A Preliminary Laboratory Study of Initial Copper Release from Dredge Residuals

A preliminary laboratory study was conducted to investigate the impact of different residual types and sediment surface roughness on copper contaminant fluxes to the water column. Sediments from Torch Lake, Michigan served as the test samples. These sediments are mining by‐products with elevated Cu levels. Six experiments were run during which the sediments were conditioned to simulate different forms of residuals. During these experiments, the water column above the sediments was circulated via peristaltic pumping or orbital shaking and the total and dissolved Cu levels were monitored periodically for 15 days. Dissolved Cu levels indicated that during the first 48 hr the water column concentrations approached equilibrium for all six cases. Total Cu levels increased with time and did reach equilibrium but were more susceptible to fluctuations in water column suspended solids levels. Analysis of the resulting dissolved Cu data indicated that the resulting water column Cu concentrations differed with sediment surface and residual type. The highest dissolved Cu water column concentrations were observed for a roughened surface with a larger surface area. The lowest water column dissolved Cu levels were observed for the case with sediment slurry placed over clean sand. The dissolved Cu levels in the water column for all six simulated conditions were several orders higher than the USEPA ambient water quality criteria for protection of aquatic life. © 2014 Wiley Periodicals, Inc.*     

Cost‐Effective Sediment Dredge Disposal Options for Small Craft Harbors in Canada

Sediment dredge disposal options were reviewed to improve cost‐effectiveness and environmental safety for dredging of coastal sediments at the Department of Fisheries and Oceans Small Craft Harbours (DFO‐SCH) program in Canada. Historically, contaminated dredge sediments exceeding federal guidelines were disposed of in nearby landfills. Recent federal regulatory changes in sediment quality guidelines adopted by provincial regulators in Canada has resulted in updates to guidelines for disposal of contaminated solids in landfills. Updates now require specific and general disposal options for contaminated dredge material destined for land‐based disposal, resulting in more expensive disposal in containment cells (if contaminated sediments exceed federal guidelines). However, as part of this study, a leachate testing method was applied to contaminated sediments to simulate migration of potential contaminants in groundwater. Using this approach, leachate quality was compared to federal freshwater criteria and drinking water quality guidelines for compliance with new regulations. Leachate testing performed on the highest sediment contaminant concentrations triggered less than 2 percent potable water exceedances, meaning that most dredge spoils could be disposed of in privately owned or provincially operated landfill sites, providing less expensive disposal options compared to containment cell disposal. Current dredge disposal practices were reviewed at 35 harbor sites across Nova Scotia and their limitations identified in a gap analysis. Improved site management was developed following this review and consultation with interested marine stakeholders. New disposal options and chemical analyses were proposed, along with improvements to cost efficiencies for management of dredged marine sediments in Atlantic Canada. © 2013 Wiley Periodicals, Inc.     

To clean or not to clean: A geostatistical approach for evaluating contaminated soils

Indicator kriging is used to estimate the probability that a discrete area of soil (known as an exposure unit) lies either above or below an action level, warranting a response of either remediation or “no further action.” Resampling procedures are introduced as a way to optimize the number of additional samples needed to meet desired Type I and Type II error rates. This article provides the reader a step-by-step guide to the kriging analysis and a case study illustrating the procedures.     

The Use of Subbottom Profiling in Refining Dredge Cuts for a Large‐Scale Sediment Remediation Project

A number of different techniques were employed to locate the target dredge grade on a large‐scale Canadian sediment remediation project. These techniques included various coring events, Seabed Terminal Impact Newton Gradiometer (STING) testing, and geotechnical borings. Despite these techniques, the data set for interpolation of the dredge grade was widely spaced, and some of the investigations were not specifically intended to be used for defining the dredge grade. In order to reduce the risk of extra expenses from contractor claims resulting from differing sediment conditions, more precise planning was required. Due to the size of the area and the desired accuracy, subbottom profiling was identified as a potential tool to provide high‐density coverage across the site. As with any geophysical tool, ground truth data were required to verify and aid in interpretation. This article describes how subbottom profiling was used to refine the dredge grade for the target layer, the associated challenges related to signal loss in some areas, and how they were overcome. ©2017 Wiley Periodicals, Inc.     

发展循环经济 开辟航空业新纪元

随着人们环保意识的逐渐增强,航空业所造成的环境和噪声污染已经越来越成为令人关注的重大问题.从5个方面介绍了发达国家航空业发展循环经济的经验,指出我国作为发展中国家,要正视与发达国家的差距,借鉴国外先进经验,转变观念、大胆创新,大力发展循环经济,开辟我国航空业的新纪元.     

