Estimating the spatial distribution of dredged material disposed of at sea using particle-size distributions and metal concentrations

We present a method to estimate the spatial distribution of dredged material disposed of at sea. Using both dredged sediments and samples of sea-bed sediment from near the Rame Head disposal site, Plymouth, UK, we applied entropy analysis to the <63 μm sediment fraction and combined the results with the trace metal data in the same fraction, to form a series of groups. We interpret the distribution of sediments in one group (F1) to approximate the distribution of material affected by the disposal site. This distribution includes locations close to the disposal site, and also locations <4 km to the SE and SW, <6 km to the NW and <2 km to the N. This approach demonstrates the feasibility of using trace metal analysis of particular grain size fractions to reduce uncertainty in interpreting the spatial distribution of impacts of dredge disposal.     

浅析塑料废物的处理与再利用

从我国塑料废物的处理现状及存在的问题出发,介绍了塑料废物回收再利用的方法,并提出了塑料废物污染的防治对策。     

Site selection for hazardous wastes: A case study from the GAP area, Turkey

The increase in the popularity of using environmental design criteria in town and country planning has brought about the need to fully identify the principles to determine the best location of hazardous wastes to be landfilled. This environmental management issue has received considerable attention because of its applications in urban and rural infrastructure planning, industrial development planning as well as health, housing, transportation and agricultural schemes. This paper explains a method to determine how to locate suitable sites for hazardous waste landfilling area by using the site screening study. It demonstrates how the criteria such as geology, topography, land use, climate, earthquake and other related factors can be introduced into the overlayer technique to determine the suitable site selection in a region. The research was undertaken in the Southeastern Anatolia Project (known as GAP in Turkey) region where identifying the land resources is crucial for agricultural and water management purposes. The paper also explains the validity of the method employed on the site selection process for hazardous wastes. The introduced method may enable more accurate design procedure for planning in environmental management in future.     

Assessment of soil and water contamination around an ash-disposal site: a case study from the Seyitömer coal-fired power plant in western Turkey

Seyitömer power plant comprises 4.8% of Turkey's total energy production. The fly ash produced has been deposited in the area, since the 1960s, by a dry disposal technique. In 1997, wet disposal was improperly exercised in the area causing ash flow over agricultural fields. This study is concerned with the chemical analysis of ash, soil and water samples collected in the area following ash-removal studies after the ash flow in 1997. The results reveal that Na, K, Ca, Mg, Mn, Al, Fe, Co, and Cr contents of soil and water are governed by basement lithology in the area, whereas Cd, Pb, Zn, and Cu contents are determined by fly ash from disposal sites. Although lithogenic Cr and Co contents are exceedingly high, comparison with the regulatory standards for drinking water, irrigation water and agricultural soils reveals no pollution pertinent to solid waste production in waters, whereas there is moderate pollution by Pb and Cu in soils.     

An environmental geomorphologic approach to site selection for hazardous wastes

Geomorphological features are essential parts of the environment and they represent an important conditioning factor for the development and distribution of certain biological assemblages, as well as for a variety of human activities. However, environmental geomorphology usually receives very limited or no attention at all in the process of environmental impact assessment (EIA). Nevertheless, the site selection process for hazardous wastes in environmental impact studies for individual projects plays an essential role. In order to determine the most suitable site in a region for municipal/hazardous wastes, several criteria are used, including geology, groundwater condition, climate, and land use. The present work describes a methodology taking advantage of environmental geomorphological features, and reducing these criteria in the site selection procedure in land disposal of waste; in addition, a case study is presented to demonstrate the applicability of the proposed methodology. The validity of the adopted site screening method is explained. This methodology comprises the use of a single geomorphological map to locate suitable landfilling sites for hazardous waste, instead of using separate maps for geological features, climatic features (temperature, precipitation, and speed and direction of the prevailing wind), slope and erosion. Furthermore, the present study is compared with a previous study performed in the GAP region, where the use of land resources is crucial for agricultural and water management purposes. The application of the described selection process and the verified method in this region shows that the adopted method and detailed criteria are valid.     

海气耦合随机模式中随机项的处理

本文对海气相互作用随机动力模式中随机项的处理作了探讨,分析了目前对随机项的简单处理而产生的问题,在此基础上,对随机项处理进行了重新认识和改进,并由此解释了相应合理的模式解。     

缓冲／回填材料与添加剂的选择

缓冲／回填材料是高放废物处置库的重要工程屏障之一。本文着重讨论了处置库多道屏障的意义、国内外的研究概况、添加剂的选择和选择缓冲／回填材料时应注意的问题。     

南京市危险废弃物处置中心填埋区岩土工程特征及对策

介绍了南京市危险废弃物处置中心填埋库区岩土工程地质特征，并介绍了国内外填埋材料方面的研究成果。就南京市危险废弃物处置中心填埋库区填埋坑的稳定、沉降、防渗等问题展开讨论，提出了较为合理的解决方案。     

An investigation into contaminant transport processes through single-phase cement–bentonite slurry walls

Cement–bentonite walls are commonly used for remediation by containment or pollution prevention, in addition to their use as a barrier to water flow in more conventional construction. The results from an investigation of an in situ single-phase cement–bentonite slurry wall are detailed, with particular attention paid to the role of advective and diffusive fluxes in contaminant transport.

The wall under investigation was installed, using standard methods and with a normal mix design, in August 1995 in order to contain leachates arising from ‘piggy-backing’ of an existing ‘dilute and disperse’ landfill site. In September 1998, the wall was investigated during which the top of the wall was exposed at adjacent locations allowing the drilling of three boreholes using rotary coring techniques. Core recovery and quality were high and samples obtained during coring were retained for testing in the laboratory.

The material recovered was quite strong and not treatable by conventional soil testing and preparation techniques. In addition, the material was susceptible to drying upon exposure to the atmosphere, with an accompanying loss of structure. In spite of this, meaningful laboratory tests were undertaken. Hydraulic conductivity of the samples was measured using constant flow-rate methods and the relative importance of the diffusive flux was investigated using a variety of simple techniques. The advective flux was found to be the dominant contaminant transport process. The results of the laboratory test programme are presented and placed in the context of the long-term performance of cement–bentonite slurry walls.