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61.
一株反硝化菌的分离鉴定和系统发育分析 总被引:3,自引:0,他引:3
从反硝化反应器中分离到一株异养型兼氧反硝化细菌,命名为菌株JIN1,分离菌株为革兰氏染色阴性杆状。茵落颜色为乳白色。该菌株能以硝酸钠为唯一氮源进行反硝化作用并产生亚硝酸。部分长度的16SrDNA序列分析表明,分离菌株JIN1与Aquaspirillum菌具有99%相似,与Microvirgulaaerodenitrificans菌具有99%相似。其生化性状与Aquaspirillum菌不相符。系统发育学分析表明菌株JIN1与Microvirgulaaerodenitrificans菌关系最近。故确认菌株JIN1属Microvirgulaaerodenitrificans菌。 相似文献
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For phosphorus (P) recovery from wastewater, the effect of humic substances (HS) on the precipitation of calcium phosphate was studied. Batch experiments of calcium phosphate precipitation were undertaken with synthetic water that contained 20 mg/L phosphate (as P) and 20 mg/L HS (as dissolved organic carbon, DOC) at a constant pH value in the range of 8.0-10.0. The concentration variations of phosphate, calcium (Ca) and HS were measured in the precipitation process; the crystalline state and compositions of the precipitates were analysed by powder X-ray diffraction (XRD) and chemical methods, respectively. It showed that at solution pH 8.0, the precipitation rate and removal efficiency of phosphate were greatly reduced by HS, but at solution pH ≥9.0, the effect of HS was very small. The Ca consumption for the precipitation of phosphate increased when HS was added; HS was also removed from solution with the precipitation of calcium phosphate. At solution pH 8.0 and HS concentrations ≤3.5 mg/L, and at pH ≥ 9.0 and HS concentrations ≤ 10 mg/L, the final precipitates were proved to be hydroxyapatite (HAP) by XRD. The increases of solution pH value and initial Ca/P ratio helped reduce the influence of HS on the precipitation of phosphate. 相似文献
65.
Ying Cui Feng Tan Yan Wang Suyu Ren Jingwen Chen 《Frontiers of Environmental Science & Engineering》2020,14(6):111
66.
CPB改性沸石对磷酸盐的吸附-解吸性能研究 总被引:2,自引:1,他引:1
采用溴化十六烷基吡啶(CPB)对天然沸石进行改性,并考察了CPB改性沸石对磷酸盐的吸附-解吸性能。结果表明,CPB改性沸石对磷酸盐具备一定的吸附能力,且吸附行为满足Langmuir等温吸附模型;粒径、改性剂投加量、反应温度、pH值及共存阴离子等因素均会影响CPB改性沸石对磷酸盐的吸附能力;减小粒径和降低反应温度均有利于CPB改性沸石对磷酸盐的吸附去除;粒径≤0.18 mm CPB改性沸石吸附磷酸盐较优的改性剂投加量为250 mmol/kg;当溶液的初始pH值位于4~10之间时CPB改性沸石对磷酸盐的吸附能力随pH值的增加而增强;SO42-的存在会明显降低CPB改性沸石对磷酸盐的吸附效率,而提高溶液的pH值有助于消除SO42-存在对CPB改性沸石吸附磷酸盐的负面影响;HCO3-的存在会一定程度上抑制CPB改性沸石对磷酸盐的吸附去除,而提高溶液的pH值无法消除HCO3-存在对CPB改性沸石吸附磷酸盐的负面影响;CPB改性沸石吸附磷酸盐后一定条件下可以重新解吸出来,且随着解吸液SO42-浓度的增加解吸率明显增大。 相似文献
67.
