沟渠式生物接触氧化法对有机物和氨氮的去除研究

生物接触氧化工艺是目前较为成熟的水质净化技术,国内外在河流水质净化、水体修复中都有较多的研究和应用.在实验室采用沟渠式生物接触氧化组合系统处理模拟村庄面源污水,较好地去除了有机物并实现氨氮转化.结果表明,当进水COD为130～290mg/L、氨氮为30～40mg/L、水力负荷为0.19～0.24m3/(m2·d)的条件下,该系统稳定运行11周,COD和氨氮的平均去除率分别达85%和79%.     

Seasonal and spatial occurrence and distribution of atmospheric polycyclic aromatic hydrocarbons (PAHs) in rural and urban areas of the North Chinese Plain

Passive air sampling (PAS) was employed to study the occurrence of gaseous and particle-bound PAHs in the North Chinese Plain. The averaged concentrations of gaseous and particle-bound PAHs were 485 ± 209 ng/m³ and 267 ± 161 ng/m³, respectively. The PAHs concentrations at urban sites were generally higher than those at rural ones with ratios <1.5 in spring, summer and fall, but differences between them were not significant for the wintertime and annually averaged concentrations. This urban-rural distribution pattern was related to the PAHs emission sources. PAHs spatial variation can be partially (49%) explained by emission with a simple linear regression method. Both the gaseous and particle-bound PAHs were highest in winter and lowest in summer, with winter/summer ratios of 1.8 and 8, respectively. Emission strength was the most important factor for the seasonality.     

家用洗衣粉中磷对斜生栅藻生长的影响

以洗衣粉中的有机磷为磷源,通过室内模拟的方法研究在不同磷浓度的水体条件下斜生栅藻的生长情况,以及磷对斜生栅藻的生长是否有毒害作用.通过显微计数测定藻细胞数目来探讨洗衣粉中磷对斜生栅藻生长的影响;同时分析了洗衣粉中磷对斜生栅藻96 h生长期中光合色素的影响.结果表明,洗衣粉中的磷除了促进藻生长外,其浓度过低或过高都会抑制藻的生长.由实验结果可得,磷对藻生长的富营养化作用和毒性作用取决于磷浓度的高低.     

Surface functional characteristics (C, O, S) of waste tire-derived carbon black before and after steam activation

The effects of steam activation on the surface functional characteristics of waste tire-derived carbon black were investigated. Two carbon-based materials, powdered carbon black (PCB) and PCB-derived powdered activated carbon (PCB-PAC), were selected for this study. A stainless steel tubular oven was used to activate the PCB at an activation temperature of 900 degrees C and 1 atm using steam as an activating reagent. X-ray photoelectron spectroscopy (XPS) was adopted to measure the surface composition and chemical structure of carbon surface. Various elemental spectra (C, O, and S) of each carbon sample were further deconvoluted by peak synthesis. Results showed that the surfaces of PCB and PCB-PAC consisted mainly of C-C and C-O. The PCB-PAC surface had a higher percentage of oxygenated functional groups (C=O and O-C=O) than PCB. The O1s spectra show that the oxygen detected on the PCB surface was mainly bonded to carbon (C-O), whereas the oxygen on the PCB-PAC surface could be bonded to hydrogen (O-H) and carbon (C-O). Sulfur on the surface of PCB consisted of 58.9 wt% zinc sulfide (ZnS) and 41.1 wt% S=C=S, whereas that on the surfaces of PCB-PAC consisted mainly of S=C=S. Furthermore, the increase of oxygen content from 9.6% (PCB) to 11.9% (PCB-PAC) resulted in the increase of the pH values of PCB-PAC after steam activation.     

活性炭纤维上4-氯酚及焦化废水尾水的O3催化氧化降解实验研究

选择YT-1000型活性炭纤维（ACF）作为催化剂,考察ACF与O₃协同作用催化降解水溶液中4-氯酚的最佳反应条件,并将该条件应用于焦化废水生物处理尾水中难降解有机污染物的催化氧化。ACF表面具有丰富的微孔结构,对4-氯酚有良好的吸附作用,在动力学上提高了其与O3反应的起始浓度,并且在ACF表面含氧、含氮等基团的催化作用下发生氧化反应,1 L浓度为100 mg/L的4-氯酚水样中投加2 g ACF反应6 min时,吸附作用对TOC的去除率为43.4%,而ACF协同O₃作用时的TOC去除率提高到72.5%,协同增效作用为67.1%;在选定的反应条件下,ACF协同O₃降解焦化废水生物处理尾水,60 min时的TOC与色度的去除率分别达到56.8%和96.3%。上述研究过程证明了吸附作用与催化作用的协同能有效降解生物过程不能降解的焦化废水中惰性有机污染物。     

自来水厂不同净水工艺对持久性有机物的去除效果试验研究

以多环芳烃和有机氯农药作为有机物评价指标,对某自来水厂常规处理加深度处理工艺,即混凝-沉淀-过滤-炭吸附处理工艺的去除效果评价,并对几种深度处理技术展望.结果表明,检出多环芳烃和有机氯农药均未超出生活饮用水标准(2006)的限值.在研究的净水工艺中,深度处理工艺炭滤对多环芳烃和有机氯农药的去除效果较为理想.强化混凝、臭氧 活性炭和纳滤膜技术是水厂未来经济可行的处理工艺.     

