Determination of suitable TPH remediation approach via MANOVA and inferential statistics assessment

Soil contamination resulting from petroleum hydrocarbon contaminants poses a fairly substantial hazard to human health and the environment. Phytoremediation, land farming, and chemico–biological stabilization were used to treat total petroleum hydrocarbons (TPHs) and polycyclic aromatic hydrocarbons (PAHs) at a crude oil polluted soil site in Nigeria. A field pilot study was conducted by preparing nine cells with subcells attached to each serving as a control with an overall area of 1.53 m². A complete block design method was used for the study. The prepared soil sample cells were divided into three groups with each group having approximately 300 kg of soil and delineated as low, medium, and high test plots. The low samples were spiked with 6.1 kg of crude oil, the medium samples were spiked with 12.2 kg of crudeoil, and the high samples were spiked with 18.3 kg of crude oil. Each row containing three cells with low, medium, and high concentrations were treated separately using the three treatment methods. The ratio of the soil sample to the organic amendment for the treatments was 2:1. The results showed over 90% degradation in the initial concentration of TPH and PAHs across different contaminant levels except in the control subcells where only 30% of degradation was recorded. Multivariate analysis of variance was employed to assess the significant difference in each treatment group while inferential statistics using a mean performance plot was used to ascertain the optimum treatment method. Land farming, chemico–biological stabilization, and phytoremediation ranked 1, 2, and 3, respectively. In conclusion, the three treatment methods employed all degraded the contaminants (TPH and PAHs) with land farming emerging as the best method.     

不同碳源对微生物修复石油污染土壤的促进作用

为解决石油污染土壤中以石油为唯一碳源的土著微生物生长缓慢的问题,研究了分别添加玉米淀粉、玉米粉、可溶性淀粉和葡萄糖4种碳源对土样细菌总量和石油烃降解率的影响。研究结果表明：玉米淀粉作为碳源时土样TN和TP的下降幅度均最大;添加玉米淀粉和玉米粉比添加可溶性淀粉和葡萄糖更有利于细菌的生长繁殖;细菌对直链烷烃化合物均具有较好的降解效果,但对较为复杂的芳香烃化合物降解效果较差。降解反应第40天时,分别添加玉米淀粉、玉米粉、可溶性淀粉和葡萄糖的石油烃降解率分别为67.25%、48.60%、46.30%和28.57%。     

铁活化过硫酸盐修复石油烃污染土壤的研究进展

分析了Fe~0、Fe~(2+)和Fe~(3+)活化过硫酸盐氧化石油烃的机理,介绍了土壤中石油烃污染物降解的影响因素以及总结了铁活化过硫酸盐修复石油烃污染土壤技术的不足。指出应以铁活化过硫酸盐原位修复作为土壤中高浓度有机污染物的前处置方法,再结合微生物或植物修复等技术,以减少对土壤理化性质的影响;另外,检测仪器的发展有利于土壤修复技术的应用。     

Laser-induced fluorescence and fast gas chromatography/mass spectrometry with subsurface thermal extraction of organics: Field analytical technologies for expediting site characterization and cleanup

This article describes new field-based technologies that support the Dynamic Workplan/Adaptive Sampling and Analysis Program employed to better characterize hazardous waste sites at lower cost. A laser-induced fluorescence (LIF) probe was designed and field-tested with a cone penetrometer (CP) for investigating petroleum contaminants present at under-ground tank farms. The LIF produced real-time quantitative data for naphthalene and semiquantitative results for total petroleum hydrocarbons and diesel range organics. Two different projects are described employing fast gas chromatography/mass spectrometry (GC/MS) in the field. A 70-foot heated transfer line and probe were used in combination with a cone penetrometer to thermally extract (TE) subsurface soil-bound semivolatile organics. In the second project, soil samples were collected by a Geoprobe^TM and brought to the surface for analysis. The direct measurement TECP data produced semiquantitative results while the more conventional means of collecting and analyzing samples produced risk analysis quality data in the field. A new set of mass spectrometry algorithms provided the technology breakthrough for identifying and quantifying a wide range of Environmental-Protection-Agency-listed target compounds in the presence of high levels of matrix (petroleum) interferents under fast, 7 min/sample, GC conditions.     