Policy Barriers To 50% Diversion Of Municipal Solid Waste

A number of policy barriers must be addressed by the governments in Europe and North America which have adopted objectives of diverting from disposal something like 50% of the solid waste stream by means of reduction, re-use and recycling. These include: the need for clarification of responsibilities of all levels of government and of private sector product manufacturers and waste disposers; putting in place incentives for source separation; ensuring markets for recyclables; and allocating the increased cost of waste management. This paper reports on findings of a research project undertaken in 1991-92 on steps being taken by different jurisdictions to overcome such barriers.     

Consensus Oriented Public Relations As A Solution To The Landfill Conflict

The siting of landfills usually meets with the disapproval of residents living in the immediate proximity of potential landfill sites and frequently arouses public protest. Also in Austria, the public's readiness to safeguard their interests has been increasing, thus such conflicts can no longer be avoided. This fact raises the question among future landfill operators, as to how to react in such cases, and how a thus sensitized public can be dealt with. Seen from the viewpoint of communication, landfill operators must direct more attention to public relations.Within a research project at the University of Vienna, we have developed a public relations model which is intended to support a consensus between the landfill operators and the residents immediately affected by the operators' activities. The results prove that the so called "consensus-oriented public relations" approach is principally right. That is, those people who, due to our survey in the communities, could envisage a landfill site being installed, broadly agreed with the landfill operator on the levels of understanding provided by the model.     

基于循环经济理念发展再生资源产业

探讨了循环经济理念下的资源观和资源循环规律,论述了循环经济赋予再生资源新的内涵、新的产业地位,分析了我国再生资源产业现状、面临的形势和存在的问题.最后从立法、政策、回收体系建设等方面给出产业发展建议.     

What is waste? To whom?--An anthropological perspective on garbage.

What is waste? To whom?--An anthropological perspective on garbage explores the fact that what constitutes waste is a highly subjective notion. In Tacna, Peru, the place from where this article draws its empirical material, waste is not only seen as a risk to public health and the environment. Some find it is a mere aesthetic inconvenience, for others it is the only source of income. Yet another way of perceiving waste is as a social contagion, in which the negative qualities of garbage are transmitted to surrounding people in the eyes of others. Such perceptions of waste, it is argued, are important parts of local waste management systems, and the understanding of such perceptions might increase the effectiveness of waste management campaigns.     

Microwave-Assisted Solvent-Free or Aqueous-Based Synthesis of Biodegradable Polymers

Microwave radiation was used as the energy source for various types of chemical derivatizations of polysaccharides and for the synthesis of biodegradable polyesters in solvent-free or aqueous-based reaction systems. A medium to high degree of substitution was obtained for starch acetates, starch succinates, carboxymethyl konjac, aminated starch, and aminated chitosan. Ring-opening polymerization of lactide and -caprolactone proceeded rapidly even at low power output in the presence of tin octanoate catalyst. Complete monomer conversion and high molecular weight were achieved in less than 6 minutes under nonisothermal conditions. The yield rapidly increased with increasing power output and showed no significant change in a wide range of batch sizes. Polycaprolactone was successfully grafted from starch and konjac acetate in 3 minutes, yielding as high as 24% grafting efficiency and 25% grafting degree.     

Release Of Some Trace Elements From Sluiced Fly Ash On Acidic Soils With Particular Reference To Boron

The purpose of this study was to examine the relationship between the concentration of boron (B) and some other selected trace elements in soil solution as effected by hydrogen ion activity within the normal pH range for acidic soils commonly amended with agricultural limestone and, alternatively, alkaline fly ash. Sluiced alkaline fly ash was applied to an acidic, clay textured soil at rates equivalent to 0, 42, 84, 125 and 167 tonne ha^-1 based on the soil lime requirement. After wheat was grown and harvested the soil-ash mixtures were maintained at field capacity moisture content for an additional 4 months before pore water samples were extracted by immiscible displacement. The total concentrations of Co, Cr, Fe, V and Zn in the ash treated soils increased by < 10% at the highest application rate of ash, the content of Cu was increased by 13% and B by 38%. Only the concentration of boron increased appreciably in the pore water extracts. Release of B from the ash was correlated with the solubility behaviour of Ca and Mg, and not with the dissolution of glass phases in the ash. Speciation and adsorption calculations for the extracts were carried out using the program MINTEQ. Common Ca, Mg and Na borate minerals were undersaturated with respect to the equilibrated solutions. Application of the constant capacitance model to the adsorption of B on mineral surfaces suggested that adsorption had little effect on total dissolved B at pH values below 6.0. Predicted concentrations of B in solutions, equilibrated with calcite in a subsurface horizon, were up to 10.6 mg dm^-3; more than double the recommended maximum concentration for B (5mg dm^-3) in potable water in Ontario.     

