油泥（砂）处理技术研究

对油泥(砂)进行处理实验,确定采用破乳脱稳—离心分离—固化处理工艺。分离出的原油可以回用;处理后的水质达到了SY/T5329-94《碎屑岩油藏注水水质推荐指标及分析方法》回注要求;固化物浸出液的分析结果符合国家GB5085.3-2007《危险废物鉴别标准浸出毒性鉴别》、GB5085.1-2007《危险废物鉴别标准腐蚀性鉴别》和GB8978-1996《污水综合排放标准》一级标准。实验结果表明:该工艺在处理油田油泥(砂)方面具有可行性和实用性。     

低含油污泥固化处理技术研究*

针对辽河油田欢采水厂低含油污泥,采用固化处理方法,测定了固化剂用量对抗压强度的影响和促凝剂用量对固化时间的影响,得到含油污泥:固化剂:促凝剂最佳配比为100:12:1.5。对含油污泥固化块进行浸出液毒性监测,分析结果表明:含油污泥固化块浸出液中重金属Cu、Pb、Cr、As、Zn、Ni、Cd的含量明显降低,远低于GB5085.3-2007《危险废物鉴别标准浸出毒性鉴别》;浸出液中COD降低了77%。     

超声萃取法处理含油污泥

应用超声强化技术,对以汽油为萃取剂的超声萃取法处理含油污泥的工艺进行了研究,筛选了调整剂、絮凝剂、破乳剂,探讨了萃取温度、萃取时间、超声频率、超声功率等对处理效果的影响。结果表明:在调整剂为采油废水、物料配比为v(萃取剂)∶v(调整剂)∶v(油污泥)=4∶4∶1的条件下,萃取工艺为萃取温度40℃、萃取时间15 min、超声频率40kHz、超声功率150 W时,可回收含油污泥中83.7%的油品。     

Fractionation and speciation of arsenic in three tea gardens soil profiles and distribution of As in different parts of tea plant (Camellia sinensis L.)

The distribution pattern and fractionation of arsenic (As) in three soil profiles from tea (Camellia sinensis L.) gardens located in Karbi-Anglong (KA), Cachar (CA) and Karimganj (KG) districts in the state of Assam, India, were investigated depth-wise (0-10, 10-30, 30-60 and 60-100 cm). DTPA-extractable As was primarily restricted to surface horizons. Arsenic speciation study showed the presence of higher As(V) concentrations in the upper horizon and its gradual decrease with the increase in soil depths, following a decrease of Eh. As fractionation by sequential extraction in all the soil profiles showed that arsenic concentrations in the three most labile fractions (i.e., water-soluble, exchangeable and carbonate-bound fractions) were generally low. Most arsenic in soils was nominally associated with the organic and Fe-Mn oxide fractions, being extractable in oxidizing or reducing conditions. DTPA-extractable As (assumed to represent plant-available As) was found to be strongly correlated to the labile pool of As (i.e. the sum of the first three fractions). The statistical comparison of means (two-sample t-test) showed the presence of significant differences between the concentrations of As(III) and As(V) for different soil locations, depths and fractions. The risk assessment code (RAC) was found to be below the pollution level for all soils. The measurement of arsenic uptake by different parts of tea plants corroborated the hypothesis that roots act as a buffer and hold back contamination from the aerial parts.     

Lumbricus terrestris L. activity increases the availability of metals and their accumulation in maize and barley

The effect of the earthworm Lumbricus terrestris L. on metal availability in two mining soils was assessed by means of chemical extraction methods and a pot experiment using crop plants. Results from single and sequential extractions showed that L. terrestris had a slight effect on metal fractionation in the studied soils: only metals bound to the soil organic matter were significantly increased in some cases. However, we found that L. terrestris significantly increased root, shoot and total Pb and Zn concentrations in maize and barley for the soil with the highest concentrations of total and available metals. Specifically, shoot Pb concentration was increased by a factor of 7.5 and 3.9 for maize and barley, respectively, while shoot Zn concentration was increased by a factor of 3.7 and 1.7 for maize and barley, respectively. Our results demonstrated that earthworm activity increases the bioavailability of metals in soils.     

