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281.
针对我国生活垃圾的特点,提出了厨余等有机生活垃圾单独收集,在产生源头进行好氧堆肥处理。研制了好氧堆肥设备,由加热装置、通风装置、冷凝水收集和回灌装置,以及与该生物堆肥设备配套的生物过滤除臭装置、自控系统和数据采集软件几部分构成。自控系统由氧气、温度、湿度三路传感器以及2个控制器构成,并与加热装置、通风装置连接,能满足物料加热、供氧和散热的要求。本研究通过为期30 d的试运行实验表明,物料快速升温并稳定保持在高温阶段(50~60℃),物料中的氧气浓度保持在14%~16%范围内。在堆肥实验结束时,物料的含水率降至36.4%,有机质含量降至49%,另外,通过好氧速率指标也可判定物料达到腐熟。 相似文献
282.
生物强化修复石油污染土壤 总被引:2,自引:0,他引:2
筛选高效石油降解菌,考察菌株的降解性能及降解机理,进行花盆模拟高效外源菌强化修复石油污染土壤实验,在降解后期添加激活剂H2O2以及木屑来试图改善微生物的修复环境,减缓微生物的衰亡,并考察修复效果。结果表明,菌株L-1的降解效果较好,其对pH和温度有较大范围的适应性,能分泌较多的表面活性物质,细胞疏水性较强。将其应用于土壤修复中,经过50 d的修复,石油残留率达到50.6%左右,生物强化比自然修复残留率降低了8%左右。在第45天添加激活剂能有效改善修复效果,70 d时添加外源菌的土样最小石油残留率达到37.9%。 相似文献
283.
以氯化铁为铁源,硼氢化钠为还原剂,壳聚糖为稳定剂,采用液相还原法制备壳聚糖稳定纳米铁(CS-nZⅥ);研究了印染废水中常见助剂NaNO3、Na2SO4、NaH2PO4、K2Cr2O7、EDTA二钠盐存在下,超声波辅助CS-nZⅥ对酸性品红(AF)降解的影响。结果表明,反应15 min,0.01 g CS-nZⅥ对25 mL、100 mg/L AF的去除率高达99.9%;各种助剂的存在使得纳米铁表面不同程度失活,阻碍反应的进行,使得AF的去除率下降。NaNO3、K2Cr2O7、EDTA二钠盐与纳米铁发生反应,与AF存在明显的竞争作用。重复利用实验表明,CS-nZⅥ重复利用7次仍具有一定的反应活性。此外,CS-nZⅥ对加标(50 mg/L)实际废水中AF的去除率达到99%以上,表明CS-nZⅥ是一种潜在的环境修复材料。 相似文献
284.
A study has been made of the effect a reactive barrier made of pine (softwood) or oak (hardwood) wood intercalated in a sandy soil column has on the retention of linuron, alachlor and metalaxyl (pesticides with contrasting physicochemical characteristics). The leaching of pesticides has been carried out under a saturated flow regime and breakthrough curves (BTCs) have been obtained at flow rates of 1 mL min−1 (all pesticides) and 3 mL min−1 (linuron). The cumulative curves in the unmodified soil indicate a leaching of pesticides >80% of the total amount of compound added. After barrier intercalation, linuron leaching decreases significantly and a modification of the leaching kinetics of alachlor and metalaxyl has been observed. The theoretical R factors increased ∼2.6-3.3, 1.2-1.6-fold, and 1.4-1.7-fold and the concentration of the maximum peak decreased ∼6-12-fold, 2-4-fold and 1.2-2-fold for linuron, alachlor and metalaxyl, respectively. When considering the three pesticides, significant correlations have been found between the theoretical retardation factor (R) and the pore volume corresponding to the maximum peaks of the BTCs (r = 0.77; p < 0.05) or the total volume leached (r = −0.78; p < 0.05). The results reveal the efficacy of reactive wood barriers to decrease the leaching of pesticides from point sources of pollution depends on the type of wood, the hydrophobicity of the pesticide and the adopted water flow rate. Pine was more effective than oak in decreasing the leaching of hydrophobic pesticide linuron or in decreasing the maximum peak concentration of the less hydrophobic pesticides in soils. Efficacy of these wood barriers was limited for the least hydrophobic pesticide metalaxyl. 相似文献
285.
