哀牢山山区降水时空分布的影响因素及插值方法比较

为了研究哀牢山山区降水的影响主要因素并探索适于山区降水的空间插值方法,本文利用研究区内30个地面测站10年(2005~2014)的降雨实测数据,根据降雨的时间分布特征,将研究时段划分为年季、干季和湿季,并对影响降水的因素进行空间自相关分析,确定并组合得到影响降水的主要因子,使用留一法交叉检验插值精度,通过分析验证,寻求最优的降雨插值方法。研究结果表明,1)影响降水的主要因子为高程、纬度、坡度、坡向和主风向效应指数(PWEI);2)影响年季降水变化的主要因子为高程、纬度、坡度和坡向;影响湿季降水的主要因子为高程、纬度、坡度和PWEI;影响干季降水的主要因子为高程、坡度、纬度和坡向;3)插值过程中结合环境特征引入影响降水的因子,很大程度上提高了插值结果的精确性。由此可见,降雨插值精度不仅和插值方法本身的结构有关,更重要的是在降水特征的基础上合理筛选及引入主要环境影响因子。     

某钼矿尾矿库地下水污染的随机模拟

为分析参数不确定性对地下水污染数值模拟模型输出结果的影响,以某钼矿尾矿库地下水污染问题作为研究实例,选取钼离子作为模拟因子,建立该钼矿尾矿库地下水污染数值模拟模型,对输出结果进行不确定性分析.为降低替代模型的维数,运用灵敏度分析法筛选出对模拟模型输出结果影响较大的2个参数作为模型中的随机参数.为减少反复调用数值模拟模型产生的计算负荷,分别运用克里格方法和支持向量机法建立模拟模型的替代模型,并比较二者的精度,选择精度较高的替代模型完成蒙特卡罗随机模拟.最后,对随机模拟的输出结果进行统计分析与区间估计,对地下水污染超标的风险进行评价.结果表明：置信度为80%时,井1,2,3浓度值的置信区间分别为0.71~2.29,0.28~1.02,1.55~3.25mg/L.此外,结合《地下水质量标准》以及污染物浓度分布函数曲线,井1,2,3中水质达到地下水质量标准Ⅴ类的概率分别为99.7%,97.1%,99.6%.本研究可为地下水污染防治提供更科学、全面的参考依据.     

洱海流域农业面源污染空间分布特征及分类控制策略

作为典型的高原坝区农业型流域,洱海流域农业面源污染严重,威胁洱海水质.以洱海流域为研究对象,综合数理分析及GIS技术,开展流域农业面源污染负荷分析及评价,使用排污系数法估算了2018年洱海流域农村生活、畜禽养殖业和种植业污染中COD（化学耗氧量）、TN（总氮）、TP（总磷）的排放负荷,并通过等标污染负荷法在GIS空间分析反映流域内污染排放分布情况.结果表明:①2018年洱海流域农业面源主要污染物COD、TN、TP的排放量分别为11 188.20、2 752.56和259.33 t.COD排放量主要来自畜禽养殖,TN与TP的排放量均主要来自种植业.②洱海流域农业面源主要污染物COD、TN、TP等标污染负荷分别为559.41、2 752.56和1 296.63 m3/a.种植业等标污染负荷在总等标污染负荷中的占比最高,为36.40%,其次是畜禽养殖业,为34.44%.③各乡镇的等标污染负荷差异较大,等标污染负荷范围为（286.16±150.67）m3/a,等标污染负荷强度范围（0.13±0.067）m3/a.④聚类分析结果表明,洱海流域农业面源污染可分为种植业主导型、种植业高污染型、生活污染主导型和畜禽养殖业主导高污染型等4种类型.研究显示:来源于种植业的面源污染是洱海流域水环境保护需要控制的首要污染源,TN是需要控制的首要污染物;排放量与等标污染负荷的空间分布特征均呈流域北部乡镇污染物排放量较高,但流域西部各乡镇排放强度较大的特征;流域内各乡镇防治面源污染需要针对其污染来源特点分别采取推进种养平衡、推广绿色种植、分区控制农田径流以及推进农村生活污水治理等分类控制策略.      