Assessment of aided phytostabilization of copper-contaminated soil by X-ray absorption spectroscopy and chemical extractions

Field plots were established at a timber treatment site to evaluate remediation of Cu contaminated topsoils with aided phytostabilization. Soil containing 2600 mg kg⁻¹ Cu was amended with a combination of 5 wt% compost and 2 wt% iron grit, and vegetated. Sequential extraction was combined with extended X-ray absorption fine structure (EXAFS) spectroscopy to correlate changes in Cu distribution across five fractions with changes in the predominant Cu compounds two years after treatment in parallel treated and untreated field plots. Exchangeable Cu dominated untreated soil, most likely as Cu(II) species non-specifically bound to natural organic matter. The EXAFS spectroscopic results are consistent with the sequential extraction results, which show a major shift in Cu distribution as a result of soil treatment to the fraction bound to poorly crystalline Fe oxyhydroxides forming binuclear inner-sphere complexes.     

Distribution, speciation and availability of antimony (Sb) in soils and terrestrial plants from an active Sb mining area

Here, we present one of the first studies investigating the mobility, solubility and the speciation-dependent in-situ bioaccumulation of antimony (Sb) in an active Sb mining area (Xikuangshan, China). Total Sb concentrations in soils are high (527-11,798 mg kg⁻¹), and all soils, including those taken from a paddy field and a vegetable garden, show a high bioavailable Sb fraction (6.3-748 mg kg⁻¹), dominated by Sb(V). Elevated concentrations in native plant species (109-4029 mg kg⁻¹) underpin this. Both chemical equilibrium studies and XANES data suggest the presence of Ca[Sb(OH)₆]₂, controlling Sb solubility. A very close relationship was found between the citric acid extractable Sb in plants and water or sulfate extractable Sb in soil, indicating that citric acid extractable Sb content in plants may be a better predictor for bioavailable Sb in soil than total acid digestible Sb plant content.     

中置曝气生物活性炭工艺中的微絮凝

利用新型炭滤-砂滤工艺对南方湿热地区微污染源水进行中试规模的微絮凝实验研究。结果表明,接触絮凝时间为2~5 min时,投加1.0 mg/L的PAC微絮凝效果最好。运行稳定后,砂滤器出水浊度≤0.1 NTU,对COD Mn的去除效果有一定改善,微型水生生物的种类和数量也较炭滤器有大幅度下降,其中双层砂滤的效果优于单层粗砂,但其水头损失增长较快。通过微絮凝,砂滤器对炭滤器反冲洗后初滤水能有较好处理效果,可有效简化运行工艺。同时可保证滤后水中铝含量满足《生活饮用水卫生标准》的要求。     

The persistence of insecticidal chemicals in soils treated with granular formulations of disulfoton and their uptake by potato plants

Abstract

Potatoes were grown from cut seed in Plainfield sand treated in‐furrow with disulfoton (Di‐Syston 15G, 3.36 kg Al/ha) in 1983 and from whole seed in similarly treated loam in 1991. Soils were contained in 2 m² field plots. Soil, seed potato and foliage were analyzed for the insecticide and its sulfoxide and sulfone metabolites during the 8–12 wk following planting. Disulfoton disappeared at different rates from the two soils (k_sand=0.024 day^‐1, k_loam=0.056 day^‐1) with partial conversion to the sulfoxide and sulfone in both. Larger quantities of the three insecticidal components were absorbed by the seed potato in the cut‐seed/sand combination. The relative amounts of these components in the seed potato also differed between treatments with disulfoton being the largest component of the cut‐seed/sand and smallest in the whole‐seed/loam. Disulfoton sulfoxide and sulfone were the major insecticidal components of the foliage and concentrations in the initial foliage (each ca. 10 ppm) were similar for both treatments. Sulfoxide concentrations in the foliage decreased more rapidly than the sulfone and the decrease in concentration of each of the components was similar for the two treatments.