基于模糊综合评价的流域社会经济活动对太湖生态影响评价研究

太湖是我国的五大淡水湖之一。太湖流域是我国经济最发达、水污染最严重的地区之一,正面临着严重的环境问题。随着太湖流域社会经济的发展,太湖流域生态环境将承受更大的压力。因此,分析人类社会经济活动对太湖流域生态的影响,对研究太湖生态环境具有重要意义。采用系统分析的方法,围绕流域人类社会经济活动对湖泊生态安全的影响,建立湖泊生态安全的评价指标体系,利用层次分析法计算各指标因子的权重。在此基础上,以太湖流域2005年和2006年相关数据为依据,以MATLAB为工具,根据模糊数学的原理,利用多级模糊综合评价的方法对太湖进行生态综合评价,确定流域社会经济活动对整个湖泊生态系统的影响。研究结果表明,3个重要指数得分高低顺序依次为：水体环境状态指数＞水体污染负荷指数＞社会经济压力指数;除了点源污染以外,面源污染也是太湖流域生态环境问题的重要根源。     

Anaerobic degradation of nonylphenol in soil

This study investigated the effects of various factors on the anaerobic degradation of nonylphenol (NP) in soil. The results show that the optimal pH for NP degradation was 7.0 and that the degradation rate was enhanced when the temperature was increased. The addition of compost enhanced NP degradation. The individual addition of the electron donors lactate, acetate, and pyruvate inhibited NP degradation. The high-to-low order of NP degradation rates under three anaerobic conditions was sulfate-reducing conditions > methanogenic conditions > nitrate-reducing conditions. The results show that sulfate-reducing bacteria, methanogen, and eubacteria are involved in the anaerobic degradation of NP, with sulfate-reducing bacteria being a major component of the soil. Of the anaerobic strains isolated from the soil samples, strain AT3 expressed the best ability to biodegrade NP.     

Aerobic degradation of bisphenol A by Achromobacter xylosoxidans strain B-16 isolated from compost leachate of municipal solid waste

A novel bacterium designated strain B-16 was isolated from the compost leachate of the municipal solid waste (MSW) in a laboratory reactor. This strain was identified as a gram-negative bacterium, Achromobacter xylosoxidans that could grow on bisphenol A (BPA, a representative endocrine disruptor) as a sole carbon source under aerobic condition. BPA-degrading characteristics of strain B-16 were investigated in liquid cultures. The results show that BPA degradation was influenced by several factors (e.g. inoculum size, substrate concentration, temperature and pH, etc). The half-lives, optimum temperature and pH were found to be 0.58-3.1d, 35 degrees C and 7.0, respectively. BPA-degrading activity and cell growth were inhibited at high substrate concentration. Metabolic intermediates detected during the degradation process were identified as p-hydroxybenzaldehyde, p-hydroxybenzoic acid and p-hydroquinone, respectively. Metabolic pathway of BPA degradation was proposed in this study.     

Catalytic hydrogenation of polyaromatic hydrocarbon (PAH) compounds in supercritical carbon dioxide over supported palladium

A series of supported palladium catalysts were evaluated for their ability to mediate the complete hydrogenation of polycyclic aromatic hydrocarbon (PAH) compounds. Benzo[a]pyrene (B[a]P) or phenanthrene (Phe) in hexane was merged with a hydrogen-carbon dioxide [5% (w/w) H(2)/CO(2)] stream and transferred to a flow through mini-reactor (capacity ca. 1 g) that was maintained at 90 degrees C under a back-pressure of 20.68 MPa. Effluent from the reactor trapped in hexane was monitored/quantified by gas chromatography-mass spectrometry. Catalyst formulations supported on iron powder, high density polyethylene (HDPE) or gamma-alumina were prepared and compared in terms of hydrogenation activity as measured by the quantity of substrate per unit time that could be perhydrogenated to toxicologically innocuous products. Both of the Pd preparations supported on gamma-alumina were more efficient than a commercial Pd(0) (5% w/w) on gamma-Al(2)O(3) formulation or preparations supported on HDPE or the iron powder. Bimetallic mixtures with Pd increased the hydrogenation activity when co-deposited with Cu or Ni but not with Ag or Co. However, increases in hydrogenation activity by increasing the loading of Pd (or bimetallic mixture) on this surface were limited. Despite using supercritical carbon dioxide (scCO(2)) to swell the surfaces of the polymer, the deposition of nanoparticles within the polyethylene formulation was appreciably less active than either the oxidic or the Fe(0) formulations.