内电解法处理含N,N-二甲基乙酰胺工业废水

用内电解法处理含N,N-二甲基乙酰胺(DMAC)工业废水,研究pH、Fe∶C(体积比)、活性炭粒径和水力停留时间(HRT)等对该废水处理效果的影响,并确定最佳工艺条件。实验结果表明:在进水浓度维持在50 mg/L左右,最佳的工艺参数pH、Fe∶C和HRT分别为3.0、1∶1和60 min时,DMAC去除率高达到95%,处理水DMAC浓度小于5 mg/L。处理后废水的可生化性有明显的改善,BOD5/COD由0.21提高至0.66;而DMAC的去除基本符合二级动力学规律。     

Comparison of SOC estimates and uncertainties from aerosol chemical composition and gas phase data in Atlanta

In the Southeastern US, organic carbon (OC) comprises about 30% of the PM_2.5 mass. A large fraction of OC is estimated to be of secondary origin. Long-term estimates of SOC and uncertainties are necessary in the evaluation of air quality policy effectiveness and epidemiologic studies. Four methods to estimate secondary organic carbon (SOC) and respective uncertainties are compared utilizing PM_2.5 chemical composition and gas phase data available in Atlanta from 1999 to 2007. The elemental carbon (EC) tracer and the regression methods, which rely on the use of tracer species of primary and secondary OC formation, provided intermediate estimates of SOC as 30% of OC. The other two methods, chemical mass balance (CMB) and positive matrix factorization (PMF) solve mass balance equations to estimate primary and secondary fractions based on source profiles and statistically-derived common factors, respectively. CMB had the highest estimate of SOC (46% of OC) while PMF led to the lowest (26% of OC). The comparison of SOC uncertainties, estimated based on propagation of errors, led to the regression method having the lowest uncertainty among the four methods. We compared the estimates with the water soluble fraction of the OC, which has been suggested as a surrogate of SOC when biomass burning is negligible, and found a similar trend with SOC estimates from the regression method. The regression method also showed the strongest correlation with daily SOC estimates from CMB using molecular markers. The regression method shows advantages over the other methods in the calculation of a long-term series of SOC estimates.     

Concentrations, distribution, and bioaccumulation of synthetic musks in the Haihe River of China

Seven typical synthetic musks (SMs) in the samples from the surface water, sediment and fish of the Haihe River were measured. The SM concentrations in the sediment and surface water of the Haihe River were significantly lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Along the flow direction, the SM concentrations in surface water and sediment tended to increase from the upstream to the downstream of Dagu Drainage River. The Bioaccumulation factors (BAFs) of galaxolide (HHCB) and tonalide (AHTN) were calculated at high levels in the muscles of crucian carp, common carp, and silver carp. Most of the biota-sediment accumulation factors (BSAFs) for HHCB and AHTN were higher than 1.7, suggesting magnification possibly exist in the musk bioaccumulations of the three fishes in the Haihe River. No significant differences in HHCB/AHTN ratios were observed among the water, fish, and sediment samples (p > 0.05). However, the HHCB/AHTN values in the Haihe River were much lower than those in the Dagu Drainage River and Chentaizi Drainage River (p < 0.05). Compared with several typical persistent organic pollutants (POPs), the musk concentrations were higher or comparable in the Haihe River.     

Sources and distribution of polychlorinated-dibenzo-p-dioxins and -dibenzofurans in soil and sediment from the Yellow Sea region of China and Korea

Polychlorinated-dibenzo-p-dioxins and -dibenzofurans (PCDD/Fs) were measured in soils and sediments from the Yellow Sea region. Korean soils and sediments mostly contained detectable PCDD/Fs and showed a widespread distribution among locations. Soil and sedimentary PCDD/Fs from China were comparable to or less than those in Korea. The patterns of relative concentrations of individual congeners in soils were different between the two countries, but similar in sediments. Sources of PCDD/Fs in China and Korea were found to be independent of each other and their distributions reflected matrix-dependent accumulation. Spatial distribution indicated some point sources in Korea while Chinese sources were more widespread and diffuse. PCDD/Fs measured in the coastal areas of the Yellow Sea were comparable to or less than those previously reported in for eastern Asia. However, ∑TEQs in soils and sediments were near to or, in some cases exceeded environmental quality guidelines.     

