高炉煤气干法布袋除尘技术的应用

高炉煤气干法布袋除尘技术是钢铁行业重要的综合节能环保技术之一,以其煤气净化质量高、节水、节电、投资省、运行费用低、环境污染小等优点,优于传统的湿法洗涤除尘工艺,是国家大力推广的清洁生产技术。本文以承德钢厂1260米3高炉干法布袋除尘技术为例,介绍了该技术的工艺流程及主要参数,对设计过程中要注意的几个问题进行了分析论述,同时对该技术进一步的发展方向提出了见解,并建议国家相关部门应大力推广和使用这一技术,使其在节约能源和环境保护的建设中发挥更大作用。     

甘肃平凉市大气湿沉降中氮、硫污染物循环特征分析

大气环境中氮,硫污染物的循环,正在自然系统改变。人为活动已明显冲击了氮、硫元素的循环过程,它们可能对生物多样性,局地气侯变暖,土壤,水体,人体健康等逐渐带来严重影响。氮、硫污染物亦是大气酸沉降的主要来源。通过对甘肃平凉市大气湿沉降中氮、硫污染物特征分析,掌握氮、硫污染物动态变化,分析它们在大气湿沉降中的化学变化及污染循环特征,为做好节能减排工作提供理论依据。使氮、硫元素的循环趋于平衡,防止酸沉降在我市发生,进一步提高我市环境空气质量。     

降低总氮空白吸光值的因素探讨

为了有效控制总氮的空白吸光值,本文从容器的洗涤、实验用水、试剂纯度、样品的消解、后处理阶段等环节进行分析,通过科学实验,探讨了其影响因素,找到最佳条件：用1：3的硫酸清洗容器消除有机物的干扰,GR级的过硫酸钾和AR级的氢氧化钠分别进行溶解作为消解剂,控制消解的时间超过30分钟,最后用1：9的盐酸消除干扰,总氮的空白值可以控制在0.020之内。     

利用化学沉淀法降低焦化废水氨氮浓度的预处理工艺研究

为了有效净化高浓度氨氮工业废水,采用向废水中投加MgCl2·6H2O和Na3PO4·12H2O生成磷酸氨镁沉淀的方法,以去除其中的高浓度氨氮。结果表明,在pH值为9.0,Mg^2＋、NH4^＋、PO4^3-的摩尔比为1.2：1：0.9,反应温度为25℃,反应时间为20 min,沉淀时间为50 min的条件下,氨氮质量浓度可由3 100 mg/l降低到56mg/l,去除率达到98%以上,为后续生化处理创造了条件。     

Effect of soil crust on evaporation and dew deposition in Mu Us sandy land, China

The development of soil crust on sandy land may affect the surface hydrological process. This paper investigates the process of evaporation and dew deposition influenced by different soil surface types which were dominated by sand, primitive biotic crust, and advanced biotic crust, respectively, in the south fringe of Mu Us sandy land in Northwest China from July to September of 2006. The experimental results indicate that the advanced biotic crust could increase evaporation and dew deposition compared to the primitive biotic crust and bare sand although the differences between them were not significant. The average evaporation from advanced biotic crust, primitive biotic crust and sand was 6.8, 6.6, and 6.5 mm/d, respectively, and water content is around 16.2 % in the condition of initially identical soil. The average dew amount on advanced biotic crust was 0.116 mm/d with extreme 0.05 and 0.24 mm/d. The average values on primitive biotic crust and sand were 0.105 and 0.101 mm/d, respectively, with extreme 0.04 and 0.21 mm/d for both treatments. Also, the dew deposition on advanced biotic crust seemed stable and might rest for a longer time than that on primitive biotic crust and sand. The results suggest that the advanced biotic crust possibly facilitates evaporation and dew deposition. Therefore, the development of biotic crust may potentially enhance the hydrological circulation in the upper sand layer in sandy land.     

Performance of completely autotrophic nitrogen removal over nitrite process under different aeration modes and dissolved oxygen

In this study, three sequential batch biofilm reactors (SBBRs) were operated for 155 days to evaluate the performance of completely autotrophic nitrogen removal over nitrite (CANON) process under different aeration modes and dissolved oxygen (DO). Synthetic wastewater with 160-mg NH4 ⁺-N/L was fed into the reactors. In the continuously-aerated reactor, the efficiency of the ammonium nitrogen conversion and total nitrogen (TN) removal reached 80% and 70%, respectively, with DO between 0.8–1.0 mg/L. Whereas in the intermittently-aerated reactor, at the aeration/non-aeration ratio of 1.0, ammonium was always under the detection limit and 86% of TN was removed with DO between 2.0–2.5 mg/L during the aeration time. Results show that CANON could be achieved in both continuous and intermittent aeration pattern. However, to achieve the same nitrogen removal efficiency, the DO needed in the intermittently-aerated sequential batch biofilm reactor (SBBR) during the aeration period was higher than that in the continuously-aerated SBBR. In addition, the DO in the CANON system should be adjusted to the aeration mode, and low DO was not a prerequisite to CANON process.     