Chemical formation and source apportionment of PM2.5 at an urban site at the southern foot of the Taihang mountains

The region along the Taihang Mountains in the North China Plain (NCP) is characterized by serious fine particle pollution. To clarify the formation mechanism and controlling factors, an observational study was conducted to investigate the physical and chemical properties of the fine particulate matter in Jiaozuo city, China. Mass concentrations of the water-soluble ions (WSIs) in PM_2.5 and gaseous pollutant precursors were measured on an hourly basis from December 1, 2017, to February 27, 2018. The positive matrix factorization (PMF) method and the FLEXible PARTicle (FLEXPART) model were employed to identify the sources of PM_2.5. The results showed that the average mass concentration of PM_2.5 was 111 μg/m³ during the observation period. Among the major WSIs, sulfate, nitrate, and ammonium (SNA) constituted 62% of the total PM_2.5 mass, and NO₃^? ranked the highest with an average contribution of 24.6%. NH₄⁺ was abundant in most cases in Jiaozuo. According to chemical balance analysis, SO₄^2?, NO₃^?, and Cl^? might be present in the form of (NH₄)₂SO₄, NH₄NO₃, NH₄Cl, and KCl. The liquid-phase oxidation of SO₂ and NO₂ was severe during the haze period. The relative humidity and pH were the key factors influencing SO₄^2- formation. We found that NO₃^? mainly stemmed from homogeneous gas-phase reactions in the daytime and originated from the hydrolysis of N₂O₅ in the nighttime, which was inconsistent with previous studies. The PMF model identified five sources of PM_2.5: secondary origin (37.8%), vehicular emissions (34.7%), biomass burning (11.5%), coal combustion (9.4%), and crustal dust (6.6%).     

酸性矿山废水天然中和形成的富铁沉淀及其环境属性

采集了云南王家滩铁矿的酸性矿山排水及其与溪流中和后的溪水与沉积物, 运用谱学及电子显微分析等方法,对采集样品的化学及矿物学等方面的特征进行了分析. 结果表明, 王家滩铁矿的酸性矿山排水在与未污染溪水中和时, 酸度和电导率均显著降低, 但元素的浓度变化不很一致, 沿水流方向,除Fe3+、SO2-4、 Ca2+等少数元素, 大多数元素的浓度都未发生明显的降低. 中和成因沉淀物具有富铁的特征,矿物组成以水铁矿为主, 此外在下游沉积物中还见有少量针铁矿及纤铁矾. 其中上游中和区水铁矿以2线水铁矿为主, 下游以6线水铁矿为主. 而各处沉积均具有明显的分层特征,且均为外层以2线水铁矿为主, 内层以6线水铁矿及针铁矿为主. 以水铁矿为主要矿物的中和沉积物对各种有毒有害元素具有较强的吸持作用. 对这些结果的进一步分析表明, 在成因上,pH值和SO2-4的浓度共同控制了水铁矿的形成;在重(类)金属吸持方面,水铁矿的迁移及相应的对AMD中重(类)金属的自净化作用受中和区域的水动力条件影响较大.     

施用磷酸盐和沸石对土壤镉形态转化的影响

本试验在室内模拟外源Cd污染土壤,研究了磷酸二氢钾、磷酸氢二铵和沸石单独施用,以及沸石和磷酸氢二钾、沸石和磷酸氢二铵二者配施,对Cd污染土壤形态变化的影响.结果表明,施用不同改良剂后,土壤交换态Cd含量出现不同程度降低,而碳酸盐结合态、铁锰氧化物结合态、有机结合态和残渣态Cd含量增加.与对照相比,单独施用磷酸二氢钾、磷酸氢二铵和沸石,以及沸石和磷酸氢二钾配施、沸石和磷酸氢二铵配施分别使土壤有效Cd含量降低25.2%~51.7%、21.6%~46.8%、6.4%~23.2%、38.6%~61.4%和34.1%~56.4%.各处理均能提高土壤速效磷含量,且土壤速效磷含量与有效态Cd含量呈极显著负相关,相关系数r=-0.902 6,各处理之间土壤p H值与有效态Cd含量存在负相关关系.由此可知,在施用磷酸盐和天然沸石条件下,土壤速效磷含量的变化是降低土壤镉有效性的主要因素.     

