Comparison of the performance of different methods to stabilize mercury-containing waste

Journal of Material Cycles and Waste Management - The work is devoted to the study of a possible technology for the immobilization of mercury in waste, based on the principles of converting mercury...     

Application of the operating window concept to remediation‐option selection

An Erratum has been published for this article in Remediation 14(4) 2004, 141. The selection of remediation options for the management of unacceptable risks at contaminated sites is hindered by insufficient information on their performance under different site conditions. Therefore, there is a need to define “operating windows” for individual remediation options to summarize their performance under a variety of site conditions. The concept of the “operating window” has been applied as both a performance optimization tool and decision support tool in a number of different industries. Remediation‐option operating windows could be used as decision support tools during the “options appraisal” stage of the Model Procedures (CLR 11), proposed by the Environment Agency (EA) for England and Wales, to enhance the identification of “feasible remediation options” for “relevant pollutant linkages.” The development of remediation‐option operating windows involves: 1) the determination of relationships between site conditions (“critical variables”) and option performance parameters (e.g., contaminant degradation or removal rates) and 2) the identification of upper‐ and lower‐limit values (“operational limits”) for these variables that define the ranges of site conditions over which option performance is likely to be sufficient (the “operating window”) and insufficient (the “operating wall”) for managing risk. Some research has used case study data to determine relationships between critical variables and subsurface natural attenuation (NA) process rates. Despite the various challenges associated with the approach, these studies suggest that available case study data can be used to develop operating windows for monitored natural attenuation (MNA) and, indeed, other remediation options. It is envisaged that the development of remediation‐option operating windows will encourage the application of more innovative remediation options as opposed to excavation and disposal to landfill and/or on‐site containment, which remain the most commonly employed options in many countries. © 2004 Wiley Periodicals, Inc.     

建立再生资源回收体系产业链条促进回收体系产业化发展

介绍了北京市海淀区再生资源回收体系产业化发展的经验。作为建设主体企业,海淀区物资回收公司合理规划、布局回收网点,疏通物流运输渠道,建设专业化分拣中心,开展厂商直挂业务,有效推进海淀区再生资源回收体系建设。     

An approach to evaluate the application of the vulnerability index for oil spills in tropical Red Sea environments

The Egyptian national marine oil pollution contingency plan was urgently initiated after the Nabila oil spill in 1982, to provide an estimate of its environmental effects on the Egyptian Red Sea coastal areas and to determine geomorphological features and cuastal processes, together with physical, chemical and biological baseline data for this tropical environment.The ‘Vulnerability Index’ (VI) was applied to evaluate and calibrate the effect of the Nabila oil spill on the Egyptian Red Sea Coastal area. A detailed in situ coastal survey was conducted during two visits in November 1982 and May 1983 to 80 shore sites from Suez to Ras Banas to monitor the oil pollution and to apply the ‘Vulnerability Index’. A comparative assessment of the index over time by comparing it with a quick ground inspection in November 1993 to some sites to evaluate the applicability of this index for oil spills in such environments. In addition, the physical effects of fresh and weathered crude oil and/with dispersant on water filtration by different beaches were preliminary studied.The geomorphological/Vulnerability Index results show that most of the Egyptian Red Sea coastal environments have medium to high vulnerability to immediate and medium term oil spill damage. The oil pollution spread estimated to be 250 km south of the oil spill and about 200 km north of it. The quantity of oil along the shoreline was reduced by about 60% due to natural and authorities clean up. The third survey after 11 years showed that the VI could be used as a predictive tool for assessment of oil spill effects on such tropical environments.     

