Bioremediation of polycyclic aromatic hydrocarbons: current knowledge and future directions

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic compounds that have accumulated in the natural environment mainly as a result of anthropogenic activities such as the combustion of fossil fuels. Interest has surrounded the occurrence and distribution of PAHs for many decades due to their potentially harmful effects to human health. This concern has prompted researchers to address ways to detoxify/remove these organic compounds from the natural environment. Bioremediation is one approach that has been used to remediate contaminated land and waters, and promotes the natural attenuation of the contaminants using the in situ microbial community of the site. This review discusses the variety of fungi and bacteria that are capable of these transformations, describes the major aerobic and anaerobic breakdown pathways, and highlights some of the bioremediation technologies that are currently available. Copyright © 2005 Society of Chemical Industry     

污水污泥裂解油中多环芳烃的分析

引言在一些发达国家,污水污泥热裂解技术作为能量回收型污泥处理技术已经进入商业应用阶段,其裂解产生的液体燃料能直接用于柴油机车,并与石油提炼厂生产出来的石油低级馏出液相似     

Effect of vegetable oil addition on bioaccessibility and biodegradation of polycyclic aromatic hydrocarbons in historically contaminated soils

BACKGROUND: Bioaccessibility is often the limiting factor for the biodegradation of polycyclic aromatic hydrocarbons (PAH) in soils. The present study explores the potential of amending canola oil, an economically and ecologically attractive soil additive, for the enhancement of bioaccessibility and, in consequence, biodegradation of PAH in historically contaminated, bioaccessibility limited soils. RESULTS: The amendment of canola oil (1% and 5%, w/w) to contaminated soils increased the bioaccessibility and the subsequent biodegradation of PAH with up to four rings. Residual concentrations of pyrene and fluoranthene in oil‐treated soils were 38–53% lower compared to the unamended tests. The continuous removal of bioaccessible PAH with a passive sampling system confirmed that oil amendment indeed increased bioaccessibility, leading to a lower non‐accessible PAH fraction. Canola oil amendment did, by contrast, not increase the bioaccessibility of high molecular weight PAH, likely due to their strong binding to soil organic carbon compounds. CONCLUSION: Canola oil can be used efficiently in low concentrations to render PAH up to four rings accessible for biodegradation in historically contaminated soils. Contaminants remaining in soil after treatment may pose a significantly lowered environmental risk, as is indicated by the lack of mobilisation by a solubilising agent such as canola oil. Copyright © 2009 Society of Chemical Industry     

污泥热解过程中多环芳烃排放规律

研究了不同温度（350~1050℃）下污泥热解过程液、气、固三相产物中16种多环芳烃（PAHs）排放规律。结果表明,PAHs趋向富集于液相产物中,其次为气相产物,在液相产物中检测到所有16种PAHs,650℃液相产物中16种PAHs（∑₁₆PAHs）总质量比最高,为96%;750℃气相产物中∑₁₆PAHs质量比最高,为21.3%以上;固相产物中PAHs含量极少,仅在650℃时达1%。所有温度下液相产物中2、3和4环PAHs均占据主导地位,∑_2,3,4环PAHs质量比达95%以上,850℃时液相产物中∑EPA-PAHs含量最高,达15.25 mg·kg^-1。气相产物主要以萘（NaP）、苊烯（Acp）、芴（Flu）和蒽（Ant）PAHs为主,未检测到高环PAHs。在高温热解阶段,污泥大分子结构裂解到达高峰,伴随产物的二次断裂、合成、环化等反应,气相产物中∑_低PAHs生成含量达到最高7.248 mg·kg^-1。不同温度下污泥热解产物中PAHs的毒性当量（TEQ）变化规律与其生成量变化基本一致,在850℃时液相产物中PAHs的TEQ最高达1.129。     

Solubilization of hydrocarbons from oil sludge by synthetic surfactants

Disposal of oil sludges poses an environmental pollution problem due to the presence of high molecular weight hydrocarbons which are hydrophobic and hence non-biodegradable in nature. In-situ transformation of hydrophobic hydrocarbons into hydrophilic moieties using surfactants and further degradation of solubilized hydrocarbons by microorganisms could be the viable solution for disposal of these sludges. Treatment of oil sludge with the synthetic surfactant polyoxyethylene sorbitan monooleate indicated the release of hydrocarbons in the aqueous phase. Increase in soluble chemical oxygen demand with increase in concentration of surfactant and contact time was observed indicating enhancement in solubility of hydrocarbons in the aqueous phase. The optimum ratio of sludge to surfactant was found to be 10: 1. While a two-fold increase in solubility of hydrocarbons was observed due to agitation of sludge samples, variation in pH did not affect the solubilization.     