Phosphorus release potential and pollution characteristics of sediment in downstream Nansi Lake, China

The research aimed to evaluate present and potential phosphorous pollution due to high sedimentary phosphorus load and release from sediment, when external phosphorus was reduced in downstream Nansi Lake. Pollution load of the sediment and overlying water was investigated. Kinetics and isotherms of adsorption/release of sedimentary phosphorus were studied to determine equilibrium phosphate concentration (EPC₀) and release potential. Kinetics of phosphorus adsorption on sediment and release from sediment were well described by both the pseudo-first-order rate equation and the pseudo-second-order rate equation, but more appropriate to the pseudo-second-order rate equation with the adsorption/release capacity more close to the measured values, suggesting that the processes were chemically rate controlled and dependent on adsorption capacity. Soluble reactive phosphorus (SRP) sorption isotherms on sediment were best fitted by the modified Langmuir model indicating a monolayer adsorption. By comparing EPC₀ and SRP of water, the status (adsorption, releasing or in equilibrium) of sediment phosphorus could be determined. The sediments at site S1, S3, S4, S5, and S7 where the EPC₀s were greater than the SRPs, had a potential to release phosphorus into the water column. However, those sediments at S9, S10, and S12, where the EPC₀s were approximately equal to the SRPs, were in impermanent equilibrium with overlying water in status of phosphorus, the sediments can be likely to release phosphorus to the water column once the equilibrium was broken. Therefore, sedimentary phosphorus can be a secondary pollution source in downstream Nansi Lake.     

Reutilize tire in microbial fuel cell for enhancing the nitrogen removal of the anammox process coupled with iron-carbon micro-electrolysis

• MFC promoted the nitrogen removal of anammox with Fe-C micro-electrolysis. • Reutilize pyrolysis waste tire as micro-electrolysis and electrode materials. • Total nitrogen removal efficiency of modified MFC increased to 85.00%. • Candidatus kuenenia and SM1A02 were major genera responsible for nitrogen removal. In this study, microbial fuel cells (MFCs) were explored to promote the nitrogen removal performance of combined anaerobic ammonium oxidation (anammox) and Fe-C micro-electrolysis (CAE) systems. The average total nitrogen (TN) removal efficiency of the modified MFC system was 85.00%, while that of the anammox system was 62.16%. Additionally, the effective operation time of this system increased from six (CAE system alone) to over 50 days, significantly promoting TN removal. The enhanced performance could be attributed to the electron transferred from the anode to the cathode, which aided in reducing nitrate/nitrite in denitrification. The H⁺ released through the proton exchange membrane caused a decrease in the pH, facilitating Fe corrosion. The pyrolyzed waste tire used as the cathode could immobilize microorganisms, enhance electron transport, and produce a natural Fe-C micro-electrolysis system. According to the microbial community analysis, Candidatus kuenenia was the major genus involved in the anammox process. Furthermore, the SM1A02 genus exhibited the highest abundance and was enriched the fastest, and could be a novel potential strain that aids the anammox process.     

Combination of steam-enhanced extraction and electrical resistance heating for efficient remediation of perchloroethylene-contaminated soil: Coupling merits and energy consumption

● Coupling merits of SEE and ERH were explored by a laboratory-scale device. ● SEE promotes the soil electrical conductivity and ERH process. ● Preheating soil by ERH improves the soil permeability and SEE. ● Combined method is more energy-efficient for perchloroethylene extraction. In situ thermal desorption (ISTD) technology effectively remediates soil contaminated by dense nonaqueous phase liquids (DNAPLs). However, more efforts are required to minimize the energy consumption of ISTD technology. This study developed a laboratory-scale experimental device to explore the coupling merits of two traditional desorption technologies: steam-enhanced extraction (SEE) and electrical resistance heating (ERH). The results showed that injecting high-density steam (> 1 g/min) into loam or clay with relatively high moisture content (> 13.3%) could fracture the soil matrix and lead to the occurrence of the preferential flow of steam. For ERH alone, the electrical resistance and soil moisture loss were critical factors influencing heating power. When ERH and SEE were combined, preheating soil by ERH could increase soil permeability, effectively alleviating the problem of preferential flow of SEE. Meanwhile, steam injection heated the soil and provided moisture for maintaining soil electrical conductivity, thereby ensuring power stability in the ERH process. Compared with ERH alone (8 V/cm) and SEE alone (1 g/min steam), the energy consumption of combined method in remediating perchloroethylene-contaminated soil was reduced by 39.3% and 52.9%, respectively. These findings indicate that the combined method is more favorable than ERH or SEE alone for remediating DNAPL-contaminated subsurfaces when considering ISTD technology.     

修复受污染水体的潜流人工湿地微生物多样性研究

进行了潜流人工湿地修复受污染水体试验研究,并比较单一植物与单一填料系统与多种植物系统与多种填料系统的处理效果.运用PCR-DGGE技术研究3种不同类型的潜流人工湿地中微生物种群结构,结合多样性分析和聚类分析方法,分析了人工湿地微生物种群结构特征.