In the present study, we have investigated the influence of polymorphism of GSTM1 and GSTT1 genes and confounding factors such as age, sex, exposure duration and consumption habits on cytogenetic biomarkers. Frequency of sister chromatid exchanges (SCEs), high frequency cell (HFC) and cytokinesis blocked micronuclei (CBMN) were evaluated in peripheral blood lymphocytes of 115 occupationally exposed road construction workers and 105 unexposed individuals. The distribution of null and positive genotypes of glutathione-S transferase gene was evaluated by multiplex PCR among control and exposed subjects. An increased frequency of CBMN (7.03 ± 2.08); SCE (6.95 ± 1.76) and HFC (6.28 ± 1.69) were found in exposed subjects when compared to referent (CBMN - 3.35 ± 1.10; SCE - 4.13 ± 1.30 and HFC - 3.98 ± 1.56). These results were found statistically significant at p < 0.05. When the effect of confounding factors on the frequency of studied biomarkers was evaluated, a strong positive interaction was found. The individuals having GSTM1 and GSTT1 null genotypes had higher frequency of CBMN, SCE and HFC. The association between GSTM1 and GSTT1 genotypes and studied biomarkers was found statistically significant at p < 0.05. Our findings suggest that individuals having null type of GST are more susceptible to cytogenetic damage by occupational exposure regardless of confounding factors. There is a significant effect of polymorphism of these genes on cytogenetic biomarkers which are considered as early effects of genotoxic carcinogens. 相似文献
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289.
The recovery and utilization of recovered paper have increased over past decades all over the world due to economic, environmental, and social issues. However, it is well known that an extended recovered paper collection is detrimental to its quality, either by the exploitation of lower quality sources such as households, or the spreading of commingled systems instead of selective collection systems. The influence of these two factors was assessed by analyzing the quality of different recovered paper grades used as raw material in a mill located in Madrid (Spain) producing newsprint and light weight coated paper from recovered paper. Part 1 of the paper deals with the impact of increased collection rates on the quality of recovered paper and Part 2 with the use of commingled collection systems. Results of Part 1 show that increased collection rates have a large impact on the quality of the recovered paper. The quality, measured as total unusable material and moisture contents, had deteriorated very rapidly in only 4 years (2005–2008) as a consequence of increased collection rates. Collection rates increased in Spain from 58.5% to 68.6% during this period, resulting in more than 50% increase of total unusable material and 25% of moisture content. The downgrading of the quality of recovered paper is one of the major threats for extending the current limits of paper recycling. Therefore, future challenge is to increase its availability but maintaining its quality. 相似文献
290.
Allan IJ Nilsson HC Tjensvoll I Bradshaw C Næs K 《Environmental pollution (Barking, Essex : 1987)》2011,159(10):2393-2397
Integrative passive sampling with devices such as semipermeable membrane devices generally relies on rigs for month-long static exposures in water. We evaluate here whether mobile exposures of passive samplers can provide reliable estimates of dissolved contaminant concentrations. Mobile exposures were obtained by towing samplers fastened to the end of a benthic trawl net. Significant and reproducible absorption of polycyclic aromatic hydrocarbons during 5 h-long deployments was made possible by high sampling rates resulting from high water turbulences during towing at 1.2-1.5 knots. Sampling rates (72-215 L d−1) estimated from the dissipation of performance reference compounds were supported by in situ calibration with samplers exposed for a 30 days in the vicinity of the test site. Higher fluoranthene and pyrene absorption in samplers exposed to the trawling-induced sediment plume could be attributed to desorption from re-suspended sediments. This mode of exposure has the potential to be used in monitoring programmes. 相似文献