Petroleum Hydrocarbons Rhizodegradation by Sebastiania commersoniana (Baill.) L. B. SM. & Downs

Petroliferous activities in Brazil have an accelerated development in the last years. As a consequence, the incidence of environmental accidents such as oil spills and contamination of soils has increased significantly. Therefore, it is extremely necessary to develop remediation techniques with lower costs, decontamination efficiency and impact minimisation. The aim of this work was to evaluate Sebastiania commersoniana phytoremediation potential in soil contaminated by petroleum. This species, which is a native tree, was selected due to its proven capacity for surviving in areas contaminated by petroleum. Experiments were carried out with soils that were vegetated but non-contaminated, soils that were freshly contaminated (25, 50 and 75 g kg^?1) but non-vegetated, and soils that were vegetated and contaminated, samples were collected 60 and 424 days after contamination with the purpose of evaluating the percentage of petroleum degradation in relation to the time. The results obtained in the present study allow us to state that S. commersoniana proves to be tolerant to petroleum contamination with respect to plant’s growth. The degradation of petroleum hydrocarbons was evaluated by gas chromatography with a flame ionisation detector (GC-FID) equipped with a capillary column HP-5 (5% phenyl-methylpolysiloxane, 30 m; 0.25 mm; 0.25 μm). According to chromatographic analysis, samples in contact with S. commersoniana showed a significant area reduction of the hydrocarbon peaks. Analysis of the 60-day samples showed a reduction of petroleum hydrocarbons area higher than 60% and the 424-day samples showed a reduction higher than 94%, which demonstrates that a petroleum degradation process is occurring.     

An accelerated laboratory study evaluating the disintegration rates of plastic films in simulated aquatic environments

Six plastic films were exposed to accelerated sunlight while in simulated aquatic environments to determine the effects of chemical composition and environment on the disintegration rates. An environment of UV light/no water was used as a control to determine if the microorganisms in the aquatic systems enhanced the breakdown of the plastic films. The disintegration rate of the plastics was determined by monitoring changes in selected physical properties. The plastics included two conventional plastics commonly used in packaging (LDPE and polystyrene) and four plastics enhanced to have more rapid breakdown in the environment (2% ECO, 10% ECO, PE with ketone graft, and PE with starch). The two ECO copolymers had a significantly faster loss of physical properties than the other plastics evaluated in this study. Degradation was influenced by environmental conditions. Those plastics that showed a change in physical properties had a greater change faster in the UV light/no water than in the environments where water was present. Plastics on the surface of the water showed a more rapid loss of properties than those samples partially or completely submerged. This can be attributed to decreased light intensity and the lack of heat buildup.     

Study of fine sediments for making lightweight aggregate.

The objective of this study was to investigate the recycling of the fine sediments of Shih-Men Reservoir to manufacture lightweight aggregate. By qualitative and quantitative analysis of the fine sediment and sintered aggregate through soil test, X-ray fluorescence, X-ray diffraction and scanning electron microscopy, a strategy of recycling fine sediment as aggregate for other similar material is proposed. The test results indicate that such fine sediment can be classified as low plastic clay, and clay of such chemical composition is located in the Riley's 'area of bloating'. The particle density of sintered lightweight aggregate decreases when the sintering temperature increases especially above 1200 degrees C due to phase transformation and formation of a vitrified layer on the surface through subsequent dehydration, bloating and collapsing stages. Our findings show that the fine sediment of Shin-Men Reservoir could be a suitable raw material for making expanded lightweight aggregate sintered at 1200 to 1300 degrees C for 10 to 12 min by a programmable furnace and a diffusion process.     

