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851.
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853.
854.
喀斯特坡耕地浅层地下孔(裂)隙发育过程中径流产污特征 总被引:5,自引:0,他引:5
降雨径流产生的非点源污染是地下水污染的重要来源,喀斯特坡耕地浅层地下孔(裂)隙养分流失是造成该地区地下水污染的关键因素.通过模拟喀斯特坡耕地地下孔(裂)隙特征,采用人工模拟降雨和室内分析相结合的方法,研究浅层地下孔(裂)隙发育过程中降雨径流产污特征.结果表明:喀斯特坡耕地地下径流产污是一个极其复杂的过程,微度(1%)孔(裂)隙发育的坡耕地径流全氮、全磷和全钾流失量随雨强变化不明显,全氮和全磷流失量均在70 mm·h-1雨强达到最大值;轻度(3%)孔(裂)隙发育的坡耕地全氮、全磷流失量在雨强50 mm·h-1时达到最大值;中度(5%)孔(裂)隙发育的坡耕地全氮、全磷、全钾流失量则在雨强为90 mm·h-1时达到最大值;各孔(裂)隙发育条件下的全氮、全磷、全钾养分流失量对坡度的响应不明显,轻度发育下的全氮和全磷流失量最大,在中度发育条件下,坡耕地土壤中全钾流失总量最大;不同雨强、坡度条件下的地下径流全氮、全磷和全钾次产污模数随地下孔(裂)隙度变化亦不明显,其中全氮次产污模数在4.38~58.72 mg·h-1·m-2,全磷在0.16~3.15 mg·h-1·m-2,全钾在0.16~3.03 mg·h-1·m-2范围变化. 相似文献
855.
856.
Antić MP Jovancićević BS Ilić M Vrvić MM Schwarzbauer J 《Environmental science and pollution research international》2006,13(5):320-327
Background, Aims and Scope It is well known that the composition of petroleum or some of its processing products changes in the environment mostly under
the influence of microorganisms. A series of experiments was conducted in order to define the optimum conditions for an efficient
biodegradation of petroleum pollutant, or bioremediation of different segments of the environment. The aim of these investigations
was to show to what extent the hydrocarbons of a petroleum pollutant are degraded by microbial cultures which were isolated
as dominant microorganisms from a surface water of a wastewater canal of an oil refinery and a nitrogen plant. Biodegradation
experiments were conducted on one paraffinic, and one naphthenic type of petroleum during a three month period under aerobic
conditions, varying the following parameters: Inorganic (Kp) or an organic medium (Bh) with or without exposition to light.
Methods Microorganisms were analyzed in a surface water sample from a canal (Pančevo, Serbia), into which wastewater from an oil
refinery and a nitrogen plant is released. The consortia of microorganisms were isolated from the water sample (most abundant
species: Phormidium foveolarum - filamentous Cyanobacteria, blue-green algae and Achanthes minutissima, diatoms, algae). The
simulation experiments of biodegradation were conducted with the biomass suspension and crude oils Sirakovo (Sir, paraffinic
type) and Velebit (Ve, naphthenic type). After a three month period, organic substance was extracted by means of chloroform.
In the extracts, the content of saturated hydrocarbons, aromatic hydrocarbons, alcohols and fatty acids was determined (the
group composition). n-Alkanes and isoprenoid aliphatic alkanes, pristane and phytane, in the aliphatic fractions, were analyzed
using gas chromatography (GC). Total isoprenoid aliphatic alkanes and polycyclic alkanes of sterane and triterpane types were
analyzed by GC-MS.
Results and discussion. Paraffinic type petroleums have a significant loss of saturated hydrocarbons. For naphthenic type petroleum,
such a trend has not been observed. The most intensive degradation of n-alkanes and isoprenoid aliphatic alkanes (in paraffinic
oil) and isoprenoids (in naphthenic oil) was observed using the inorganic medium Kp in the light; the microbial conversion
is somewhat lower with Kp in the dark; with organic medium Bh in the light the degradation is of low intensity; with the same
medium in the dark the degradation is hardly to be seen. Steranes and triterpanes were not affected by microbial degradation
under the conditions used in our experiments. Obviously, the petroleum biodegradation was restricted to the acyclic aliphatics
(n-alkanes and isoprenoids).