PBDD/F impurities in some commercial deca-BDE

The study presented the concentrations and distributions of polybrominated dibenzo-p-dioxins and polybrominated dibenzofurans (PBDD/Fs) as impurities in some commercial decabromodiphenyl ether (DBDE) mixtures that were produced by several manufacturers. The total concentrations of 12 2,3,7,8-substituted tetra- to octa-BDD/F congeners were found to be in the range of 3.4-13.6 (mean 7.8) μg/g, averagely accounting for 99% of total PBDD/Fs. OBDF was the prevailing congener, followed by 1,2,3,4,6,7,8-HpBDF. In addition, OBDD and 1,2,3,4,7,8-HxBDF were also obviously detectable. The total concentrations of PBDD/Fs varied both between the manufacturers and between the lots. On the basis of the global demand for the commercial DBDE in 2001, the annual potential emissions of PBDD/Fs were calculated coarsely to be 0.43 (range: 0.21-0.78) tons. The major dioxin congeners, OBDF and 1,2,3,4,6,7,8-HpBDF, presenting in DBDE, were estimated to be formed from BDE-209, BDE-206, and/or BDE-207 via an intra-molecular elimination of Br₂/HBr.     

UV/H2O2工艺降解环丙沙星的研究

采用UV/₂O₂工艺去除水体中的喹诺酮类抗生素环丙沙星（CIP）。考察了溶液pH值、₂O₂投加量以及水体基质对环丙沙星降解效率的影响,分析了降解产物的生成情况。研究表明,环丙沙星的降解符合拟一级反应动力学模型。降解速率受溶液pH值的影响,酸性及中性条件,有利于环丙沙星的降解。₂O₂投加量的增大,使得降解速率逐渐增大,但速率增幅逐渐变缓;最佳₂O₂/环丙沙星摩尔比为2 000。实际水体中存在的NOM、NO^-₃,促进了单独UV作用下,环丙沙星的降解。水体中的?OH焠灭剂,抑制了UV/₂O₂联合作用下,环丙沙星的降解;实际水体中的光解速率常数低于超纯水中的光解速率常数。GC-MS分析表明,UV/₂O₂工艺,使环丙沙星氧化降解生成氨基乙酸、丙二酸、丙三醇和对苯二甲酸等小分子有机物。     

高声能密度超声波破碎污泥细胞效能的研究

采用超声波在较高声能密度下处理SBR的剩余污泥,主要考察了含固率、声能密度和作用时间对污泥细胞破碎效果的影响。结果表明,在声能密度0.5～3 W/mL内,含固率1%～1.5%的剩余污泥经超声波作用后,上清液SCOD随作用时间呈线性升高;在声能密度1～3 W/mL内,含固率0.25%～0.5%的剩余污泥经超声波作用后,上清液SCOD随作用时间呈平缓缓慢升高。高声能密度超声波更适合对较高含固率污泥的细胞破碎;此情况下,上清液SCOD增幅、NH4＋-N、TN及TP升幅均与声能密度正相关。经超声波作用6 min后,污泥形态结构已破坏。     

氧化节杆菌对铜溶液的吸附特性

以氧化节杆菌为吸附剂,处理Cu（NO3）2、CuSO4和CuCl2溶液,研究菌体对Cu2＋和NO3-的吸附效果,以及NO 3-、SO42-和Cl-对Cu2＋吸附的影响。结果表明氧化节杆菌对Cu2＋和NO 3-的吸附具有选择性。Cu2＋的吸附效果理想,0.1 g/L菌体在10 min时,对2 mg/L Cu2＋的吸附率达...     

诺氟沙星水溶液的湿式氧化分解及其产物的生成途径

以诺氟沙星(NOR)水溶液作为抗生素废水的代表,在湿式氧化的环境中考察其分解规律与产物生成途径,为含抗生素废水的湿式氧化处理提供方法基础.在温度为473～513 K,压力为3 MPa,NOR初始浓度约为500 mg/L,H2O2投加量为0和32 200 mg左右以及停留时间为10～60 s的条件下进行湿式氧化实验,以诺...     

ClO2溶胞对SBR处理系统污泥减量研究

通过烧杯溶胞实验,考察了ClO2处理SBR剩余污泥上清液△SCOD随处理时间的变化,以确定ClO2溶胞最佳方式;在SBR中试系统,把系统排出剩余污泥的50%经ClO2处理后回流至处理系统,运行50 d,考察处理系统的污泥减量效果及其对系统污水处理效果的影响.结果表明,ClO2具有良好的溶胞作用,在最佳投量为8 mg C...