恒液位推流式改良SBR工艺处理生活污水

通过对恒液位推流式改良SBR工艺处理生活污水工程应用的研究,结果表明:恒液位推流式改良SBR工艺在降低工程成本和减少设备量的同时能较好的去除污水中的污染物,具有良好的脱氮除磷效果,COD去除率可达85%~93%;TP的去除率可达84%;TN的去除率可达82%。     

Partitioning of water soluble organic carbon in three sediment size fractions： Effect of the humic substances

Water soluble organic carbon (WSOC) in sediments plays an important role in transference and transformation of aquatic pollutants. This article investigated the inherent mechanisms of how sediemnt grain size affect the partitioning coeffcient (k) of WSOC. Influences of NaOH extracted humic substances were particularly focused on. Sediments were sampled from two cross-sections of the middle Yellow River and sieved into three size fractions (< 63 μm, 63-100 μm, and 100--300 μm). The total concentration of WSOC in sediments (CWSOC) and k were estimated using multiple water-sediment ratio experiments. Results show that CWSOC ranges from 0.012 to 0.022 mg/g, while k ranges from 0.8 to 3.9 L/kg. Correlations between the spectrum characteristics of NaOH extracted humic substances and k were analyzed. Strong positive correlations are determined between k and the aromaticity indicators of NaOH extracted humic substances in different sediment size fractions. Comparing with finer fractions (< 63 μm), k is higher in larger size fractions (63--100 and 100--300 μm) related to higher aromaticity degree of NaOH extracted humic substances mostly. While negative relationship between k and the area ratio of fourier transform infrared spectroscopy (FT-IR) at 3400 and 1430 cm-1 implied that the lowest k was related to the highest concentration of the acidic humic groups in particles < 63 μm. WSOC in finer fractions (< 63 μm) is likely to enter into pore water, which may further accelerate the transportation of aquatic contaminants from sediment to water.     

Combined fluorescence and electrochemical investigation on the bindinginteraction between organic acid and human serum albumin

Human serum albumin (HSA) is a plasma protein responsible for the binding and transport of fatty acids and a variety of exogenous chemicals such as drugs and environmental pollutants. Such binding plays a crucial role in determining the ADME (absorption, distribution, metabolism, and excretion) and bioavailability of the pollutants. We report investigation on the binding interaction between HSA and acetic acid (C2), octanoic acid (C8) and dodecanoic acid (C12) by the combination of site-specific fluorescent probe, tryptophan intrinsic fluorescence and tyrosine electrochemistry. Two fluorescent probes, dansylamide and dansyl-L-proline, were employed in the displacement measurement to study fatty acid interaction with the two drug-binding sites on HSA. Intrinsic fluorescence of tryptophan in HSA was monitored upon addition of the fatty acids into HSA. Electrocatalyzed response of the tyrosine residues in HSA by a redox mediator was used to investigate the binding interaction. Qualitatively, observations made by the three approaches are very similar. HSA did not show any change in either fluorescence or electrochemistry after mixing with C2, suggesting there is no significant interaction with the short-chain fatty acid. For C8, the measured signal dropped in a single-exponential fashion, indicative of independent and non-cooperative binding. The calculated association constant and binding ratio is 3.1×106 L/mol and 1 with drug binding Site I, 1.1×107 L/mol and 1 with Site II, and 7.0×104 L/mol and 4 with the tryptophan site. The measurement with C12 displayed multiple phases of fluorescence change, suggesting cooperativity and allosteric effect of C12 binding. These results correlate well with those obtained by the established methods, and validate the new approach as a viable tool to study the interactions of environmental pollutants with biological molecules.     

Acid deposition critical loads modeling for the simulation of sulfur exceedanceand reduction in Guangdong, China

The current acid deposition critical loads in Guangdong, China were calculated using the PROFILE model with a 3 km × 3 km resolution. Calculations were carried out for critical loads of potential acidity, actual acidity, sulfur and nitrogen, with values in extents of 0–3.5, 0–14.0, 0–26.0 and 0–3.5 kmol/(hm2·year), respectively. These values were comparable to previously reported results and reflected the influences of vegetation and soil characteristics on the soil acid buffering capacity. Simulations of S...     

Analysis of diffusion-adsorption equivalency of landfill liner systems for organic contaminants

The equivalence between multilayered barriers regarding diffusion and adsorption is analyzed by means of an analytical method. The bottom boundary of the liner system is defined by assuming concentration continuous and flux continuous conditions of the contaminant between the bottom liner layer and the underlying soil. Five different liner systems were compared in terms of solute breakthrough time. The results of the analysis show that breakthrough time of the hydrophobic organic compounds for a 2-meter-thick compacted clay liner (CCL) can be 3-4 orders of magnitude greater than the breakthrough time for a geosynthetic clay liner (GCL) composite liner. The GM/GCL and GM/CCL composite liner systems provide a better diffusion barrier for the hydrophilic organic compounds than that for the hydrophobic compounds due to their different Henry's coefficient. The calculated breakthrough times of the organic contaminants for the Chinese standard liner systems were found to be generally greater than those for the GCL alternatives, for the specific conditions examined. If the distribution coefficient increases to 2.8 for the hydrophobic compounds or 1.0 for the hydrophilic compounds, the thickness of the attenuation layer needed to achieve the same breakthrough time as the standard liner systems can be reduced by a factor of about 1.9-2.4. As far as diffusive and adsorption contaminant transport are concerned, GM or GCL is less effective than CCL.     