石油烃污染土壤微生物修复促进技术

采用原位修复法处理石油烃污染土壤,考察了土壤中石油烃的自然降解情况,研究了土壤改良剂和生物营养剂对石油烃降解的促进作用。实验结果表明:将总石油烃含量约为5 g/kg的实验土样降解30 d,自然降解时总石油烃降解率为7.8%;当单独加入1.0%(w)的土壤改良剂时,总石油烃降解率达36.0%;当单独加入1.0 g/kg的生物营养剂时,总石油烃降解率为51.6%;最佳促进剂配方为土壤改良剂加入量1.0%(w),生物营养剂加入量1.0 g/kg,此条件下总石油烃降解率为80.1%。     

Petroleum biodegradation in soil: The effect of direct application of surfactants

The direct application of surfactants to petroleum-contaminated soil has been proposed as a mechanism to increase the bioavailability of insoluble compounds. Solubilization of hydrophobic compounds into the aqueous phase appears to be a significant rate limiting factor in petroleum biodegradation in soil. Nonionic surfactants have been developed to solubilize a variety of compounds, thus increasing the desorption of contaminants from the soil. In this study, laboratory scale land treatment scenarios were used to monitor the bioremediation of petroleum contaminated soils. In efforts to achieve the lowest levels of residual petroleum hydrocarbons in the soil following biotreatment, 0.5 and 1.0% (volume/weight) surfactant was blended into soils under treatment. Two soil types were studied, a high clay content soil and a sandy, silty soil. In both cases, the addition of surfactant (Adsee 799®, a blend of ethoxylated fatty acids, Witco Corporation) stimulated biological activity as indicated by increased heterotropbic colony forming units per gram of soil. However, the increased activity was not correlated with removal of petroleum hydrocarbons. The results suggest that the application of surfactants directly to the soil for the purpose of solubilizing hydropbobic compounds was not successful in achieving greater levels of petroleum hydrocarbon removal.     

高效石油烃降解菌的筛选及其对原油污染土壤的修复

从陕北原油污染土壤中筛选出7株高效石油烃降解菌,其中黄杆菌属CC-2、不动细菌属SC-5、假单胞菌属SC-6表现出较强的石油烃降解能力。通过单因素试验和正交试验考察总石油烃(TPH)降解效果的影响因素,得出各因素对TPH降解率影响程度的大小次序为:溶液p H降解温度降解菌接种量摇床转速,且在降解菌接种量为7%(φ)、溶液p H为7、降解温度为30℃、摇床转速为150 r/min的最适处理条件下,菌株SC-6的TPH降解率可达61.23%。原油污染土壤生物修复实验结果表明:高效石油烃降解菌的投加有利于土壤TPH降解率和酶活性的提高;"菌株SC-6+营养剂"组修复处理42 d后的TPH降解率可达57.59%。     

Use of a novel biomarker,botryococcane, to monitor biodegradation of two lacustrine‐sourced crude oils

Bioremediation is a proven alternative for remediating petroleum‐impacted soils at exploration and production (E&P) sites. Monitoring remediation performance can involve detection and quantification of biodegradation resistant compounds such as C₃₀17α(H),21β(H)‐hopane, which requires the use of gas chromatography with mass spectrometry detection (GC/MS). Due to the remoteness of many E&P sites, this technology is not always available, and alternative methods are needed to provide reliable quantitative measurements of petroleum remediation efficiency. This study provides a detailed chemical characterization of lacustrine‐sourced crude oils and a technical basis for measuring the effectiveness of bioremediation efforts for soil impacted by those crudes. We show that the novel isoprenoid hydrocarbon botryococcane is relatively stable in lacustrine‐sourced crude oils compared with C₃₀17α(H),21β(H)‐hopane under moderate biodegradation conditions generally observed in field samples. We have also demonstrated that, due to the stability and relatively elevated concentration of botryococcane in lacustrine oils, it can be reliably measured using the more cost‐effective and available GC/FID methodology, and thereby be used to monitor the progress of ongoing soil bioremediation activities at remote sites.     

