Characterization of atmospheric PM10 and related chemical species in southern Taiwan during the episode days

The concentrations of atmospheric PM10 on days with episodes of pollution were examined at four different sampling sites (CC, DL, LY, and HK) in southern Taiwan. The related to particulates water-soluble ionic species (Na+, K+, Mg2+, Ca2+, NH4+, Cl-, NO3-, SO4(2-)), carbonaceous species (EC and OC) and metallic species (Zn, Ni, Pb, Fe, Mn, Al, Si, V) were also analyzed. On the episode days of this study, the PM10 mass concentration ranged from 155 to 210 microgm(-3), from 150 to 208 microgm(-3), from 182 to 249 microgm(-3), and from 166 to 228 microgm(-3) at CC, DL, LY, and HK, respectively. The results indicate that the dominant water-soluble species were SO4(2-), NO3-, NH4+, and Cl- at the four sampling sites on these days. Moreover, the high sulfate and nitrate conversion values (SOR and NOR) presented herein suggest that secondary formations from SO2 to SO4(2-) and from NO2 to NO3- are present in significant quantities in the atmosphere of southern Taiwan on episode days. In particular, high SOR and NOR verified that both SO4(2-) and NO3- dominated the increase of atmospheric PM10 concentration in southern Taiwan on episode days.     

Trimethylbenzoic acids as metabolite signatures in the biogeochemical evolution of an aquifer contaminated with jet fuel hydrocarbons

Evolution of trimethylbenzoic acids in the KC-135 aquifer at the former Wurtsmith Air Force Base (WAFB), Oscoda, MI was examined to determine the functionality of trimethylbenzoic acids as key metabolite signatures in the biogeochemical evolution of an aquifer contaminated with JP-4 fuel hydrocarbons. Changes in the composition of trimethylbenzoic acids and the distribution and concentration profiles exhibited by 2,4,6- and 2,3,5-trimethylbenzoic acids temporally and between multilevel wells reflect processes indicative of an actively evolving contaminant plume. The concentration levels of trimethylbenzoic acids were 3-10 orders higher than their tetramethylbenzene precursors, a condition attributed to slow metabolite turnover under sulfidogenic conditions. The observed degradation of tetramethylbenzenes into trimethylbenzoic acids obviates the use of these alkylbenzenes as non-labile tracers for other degradable aromatic hydrocarbons, but provides rare field evidence on the range of high molecular weight alkylbenzenes and isomeric assemblages amenable to anaerobic degradation in situ. The coupling of actual tetramethylbenzene loss with trimethylbenzoic acid production and the general decline in the concentrations of these compounds demonstrate the role of microbially mediated processes in the natural attenuation of hydrocarbons and may be a key indicator in the overall rate of hydrocarbon degradation and the biogeochemical evolution of the KC-135 aquifer.     

碳氮磷比例失调城市污水的同步脱氮除磷

为解决现行同步脱氮除磷工艺处理南方地区碳、氮、磷比例失调城市污水中,因C/N、C/P偏低,碳源不足而降低脱氮除磷效率的难题,试验以碳源偏低的广州市城市污水为研究对象,采用厌氧/好氧交替运行的SBR系统,通过对厌氧、好氧时段的合理调控,在无需额外添加碳源的条件下,有机物、氨氮、总氮和总磷的平均去除率分别可达90%、72%、41%和99%,不仅能使有机物和氮的出水指标达到国家排放标准,而且总磷出水浓度能达0.5 mg/L以下。通过进一步分析同步高效脱氮除磷的影响因素和控制条件,得出合理污泥龄的控制是实现同步脱氮除磷的关键,厌氧/好氧交替运行的方式不仅强化了磷的释放和吸收,而且降低了碳源偏低和硝酸盐对同步脱氮除磷影响的结论。     

Adsorption of nitrosamines in acidic solution by zeolites

Adsorption of N-nitrosopyrrolidine (NPYR) by zeolite NaZSM-5, Hbeta and NaZSM-11 in acidic solution with pH of 1 was investigated. The NPYR uptake process obeyed the first-rate Lagegren kinetic equation describing adsorption, and the equilibrium data were fitted to the Langmuir or Freundlich adsorption equation. Zeolite ZSM-5, Hbeta and NaZSM-11 possessed a higher adsorption capacity than amorphous silica or ordered mesoporous siliceous SBA-15, implying their potential application for adsorption of nitrosamines in gastric juice to anti-cancer.     