油气田含油污泥生物处理技术研究进展

油气田含油污泥是石油钻井、运输、储存过程中产生的主要污染物。随着油气田开发的逐步深入,含油污泥所带来的生产和环境矛盾越来越突出。原有的含油污泥处理方式已经不适用新的环保要求。目前,物理化学处理方法初步实现了含油污泥减量化和原油资源回收,但其并不能从根本上去除含油污泥的石油污染物,甚至有可能造成二次污染。生物处理方法有低毒、环保、效率高等特点,具有较广泛的应用前景。本文介绍了含油污泥的来源、特征、处理标准和环境影响。将生物处理技术分为生物表面活性剂（BSF）洗油法和生物降解法,并从BSF的类型和特性、洗油机理、降解工艺、降解菌、对处理效果的影响因素以及BSF增强生物降解作用等方面进行了详细阐述。文章指出BSF洗油法主要应用于高含油污泥（含油率≥6%）的处理,含油率可降到2%以下;对于低含油污泥（含油率≤6%）采用微生物降解技术处理,可达到0.3%的生态标准。生物处理技术是最有前景的满足资源回收的环保型的含油污泥处理技术。     

济钢冷轧厂轧机油垢的清洗

分析冷轧厂轧机油垢的成分、形成过程,对其清洗技术进行讨论,通过实验确定了新的清洗剂配方.在选定的操作条件下,使用该清洗剂清洗油垢,达到了预期的清洗目的.     

劣质催化柴油中多环芳烃选择加氢工艺评价

选取商品柴油加氢精制催化剂和催化柴油选择加氢裂化催化剂,采用N_2吸附-脱附、XRD、TPD、Py-IR等对催化剂进行表征,结果表明,选择加氢裂化催化剂较加氢精制催化剂具有更大的比表面积和孔容,具有更多的中强酸量和较少的弱酸量,并具有更多的B酸中心。以中石化青岛炼化公司生产的高密度、低十六烷值的FCC柴油为原料,对商品加氢精制催化剂和加氢精制/选择加氢裂化组合催化剂进行FCC柴油中多环芳烃选择加氢工艺条件的考察,结果表明,加氢精制催化剂适宜的反应条件为370℃、1.25 h~(-1)、8.0 Mpa,加氢精制/选择加氢裂化催化剂适宜的反应条件为350℃、1.25 h~(-1)、8.0 MPa,组合催化剂的多环芳烃选择加氢效果较好。     

Elimination of polycyclic aromatic hydrocarbons by bleaching of olive pomace oil

A detailed study of the efficacy of the bleaching process for elimination of polycyclic aromatic hydrocarbons in Spanish olive pomace oils has been carried out. For this purpose active carbon with bleaching earth was used as absorbent. The amount of benzo‐(α)‐pyrene was determined by reversed‐phase high‐performance liquid chromatography with a Fluorimetric detector. The use of exhausted filter‐cakes in countercurrent processes with a cake formed of active carbon and bleaching earth is very efficient for reducing the initial content of benzo‐(α)‐pyrene before the addition of fresh adsorbent, thus reducing the amounts of carbon and earth required.     

