生物柴油对原油污染砂砾原油释放的影响

生物柴油是一种优良的溶剂,具有廉价易得、可降解、可再生等优点.研究生物柴油在海滩原油污染治理中的应用具有重要的意义.研究了生物柴油对原油污染砂砾释放油的影响,讨论了在不同生物柴油种类、投加量情况下生物柴油的作用效果.研究结果表明：不同种类生物柴油对原油污染砂砾释放油的促进效果不同,实验条件下菜籽生物柴油释放率最好（70.75%）,地沟油生物柴油最差（58.39%）;砂砾上原油的释放量随着生物柴油投加量的增加而增加,当生物柴油投加量达到一定值时,其对释放量和释放速率的促进都不再明显增加,实验条件下最适投加量为油污砂砾含油量的2倍.     

生物柴油对模拟原油污染砾石释放油的影响研究

对生物柴油促进原油污染的砾石释放原油进行了模拟研究,讨论了生物柴油促进砾石上原油释放的可行性以及生物柴油投加量、投加方式对砾石上原油释放的影响.研究结果表明:生物柴油对砾石上原油的释放具有明显的促进作用;生物柴油的投加量越大,对砾石上原油的释放的促进作用越大,原油与生物柴油为2∶1时释放率为74.6%,4∶3时释放率为84.5%;生物柴油采用分批多次投加比一次性投加的效果更好,分三次投加的比一次性投加的在9d后可高出24.6%释放量.     

原油污染砾石滩联合生物修复的模拟研究

研究了生物柴油-营养盐联合修复原油污染砾石滩的可行性及不同营养配比对联合修复效率的影响.结果表明,生物柴油-营养盐联合修复原油污染的砾石滩是可行的,生物柴油不仅能够促进黏附在砾石上原油的释放,还可以提高水中降解石油微生物的数量与活性,从而促进原油的生物降解;营养盐的添加对生物修复效果的影响较大,在P含量为2.5mg/L,N/P为6∶1和8∶1时原油的降解率、降解菌的数量及活性都较高.其中,N/P为6∶1及8∶1时释放到海水中原油的降解率为84.1%、80.8%,而N/P为4∶1和10∶1时降解率仅为54.3%、69.4%.说明N/P为6∶1至8∶1时生物修复的效果较好.     

石油原油在水中的微生物降解

在54个微生态系统中,比较了化学分散剂、物理分散(机械搅拌)和营养剂投加等试验条件下,微生物对水中原油的降解效果。结果表明,化学分散剂能将原油分散成细小的油滴悬浮在水中,促进原油在水样中的微生物降解。对于原油初始浓度为0. 3 g/L左右的水样,进一步投加营养剂,能促进微生物的生长,将去除率从14%提高到24%。     

NaClO与KMnO4氧化对针杆藻灭活特性研究

以针杆藻（Synedra sp 。）为研究对象，考察了 NaClO 与 KMnO4在不同投量和不同 pH 条件下对针杆藻的灭活特点以及对光合活性的影响。结果表明，在0～5 mg／L 投加范围内，NaClO对针杆藻的灭活效果随剂量的增大而提高，投加量为3 mg／L 是抑制藻活性的最佳投量，并且在酸性条件下 NaClO 能更好的发挥其氧化降解的作用；KMnO4对针杆藻的降解效果不明显，说明投加KMnO4（≤5 mg／L）对针杆藻没有很好的灭活效果。氯化对针杆藻灭活效果好，但是会造成细胞解体，引起藻内有机物的释放，危及饮用水安全。     

水化硅酸钙强化穗状狐尾藻对底泥磷吸收能力的研究

通过在底泥中添加聚磷材料--水化硅酸钙来强化穗状狐尾藻对底泥中磷的吸收能力.比较了在不同的水化硅酸钙投加量以及底泥含磷量下,植物的生长情况以及上覆水的SRP、pH.结果表明,水化硅酸钙对于植物生长有明显的促进作用,投加量为20 g时穗状狐尾藻的总质量增加了20%,而未投加水化硅酸钙时,穗状狐尾藻的总质量反而减少了4.79%;投加水化硅酸钙能够促进底泥中磷的释放,并且该作用随水化硅酸钙投量的增加而变大;投加水化硅酸钙会提高水体的pH值,使水体的碱性增强,而植物的缓冲作用会削弱pH的变化,将pH值维持在8.5左右.     

