有机固体废物固态厌氧消化处理的研究现状与进展

有机固体废物的固态厌氧消化处理是一种在固体含量很高的条件下进行厌氧发酵,同时产生沼气的处理方法,该方法能够实现废弃物污染防治和综合利用的目标.文中介绍了有机固体废物固态厌氧消化的研究状况,并且展望了其固态厌氧消化的研究前景.      

Causes of change in nitrophytic and oligotrophic lichen species in a Mediterranean climate: impact of land cover and atmospheric pollutants

With the aim of determining the main drivers of changes in nitrophytic and oligotrophic macro-lichen communities in an industrial region with a Mediterranean climate, we considered both land-cover types and atmospheric pollutants. We determined the relation between the abundance of nitrophytic and oligotrophic species with environmental factors considering the distance of influence of land-cover types. The results showed that oligotrophic species decreased in the proximity of artificial areas, barren land and agricultural areas, associated with higher concentrations of NO₂ and Zn, and Ti, probably dust of industrial and agricultural origin. Nitrophytic species were positively related to all the mentioned land-cover types, and with higher concentrations of Fe and N. Magnesium, probably from ocean aerosols, was negatively related to oligotrophic species and positively to nitrophytic.     

The removal of lignin and phenol from paper mill effluents by electrocoagulation

This study aims to investigate the treatment of paper mill effluents using electrocoagulation. Removal of lignin, phenol, chemical oxygen demand (COD) and biological oxygen demand (BOD) from paper mill effluents was investigated at various current intensities by using different electrodes (Al and Fe) and at various electrolysis times (1.0, 2.5, 5.0 and 7.5min). It was observed that the experiments carried out at 12V, an electrolysis time of 2min and a current intensity of 77.13mA were sufficient for the removal of these pollutants with each electrode. The removal capacities of the process using an Al electrode were 80% of lignin, 98% of phenol, 70% of BOD, and 75% of COD after 7.5min. Using an Fe electrode the removal capacities were 92%, 93%, 80% and 55%, respectively. In addition, it was found that removal of lignin, phenol, BOD and COD increased with increasing current intensity. In the experiments carried out at different current intensities, higher removal can be explained through a decrease in intra-resistance of solution and consequently an increase at the transfer speed of organic species to electrodes. It was also found that Al electrode performs higher efficiency than Fe electrode except for COD removal. However, the time required for removal of BOD was more than that of COD. The results suggest that electrocoagulation could be considered as an effective alternative to paper mill effluents treatment.     

Determinants of Farmers’ Adoption of Improved Soil Conservation Technology in a Middle Mountain Watershed of Central Nepal

This study explores different socio-economic and institutional factors influencing the adoption of improved soil conservation technology (ISCT) on Bari land (Rainfed outward sloping terraces) in the Middle Mountain region of Central Nepal. Structured questionnaire survey and focus group discussion methods were applied to collect the necessary information from farm households. The logistic regression model predicted seven factors influencing the adoption of improved soil conservation technology in the study area including years of schooling of the household head, caste of the respondent, land holding size of the Bari land, cash crop vegetable farming, family member occupation in off farm sector, membership of the Conservation and Development Groups, and use of credit. The study showed that technology dissemination through multi-sectoral type community based local groups is a good option to enhance the adoption of improved soil conservation technology in the Middle Mountain farming systems in Nepal. Planners and policy makers should formulate appropriate policies and programs considering the farmers' interest, capacity, and limitation in promoting improved soil conservation technology for greater acceptance and adoption by the farmers.     

The effects of landscape-level disturbance on the composition of Minnesota caddisfly (Insecta: Trichoptera) trophic functional groups: evidence for ecosystem homogenization

Over 300,000 caddisfly specimens representing 249 species were collected from nearly 250 sites throughout Minnesota during 2000 and 2001 to determine the effects of human disturbance on the composition of caddisfly trophic functional groups at the landscape level. Canonical correspondence analysis determined that stream width was the most important variable influencing functional group composition in regions of the state with relatively low disturbance, and that differences in the caddisfly fauna between sizes of streams generally followed trends predicted by the river continuum concept. In regions of the state with moderate disturbance, both stream width and the percentage of disturbed habitat upstream of a site were important variables influencing functional group composition. In highly disturbed regions, no variables corresponded to changes in the composition of caddisfly functional groups. Instead, ecosystems were homogeneous: fine-particle filtering collectors dominated in all sizes of streams. The observed aquatic ecosystem homogenization is attributed mostly to input of fine-particle organic and inorganic sediment from extensive agriculture.     