超高效液相-荧光检测器法测定柴油中多环芳烃

建立了采用超高效色谱(UPLC)-荧光检测器法测定柴油中10种常见的多环芳烃含量的方法。这10种常见的多环芳烃为萘、苊、二氢苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、艹屈、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘和苯并[g,h,i]芘。样品经过固相萃取后用甲醇溶解,采用Acquity UPLC BEH Phenyl C18柱(100 mm×2.1 mm,1.7μm)分离,乙腈-水为流动相进行梯度洗脱,采用荧光检测器检测,并用外标法进行定量分析。结果表明,在一定质量浓度范围内,峰面积与质量浓度的线性关系良好,用标准加入法进行回收率实验,对方法的准确度进行考察,相对标准偏差为0.56%⁸.76%,加标回收率为100.04%8.76%,加标回收率为100.04%¹15.04%。与其他检测柴油中多环芳烃方法比较,该方法简单,分离效果好,快速及准确。     

超高效液相-荧光检测器法测定柴油中多环芳烃

建立了采用超高效色谱(UPLC)-荧光检测器法测定柴油中10种常见的多环芳烃含量的方法。这10种常见的多环芳烃为萘、苊、二氢苊、芴、菲、蒽、荧蒽、芘、苯并[a]蒽、艹屈、苯并[b]荧蒽、苯并[k]荧蒽、苯并[a]芘和苯并[g,h,i]芘。样品经过固相萃取后用甲醇溶解,采用Acquity UPLC BEH Phenyl C18柱(100 mm×2.1 mm,1.7μm)分离,乙腈-水为流动相进行梯度洗脱,采用荧光检测器检测,并用外标法进行定量分析。结果表明,在一定质量浓度范围内,峰面积与质量浓度的线性关系良好,用标准加入法进行回收率实验,对方法的准确度进行考察,相对标准偏差为0.56%~8.76%,加标回收率为100.04%~115.04%。与其他检测柴油中多环芳烃方法比较,该方法简单,分离效果好,快速及准确。     

两株嗜热解烃菌对原油的降黏机制

引言微生物采油技术是通过微生物自身及其代谢活动作用于原油和油藏,从而提高原油采收率的一项采油技术[1-4]。按代谢类型划分,油藏微生物主要包括解烃菌、腐生菌、厌氧发酵菌、硝酸盐还原菌、硫酸盐还原菌和产甲烷菌等[5]。其中,解烃菌是能利用石油烃作为碳源生长代谢,并产生气体、有机酸、脂肪酸以及生物表面活性剂等代谢产物的一类微生物的总称[6]。这些代谢产物可进一步改善     

复配菌对原油除蜡降黏效果分析

为提高含蜡原油流动性能,从辽河油田附近经受原油污染的土壤中筛选出两株原油降解菌。经过16S rRNA基因序列比对鉴定,菌株为纤维微菌属(Cellulosimicrobiumsp.)和假单孢菌(Pseudomonassp.),命名为7#和12#。将筛选出的7#菌与12#菌优化复配使用,研究结果表明:复配菌对液体石蜡有乳化效果,当复配菌体积比为1∶1时,乳化率最高达到77.5%;最适的生长温度为35～40℃,p H=6～8,最佳接种量(体积分数)为4%,复配菌体积比为1∶1,且培养基在初始pH,即pH=7时复配菌生长状态最佳。复配菌在37℃,pH=7条件下对原油处理7 d后,除蜡率为61.32%,降黏率达到31.58%;显微镜观察蜡晶变小,进一步说明菌株能够降解石蜡,破坏蜡晶结构,提高含蜡原油的流动性能。     

煤转化过程中多环芳烃排放的研究现状

发展煤洁净转化技术,减少污染物的排放是煤化工发展方向.目前国内外对减少煤加工过程的CO_2、NO_x、SO_x等污染物的排放研究较多,但对煤加工过程有机污染物多环芳烃(PAHs)的研究还相对不足.本文就多环芳烃的理化性质、起源及其取样和分析方法以及煤加工利用过程中多环芳烃生成与释放的影响因素等有关问题进行了综述和分析,并在此基础上提出进行煤转化过程中多环芳烃的生成与控制研究的思路.     