Green Remediation or Sustainable Remediation: Moving From Dialogue to Common Practice

Different points of view have emerged concerning how to best consider and address the largely unexamined ancillary environmental impacts, and more particularly the social and economic impacts, of remediation activities. These views are generally categorized as “green remediation” and “sustainable remediation.” This article dissects the commonalities and differences between “green” and “sustainable” remediation approaches. Several key obstacles to the broader implementation of sustainable remediation practices are identified. Similarities identified among the two concepts offer a common ground and areas of collaboration. The objective of this article is to support maturation of the remediation industry by addressing the opposition to and supporting the implementation of sustainable remediation practices, including offering recommendations for a path forward. ©2015 Wiley Periodicals, Inc.     

Potential To Use Waste Tires As Supplemental Fuel In Pulp And Paper Mill Boilers,Cement Kilns And In Road Pavement

The objective of this paper is to evaluate the recycling potential of waste tires as an energy source and for use in road pavement. North Carolina, U.S.A., is used as a case study. Scrap tires may be burned for supplemental fuel in pulp and paper mill boilers and cement kilns. Five pulp and paper mill boilers in North Carolina could consume over 90% of the 6 million tires generated annually in the state. Cement kilns located within 400 km of North Carolina population centers could consume about 6.6 million tires annually. Based on the quantity of pavement laid in North Carolina, nonproprietary and proprietary versions of asphalt rubber concrete have the potential to consume 1.8 and 7.2 million tires, respectively. Rubber modified asphalt concrete has the potential to consume up to 16.5 million tires. However, technological and economic limitations suggest that large scale implementation is unlikely for the short term. Environmental considerations pertaining to each alternative are discussed. Estimates of this nature are critical as planning regions formulate solid waste management plans which include recycling.     

Conflicting processes in the wetland plant rhizosphere: Metal retention or mobilization?

Increasingly wetlands are used for treatment of metal-contaminated water or as a cover over metal-enriched mine tailings. Natural wetlands may also be contaminated with metals from anthropogenic sources. While wetland conditions tend to be favorable for immobilization of metals, wetland plants could influence metal mobility through redox and pH processes in the rhizosphere. Our current knowledge of these processes is reviewed, focusing on the question of whether the advantages of growing wetland plants in metal-contaminated sediments outweigh the disadvantages. Wetland plants alter the redox conditions, pH and organic matter content of sediments and so affect the chemical speciation and mobility of metals. Metals may be mobilized or immobilized, depending on the actual combination of factors, and it is extremely difficult to predict which effects plants will actually have on metal mobility under a given set of conditions. However, while the effects of plants can extend several tens of centimeters into the sediments, there are no reports suggesting large-scale mobilization of metals by wetland plants.     

Co-composting rice hulls and/or sawdust with poultry manure in NE Argentina

Rice hulls and sawdust are two common C-rich wastes derived from rice and timber agro-industries in subtropical NE Argentina. An alternative to the current management of these wastes (from bedding to uncontrolled burning) is composting. However, given their C-rich nature and high C/N ratio, adequate composting requires mixing with a N-rich waste, such as poultry manure. The effect of different proportions of poultry manure, rice hulls and/or sawdust on composting efficiency and final compost quality was studied. Five piles were prepared with a 2:1 and 1:1 ratio of sawdust or rice hulls to poultry manure, and 1:1:1 of all three materials (V/V). Different indicators of compost stability and quality were measured. Thermophilic phase was shorter for piles with rice hulls than for piles with sawdust (60 days vs. 105 days). Time required for stability was similar for both C-rich wastes (about 180 days). Characteristics of final composts were: pH 5.8–7.2, electrical conductivity 2.5–3.3 mS/cm, organic C 20–26%, total N 2.2–2.9%, lignin 19–22%, total Ca 18–24 g/kg, and extractable P 6–8 g/kg, the latter representing 60% of total P. Nitrogen conservation was high in all piles, especially in the one containing both C-rich wastes. Piles with sawdust were characterized by high total and available N, while piles with only rice hulls had higher Si, K and pH. Extractable P was higher in 1:1 piles, and organic C in 2:1 piles.     

Hype or Hope: The Potential of Phytoremediation as an Emerging Green Technology

Phytoremediation is defined as the use of green plants and their associated microorganisms, soil amendments, and agronomic techniques to remove, contain, or render harmless environmental pollutants. At the present time, phytoremediation is an emerging technology and there is still a significant need to pursue both fundamental and applied research to fully exploit the metabolic and growth habits of higher plants. It is precisely the purpose of the European COST Action 837 to stimulate the development and evaluate the potential of plant biotechnology for the removal of organic pollutants and toxic metals from wastewater and contaminated sites. However, green plants grow under nonsterile conditions and thus strongly interact with many microorganisms, like bacteria and mycorrhizal fungi. In this context, an Inter‐COST Workshop on bioremediation was recently organized to address the significance of soil microorganisms for plants, and the importance of their interactions, with regard to their potential for phytoremediation. Based on the outcomes of this workshop, the potential use of phytoremediation is presented in this article. © 2001 John Wiley & Sons, Inc.