Fate of Chlorothalonil, Chlorpyrifos and Profenofos in a Vegetable Farm in cameron Highlands, Malaysia

The fate of chlorothalonil, chlorpyrifos and profenofos in sandy loam soil under tropical condition was studied in a vegetable plot in the Cameron Highlands, Malaysia. The plot was treated with chlorothalonil, chlorpyrifos and profenofos according to normal agricultural practices of the Cameron Highlands. Water (runoff and lysimeter), soil and bedload sediment samples were taken according to a sampling schedule. Residues in water, soil and bedload sediment samples were laboratory analysed to determine amount. Chlorothalonil residues were detected in the range of < 0.01–0.08 mg/kg in the soil, < 0.01–0.02 ng/mL in the leachate, < 0.01–0.02 ng/mL in the runoff and < 0.01–0.11mg/kg in the sediment. Field studies of chlorpyrifos showed residue levels of < 0.01–0.06 mg/kg in the soil, < 0.01–0.07 ng/mL in the leachate, < 0.01–0.08 ng/mL in the runoff and < 0.01–0.62 mg/kg in the sediment. Residue levels of profenofos were detected in the range of < 0.01–0.02 mg/kg in the soil, < 0.01–0.87 ng/mL in the leachate, < 0.01–0.08 ng/mL in the runoff and < 0.01–0.35 mg/kg in the sediment. The three pesticides dissipated rapidly, with DT50 (time for 50% loss) of less than two days. The study showed that these pesticides dissipated rapidly under the climatic conditions of the Cameron Highlands in Malaysia.     

Fenton氧化—微生物法降解土壤中石油烃

以长期被苯系物污染的活性污泥为菌源,采用液相“诱导物-中间产物-目标污染物”驯化模式驯化出专性混合石油降解菌群,并将其用于Fenton氧化—微生物法处理模拟石油污染土壤。高通量测序结果表明,产黄杆菌属（Rhodanobacter）、分支杆菌属（Mycobacterium）和根瘤菌属（Rhizobiales）为主导菌属。实验结果表明：接种混合菌群后降解50 d,土样的总石油烃（TPH）去除率较土著菌提高了13.4~20.5百分点;对于TPH含量（w）分别为4%,8%,11%的土样,Fenton氧化的最佳H₂O₂加入量分别为3,4,4 mol/L（Fe²⁺加入量0.04 mol/L）,TPH总去除率分别可达88.8%,65.0%,47.7%,较单独Fenton氧化或单独微生物法均有很大程度的提高,且缩短了降解时间,增加了土壤有机质。     

Effect of Accelerated Weathering on Biocomposites Processed by SMC and Compression Molding

The durability of biocomposites utilized for building components has been a subject of recent concern and questioning. To address these concerns, the long-term effects of weathering on biocomposites used as building components were evaluated using an accelerated weatherometer. The biocomposite samples were processed by sheet molding compounding (SMC) panel processing and/or compression molding. The accelerated weatherometer served to expose the samples to ultraviolet radiation (UV), condensation, and water spray at levels pertinent to actual conditions: 48 cycles of UV (340 nm) treatment at 60 °C for 2.5 h was followed by water spray for 0.5 h, and then condensation at 45 °C for 24 h. Twelve cycles were repeated in each test, and the total duration for the complete test was 2016 h. Measurements for color, surface roughness test weight change, and dynamical mechanical analysis were taken at regular intervals of time. It was found that the surface roughness increased, as the color changed, and storage modulus decreased with increases in the exposure time of the samples to accelerated weathering conditions, compared to their properties at the beginning of the test.     

Monitoring of the Degradation Activities and the Diversity of the Microbial Community Degrading Refinery Waste Sludge

The biodegradation of n-alkanes and branched alkanes from waste sludge were observed in landfarming soils of Motor Oil Hellas (a petroleum refinery) and changes in the bacterial communities in the soils were monitored during the remediation. Bacterial 16S rRNA gene (rDNA)-based community fingerprint patterns were obtained from soil samples by terminal restriction fragment length polymorphism (T-RFLP) analysis. Changes in T-RFLP fingerprints, as well as in the petroleum contaminant composition of the polluted soil, correlated with degradation activities in field tests.     