The activity concentrations of Beryllium-7 (7Be), a naturally occurring radioisotope produced in the atmosphere, were measured in leaves of birch-trees, above-ground parts of grass, soil and rainwater in the mountain massive Kralicky Sneznik (the northeast of the Czech Republic, altitude about 750 m) in the years of 2005, 2006 and 2007. Dried and ground samples of the plants and soils, and water samples from wet deposition were used to determine the 7Be content using a semiconductor gamma spectrometer. The 7Be values ranged from 147.0 to 279.6 Bq kg−1, from 48.7 to 740.8 Bq kg−1, from 2.1 to 8.7 Bq kg−1, and from 0.6 to 1.9 Bq kg−1 in birch-tree leaves, grass samples, soils, and rainwater, respectively. Insignificant inter-annual variations but significant increase in the 7Be activity concentrations during the spring and summer months were observed in birch-tree leaves and grass samples. The seasonal variation of the 7Be concentrations in grass samples correlated (R2 = 0.4663 and 0.6489) with precipitation. No similar correlation was found for 7Be in birch-tree leaves. Beryllium-7 content in birch-tree leaves and in aerial parts of grass was mainly caused by direct transport of 7Be from wet deposition into aerial parts of the observed plants. 相似文献
68.
Markus Hauck 《Environmental pollution (Barking, Essex : 1987)》2010,158(5):1127-1133
Since lichens lack roots and take up water, solutes and gases over the entire thallus surface, these organisms respond more sensitively to changes in atmospheric purity than vascular plants. After centuries where effects of sulphur dioxide and acidity were in the focus of research on atmospheric chemistry and lichens, recently the globally increased levels of ammonia and nitrate increasingly affect lichen vegetation and gave rise to intense research on the tolerance of lichens to nitrogen pollution. The present paper discusses the main findings on the uptake of ammonia and nitrate in the lichen symbiosis and to the tolerance of lichens to eutrophication. Ammonia and nitrate are both efficiently taken up under ambient conditions. The tolerance to high nitrogen levels depends, among others, on the capability of the photobiont to provide sufficient amounts of carbon skeletons for ammonia assimilation. Lowly productive lichens are apparently predisposed to be sensitive to excess nitrogen. 相似文献
69.
利用白云石石灰去除与回收污泥厌氧消化液中氮和磷 总被引:1,自引:0,他引:1
以白云石石灰为实验材料去除与回收污泥厌氧消化液中的氮磷,通过小试实验研究不同投药固液比S/L、初始pH值、反应温度、搅拌速度及反应时间对去除与回收氮磷效果的影响。实验结果表明,在最佳投药固液比S/L为300mg/L,最佳初始pH值范围为8.5~9.5,反应温度为25.0℃,搅拌速度为150 r/min,反应时间为24 h条件下,氨氮(NH+4-N)和磷(PO3-4-P)的去除率分别为37.26%和89.60%。利用X射线衍射仪(XRD)、扫描电镜(SEM)对沉淀产物进行了表征,通过分析可知沉淀产物中含有磷酸铵镁(MAP),可实现废水中氮磷经济有效的回收。 相似文献
70.
1—2-7-三氨基-8-羟基-3—6-萘二磺酸(TAHNDS)作为偶氮染料的脱色产物很难被常规的厌氧-好氧染料废水处理工艺所去除。研究了未经驯化的活性污泥对TAHNDS的缺氧转化效果。结果表明,只有在特定的缺氧条件下(ORP在-50~-150mV之间),TAHNDS才能被活性污泥所降解转化。当浓度在10—80mg/L范围内,TAHNDS可在72h内转化93%以上。加入100mg/L的硝酸盐和0.64mmol/L的氧化还原介体蒽醌-2-磺酸钠(AQS)可将40mg/L的TAHNDS的转化时间从84h缩短到36h。光谱及HPLC—MS分析表明,TAHNDS在缺氧条件下主要是通过脱氨基和脱磺酸作用生成已知可好氧生物降解的3,5-二氨基4-羟基萘-2-磺酸。因此,缺氧处理有望作为预处理工艺促进废水中TAHNDS的完全降解。 相似文献