有机物生物降解性QSBR/SBR方法初探

定量／ 定性结构生物降解性相关关系（ＱＳＢＲ／ＳＢＲ） 对研究有机物的生物降解性具有重要意义。本文比较了七种常用的ＱＳＢＲ／ＳＢＲ 模型方法,结合实例对其原理、优缺点等进行了论述。     

有机物的结构──活性定量关系及其在环境化学和环境毒理学中的应用

有机物的结构──活性定量关系及其在环境化学和环境毒理学中的应用王飞越（北京大学城市与环境学系，北京１００８７１）陈雁飞（武汉大学环境科学系）最近几十年来，有机物结构──活性定量关系研究（ＱＳＡＲ，ＱｕａｎｔｉｔａｔｉｖｅＳｔｒｕｃｔｕｒｅ－Ａｃｔｉｖ...     

石油烃在不同土壤中的气相自然衰减规律

挥发性有机物(VOCs)在包气带中的迁移扩散是土壤和地下水中可挥发污染物自然衰减的重要机制,也与蒸气入侵暴露和风险评估密切相关。采用微宇宙实验对12种挥发性石油烃(正戊烷、正己烷、正庚烷、正辛烷、环戊烷、环己烷、环庚烷、环辛烷、苯、甲苯、乙苯、对二甲苯)在4种土壤(黑土、黄土、红土、石英砂)中的气相自然衰减机制和气态生物降解动力学规律进行了研究。结果表明,正构烷烃、环烷烃和苯系物蒸气在4种土壤中的气相自然衰减去除率都遵循黑土>黄土>红土>石英砂的规律;黑土中生物降解对污染物去除率的贡献高于黄土,而红土和石英砂中的生物降解速率极低;4种苯系物的自然衰减和生物降解潜力远高于正构烷烃和环烷烃;苯系物气相生物降解速率排序为：甲苯>苯>乙苯>对二甲苯。本研究结果可为蒸气入侵定量风险评估和石油污染场地自然衰减速率定量评估提供参考。     

处理难降解有机物的新型SBR反应器的发展

本文在分析ＳＢＲ 工艺特点的基础上,从反应器本身及ＳＢＲ 反应运行工序的设计两方面对处理难降解有机物新型ＳＢＲ 反应器的发展作了论述。分析认为ＳＢＲ 工艺将在中小型企业含难降解有机物工业废水处理中广泛应用。     

定量结构──活性相关研究进展

ＱＳＡＲ方法用于预测环境中化学品的归宿及其毒性与日骤增，本文着重研究ＱＳＡＲ方法在不同领域中的进展和成就，不仅论述了我们关心的ＱＳＡＲ文献进展本身，而且还讨论了它的基础部分。精选ＱＳＡＲ模式在生态毒理学中的应用以及物理化学性质的估算等，     

球形红细菌好氧降解氯代苯研究

采用光合细菌球形红细菌在好氧条件下对氯代苯进行生物降解.结果表明,氯代苯不能作为球形红细菌生长的惟一碳源和能源,球形红细菌好氧降解氯代苯是在适宜碳源存在下以共代谢的方式进行;根据分析细胞提取液中双加氧酶活性和代谢中间产物,推断出其降解机制为邻位裂解途径,按先开环再脱氯过程进行,邻苯二酚1,2-双加氧酶的活性可以通过氯代...     

污水处理过程中BTEX迁移降解与去除途径研究

以某涂料废水为研究对象,采用实验检测废水中BTEX浓度和模式计算挥发量相结合的研究方法,对BTEX污染物在污水处理过程中的迁移降解与去除途径进行研究,分析隔油、气浮、氧化沟工艺对苯系物去除效果,同时研究了吸附、挥发和生物降解3大去除途径对苯系物去除的影响。研究表明,该工艺对BTEX的去除效率高,苯的总去除效率为88.11%,甲苯、乙苯、邻二甲苯和间、对二甲苯总去除率分别高达98.14%、98.09%、97.45%和97.68%。其中苯、甲苯、乙苯、邻二甲苯主要都是在氧化沟中去除,间、对二甲苯在气浮池和氧化沟都有较高的去除率,隔油池工艺对BTEX的去除率较低。去除途径方面,苯以挥发为主,甲苯、乙苯和邻二甲苯都以生物降解为主要去除途径,而挥发和生物降解对间、对二甲苯的去除作用相当。     