Microbial community and biochemistry process in autosulfurotrophic denitrifying biofilm

The 16S rDNA-based molecular technique was applied to analyze the microbial community of autotrophic denitrification bacteria in a biofilm developed on the surface of sulfur particles and then the biochemistry process involved in this biofilm was discussed based on the microbial community analysis. Six key operational taxonomy units were identified, which were all unknown species belonging to a wide range of bacteria from four major subdivisions (alpha, beta, gamma and delta) of the kingdom Proteobacteria and from the kingdom Chlorobia (green sulfur bacteria). One species was chemoautotrophic and related to Thiobacillus denitrificans, two species were photoautotrophic, and three were chemoheterotrophic. Contrary to expectation, T. denitrificans-like bacteria constituted only 32% of the microbial community. As a result of the study, the entire microbiology of the autosulfurotrophic denitrification process as well as the interactions between the different microbial groups in the biofilm may need to be reconsidered.     

DO和pH值在短程硝化中的作用

在SBR反应器中对DO和pH值在短程硝化和半亚硝化过程中的作用进行试验研究,结果表明,控制低DO和适宜的pH值在短程硝化过程中起着重要的作用.本试验条件下,当DO为0.5～1.0 mg/L、pH值为7.5～8.0时,在SBR反应器中很容易实现短程硝化;当DO＞0.3 mg/L时,DO越低,出水NO2--N积累率越高;当pH值＞6.8时,不会影响系统NO2--N积累的稳定性.另外,研究结果还表明,通过控制DO和pH值可以实现半亚硝化.本试验条件下,当进水氨氮浓度为120 mg/L时,控制DO为0.3～0.4 mg/L可实现出水半亚硝化;当进水氨氮浓度为200 mg/L时,控制DO为0.5～0.6 mg/L或pH值为6.8也可以实现出水半亚硝化.     

错流式动态膜-生物反应器中污泥活性的研究

应用错流式动态膜-生物反应器(CDMBR)对己内酰胺废水进行了180 d的实验,实验过程中测定反应器的膜出水和上清液的水质,并对污泥进行了耗氧呼吸速率测定.结果表明,上清液COD一直保持在100mg/L以下,而膜出水的则保持在50 mg/L以下,膜对上清液的COD去除率达50%,而对氮的去除没有贡献.可溶性细胞产物(SMP)在反应器内容易积累,停留足够的时间后能被生物降解.通过投加抑制剂测定耗氧呼吸速率,发现异养菌、硝化细菌和亚硝化细菌的活性由于F/M的降低和SMP积累受到一定的抑制,但不影响系统的处理效率.跨膜压力、膜面流速越大,通量衰减得也就越快.     

钴铜铁三元类水滑石材料催化过硫酸氢钾复合盐降解苯酚

采用共沉淀法制备过渡金属钴、铜、铁组成的钴铜铁三元类水滑石材料(CoCuFe-LDH),用于催化过硫酸氢钾复合盐(PMS)降解水中苯酚,并考察了初始pH、CoCuFe-LDH催化剂投加量、PMS用量对苯酚降解效率的影响。实验结果表明:CoCuFeLDH对PMS的催化活性较高;在pH为中性,催化剂为0.20g/L,PMS为2.5mmol/L,苯酚为50mg/L的条件下处理60min,苯酚的去除率可达96%;当催化剂投加量分别为0.05、0.10、0.15g/L,反应40min时,苯酚的去除率分别为76%、82%和91%。自由基猝灭实验表明,CoCuFe-LDH/PMS催化体系中存在硫酸根自由基和羟基自由基,但硫酸根自由基为主要活性自由基。     

Removal of carbon dioxide by a spray dryer

With the global warming due to greenhouse effects becoming serious, many efforts are carried out to decrease the emissions of CO2 from the combustion of carbonaceous materials. In Taiwan, there are 19 large-scale municipal solid waste incinerators running and their total emission of CO2 is about 16,950 kton y-1. Spray dryer is the most prevailing air pollution control devise for removing acid gas in waste incineration; however, the performance of spray dryer on the removal of CO2 is seldom studied. This study employs a laboratory-scale spray dryer to investigate the removal efficiency of CO2 under different operating conditions. The evaluated parameters include different absorbents mixed with CaOH2, operating temperature, the concentration of absorbent, and the inlet concentration of CO2. Experimental results show that the best removal efficiency of CO2 by a spray dryer is 48% as the absorbent is 10%NaOH+5%CaOH2 and the operating temperature is 150 degrees C. Comparing this result with previous study shows that the performance of spray dryer is better than traditional NaOH wet scrubber. For NaOH+CaOH2 spray dryer, the removal efficiency of CO2 is decreased with the inlet concentration of CO2 increased and the optimum operating temperature is 150 degrees C. Except NaOH+CaOH2, absorbents DEA+CaOH2, TEA+CaOH2, and single CaOH2 are not effective in removing CO2 by a spray dryer.     

田湾核电站外围辐射环境监测工作的质量保证

总结了田湾核电站外围辐射环境监测中的质量保证实施情况，包括：人员培训和考核，仪器设备溯源，样品采集、运输、贮存及生物样品前处理的质控，样品分析和现场监测的质控，数据的记录处理和管理要求等，最后提出几点建议。