PF-MBR处理城市生活污水的试验研究

为进一步提高膜生物反应器中污染物的生化降解效率,自行设计制作铁氧体粉末膜生物反应器(PF-MBR),并用之处理城市生活污水.结果表明,随着DO浓度的增加,系统对COD及NH4+-N的去除率逐渐增大;当HRT ＞6 h时,其对COD及NH4+-N去除率的影响不大;随着铁氧体粉末投加量的增加,系统对COD和NH4+-N的去除率均明显增大,表明增加铁氧体粉末投加量有利于系统对COD和NH4-N的去除;随着铁氧体粉末的比饱和磁化强度的增加,系统对COD和NH4+-N的去除率均增大,但幅度不大.PF-MBR稳定运行期间对COD的平均去除率达到了96.0％,对NH4+-N的平均去除率为93.3％.机理分析表明,膜生物反应器中加入铁氧体粉末后,在微生物降解、磁场能等共同作用下,实现了对污染物去除率的提高.     

生物柴油在稠油降黏技术中的应用研究

将生物柴油应用于稠油降黏技术中,可以减少稠油降黏对轻质油的依赖。考察了生物柴油的掺加对稠油降黏效果的影响,结果表明,加入适量的生物柴油(<10%(w))可起到良好的降黏作用,降黏效果优于柴油。通过对稠油添加生物柴油和柴油得到的两种混合油进行红外表征,证实了添加生物柴油对稠油原油氢键的取代可以解离胶质和沥青质之间的聚集体,减弱稠油中胶质与沥青质之间的相互作用,从而达到降黏的目的。随着添加量的增加,极性影响作用增大,粘度进一步降低;但当生物柴油添加量超过15%(w)时,极性作用所表现的降黏效果已不明显。     

复合微生物修复受轻度污染河水的试验研究

采用河道模拟模型,对受轻度污染河水进行了投菌法的修复研究,考察了投加方式、复投加参数以及停留时间对修复效果的影响.结果表明,最佳的投菌方式为连续投加;最佳复投加时间间隔为13 d,复投量为初投量的1/3;从投菌点算起,投菌随水流8d时,对COD和NH3-N的降解效果最佳.     

镍对餐厨垃圾厌氧消化中挥发酸降解的影响

针对高浓度有机废物厌氧消化过程中易发生反应器酸化问题,通过投加镍(Ni~(2+))来强化挥发性脂肪酸(VFAs)降解,考察镍强化VFAs降解和产生物气的效果。试验结果表明,当镍投加量为0.5 mg/kg TS时,反应11 h后,VFAs浓度降低至80.9 mg/L,生物气产量明显升高。长期连续试验发现,在反应器中积累90 d的VFAs可在投加Ni~(2+)后的10 d内完全降解,系统稳定后的平均生物产气速率达到0.548 m~3/(kg VS·d)。对古细菌群落结构和VFAs组成结构的分析表明,投加Ni~(2+)以后Methanosarcina和Methanosaeta所占比例分别从25.5%和28.8%升高至30.3%和32.6%,促进了VFAs中乙酸和丙酸的降解。     

Evidence for cooxidation of polynuclear aromatic hydrocarbons in soil

The effect of constituent matrix on the degradation of hydrocarbons was characterized and evaluated within the context of cooxidation. Current information concerning the cooxidation process applied to hydrocarbons was evaluated and results were used to define a laboratory approach for studying the effects of constituent matrix on degradation rates of 13 polynuclear aromatic hydrocarbons (PAHs) in soil. Four matrices were studied: (1) single constituents applied and incubated singly; (2) a synthetic mixture of PAHs applied and incubated together; (3) a mixture of oil refinery wastes; (4) and a creosote wood preserving waste. Initial soil concentrations of constituents were similar for each matrix evaluated. One soil was used, a Kidman fine sandy loam (Haplustoll, Utah). Incubation conditions and extraction and analysis methods were similar among the studies. Four and 5-ring PAHs were found to disappear more rapidly from soils amended with complex wastes, while degradation rates for 3-ring compounds in all matrices were similar. These results can be interpreted in the context of cooxidation and suggest a potential tool for bioremediation of PAH contaminated soils and the simultaneous protection of groundwater resources through reduction or mitigation of groundwater contamination due to vadose zone-associated PAHs.     

Sulfat-dominierter BTEX-Abbau im Grundwasser eines ehemaligen Gaswerksstandortes

In the area of a former gas-works in Düsseldorf (Germany) a soil and groundwater contamination with up to 100 mg/l BTEX (benzene, toluene, ethylbenzene and xylenes) was investigated. Benzene is the dominant aromatic hydrocarbon in the groundwater. The investigations show a natural biodegradation of BTEX by oxygen, manganese oxides, nitrate, ferric hydroxide and sulfate in the sand and gravel aquifer. Sulfate reduction is the most important degradation process in the contamined groundwater. As a product of sulfate reducion, sufids were formed in the sediments of the aquifer. A balance of oxidants is presented as a tool to quantify BTEX degradation and to differ this from sorption and dilution processes. In the contaminated area the degradation of aromatic hydrocarbons leads to the release of carbon dioxide. The highest free CO ₂ -concentration was found in the region of the groundwater table. Outgassing of CO ₂ is important and was verified by deep-specific soil-gas sampling. The knowledge of these processes in the subsoil is a requirement for making predictions for in-situ remediation effects.     