十三碳二元酸发酵有机废水处理研究

运用物化预处理和ＳＢＲ生化工艺对十三碳二元酸发酵废水中高浓度有机物的降解特征及高２硫酸钠对微生物的有害抑制作用进行处理试验,研究结果表明。采用物化预处理与ＳＢＲ生化法相结合的工艺可有效地处理该类废水。经驯化的耐盐微菌胶力和裂口虫为主,废水的ＣＯＤｃｒ去除率可达９２％以上,ＢＯＤ５去除率可达９５％以上。     

松花江中游(哨口-松花江村段)水中有毒有机物污染研究

1983—1990年,在松花江中游(哨口—松花江村)138公里江段中,进行七次五断面追踪水团采样,采用高分子微球GDX—502吸附富集,GC定性定量,GC/MS定性验证。依据有机物检出率、毒性持久性、有点源排放、分析方法适用等因素,筛选出65种主要有毒有机物。化合物总浓度逐年降低,石油烷烃、芳烃浓度增加;属致癌致变性化合物21种,EPA优测物21种,建议的优先控制黑名单20种;有点源排入的占90％以上,污染源来自吉化主要入江污水口;封冰期比其它水文期污染增强;该江段污染特征为氯代链烃、氯代苯类、硝基芳烃种类多、浓度高,应为重点控制对象。     

皮革废水SBR工艺对比试验研究

介绍皮革废水膜法ＳＢＲ对比实验，结果表ＢＳＢＲ处理效果明显好于普通ＳＢＲ法，更好于一般生化法。ＢＳＢＲ兼有生物接触氧化法和ＳＢＲ法的优点，降解速率快，污泥量少，去除率高。     

Chlorophenols and other related derivatives of environmental concern: properties, distribution and microbial degradation processes

Chlorophenols are chlorinated aromatic compound structures and are commonly found in pesticide preparations as well as industrial wastes. They are recalcitrant to biodegradation and consequently persistent in the environment. A variety of chlorophenols derivatives compounds are highly toxic, mutagenic and carcinogenic for living organisms. Biological transformation by microorganisms is one of the key remediation options that can be exploited to solve environmental pollution problems caused by these notorious compounds. The key enzymes in the microbial degradation of chlorophenols are the oxygenases and dioxygenases. These enzymes can be engineered for enhanced degradation of highly chlorinated aromatic compounds through directed evolution methods. This review underscores the mechanisms of chlorophenols biodegradation with the view to understanding how bioremediation processes can be optimized for cleaning up chloroaromatic contaminated environments.     

Effects of sorption on biodegradation rates of 2,4-D: Improvement of Rao''s model

In the presence of sorbents, the biodegradation rates of organic compounds can be decreased or increased. Four kinds of interactions have to be considered as follows: (1) chemicals in solution reacted with bacteria in solution; (2) sorbed chemicals reacted with bacteria in solution; (3) chemicals in solution reacted with sorbed bacteria and (4) sorbed chemicals reacted with sorbed bacteria. The corresponding rate constants K can be solved in our improved model. Some special situations are discussed.

The biodegradation of 2,4-D, as an example, reacted with a pure strain (Pseudomanos sp.) which was isolated from soil polluted by 2,4-D then labeled by radioactive ³²P were performed in the presence of sediment (or soil). The results showed that 2,4-D sorbed on sediment (or soil) were available to neither bacteria in solution nor bacteria on sediment (or soil), but 2,4-D in solution can be degraded by both bacteria in solution and bacteria on sediment (or soil). Biodegradation of 2,4-D in the presence of sediment (or soil) agreed with results of Rao's model.     

生物流化床反应器在处理含氯代芳香化合物废水中的应用

氯代芳香化合物是工业废水中重要污染物之一。本文介绍了氯代芳香化合物的降解机理、生物流化床的特点及其处理氯代芳香化合物的应用 ,为含氯代芳香化合物的废水处理提供参考     