Use of a dispersed iron catalyst for upgrading extra-heavy crude oil using methane as source of hydrogen

The use of an iron dispersed catalyst, derived from Fe₃(CO)₁₂, for extra-heavy crude oil upgrading using methane as source of hydrogen was studied. The upgrading reactions were carried out batchwise in a stainless-steel 300 ml Parr reactor with 250 ppm of Fe at a temperature of 410-420 °C, a pressure of 11 MPa of CH₄, and a residence time of 1 h. In the presence of Fe₃(CO)₁₂, the reaction of Hamaca extra-heavy crude oil led to a reduction of two orders of magnitude in the viscosity (from 500 to 1.3 Pa s), 14% reduction in sulfur content, and 41% conversion of the >500 °C fraction in the upgraded product with respect to the original crude. The iron catalyst was isolated from the coke produced from the upgrading reaction and was analyzed by XPS, EDAX, and Mössbauer spectroscopy. The results indicated the presence of a Fe-V mixed sulfide species with a composition ca. (Fe_0.6V_0.4)_zS, where z is in the range 0.8-0.9.     

降凝降黏剂在原油开采集输中的应用

降凝降黏剂已成为钻高难度的高温深井、大斜度定向井、水平井和各种复杂地层的重要手段,并且还可广泛地用作解卡液、射孔完井液、修井液和取心液等。由于稠油的黏度以及凝点低,防止在开采过程中出现困难,降凝降黏剂的应用需要进行一定的关注,解决其发展困难。     

原位固氮剂在污泥堆肥过程中保氮机制

高温好氧堆肥技术虽然可有效处理有机固体废物,但常常会释放大量的氨气和造成氮素损失。本文以硫酸镁、磷酸二氢钾、硫酸镁+磷酸二氢钾（分别记为MgSO₄、KP和KPM处理组）为原位固氮剂,污泥和木屑为原料,进行高温好氧堆肥试验,研究以上原位固氮剂对污泥堆肥过程中的氨气挥发和氮素损失的影响。结果表明,硫酸镁（MgSO₄）对物料pH有显著的降低效应,添加硫酸镁使堆体高温期pH降低至8.17,低于硫酸镁+磷酸二氢钾（KPM）组（8.55）和对照（CK）组（8.90）。与CK相比,MgSO₄和KPM的NH₃累积释放量分别降低了34%和28%,反而KP组增加了35%。对比不同条件下XRD图谱可知,MgSO₄的固氮效应并不是由于MgNH₄PO₄·6H₂O的生成,而是由于其对pH的降低效应造成的。堆肥结束后,除了KP组,各处理条件下的种子发芽率值（germination index,GI）均不会对后续使用带来不利影响。     

Biodegradation of quinoline in crude oil

Removal of quinoline, which is typical of nitrogen‐containing compounds in crude oil, was achieved by a biodegradation reaction by Comamonas sp TKV3‐2‐1. The aerobic strain, Comamonas sp TKV3‐2‐1, which can grow utilizing quinoline as the sources of both carbon and nitrogen, degraded quinoline to 2‐hydroxyquinoline, finally to water‐soluble substances. The degradation reaction of 2‐hydroxyquinoline was revealed to be regarded as a rate‐limiting step controlling the overall reaction of biodenitrogenation process of quinoline in crude oil. The degradation rate of 2‐hydroxyquinoline in a stirred fermenter had a maximum of 211 mg 2‐hydroxyquinoline g‐cell^?1 h^?1 when the portion of crude oil in the reaction mixture, the cell concentration and the rotational speed of agitation impeller were 83.3%(v/v), 28.5 gdm^?3 and 11.7 s^?1, respectively. After the reaction was completed, the crude oil and the cell suspension could be separated efficiently by centrifuging. The possibility of constructing a bioprocess for removing quinoline in crude oil under storage is also discussed. © 2001 Society of Chemical Industry     

Rapid determination of heavy polycyclic aromatic hydrocarbons in edible fats and oils

A new rapid method has been developed to determine polycyclic aromatic hydrocarbons (PAHs) in edible fats and oils. Samples are dissolved in isohexane/butylmethylether and PAHs are adsorbed onto a polystyrene solid‐phase extraction cartridge. Triglycerides and non‐aromatic components are eluted stepwise with different mixtures of isohexane and butylmethyether. PAHs finally are eluted with tetrahydrofurane. After evaporation of solvent, PAHs are redissolved in acetonitrile and analysed by RP‐HPLC with fluorimetric detection. Recoveries of 5‐ and 6‐nuclear PAHs are 85—95%, recoveries of 4‐nuclear PAHs are about 60—75%, for 2‐ and 3‐nuclear PAHs the solid‐phase extraction method is not suitable.