Synergistic Effect of TNPP and Carbon Black in Weathered XLPE Materials

Carbon black is one of the most widely used and most effective ultraviolet (UV) light stabilizers for plastics applications. Several important segments of the plastics industry rely on carbon black for UV stabilization of weather-resistant products, including telecommunications, power cable jacketing, and plastic pipes. In this research work a combination of Trisnonylphospate (TNPP) antioxidant and different size carbon black were applied in crosslinked polyethylene (XLPE) to improve its wetherability. The primary reason for cross-linking polyethylene (PE) is to raise the thermal stability of the material under load. This substantially improves environmental stress crack resistance and resistance to slow crack growth. The results achieved of this additive package combination show a synergism effect and improved weatherability of electrical cable. Increased weathering lifetime was also achieved. Further, we were able to confirm in this work, that the size and quality of the carbon black dispersion in a XLPE samples is an important component of both the UV-resistance and mechanical properties of the finished plastic article. Incremental improvements of carbon black dispersion can positively influence the expected life of plastic articles. Mechanical testing and FTIR were used to detect degradation of the accelerated weathered XLPE samples. The morphological considerations of UV energy absorption and presents laboratory data demonstrating the link between dispersion and weatherability as well as between morphology and weatherability     

In Situ flushing of contaminated soils from a refinery: Organic compounds and metal removals

This article demonstrates the applicability of in situ flushing for the remediation of soil contaminated with petroleum hydrocarbons at a Mexican refinery. The initial average total petroleum hydrocarbon (TPH) concentration for the demonstration field test was 55,156 g/kg. After six weeks of in situ flushing with alternate periods of water and water/surfactant, an average concentration of 1,407 mg/kg was reached, achieving a total removal efficiency of 98 percent. At the end of the process, no hydrocarbons such as diesel; gasoline; benzene, toluene, ethyl benzene, and xylene (BTEX); or petroleum aromatic hydrocarbons (PAHs) were found. Iron washing achieved a removal efficiency of 70 percent, and for vanadium, the removal efficiency was 94.4 percent. The volume of soil treated was 41.6 m³ (38 m²), equivalent to 69.5 tons of soil. A rough calculation of the process costs estimated a total cost of $104.20/m³ ($114.00/m²). Our research indicates that there are a few studies demonstrating in situ flushing experiences under field conditions where both organic (TPH, diesel, gasoline, PAHs, BTEX) and metal (iron and vanadium) removals are reported. © 2004 Wiley Periodicals, Inc.     

Genotoxicity of leachates from highly polluted lowland river sediments destined for disposal in landfill

The Matanza-Riachuelo is one of the most polluted rivers of Latin America. The complex chemical mixture of pollutants discharged into the river is accumulated in the river sediments. In this paper, Matanza-Riachuelo river sediment composition and genotoxicity were tested in order to develop a cost-effective, environmentally sound option for disposal and management of contaminated dredged materials. Sampling was performed in a rural area, in a solid waste dumpsite and also in an urban and industrial area. The concentrations of total heavy metals increased from the upper basin to the lower basin. The Ames Salmonella typhimurium test and the Saccharomyces cerevisiae D7 test were performed using toxicity characteristic leachate procedure (TCLP) leachates. The concentrations of copper, lead, and chromium in the leachates exceeded the guide levels for the protection of aquatic life. Low concentrations of organic chlorinated compounds were detected in the leachates. Genotoxic profiles were obtained by testing TCLP leachates from polluted sediment samples with Salmonella typhimurium, Saccharomyces cerevisiae D7, and water sediment suspension with Allium cepa test. No mutagenicity effects on Ames test were observed. Gene conversion and mitotic reversion in Saccharomyces cerevisiae D7 and chromosome aberration in Allium cepa were induced by the sediment samples. Results obtained suggest that dredged sediments could be classified as genotoxic hazardous waste.     

A New Respirometric Test Simulating Soil Burial Conditions for the Evaluation of Polymer Biodegradation

A new convenient and reliable method is described for assessing the biodegradation properties of polymeric materials under simulated soil burial conditions, which makes it possible to test with nutrient-rich soils. This method consists of the utilization of a minimum amount of a soil layer, in which the samples to be tested are set in close contact, sandwiched between two layers of perlite, a natural porous aluminosilicate. The biodegradation level is monitored by determining the carbon dioxide evolution derived from the test samples. The limited amount of soil used limits carbon dioxide evolution from the blanks, due to the corresponding limited overall amount of soil carbon. This experimental setup allows for an extremely satisfactory level of confidence in the analytical results, permitting a wider variety of soil types to be tested.