Effect of Earthworm(Pheretima sp.) Density on Revegetation of Lead/zinc Metal Mine Tailings Amended with Soil

Abstract

The objective of this study was to investigate the effects of earthworm density on the availability of nutrients and heavy metals in metal contaminated soils. Pb/Zn mine tailings were mixed throughly with a red yellow podzolic soil at the ratio (w/w) of 75:25. Earthworms (Pheretima sp.) were introduced to the mixture at four different densities, zero, three, six and nine individuals per pot planted with ryegrass (Loliun multiflorum). The results indicated that earthworm activity significantly enhanced ryegrass shoot biomass. However, as denser earthworm population was introduced, shoot biomass tended to decrease. Earthworm activity significantly increased soil pH and availability of N, P and K in the tailings and soil mixture. There was a general tendency that uptake of Zn by ryegrass increased after earthworm inoculation, although the increase in extractable Zn in tailings and soil mixture was not significant. On the contrary, there seemed to be a lower uptake of Pb by ryegrass under earthworm inoclation, despite the fact that higher extractable Pb concentrations were observed. The present project indicated that the improved growth of ryegrass was due to improved nutrient availability and other soil conditions, by inoculation of earthworms at an appropriate rate. Further studies are needed to illustrate the relationship between metal availability and earthworm activity in the field.     

根据阵流估计泥石流堆积参数

泥石流堆积是泥石流产生灾害的主要方式，也是进行泥石流灾害评估的主要依据。根据泥石流堆积的形态特征提出了堆积的元过程叠加，将堆积与间歇性的阵流运动联系起来；利用近20年来蒋家沟泥石流阵流序列的观测数据，估计了堆积的相关因子，如速度、流深、流量、堆积厚度等。这些因子表现出一定的频率分布特征，它可能改变过去确定论的泥石流观念，同时也为提出新的泥石流评估模式提供了定量的依据。     

氮沉降对陆地生态系统土壤有机碳含量影响的Meta分析

研究已证实大气氮沉降的增加显著影响了土壤有机碳的含量,然而其变化幅度在不同的实验样地具有较大的差异.基于在我国开展的49个模拟氮沉降野外实验的408组数据,利用Meta分析、Meta回归和线性回归等方法系统研究了样地气候、土壤属性以及氮素施用参数对施氮后土壤有机碳含量的影响.结果表明,样地的年均温（MAT）和年均降水量（MAP）与施氮后土壤有机碳含量变化幅度显著正相关（P<0.05）.在MAT或MAP较低（MAT<3℃,MAP<500 mm）的样地中,施氮后土壤有机碳含量显著下降;而在MAT或MAP较高（MAT>3℃,MAP>500 mm）的样地中,施氮后土壤有机碳含量则显著升高.土壤属性方面,在C：N较高（>15）或酸性（pH<6.5）土壤中,施氮后土壤有机碳积累明显（P<0.05）;而在C：N较低（≤15）以及中性或碱性（pH≥6.5）土壤中,施氮后土壤有机碳变化不明显（P >0.05）.此外,施氮后草原生态系统土壤有机碳含量明显下降（-5.34%）;而湿地生态系统土壤有机碳含量变化不明显;森林生态系统土壤有机碳表现出明显积累（10.52%）,特别是阔叶林生态系统（13.10%）.所有的因子中,土壤C：N是影响施氮后土壤有机碳变化幅度的主导因子.在施氮类型方面,施加硝酸铵或尿素后土壤有机碳含量显著升高,而施加硝态氮对其影响不显著.综上所述,在精确评估、预测和分析氮沉降对土壤有机碳含量的影响时,应综合考虑样地的气候、土壤属性以及氮素施用参数等因素对实验结果的影响.     

稻田微氧层和还原层土壤有机碳矿化对氮素添加的响应

田间条件下,淹水稻田由于上覆水中溶解氧的扩散作用,使其表层土壤存在约1 cm厚的微氧层,这个特殊层次中碳氮转化的特征尚未明晰.以亚热带典型稻田土壤为对象,采用100 d室内模拟培养试验,结合¹³C稳定同位素示踪和磷脂脂肪酸(PLFA)分析技术,研究稻田土壤微氧层(0～1 cm)和还原层(1～5 cm)外源新鲜有机碳(¹³C-水稻秸秆)和原有土壤有机碳矿化对氮肥施用[(NH₄)₂SO₄]的响应规律及其微生物过程.结果表明,氮素添加使土壤总CO₂和¹³C-CO₂累积排放量分别提高11.4%和12.3%;培养结束时,氮素添加下还原层比微氧层土壤总有机碳含量和¹³C回收率分别降低2.4%和9.2%.培养前期(5 d),氮素添加提高还原层微生物总PLFAs,且细菌和真菌PLFAs响应一致,但对微氧层微生物丰度无显著影响;氮素添加对微氧层和还原层总¹³C-PLFAs丰度均无显著影响...