Conclusion Phormidium foveolarum (filamentous Cyanobacteria - blue-green algae) and Achanthes minutissima (diatoms, algae), microbial
cultures isolated as dominant algae from a surface water in a wastewater canal of an oil refinery and a nitrogen plant, have
degradable effects dominantly involving petroleum hydocarbons. Petroleum microbiological degradation is more intensive when
inorganic medium (in the light) is applied. Having in mind that the inorganic pollutants have been released into the canal
as well, this medium reflects more the natural environmental conditions. Polycyclic alkanes of sterane and triterpane type,
in spite of the fact that these compounds could be degraded, have remained unchanged regarding abundance and distribution.
Since this is the case even for naphthenic type petroleum (which is depleted in n-alkanes), it can be concluded that the biodegradation
of petroleum type pollutants, under natural conditions, will be restrained to the n-alkane and isoprenoid degradation.
Recommendation and Outlook Performed experiments and simulations of petroleum microbiological degradation may serve for the prediction of the fate of
petroleum type pollutants, as well as for definition of conditions for bioremediation of some environmental segments. 相似文献
857.
Rai HS Singh S Cheema PP Bansal TK Banerjee UC 《Journal of environmental management》2007,83(3):290-297
In the present study, decolorization of a simulated dye waste containing three different triphenylmethane (TPM) dyes--Magenta, Malachite Green and Crystal Violet, was investigated in a laboratory scale, two-stage anaerobic high-rate reactor. The effect of various parameters (influent dye concentration, hydraulic and co-substrate loading rates) on color and COD removal efficiency of the reactor has been studied. It has been shown that the influent dye concentration had little effect on overall COD and color removal efficiency. More than 99% color removal and 96% COD removal efficiency were maintained even at a dye concentration of 500 mg/l and a dye loading rate of 1000 mg/l day. However, a minimum level of glucose as supplementary carbon source is required to maintain the maximum color removal efficiency and it drops appreciably when no glucose is added to the influent. The study also showed that the acidogenic phase of the reaction plays an important role in decolorization of the TPM dyes. In addition, the two-stage anaerobic reactor was observed to have distinct advantages over the single-stage system, as the drop in color and COD removal efficiency of stage 1 are adequately compensated by stage 2 of the reactor especially under high dye loading rates accompanied by low co-substrate loading and under reduced HRTs. 相似文献
858.
采用自行设计的生物膜/颗粒污泥耦合反应器,研究不同好/厌氧区容积负荷对该工艺脱氮除磷的影响.试验过程中设置了3种不同的工况,每种工况的好氧区和厌氧区容积均不同,工况Ⅰ的是9.66 L和15.34 L,工况Ⅱ的分别为12.56 L和12.44 L,工况Ⅲ的是15.42 L和9.58 L.不同的好/厌氧区容积对应不同的容积负荷.结果表明,工况Ⅰ的氨氮与磷酸盐去除效果稍差,工况Ⅲ出水硝态氮较高,造成总氮去除率较低.工况Ⅱ是最佳运行条件,系统的氨氮去除率为80.63%,氮容积去除负荷为150.27 g·(m3·d)-1,COD去除率为83.24%,释磷量与吸磷量分别为7.23 mg·L-1和11.93 mg·L-1. 相似文献
859.
860.
太湖出入湖河道与湖体水质季节差异分析 总被引:3,自引:0,他引:3
基于2016年太湖16条主要河道及对应湖体的水质逐月监测数据,深入探讨了太湖流域不同分区河道的外源营养盐输入对湖体水质影响及其季节变化.结果发现:(1)太湖流域河道总氮(TN)、溶解性总氮(DTN)、总磷(TP)和溶解性总磷(DTP)的月平均浓度均高于对应湖体,主要入流区河道与临近湖体的营养盐浓度呈现显著正相关,表明外源补给对湖体营养盐浓度产生巨大影响;(2)无论是河道还是湖体的营养盐浓度,均呈现明显的季节变化,且峰值产生月份不同:河道平均TN最高值出现在3月,为4.82 mg·L-1,平均TP最高值出现在12月,为0.218 mg·L-1;湖体TN、TP峰值均出现在蓝藻水华暴发期间(7月),分别为4.13 mg·L-1和0.255 mg·L-1;(3)极端降水过程短期内能明显降低河道营养盐浓度,但会引起湖体营养盐外源负荷的明显增高,不利于湖体富营养化控制.本研究表明,对于空间异质性较高的大型浅水湖泊,流域河道入湖污染对湖体营养盐时空格局具有重要的塑造作用,而湖体的污染物自净能力、蓝藻水华物质的空间堆积及风浪引发的底泥再悬浮作用等也都对湖体营养盐浓度、时空格局产生重要影响. 相似文献