Biomarker responses and PAH uptake in Mya truncata following exposure to oil-contaminated sediment in an Arctic fjord (Svalbard)

Expanding industrial activity (notably oil and gas exploration) in the Arctic requires assessment of the potential impact of chemicals on marine organisms living in seawater at low temperature. The bivalve Mya truncata is common in Svalbard fjord (Norway) where it experiences low temperature throughout the year. To measure the impact of polycyclic aromatic hydrocarbons (PAH) on M. truncata, the responses of three biomarkers [total oxyradical scavenging capacity-assay (TOSC), plasma membrane stability of haemocytes and respiration rates] were investigated from bivalves exposed to sediment contaminated with a PAH mixture (crude oil). After two weeks of exposure to the contaminated sediment, TOSC showed no change. The high TOSC value (4010+/-1339 unit mg(-1) protein) of Mya truncata (control group) is thought to protect biomolecules with a low turnover rate efficiently in a low food availability environment. In the exposed bivalves, the haemocyte cellular membranes were significantly destabilised compared with controls (P<0.05). Respiration rate of control and PAH-exposed individuals (0.055+/-0.020 mg O(2) dw(-1) h(-1)) was similar and relatively low as is typical for polar bivalves, reflecting a strategy to minimise energy expenditure to cope with 9 months of starvation. Bioaccumulation of PAH by M. truncata was also low, due probably to a combination of low metabolic rate and reduced solubility of the oil compounds at low temperature. Data indicated an uptake of mainly low molecular weight compounds (two and three ring molecules). A good correlation of logBAF(lipid) (bioaccumulation factor) and logK(ow) (octanol/water partitioning coefficient) was shown (r(2)=0.87). Tissue sensitivity and/or functional differences (digestive gland vs. haemocytes), PAH uptake route (dietary vs. gills), the low metabolic rate of M. truncata and the low environmental temperature (reducing the bioavailability of PAH) are factors that help explain these findings.     

土壤中原油的解吸试验研究

对土壤中原油的解吸动力学及土壤粒径、pH值和温度3个影响因素进行了研究.研究结果表明:土壤中原油的解吸动力学符合Lagergren准二级动力学方程;原油污染土壤粒径越小,解吸的原油量越多;在pH值2～12范围内土壤中原油的解吸量随pH值的增大而增大;随着温度的升高,原油的解吸量逐渐增大.     

Emission comparison of urban bus engine fueled with diesel oil and 'biodiesel' blend

The chemical and toxicological characteristics of emissions from an urban bus engine fueled with diesel and biodiesel blend were studied. Exhaust gases were produced by a turbocharged EURO 2 heavy-duty diesel engine, operating in steady-state conditions on the European test 13 mode cycle (ECE R49). Regulated and unregulated pollutants, such as carcinogenic polycyclic aromatic hydrocarbons (PAHs) and nitrated derivatives (nitro-PAHs), carbonyl compounds and light aromatic hydrocarbons were quantified. Mutagenicity of the emissions was evaluated by the Salmonella typhimurium/mammalian microsome assay. The effect of the fuels under study on the size distribution of particulate matter (PM) was also evaluated. The use of biodiesel blend seems to result in small reductions of emissions of most of the aromatic and polyaromatic compounds; these differences, however, have no statistical significance at 95% confidence level. Formaldehyde, on the other hand, has a statistically significant increase of 18% with biodiesel blend. In vitro toxicological assays show an overall similar mutagenic potency and genotoxic profile for diesel and biodiesel blend emissions. The electron microscopy analysis indicates that PM for both fuels has the same chemical composition, morphology, shape and granulometric spectrum, with most of the particles in the range 0.06-0.3 microm.     

Microcosm experiments of oil degradation by microbial mats

Several microcosm experiments were run in parallel to evaluate the efficiency of microbial mats for crude oil degradation as compared with physico-chemical weathering. The oils used in the experiments constituted representative examples of those currently used for commercial purposes. One was aliphatic and of low viscosity (33.4 American Petroleum Institute degrees, degrees API) and the other was predominantly aromatic, with high sulphur content (ca. 2.7%) and viscosity (16.6 degrees API). After crude oil introduction, the microcosms were kept under cyclic changes in water level to mimic coastal tidal movements. The transformations observed showed that water weathering leads to more effective and rapid elimination of low molecular weight hydrocarbons than microbial mat metabolism, e.g. n-alkanes with chain length shorter than n-pentadecane or n-heptadecane, regular isoprenoid hydrocarbons with chain length lower than C16 or C18 or lower molecular weight naphthalenes. Microbial mats preserved these hydrocarbons from volatilization and water washing. However, hydrocarbons of lower volatility such as the C24-C30 n-alkanes or containing nitrogen atoms, e.g. carbazoles, were eliminated in higher proportion by microbial mats than by water weathering. The strong differences in composition between the two oils used for the experiments were also reflected in significant differences between water weathering and microbial mat biodegradation. Higher oil viscosity seemed to hinder the former but not the later.     

