A biological aerated filter （BAF） was evaluated as a fixed-biofilm process to remove water-borne volatile organic compounds （VOCs） from a multiple layer ceramic capacitor （MLCC） manufacturing plant in southern T...A biological aerated filter （BAF） was evaluated as a fixed-biofilm process to remove water-borne volatile organic compounds （VOCs） from a multiple layer ceramic capacitor （MLCC） manufacturing plant in southern Taiwan. The components of VOC were identified to be toluene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, bromodichloromethane and isopropanol （IPA）. The full-scale BAF was constructed of two separate reactors in series, respectively, using 10- and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility. Experimental results show that the BAF removed over 90% chemical oxygen demand （COD） from the influent with （1188 ± 605） mg/L of COD. A total organic loading of 2.76 kg biochemical oxygen demand （BOD）/（m3 packing·d） was determined for the packed bed, in which the flow pattern approached that of a mixed flow. A limited VOC concentration of （0.97 ± 0.29） ppmv （as methane） was emitted from the BAF system. Moreover, the emission rate of VOC was calculated using the proposed formula, based on an air-water mass equilibrium relationship, and compared to the simulated results obtained using the Water 9 model. Both estimation approaches of calculation and model simulation revealed that 0.1% IPA （0.0031-0.0037 kg/d） were aerated into a gaseous phase, and 30% to 40% （0.006-0.008 kg/d） of the toluene were aerated.展开更多
The indoor total volatile organic compound (TVOC) concentrations and their relationship to potential influencing factors were evaluated. Samples (n = 2302) were collected from 2007 to 2009 both in old structures and n...The indoor total volatile organic compound (TVOC) concentrations and their relationship to potential influencing factors were evaluated. Samples (n = 2302) were collected from 2007 to 2009 both in old structures and new construction in the city of Hangzhou from bedrooms, sitting rooms and studies that had been decorated within the previous year. The average TVOC concentration in all the newly decorated rooms was 0.65±0.69 mg/m 3 . 35.8% of samples exceeded the China standard. Over the past 3 years, the TVOC concentration decreased and then increased (P < 0.05). The percentage of samples exceeding the China standard in the three rooms decreased in the following order: sitting room>study>bedroom. The characteristics of the TVOC source were a key factor influencing the TVOC concentration. In addition, the TVOC concentration was also (P < 0.05) related to the temperature, humidity, time from the end of decoration to sampling (DR), and the amount of time windows and doors were closed before sampling (DC). The temperature and humidity were less important than the DR and DC. A model to relate the TVOC concentration to the five factors (temperature, humidity, source, DR, and DC) was established based on 288 samples (R 2 = 0.83). The model illustrated that the time for the TVOC concentration to meet the China standard was different for the various rooms, and when the other factors were fixed, the impact of DC (t 1 ) on the TVOC concentration could be quantified as (((t 1 +1)/2) 0.212 1)×100%.展开更多
文摘A biological aerated filter （BAF） was evaluated as a fixed-biofilm process to remove water-borne volatile organic compounds （VOCs） from a multiple layer ceramic capacitor （MLCC） manufacturing plant in southern Taiwan. The components of VOC were identified to be toluene, 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, bromodichloromethane and isopropanol （IPA）. The full-scale BAF was constructed of two separate reactors in series, respectively, using 10- and 15-cm diameter polypropylene balls as the packing materials and a successful preliminary bench-scale experiment was performed to feasibility. Experimental results show that the BAF removed over 90% chemical oxygen demand （COD） from the influent with （1188 ± 605） mg/L of COD. A total organic loading of 2.76 kg biochemical oxygen demand （BOD）/（m3 packing·d） was determined for the packed bed, in which the flow pattern approached that of a mixed flow. A limited VOC concentration of （0.97 ± 0.29） ppmv （as methane） was emitted from the BAF system. Moreover, the emission rate of VOC was calculated using the proposed formula, based on an air-water mass equilibrium relationship, and compared to the simulated results obtained using the Water 9 model. Both estimation approaches of calculation and model simulation revealed that 0.1% IPA （0.0031-0.0037 kg/d） were aerated into a gaseous phase, and 30% to 40% （0.006-0.008 kg/d） of the toluene were aerated.
基金supported by the National Natural Science Foundation of China (20890111,20977075)National High-Tech R&D Program of China (2010AA064902)the Key Innovation Team for Science and Technology of Zhejiang Province (2009R50047)
文摘The indoor total volatile organic compound (TVOC) concentrations and their relationship to potential influencing factors were evaluated. Samples (n = 2302) were collected from 2007 to 2009 both in old structures and new construction in the city of Hangzhou from bedrooms, sitting rooms and studies that had been decorated within the previous year. The average TVOC concentration in all the newly decorated rooms was 0.65±0.69 mg/m 3 . 35.8% of samples exceeded the China standard. Over the past 3 years, the TVOC concentration decreased and then increased (P < 0.05). The percentage of samples exceeding the China standard in the three rooms decreased in the following order: sitting room>study>bedroom. The characteristics of the TVOC source were a key factor influencing the TVOC concentration. In addition, the TVOC concentration was also (P < 0.05) related to the temperature, humidity, time from the end of decoration to sampling (DR), and the amount of time windows and doors were closed before sampling (DC). The temperature and humidity were less important than the DR and DC. A model to relate the TVOC concentration to the five factors (temperature, humidity, source, DR, and DC) was established based on 288 samples (R 2 = 0.83). The model illustrated that the time for the TVOC concentration to meet the China standard was different for the various rooms, and when the other factors were fixed, the impact of DC (t 1 ) on the TVOC concentration could be quantified as (((t 1 +1)/2) 0.212 1)×100%.
