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111.
磷酸钙盐法回收剩余污泥超声波处理上清液中磷的研究 总被引:3,自引:3,他引:0
在污泥减量化处理中,细胞微生物中的碳氮磷等会释放到上清液中。为了对上清液中的磷进行有效回收,在前期研究的基础上,以生物厌氧好氧除磷(An/O)工艺的剩余污泥超声波处理上清液为研究对象,考察了磷酸钙盐(HAP)法的磷回收效果。结果表明:HAP法反应较快,5 min时反应基本完成;初始pH值在8.5~10.0时,回收率均可保持在较高水平;最佳钙磷比(Ca2+/PO34--P)为3.87。在以上最佳工艺条件下,总磷(TP)、正磷酸盐(PO34--P)的回收率分别达到88.4%、94.0%,同时对上清液中的有机物、氮也有一定的去除。 相似文献
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北京市大气细粒子的来源分析 总被引:90,自引:12,他引:78
细粒子(空气动力学直径小于2.5μm的颗粒物)污染是许多城市重要的大气环境问题.从1999年至2000年对北京市细粒子展开了4次采样和化学分析,有效采样天数为40d.利用正定矩阵分解(PMF)方法对细粒子的来源进行了分析.化学成分包括EC(元素碳)、有机物、SO42-、F-、Cl-、Fe、Ca、K、Mg、Al、Na、Zn、Mn、Ti、Pb、Ba和P等17种.发现主要来源有6类:地面扬尘、建筑源、生物质燃烧、二次源、机动车排放和燃煤. 相似文献
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本文对以稳定剂H_2O_2和Na_2CO_3与ClO_2制备的所谓"稳定性二氧化氯"溶液的UV吸收光谱、纸层析特性、微观结构及离子色谱进行了分析,并与纯NaClO_2及ClO_2溶液做了对比.结果表明,“稳定性二氧化氯” 与NaClO_2在UV吸收光谱、层析比移值、微观结构、离子色谱这几方面都具有很好或极其相似的一致性 表明“稳定性二氧化氮’与NaClO_2溶液中氯氧化物存在型体的一致性.因此,认为“稳定性二氧化氯“溶液中ClO_2是以亚氯酸盐ClO_2~-的型体存在的. 相似文献
115.
杉木观光木混交林和杉木纯林群落细根生产力、分布及养分归还 总被引:17,自引:3,他引:17
研究了福建三明27a生杉机光木混交林和杉木群落细根(d<2mm)的生产力、分布、和养分归还。结果表明,混交林细根生物量、N、P养分现存量分别为5.381thm^2、48.085kghm^-2和4.174kghm^-2,分别比杉木纯林增加17.4%、27.2%和20.0%,混交林林细根的年净生产力达4.124thm^-2a^-1,比纯林高出16.9%,混交林杉木和观光木细根均在表层土壤富集,而在较深层土壤再会得分布具镶嵌性;与混交林杉林相比,纯林杉木土吉表层细根量较少,最大分布层次下移,混交林中观光木细根的周转速率咪1.16,杉木为0.96和0.95;而林下植被层细根周转速率(1.46-1.52)均同于相应的乔木层,混交林细根的年死亡量、N和P养分年归还量分别达2.119thm^-2、18.559kghm^-21.565kgkhm^-2,分别是纯林的1.21倍、1.23倍和1.14 倍,其中林下植被细根占有较为重要位置,对细根分布与土壤性质的相关分析表明,细根的垂直分布与土壤全N的相关性最强(0.87-0.89)。 相似文献
116.
Rosborg I Nihlgård B Gerhardsson L Gernersson ML Ohlin R Olsson T 《Environmental geochemistry and health》2005,27(3):217-227
This study presents the concentrations of about 50 metals and ions in 33 different brands of bottled waters on the Swedish market. Ten of the brands showed calcium (Ca) concentrations ≤10 mg L−1 and magnesium (Mg) levels <3 mg L−1, implying very soft waters. Three of these waters had in addition low concentrations of sodium (Na; <7 mg L−1), potassium (K; <3 mg L−1) and bicarbonate (HCO3 ≤31 mg L−1). These brands were collected from barren districts. Nine of the brands were collected from limestone regions. They showed increased Ca-levels exceeding 50 mg L−1 with a maximum of 289 mg L−1. Corresponding Mg-levels were also raised in two brands exceeding 90 mg L−1. Two soft and carbonated waters were supplemented with Na2CO3 and NaCl, resulting in high concentrations of Na (644 and 648 mg L−1) and chloride (Cl; 204 and 219 mg L−1). Such waters may make a substantial contribution to the daily intake of NaCl in high water consumers. The storage of carbonated drinking water in aluminum (Al) cans increased the Al-concentration to about 70 μg L−1. Conclusion As there was a large variation in the material as regards concentrations of macro-elements such as Ca, Mg, Na, K and Cl. Supplementation with salts, e.g., Na2CO3, K2 CO3 and NaCl, can lead to increased concentrations of Na, K and Cl, as well as decreased ratios of Ca/Na and larger ratios of Na/K. Water with high concentrations of e.g., Ca and Mg, may make a substantial contribution to the daily intake of these elements in high water consumers. Al cans are less suited for storage of carbonated waters, as the lowered pH-values may dissolve Al. The levels of potentially toxic metals in the studied brands were generally low. 相似文献
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原子吸收分光光度法测定植株中钙、镁的几种样品前处理方法的比较 总被引:1,自引:0,他引:1
本文比较了原子吸收分光光度法测定植株中钙、镁的三种样品前处理方法:干友化法、1mol/LHCl振荡提取法(振荡法)和1mol/LHCl静止浸泡提取法(浸泡法).结果表明,振荡法和浸泡法对钙的测定结果平均分别为干灰化法的101%和92.0%,对镁的测定结果平均分别为103%和97.6%.振荡法和浸泡法与干灰化法之间不存在显著性差异(α=0.05),它们之间有极显著的正相关性(相关系数在0.99以上).因此,在大批量样品的常规分析中,1mol/LHCl提取法可代替干灰化法. 相似文献
120.
Vincent T. Breslin 《Journal of Polymers and the Environment》1998,6(1):9-21
The compostability of starch–CaCO3 disposable packaging was examined in a source-separated municipal solid waste (MSW) composting facility located in East Hampton, NY. Source-separated MSW:starch–CaCO3 container mixtures of 0 (control), 5, and 20% (by volume) were prepared as feedstock for composting. Compost samples were collected weekly or biweekly during the composting process and examined for fragments of the starch–CaCO3 containers. Changes in compost quality due to the presence of starch–CaCO3 containers were assessed by measuring the nutrient and metal content of the three resultant MSW:starch–CaCO3 composts. Finally, plant growth studies were conducted to examine the composts for possible plant growth inhibition due to the deterioration of the starch–CaCO3 containers. Results showed that portions of the starch–CaCO3 containers were not identified in any of the 5 and 20% sieved and characterized compost fractions > 1.3 cm following 1–3 weeks of composting. Mechanical agitation of the waste along with optimum composting conditions were sufficient to initiate the rapid degradation of the starch–CaCO3 composites. Degradation of starch–CaCO3 containers did not affect compost nutrient and trace element content. Grass biomass measurements were performed once weekly over 28 days for grass grown in control (0%), 5%, and 20% starch–CaCO3-containing compost:soil mixtures. Significant differences in grass biomass for these compost:soil mixtures were measured only for the 0 and 20% starch–CaCO3-containing compost:soil mixtures at 28 days (9.07 vs 11.05 g, respectively; P = 0.046). 相似文献