Characterization of organic matter in total suspended particles bythermodesorption and pyrolysis-gas chromatography-mass spectrometry

The organic matter in tropospheric aerosol plays an important role in atmospheric physical and chemical processes. The bulk oforganic matter, representing a significant proportion of the total suspended particulate (TSP) mass, is bound to polymeric materialwhose structure and properties are largely unknown. Here we used thermodesorption gas chromatography/mass spectrometry (Td-GC/MS) to study organic compounds of low molecular mass and pyrolysis gas chromatography/mass spectrometry (Py-GC/MS) tocharacterize the chemical structure of macromolecules in TSP samples collected in di erent seasons from di erent sites in Guangzhou.n-Alkanes, fatty acids and nitriles were the predominant compounds in the thermodesorption products, whereas aromatics, fatty acids,nitriles and n-alkanes/alkenes were the major compounds in the pyrolysates. The results indicated that aromatics were main units inmacromolecules. The fatty acids and nitriles formed from carboxylic ammonium salts were detected in both thermodesorption productsand pyrolysates at a certain concentration, indicating the importance of these compounds in TSP formation. The TSP source mainlydetermined the occurrence of compounds in samples from urban, suburban and forest sites, whereas the TSP source and formationprocess maybe controlled the seasonal variation in compounds detected. High levels of nitriles in summer samples from suburban andforest sites coincide with the release of ammonium from the land and of fatty acids from vegetation at these sites.     

Pollutants removal and simulation model of combined membrane process forwastewater treatment and reuse in submarine cabin for long voyage

A laboratory scale test was conducted in a combined membrane process (CMP) with a capacity of 2.91 m3/d for 240 d totreat the mixed wastewater of humidity condensate, hygiene wastewater and urine in submarine cabin during prolonged voyage.Removal performance of chemical oxygen demand (COD), ammonia nitrogen (NH4+-N), turbidity and anionic surfactants (LAS)was investigated under di erent conditions. It was observed that the e uent COD, NH4+-N, turbidity and LAS flocculated in ranges of0.19–0.85 mg/L, 0.03–0.18 mg/L, 0.0–0.15 NTU and 0.0–0.05 mg/L, respectively in spite of considerable fluctuation in correspondinginfluent of 2120–5350 mg/L, 79.5–129.3 mg/L, 110–181.1NTU and 4.9–5.4 mg/L. The e uent quality of the CMP could meet therequirements of mechanical water and hygiene water according to the class I water quality standards in China (GB3838-2002). Theremoval rates of COD, NH4+-N, turbidity and LAS removed in the MBR were more than 90%, which indicated that biodegradationis indispensable and plays a major role in the wastewater treatment and reuse. A model, built on the back propagation neural network(BPNN) theory, was developed for the simulation of CMP and produced high reliability. The average error of COD and NH4+-N was5.14% and 6.20%, respectively, and the root mean squared error of turbidity and LAS was 2.76% and 1.41%, respectively. The resultsindicated that the model well fitted the laboratory data, and was able to simulate the removal of COD, NH4+-N, turbidity and LAS. Italso suggested that the model proposed could reflect and manage the operation of CMP for the treatment of the mixed wastewaters insubmarine.     

地球系统工程与区域环境问题调控的原则

论述了地球系统科学和工程研究的发展历史、研究对象和方法,及其在解决全球性环境危机中的作用;阐述了提高共识、言行一致、保护全球公共资源、实现可持续性目标等地球系统工程的基本原则. 论述了区域性与地球系统环境问题间的关系,提出区域环境问题调控的4条基本原则:系统性调控、区际公平、多方合作、综合手段和共同约束. 指出应注重应用地球系统科学与工程的理论与方法解决区域环境与生态问题;应深入探讨地球系统及区域环境与生态压力在中国现阶段的特征,统筹全局与长远调控区域环境问题;应开展长期连续观测和信息共享,创新调控全球与区域环境与生态的技术、方法.      

包埋类脂的吸附剂制备及吸附POPs性能

用丙酮作溶剂将三油酸甘油酯分散到醋酸纤维(CA)基体中,采用悬浮聚合的方法制备出了一种兼具亲水性,又能高倍富集持久性有机污染物的球形复合吸附剂。通过对分散剂的种类及其用量、悬浮介质的种类及其用量的研究,获得了球形复合吸附剂的最佳合成路线与工艺.球形吸附剂粒径为1～2mm。通过荧光分析和电镜扫描分析,表明三油酸甘油酯已被包埋到醋酸纤维基体中,并得到了均匀分散。采用七氯、狄氏剂、异狄氏剂、灭蚁灵为代表性的持久性有机污染物(POPs)。动力学吸附实验表明,当初始浓度为1μg/L时,在快速吸附阶段,溶液中80%的氯、狄氏剂、异狄氏剂可得到有效去除,但并没有达到吸附平衡。快速吸附完后,还在持续地进行慢速吸附。而对于灭蚁灵,吸附速度远远低于其他几种POPs。实验证明了吸附速度不仅与辛醇/水系数有关,而且还与有机污染物的分子结构有关。     

现应用的染整助剂环境毒理概述

文章阐述了染整助剂的环境行为、环境毒理和对生物体的毒性。阐述了开发无毒害和可降解的染整助剂的重要性。