Interactions between water and land in The Netherlands

The Netherlands are one of the most densely populated coastal countries in the world and there is only limited space for living, working, transport and recreation, while there is also the need to preserve and expand valuable natural habitats. In order to solve many existing and future conflicts of interest, and in order to create ‘added value’, strategies are developed to optimize the use of water-land systems. The principle of ‘building with nature’ is applied in order to integrate land in sea and water in land in such a way that future generations will be able to use coastal resources in a sustainable way, including a minimal effort to maintain the coastline and the promotion of a multiple-use system. The concept of Integrated multifunctional sustainable coastal zone development is introduced. This concept deals with a balanced approach to the lack of space for present and future coastal uses in relation to each other, to the hinterland, and to the sea. Flexible master plans are developed, taking into account many functions of the coastal zone, and facilitating adaptation to future developments—e.g. impacts of climate change and relative sea level rise. In this regard increasing the flexibility of the coastal zone is of vital importance. Large-scale coastal land reclamations in The Netherlands are dealt with, based on two different principles: (1) polder systems (low lying land reclamations surrounded and protected by dikes), (2) systems of ‘building with nature’—land reclamation protected by man-made foreshores, beaches and dunes. In the latter type new flexible dynamic-equilibrium coasts are created for many functions, while coastal vulnerability is reduced and a flexible coast is developed.     

极近距离煤层综放开采工作面覆岩“两带”发育规律研究

为深入研究极近距离煤层综放开采工作面覆岩“两带”的动态发育规律,采用理论推导、数值模拟和现场实测相结合的方法,分析袁店一矿824工作面覆岩“两带”的裂隙演化特征。结果表明：从岩层层向拉伸率角度,研究上覆岩层垮落带和导水裂隙带的垮落程度,考虑角度影响推导出岩层弯曲下沉边缘段变形前后的长度计算公式,根据覆岩的碎胀特征计算各岩层的最大下沉量,预测垮落带和裂隙带的范围分别为30.2～41.2 m和70.7～78.2 m;采用3DEC数值模拟分析该矿824工作面开挖后上覆岩层垮落的基本形态和裂隙分布规律,结合其应力、位移云图和监测线位移曲线的分布特征,得出垮落带和裂隙带的高度分别为32.50 m和77.25 m;采用分布式光纤应变监测系统,监测工作面前方80 m处上部顶板的受力情况,得出受采动影响的光纤应变呈起伏变化,且应变分布与地层岩性存在对应关系,得出垮落带高度约30.4 m,裂隙带高度约74.8 m,验证采用层向拉伸率和覆岩碎胀性2个方面来预测工作面覆岩“两带”高度的合理性,可为类似方面的研究与施工提供相应的技术依据。     

关于改善石家庄市空气质量的建议

针对电力和供热导致石家庄市空气污染严重的问题，结合该市目前的电力和供热现状，提出了减少污染的措施及建议，希望对改善该市空气质量起到促进作用。     

密封消解法测定高氯离子含盐废水COD_(Cr)的探讨

针对国标重铬酸钾法测定高氯离子含盐废水CODCr时的不足,提出用密封消解法来测定高盐废水CODCr的观点,通过丁酮氧化率、氯离子干扰、混配水样和实际水样测定结果的比较,对国标法和密封消解法进行了验证。试验结果表明:在测定高氯离子含盐废水CODCr值时,密封消解法优于重铬酸钾法,能够真实准确地反映废水的CODCr。     

阿哈水库浮游植物功能群时空分布特征及其影响因子分析

为了解贵州高原阿哈水库的浮游植物功能类群时空分布特征及其影响因素,于2012年至2013年枯水期(11月)、平水期(4月)、丰水期(7月)对浮游植物与水样进行分层采样分析.研究结果表明:浮游植物可分为23个功能群,优势功能群为B、D、J、LO、P、S1和X1,其时空分布特征表现为:枯水期、平水期与丰水期分别以B+D+P+LO、S1+LO以及S1为主,其丰度由枯水期至丰水期依次递增;优势功能群主要在15 m以下水体发生变化,营养物质分布差异及人工放闸泄水是产生该特征的主要原因;采样点大坝和库中的优势功能群季节变化大致相同,但却表现出大坝多于库中,而其丰度却低于库中的特征,水动力条件是导致这一变化的主要原因.经RDA分析得出,优势功能群丰度与水温呈正相关,与总氮、透明度、磷酸盐、硝氮呈负相关,其中水温、透明度为影响浮游植物功能群时空分布的主要因子.