污染底泥的修复技术

美国环保局对污染底泥提出了三种修复方法(MNR、覆盖法、捕捞与挖掘法),本文对这三种方法进行了全面的介绍和比较,并对挖掘-脱水-安全填埋的底泥处置方案作了重点简要叙述.     

疏浚底泥生态毒理性风险分析方法的研究进展

疏浚底泥土地利用应该尽可能避免对施用土壤、周围地表水及地下水的污染,通过生物聚积试验和急性、亚急性毒性试验考查底泥对水及土壤中生物、植物发芽生长的影响,通过渗滤试验评价其对地下水层的污染。疏浚底泥土地利用前,其生态毒理性风险分析的方法包括风险简化评价和风险详细评价。通常简化评价方法用于估计底泥土地利用对生态系统影响程度;详细评价法进一步通过生物毒性试验和柱状渗滤试验来确定其生态毒理性影响,界定其风险特性。     

湖库底泥疏浚工程环评技术要点

底泥疏浚是治理污染水体的重要手段之一,通过对污染底泥的疏浚,可清除内污染源。作为环境治理工程,在水资源和水环境保护方面具有重要作用,但是工程实施过程中将不可避免地要产生一些污染物,同时也会造成水体水生生态系统的破坏。本文结合国内已完成的滇池、巢湖、太湖底泥疏浚工程的环境影响报告,对此类项目环境影响评价的技术要点进行探索和分析,为开展类似项目环评提供借鉴。     

污染底泥修复治理技术

我国目前有90%的城市河流受到严重污染,河道治理问题已提上日程。而随着截污工程的引入,底泥的二次污染问题就成为影响河水水质的一个重要原因。本文简要分析了底泥中的主要污染物及其危害性,并总结了近年来国内外环境学者对底泥中有机物污染修复治理技术研究的主要成果。     

复合酶生物促进剂在底泥生物修复中的应用

通过测定河道底泥中微生物的生化呼吸线来表征复合酶生物促进剂对河道自净过程的影响。研究结果表明复合酶生物促进剂对微生物具有激活作用,使微生物的累积耗氧量明显增加,有效地提升了水体的自净能力。复合酶生物促进剂能够有效地修复受萘污染的底泥,修复后底泥中多环芳烃萘的释放量和有机质的含量均明显低于对照样,并可显著降低底泥对上覆水...     

杭州城区河道底泥重金属污染及潜在生态风险评价

对杭州城区34条河道45个点位河道底泥进行采样,分析了pH及汞、砷、铅、铬、镉、铜、锌、镍等重金属含量,并进行污染及潜在生态风险评价。结果表明,监测点位的底泥为中性偏碱性,重金属含量分布不均,且范围波动很大,部分河道底泥重金属中汞、铅、镉、铬、锌、镍等有不同程度的超标,少数河道镉、铬、锌污染严重;按《农用污泥中污染物控...     

徐州云龙湖底泥重金属污染评价

本文测定了云龙湖底泥中铅(Pb)、锌(Zn)、铜(Cu)、锰(Mn)4种重金属元素含量。运用了累积指数法和潜在生态风险指数法对其污染程度和潜在生态风险进行评价:4种重金属中Cu为中度污染,Pb为轻度污染,其余2种均未构成污染。云龙湖底泥中重金属污染的潜在生态风险表现为轻微的程度,生态风险顺序是Mn>Cu>Pb>Zn。     

河道疏浚底泥脱水技术及工艺优化研究进展

底泥脱水是底泥实现后续处置的最重要一环。归纳总结了目前底泥脱水技术研究现状,对常用的底泥脱水技术、底泥脱水调理剂进行了调研,并对底泥脱水设备的工艺优化进行了总结,发现目前单一的底泥脱水技术均有一定的缺陷。建议在对单一技术进行优化的同时,开发其他辅助高效低耗的新型底泥脱水技术。以期为底泥脱水技术在我国的发展和研究工作提供有效借鉴。     