Quantifying the sorption of organic chemicals on sediments

The use of a reference compound to quantify the sorption of nonpolar organic chemicals is proposed. This is because organic carbon normalized sorption coefficients (K_OC) do appear to be dependent on the type of sediment, and are thus not generally applicable to characterize the sorption properties of chemicals. Therefore, in this paper the hypothesis that nonpolar chemicals sorb in a constant ratio, independent of the sediment, has been investigated. Evidence for this hypothesis is shown with data from the literature. This enables one to compare sorption properties of nonpolar compounds on different sediments, if the differences between the sediments are normalized with a reference chemical rather than with the organic carbon content. Sediments with an organic carbon content of less than 0.1% seem to be unsuitable, because the compounds do not sorb mainly on the organic carbon, but also on other parts of the sediment. Sorption coefficients of compounds with aqueous solubilities in the μg per liter range or octan-1-ol water partition coefficients of more than 10⁵ are strongly influenced by the experimental techniques used. For these compounds the sorption coefficients measured by different techniques are less comparable. To enable comparison of sorption coefficients of hydrophobic chemicals, the use of a chlorobenzene as a reference compound in sorption experiments is suggested.     

Biodegradability assessment of several priority hazardous substances: choice, application and relevance regarding toxicity and bacterial activity

Nineteen compounds listed in the category of priority substances (PS) were selected for a biodegradation study using standardized tests. The compounds consist of pesticides, chlorinated solvents and volatile organic compounds (VOCs). In this paper, the choice of the most suitable method is discussed in relation to the physico-chemical properties of each substance. Zahn-Wellens, manometric respirometry and closed-bottle tests are alternatively used. Experimental results are presented and interpreted. Toxicity (Microtox) and bacterial viability (Bac-light) are also used as tools to investigate the influence of each substance on the microbial population (activated sludge). In addition, experimental values are compared with predictive data calculated according to quantitative structure activity relationships (QSARs) models. Biodeg Models were permitted to correctly estimate 17 substances; Survey Models and screening tests also revealed the same behavior for 16 target compounds.     

The Effectiveness of Aeration Recirculation in Controlling VOC Emissions from Publicly Owned Treatment Works

Abstract

The effects of aeration recirculation on oxygen transfer and the fate of five volatile organic compounds (VOCs) commonly found in publicly owned treatment works (POTWs) influent are studied using various modeling approaches. The five compounds are benzene, chloroform, methylene chloride, toluene, and trichloroethylene. The models predict that the overall oxygen transfer efficiency can be increased by 96.7% at 50% aeration recirculation with only a 9.6% drop in oxygen transfer rate. The emission reductions and biodegradation improvements are compound specific; for the compounds investigated here, about 40% emission reductions and 16% biodegradation increases can be achieved at 50% aeration recirculation. The temperature effect on the VOC fate mechanisms is also investigated. Overall, the model predictions reveal that up to 50% aeration recirculation is effective in controlling VOC emissions.     

Recalcitrance of polycyclic aromatic hydrocarbons in soil contributes to background pollution

The microbial accessibility of native phenanthrene and pyrene was determined in soils representing background scenarios for pollution by polycyclic aromatic hydrocarbons (PAHs). The soils were selected to cover a wide range of concentrations of organic matter (1.7-10.0%) and total PAHs (85-952 μg/kg). The experiments included radiorespirometry determinations of biodegradation with ¹⁴C-labeled phenanthrene and pyrene and chemical analyses to determine the residual concentrations of the native compounds. Part of the tests relied on the spontaneous biodegradation of the chemicals by native microorganisms; another part also involved inoculation with PAH-degrading bacteria. The results showed the recalcitrance of PAHs already present in the soils. Even after extensive mineralization of the added ¹⁴C-PAHs, the concentrations of native phenanthrene and pyrene did not significantly decrease. We suggest that aging processes operating at background concentrations may contribute to recalcitrance and, therefore, to ubiquitous pollution by PAHs in soils.     

水中氯代有机化合物处理方法及研究进展

对氯代有机物的污染进行治理是水污染控制的重要课题。本文总结了可用于水中氯代有机物处理的一些方法的近期研究成果，同时也讨论了生物法、光催化氧化法和双金属还原法的各自特点及应用前景     

An analysis of the 'Modified Sturm Test' data

The 'Modified Sturm Test' uses carbon dioxide production as the primary end point in assessing the biodegradation potential of organic chemicals. This test was conducted by a commercial laboratory to assess the potential biodegradability of an oil stabilizer sample from an oil company in Canada. There was a high percentage conversion of total organic carbon present in the sample but carbon dioxide measured was low. Many possibilities were analyzed in this paper in order to understand the situation. The analysis showed that the test was subject to criticism from the point of view of CO2 measurement, 10-day window period, and aeration/mixing conditions.