time of 2 hr and an upper airflow rate of 2.02 L/day. Additionally, a minimum CH4 concentration of 0.04% with no trace of H2S gas was detected in the off gas. Meanwhile, a white precipitate was captured on the carrier showing the formation of sulfur. According to the developed mathematical model, an upper airflow rate of greater than 2.02 L/day showed a small deterioration in CH4 removal performance after reaching the maximum value, whereas a 50 L/day bottom airflow rate was required to strip the CO2 efficiently and raise the effluent p H from 5.64 to 7.3. Microbiological analysis confirmed the presence of type 1 methanotroph communities dominated by Methylobacter and Methylocaldum. However, bacterial communities promoting sulfide oxidation were dominated by Hyphomicrobium.
基金Supported by Science Research Special Item of Marine Public Service Sectors of State Oceanic Administration,China(2013418038-6)
文摘To understand the change regions of pH and the effect on phytoplankton while the acidic effluent of desulfuration from power plants drai- ning into seawater, the changing modes of phytoplankton species and quantity to pH were established in seawater through laboratory survey in this work. Then, the ECOMSED model was applied to predict the change scope of pH and the ecological influences on phytoplankton due to the acidic effluent from a programming power plant in Zhanjiang Bay. The experimental results in laboratory showed that the species of phytoplankton changed with pH in a rule of convex parabola, and the quantity of phytoplankton decreased linearly with the fall of pH. The results of pH numerical simulation indicated that the acidic effluent from the power plant flowed zonally with tide. When the pH value of surface seawater decreased from the back- ground value of 8.0 to 7.8, the extreme area influenced harmfully by the acidic effluent was near 30.70 km2, accounting for about 16.2% of the to- tal area of Zhanjiang Bay （190 km2）. The predict results of ecological impact showed that if the species and quantity of phytoplankton decreased by 5% in surface seawater, the corresponding extreme areas influenced harmfully by the acidic effluent were 0.40 and 10.81 km2, accounting respec- tively for 0.21% and 0.53% of the total area of Zhanjiang Bay. Moreover, around the outlet of the power plant where the pH value of seawater was near to 6.8, the species and quantity of phytoplankton decreased most. However, the corresponding influenced area was rather small, just about 0.15 km2, accounting for 0.08% of the total area of Zhanjiang Bay.
基金supported by the National High Technology Research and Development Program (863) of China (No.2008AA062502)
文摘Endocrine disrupting chemicals（EDCs） in the secondary effluent discharged from wastewater treatment plants（WWTPs） are of great concern in the process of water reuse.Ozonation has been reported as a powerful oxidation technology to eliminate micropollutants in water treatment.Due to the complexity of the wastewater matrix,orthogonal experiments and single factor experiments were conducted to study the influence of operational parameters on the degradation of 17α-ethinylestradiol（EE2） in the synthetic secondary effluent.The results of the orthogonal experiments indicated that the initial ozone and natural organic matter（NOM） concentration significantly affected EE2 degradation efficiency,which was further validated by the single factor confirmation experiments.EE2 was shown to be effectively degraded by ozonation in the conditions of low pH（6）,NOM（10 mg/L）,carbonate（50 mg/L）,but high suspended solid（20 mg/L） and initial ozone concentration（9 mg/L）.The study firstly revealed that the lower pH resulted in higher degradation of EE2 in the synthetic secondary effluent,which differed from EDCs ozonation behavior in pure water.EE2 degradation by ozone molecule instead of hydroxyl radical was proposed to play a key role in the degradation of EDCs by ozonation in the secondary effluent.The ratio between O3 and TOC was identified as an appropriate index to assess the degradation of EE2 by ozonation in the synthetic secondary effluent.