污染底泥掩蔽材料筛选综述

随着经济的高速发展,水体底泥污染已成为世界性的一个环境问题。掩蔽修复是一种修复效果明显,且工程造价较低的水体底泥修复技术,而掩蔽技术的关键在于掩蔽材料的选择。本文主要介绍了水泥、粉煤灰、沸石、方解石、铝盐等研究较为成熟的且具有应用前景的掩蔽材料,分析其各自的原理及优缺点。同时作者在文章中提出了一种新的掩蔽剂——净水厂改性污泥,对其的可行性进行了分析。并就掩蔽材料的选择的技术要求以及原则作出分析。     

磐石市矿山生态环境现状与恢复治理对策

磐石市矿山生态环境问题日益突出,主要是矿山"三废"排放污染生态环境,侵占土地和农田,严重影响了矿山经济的可持续发展.矿山生态环境恢复治理要坚持"在开发中保护,在保护中开发"和"谁开发,谁保护;谁污染,谁治理;谁破坏,谁恢复"的原则,多渠道增加复垦资金,建立监督管理新机制,依靠科技进步提高环境保护水平.     

Biological Effects of Fine Sediment in the Lotic Environment

/ Although sedimentation is a naturally occurring phenomenon inrivers, land-use changes have resulted in an increase in anthropogenicallyinduced fine sediment deposition. Poorly managed agricultural practices,mineral extraction, and construction can result in an increase in suspendedsolids and sedimentation in rivers and streams, leading to a decline inhabitat quality. The nature and origins of fine sediments in the loticenvironment are reviewed in relation to channel and nonchannel sources andthe impact of human activity. Fine sediment transport and deposition areoutlined in relation to variations in streamflow and particle sizecharacteristics. A holistic approach to the problems associated with finesediment is outlined to aid in the identification of sediment sources,transport, and deposition processes in the river catchment. The multiplecauses and deleterious impacts associated with fine sediments on riverinehabitats, primary producers, macroinvertebrates, and fisheries are identifiedand reviewed to provide river managers with a guide to source material. Therestoration of rivers with fine sediment problems are discussed in relationto a holistic management framework to aid in the planning and undertaking ofmitigation measures within both the river channel and surrounding catchmentarea.KEY WORDS: Sedimentation; Fine sediment; Holistic approach; Ecologicalimpact; River restoration     

环境污染对农业生产的影响

农业和农村环境是人类生存、经济发展和社会安定的基础和根本保证。但是,随着经济的发展和人口的增长,各种工业废弃物和农用化学物质不断地涌入农业环境,使得农业环境的污染负荷增加,农业本身产生的污染问题也日益严重,农业环境正面临一系列严重的环境污染和生态破坏的问题。环境各个要素的污染都会影响正常的农业生产,主要介绍了大气污染、水污染、土壤污染的基本特征及其对农业生产的影响。     

矿山生态环境恢复治理保证金制度在迁安的实践

以迁安市矿山环境恢复治理保证金制度实施情况及效果的调查为基础,总结了迁安市的成功实践经验,强化全社会对资源环境问题的认识,健全矿山生态环境建设责任制,建立矿山生态环境保护与治理数据库,提高矿山环境治理的技术水平。     

Development of Sediment and Nutrient Export Coefficients for U.S. Ecoregions

Water quality impairment due to excessive nutrients and sediment is a major problem in the United States (U.S.). An important step in the mitigation of impairment in any given water body is determination of pollutant sources and amount. The sheer number of impaired waters and limited resources makes simplistic load estimation methods such as export coefficient (EC) methods attractive. Unfortunately ECs are typically based on small watershed monitoring data, which are very limited and/or often based on data collected from distant watersheds with drastically different conditions. In this research, we seek to improve the accuracy of these nutrient export estimation methods by developing a national database of localized EC for each ecoregion in the U.S. A stochastic sampling methodology loosely based on the Monte‐Carlo technique was used to construct a database of 45 million Soil and Water Assessment Tool (SWAT) simulations. These simulations consider a variety of climate, topography, soils, weather, land use, management, and conservation implementation conditions. SWAT model simulations were successfully validated with edge‐of‐field monitoring data. Simulated nutrient ECs compared favorably with previously published studies. These ECs may be used to rapidly estimate nutrient loading for any small catchment in the U.S. provided the location, area, and land‐use distribution are known.     