将农业再生资源回收利用事业推向新高度

<正>农业再生资源是再生资源的一个特殊而重要的组成部分,与其他品种再生资源相比,具有两大特点:一是产出量大,我国是农业大国,据统计,我国每年产生各类农作物秸秆约6.5亿t,畜禽粪便产生量约20亿     

A comparative study of two composts as filter media for the removal of gaseous reduced sulfur compounds (RSCs) by biofiltration: Application at industrial scale

This work presents the use of two composts as filter media for the treatment by biofiltration of odors emitted during the aerobic composting of a mixture containing sewage sludge and yard waste. The chemical analysis of the waste gas showed that the malodorous compounds at trace level were the reduced sulfur compounds (RSCs) which were dimethyl sulfide (Me₂S), methanethiol (MeSH) and hydrogen sulfide (H₂S). Laboratory tests for biofiltration treatment of RSCs were performed in order to compare the properties of two filter media, consisted of a mature compost with yard waste (YW) and a mixture of mature compost with sewage sludge and yard waste (SS/YW). The maximum elimination capacity (EC) values obtained with the YW mature compost as packing material were 12.5 mg m^?3 h^?1 for H₂S, 7.9 mg m^?3 h^?1 for MeSH and 34 mg m^?3 h^?1 for Me₂S, and the removal efficiency decreased in the order of: H₂S > MeSH > Me₂S. Moreover, the YW compost filter medium had a better behavior than the filter medium based on SS/YW in terms of acclimation of the microbial communities and moisture content. According to these results, a YW mature compost as packing material for an industrial biofilter were designed and this industrial biofilter was found effective under specified conditions (without inoculation and addition of water). The results showed that the maximum EC value of RSCs was 935 mg m^?3 h^?1 (100% removal efficiency, RE) for an inlet loads (IL) between 0 and 1000 mg m^?3 h^?1. Thus, YW compost medium was proven efficient for biofiltration of RSCs both at laboratory and industrial scale.     

Rapid screening procedure to optimise the anaerobic codigestion of industrial biowastes and agricultural livestock wastes in Cyprus

Small-scale experimental investigations were undertaken on the anaerobic digestion (AD) and codigestion of livestock waste and industrial biowastes. A simple procedure was developed to rapidly determine the suitability of wastes for digestion. The experiment was split into two phases; initially, the seed (digested brewery waste) was replaced by the test waste over a period of 5 days. During the second phase, the test waste was incubated and monitored for methanogenesis. Dairy cattle slurry was the most efficient co-substrate which, when codigested with pig slurry in an equal ratio achieved volatile solids destruction of 32%, CH(4) production rate of 97.4 ml d(-1), maximum CH(4) content of 61.6% and total gas yield of 2229 ml after 529 h. High fat content wastes were unsuitable for AD due to low pH value and because the dominant microbial reaction was fermentation. Codigestion was investigated to overcome any inhibitions; however, dairy cattle slurry, abattoir wastewater and NaOH additions did not lead to methanogenesis. Treating these wastes by AD is feasible but without CH(4) production.     

Application of the dynamic model of Saeman to an industrial rotary kiln incinerator: Numerical and experimental results

In order to simulate granular materials structure in a rotary kiln under the steady-state regime, a mathematical model has been developed by Saeman (1951). This model enables the calculation of the bed profiles, the axial velocity and solids flow rate along the kiln. This model can be coupled with a thermochemical model, in the case of a reacting moving bed. This dynamic model was used to calculate the bed profile for an industrial size kiln and the model projections were validated by measurements in a 4 m diameter by 16 m long industrial rotary kiln. The effect of rotation speed under solids bed profile and the effect of the feed rate under filling degree were established. On the basis of the calculations and the experimental results a phenomenological relation for the residence time estimation was proposed for the rotary kiln.     

A Global Outlook to the Carbon Dioxide Emissions in the World and Emission Factors of the Thermal Power Plants in Turkey

World primary energy demand increases with increases in population and economic development. Within the last 25 yr, the total energy consumption has almost doubled. For the purpose of meeting this demand, fossil energy sources are used and various pollutants are generated. CO₂ is also one of these gases, which cannot be removed like other pollutants, and it causes greenhouse effect and climate change. Reducing the CO₂ emission is very important because of the environmental concerns and regulations, especially the Kyoto Protocol. This paper reviews the estimated world carbon emissions, Turkey's situation in electrical energy production, emission amounts estimated until the year 2020 and emission factors for dust, SO₂, NO_x and CO₂. The estimated results show that CO₂ emissions from thermal power plants in Turkey will make about 0.66 % of the global CO₂ emissions in 2020.     