Effects of dispersed oil exposure on the bioaccumulation of polycyclic aromatic hydrocarbons and the mortality of juvenile Liza ramada

Dispersing an oil slick is considered to be an effective response to offshore oil spills. However, in nearshore areas, dispersant application is a controversial countermeasure: environmental benefits are counteracted by the toxicity of dispersant use. In our study, the actual toxicity of the dispersant response technique in the nearshore areas was evaluated through an experimental approach using juvenile Liza ramada. Fish were contaminated via the water column (i) by chemically dispersed oil, simulating dispersant application, (ii) by dispersant, as an internal control of chemical dispersion, (iii) by mechanically dispersed oil, simulating only the effect of natural mixing processes, without dispersant application, and (iv) by the water soluble fraction of oil, simulating the toxicity of an oil slick before recovery. Bioconcentrations of polycyclic aromatic hydrocarbons (PAH) and mortality were evaluated, and related to both total petroleum hydrocarbon (TPH) and polycyclic aromatic hydrocarbon (PAH) concentrations in seawater.Fish exposed to chemically dispersed oil showed both a higher bioconcentration of PAH and a higher mortality than fish exposed to either the water soluble fraction of oil or the mechanically dispersed oil. These results suggest that (i) dispersion is a more toxic response technique than containment and recovery of the oil slick; (ii) in turbulent mixing areas, dispersant application increases the environmental risk for aquatic organisms living in the water column. Even if the experimental aspects of this study compel us to be cautious with our conclusions, responders could consider these results to establish a framework for dispersant use in nearshore areas.     

固定化微生物修复石油污染土壤特性试验

利用梯度稀释法分离筛选原油降解混合菌,采用吸附法将混合菌固定在砾石和草炭土上,探讨固定化混合菌对土壤石油烃的去除效果。结果表明:分离得到的混合菌8-2,菌群结构简单,石油烃降解率可达52.1%。与砾石相比,草炭土所固定的微生物数量和活性较高,可达1.3×108 cfu/g和0.24A487。草炭土固定的混合菌8-2,修复含油量为30g/kg的污染土壤30d后,石油烃降解率达28.4%,高于游离降解菌的24.3%。固定化载体草炭土在修复过程中起到了微生物缓释剂的作用。     

Complications with remediation strategies involving the biodegradation and detoxification of recalcitrant contaminant aromatic hydrocarbons

Environmentally persistent aromatic hydrocarbons known as unresolved complex mixtures (UCMs) derived from crude oil can be accumulated by, and elicit toxicological responses in, marine organisms (e.g. mussels, Mytilus edulis). Comprehensive two-dimensional gas chromatography time-of-flight mass-spectrometry (GC × GC-ToF-MS) previously revealed that these UCMs included highly branched alkylated aromatic hydrocarbons. Here, the effects of biodegradation on the toxicity and chemical composition of an aromatic UCM hydrocarbon fraction isolated from Tia Juana Pesado (TJP) crude oil were examined. 48 h exposure of mussels to the aromatic hydrocarbon fraction (F2) resulted in tissue concentrations of 900 µg g^− 1 (dry wt.) and ∼ 45% decrease in clearance rate. Over 90% of the hydrocarbon burden corresponded to an UCM. Following a 5 day recovery period, GC × GC-ToF-MS analysis of the tissues indicated depuration of most accumulated hydrocarbons and clearance rates returned to those observed in controls. To assess the potential of biodegradation to reduce UCM toxicity, TJP F2 was exposed to bacteria isolated from Whitley Bay, UK, for 46 days. Mussels exposed to the undegraded TJP F2 from the abiotic control exhibited a reduction in clearance rate comparable with values for the pure crude oil TJP F2. Clearance rates of mussels exposed to biodegraded TJP F2 were statistically similar to seawater controls, suggesting biodegradation had reduced the TJP F2 toxicity. GC × GC-ToF-MS analysis revealed the same compound groups in the tissue of mussels exposed to pure TJP F2, undegraded TJP F2 and biodegraded TJP F2 samples; however > 300 fewer compounds were observed in the biodegraded (954 compounds) compared to the undegraded TJP F2 (1261). The compound distributions were markedly different, possibly accounting for the decrease in toxicity. Extraction and analysis of pelleted bacterial cell material revealed that a significant proportion of the TJP F2 had adsorbed onto the cells. Thus extreme care must be taken in interpreting biodegradation data from recalcitrant UCM hydrocarbons.