石油类污染物在水环境中的归宿

石油类污染物在各种水环境中 ,由于水体的特点不同 ,其归宿也不同。通过对焉耆盆地石油开发区域内博斯腾湖、开都河及相邻湿地的研究 ,对石油类污染物在各水环境中扩散、挥发、溶解、分解、乳化、氧化、生物降解、沉降、吸附与吸收、分配与富集等进行了定量分析 ,为石油类污染的控制和清除提供了可靠依据     

On the Role of Spatial,Temporal, and Climatic Forces on Stream Sediment Loading from Rural and Urban Ecosystems

In this study, we characterize the greatest sediment loading events by their sediment delivery behavior; dominant climate, watershed, and antecedent conditions; and their seasonal distribution for rural and urban land uses. The study area is Paradise Creek Watershed, a mixed land use watershed in northern Idaho dominated by saturation excess processes in the upstream rural area and infiltration excess in the downstream urban area. We analyzed 12 years of continuous streamflow, precipitation, and watershed data at two monitoring stations. We identified 137 sediment loading events in the upstream rural section of the watershed and 191 events in the downstream urban section. During the majority of these events conditions were transport limited and the sediment flush occurred early in the event, generally in the first 20% of elapsed event time. Statistical analysis including two dozen explanatory variables showed peak discharge, event duration, and antecedent baseflow explained most of the variation in event sediment load at both stations and for the watershed as a whole (R² = 0.73‐0.78). In the rural area, saturated soils combined with spring snowmelt in March led to the greatest loading events. The urban area load contribution peaked in January, which could be a re‐suspension of streambed sediments from the previous water year. Throughout the study period, one event contributed, on average, 33% of the annual sediment load but only accounted for 2% of the time in a year.     

LAKE RESTORATION BY SEDIMENT REMOVAL1

ABSTRACT: Fresh water lake sediment removal is usually undertaken to deepen a lake and increase its volume to enhance fish production, to remove nutrient rich sediment, to remove toxic or hazardous material, or to reduce the abundance of rooted aquatic plants. Review of more than 60 projects and five case histories reveals that the first three objectives are usually met through sediment removal. Dredging to control aquatic plants has not been well documented. Disadvantages of dredging include cost, temporary phosphorus release from sediment, increased phytoplankton productivity, noise, lake drawdown, temporary reduction in benthic fish food organisms, the potential for toxic material release to the overlying water and potential for environmental degradation at the dredged material disposal site. The technique is recommended for deepening and for long range reduction of phosphorus release from sediment. Sediment removal to control toxic materials is possible with minimal environmental impact when proper equipment is used, but it may more than double the cost. Lack of definitive information about rooted plant regrowth rates in dredged areas prohibits explicit recommendations on sediment removal to control plant growth.     

Modeling of Vertical Solute Dispersion in a Sediment Bed Enhanced by Wave‐Induced Interstitial Flow1

Abstract: Mass (solute) transport in a stream or lake sediment bed has a significant effect on chemical mass balances and microbial activities in the sediment. A “1D vertical dispersion model” is a useful tool to analyze or model solute transfer between river or lake water and a sediment bed. Under a motionless water column, solute transfer into and within the sediment bed is by molecular diffusion. However, surface waves or bed forms create periodic pressure waves along the sediment/water interface, which in turn induce flows in the pores of the sediment bed. The enhancement of solute transport by these interstitial periodic flows in the pores has been incorporated in a 1D depth‐dependent “enhanced dispersion coefficient (D_E).” Typically, D_E diminishes exponentially with depth in the sediment bed. Relationships have been developed to estimate D_E as a function of the characteristics of sediment (particle size, hydraulic conductivity, and porosity) and pressure waves (wave length and height). In this paper, we outline and illustrate the calculation of D_E as well as the penetration depth (d_p) of the flow effect. Sample applications to illustrate the computational procedure are provided for dissolved oxygen transfer into a stream gravel bed and release of phosphorus from a lake bed. The sensitivity of the results to input parameter values is illustrated, and compared with the errors obtained when interstitial flow is ignored. Maximum values of D_E near the sediment surface can be on the order of 1 cm²/s in a stream gravel bed with standing waves, and 0.001 cm²/s in a fine sand lake bed under progressive surface waves, much larger than molecular diffusion coefficients.