Hazard property classification of waste according to the recent propositions of the EC using different methods

Hazard classification of waste is a necessity, but the hazard properties (named “H” and soon “HP”) are still not all defined in a practical and operational manner at EU level. Following discussion of subsequent draft proposals from the Commission there is still no final decision. Methods to implement the proposals have recently been proposed: tests methods for physical risks, test batteries for aquatic and terrestrial ecotoxicity, an analytical package for exhaustive determination of organic substances and mineral elements, surrogate methods for the speciation of mineral elements in mineral substances in waste, and calculation methods for human toxicity and ecotoxicity with M factors.In this paper the different proposed methods have been applied to a large assortment of solid and liquid wastes (>1 0 0).Data for 45 wastes – documented with extensive chemical analysis and flammability test – were assessed in terms of the different HP criteria and results were compared to LoW for lack of an independent classification. For most waste streams the classification matches with the designation provided in the LoW. This indicates that the criteria used by LoW are similar to the HP limit values.This data set showed HP 14 ‘Ecotoxic chronic’ is the most discriminating HP. All wastes classified as acute ecotoxic are also chronic ecotoxic and the assessment of acute ecotoxicity separately is therefore not needed. The high number of HP 14 classified wastes is due to the very low limit values when stringent M factors are applied to total concentrations (worst case method). With M factor set to 1 the classification method is not sufficiently discriminating between hazardous and non-hazardous materials. The second most frequent hazard is HP 7 ‘Carcinogenic’. The third most frequent hazard is HP 10 ‘Toxic for reproduction’ and the fourth most frequent hazard is HP 4 “Irritant – skin irritation and eye damage”. In a stepwise approach, it seems relevant to assess HP 14 first, then, if the waste is not classified as hazardous, to assess subsequently HP 7, HP 10 and HP 4, and then if still not classified as hazardous, to assess the remaining properties.The elements triggering the HP 14 classification in order of importance are Zn, Cu, Pb, Cr, Cd and Hg. Progress in the speciation of Zn and Cu is essential for HP 14. Organics were quantified by the proposed method (AFNOR XP X30-489) and need no speciation. Organics can contribute significantly to intrinsic toxicity in many waste materials, but they are only of minor importance for the assessment of HP 14 as the metal concentrations are the main HP 14 classifiers. Organic compounds are however responsible for other toxicological characteristics (hormone disturbance, genotoxicity, reprotoxicity…) and shall be taken into account when the waste is not HP 14 classified.     

Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill

A wide range of waste characterization methods are available, each developed for a specific purpose such as determining compost stability, or for landfill acceptance criteria. Here test methods have been evaluated for the purpose of assessing waste treatment process performance and monitoring the diversion of biodegradable municipal waste (BMW) from landfill. The suitability factors include the timescale of the method, applicability to a wide range of materials and ability to indicate the long-term biodegradability of organic waste samples. The anaerobic test methods, whilst producing reliable results, take at least several weeks to complete, therefore, not allowing for regular routine analysis often required for diversion assessments. Short-term tests are required which can correlate with, and, therefore, estimate, values obtained from long-term anaerobic methods. Aerobic test methods were found to offer a significantly improved timescale compared with anaerobic test methods; however, they have limitations due to not measuring the full extent of sample biodegradability. No single test method was found to be completely sufficient for routine biodegradability analysis suitable for monitoring the BMW diversion from landfill. Potential areas for further research include spectrographic FT-IR or enzyme-based approaches such as the ECD or EHT methods.     

Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill

This response follows on from a recent discussion by Sánchez (2009) on test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill. Test methods to assess the biodegradability/biodegradable content of organic waste are of great interest across Europe for different purposes, such as landfill acceptance criteria, monitoring treatment facility performance and for monitoring the diversion of biodegradable municipal waste (BMW) from landfill. Many studies have recently attempted to correlate short-term test methods with long-term anaerobic test methods. This response discusses recent findings and conclusions made by Sánchez (2009) and describes recent work undertaken at Cranfield University to develop the enzymatic hydrolysis test (EHT) method. The EHT has previously shown potential as a short-term, non-biological, biodegradability assessment tool, however there is a requirement to further develop this test method. We conclude that aerobic and anaerobic biological test methods are not the only suitable methods of assessing waste treatment process performance; and that alternative methods such as EHT are feasible and potentially suitable.     

Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill

This discussion explores one crucial point about the use of biodegradability indicators to monitor biological processes in organic solid waste treatment plants. Today, some different measures are being used for the determination of biodegradable organic matter and most of them are based on respiration indices (oxygen consumption or carbon dioxide production under aerobic conditions) or biogas production tests (under strict anaerobic conditions). However, it is not evident from scientific literature that both tests may be equivalent or comparable. This discussion includes the results obtained when trying to correlate both anaerobic and aerobic tests to complement the recent work published by Wagland et al. [Wagland, S.T., Tyrrel, S.F., Godley, A.R., Smith, R., 2009. Test methods to aid in the evaluation of the diversion of biodegradable municipal waste (BMW) from landfill. Waste Management 29, 1218–1226].     

The use of the removable thin film coating technique as an alternative to traditional decontamination methods to mitigate and abate hazardous particulates

This article summarizes a study that evaluated a new decontamination technique for the mitigation and abatement of hazardous dust and particulates. Traditional decontamination methods are time‐consuming, expensive, can create airborne hazards, and do not always bring the concentration of the contaminant to acceptable levels. The use of the removable thin film coating will increase efficiency, will not generate airborne hazards, will decrease costs, and, with one application, will bring the hazardous dust concentrations to acceptable levels. Qualitative tests demonstrated that the removable thin film coating reduced the amount of visible luminescent dust (a surrogate for hazardous dust) from various surfaces. It also indicated that wherever there were minute scratches, the coating did not remove all of the dust. However, the qualitative tests showed that this decontamination method worked well as a preventative method, protecting clean areas from becoming contaminated when exposed to the luminescent dust. Further investigation was conducted using a scanning electron microscope (SEM) and carbon dust. Overall, the SEM experiment demonstrated that there was a statistically significant (p = 0.00007) removal of carbon dust (less than 10 μm in size) from surfaces with crevasses larger than 3 μm. The SEM also revealed that there were some limitations where there were large clusters of carbon dust; in these instances, the coating would tear and remain on the sample surface. One method to resolve this limitation involved adding Kevlar^TM fibers to the removable thin film coating. It was thought that this would increase the strength of the coating and eliminate the coating from tearing when removing large clusters of a contaminant. Unfortunately, this did not alleviate the issue. The use of an engineered textile, saturated with the coating, appeared to eliminate the problem with the coating not being able to remove the contaminant from the minute surface scratches and improved the removal process of the coating. © 2008 Wiley Periodicals, Inc.     

Description and identification of difficulties arising from the application of a cleaning process in operating conditions for the treatment of components used on liquid metal fast reactors (LMFR). A technical designed approach to avoid these situations

The cleaning process is one of the major maintenance operation for liquid metal fast reactors (LMFRs), both in operation and in their decommissioning stage. Russian and French cleaning processes are briefly described, including problems which have arisen during the processes. It appears that the cause of these problems is always connected to bad draining of the component, resulting in a vigorous reaction between vapour or liquid water and the bulk of sodium. From this discussion, the paper makes major recommendations for the efficient and safe cleaning of sodium wetted components, and proposes several processes which should be developed in order to deal with difficult situations, for example the removal of large amounts of undrainable sodium.