bluuebunny/crossref_metadata_2025 huggingface dataset:
Toxicity and hazardous properties of solvent base adhesive wastes
Authors: Sabater M. C. , Martínez M. A. , Font R.
Published: April 2009

In this work, the hazardous properties of solvent base adhesive wastes generated in the footwear manufacturing process have been studied. The characterisation procedures and criteria used are those contained in the legal documents European Union Council Decision 94/904/CE and October 13th Spanish Ministerial Order.

The properties studied were the following: flash point, reactivity (gas generation), ecotoxicity, main contaminants extracted by the leaching process and main harmful substances contained in wastes. An additional study of the relationship between flash point and solvent concentration in waste was carried out for polyurethane-acetone and neoprene-toluene systems.

The wastes considered were metal containers with remains of dry or semi-dry adhesive. The results obtained show that the presence of solvent in wastes confers on them hazardous characteristics (flash point and harmful composition) depending on the solvent type and its concentration.
Economic considerations of chromium recovery from tanning wastewater
Authors: Panswad T. , Chavalparit O. , Chandung C. , Anotai J.
Published: April 2009

The chrome recovery from tanning wastewater was investigated in field conditions using a real-sized pilot plant. The tested wastewaters were from the tanning process both without and with tanning additives, whereas the precipitating chemicals of interest were magnesium oxide (MgO) and sodium carbonate (Na2CO3). The precipitation with MgO followed by 1-hour sedimentation was the best solution. The optimal dosages were 2 and 4 times that of stoichiometric requirements for conditions without and with the additives, respectively. By redissolving the obtained sludge with 1:1 diluted sulfuric acid and maintaining the pH between 2.5 and 2.8, the chromium recovery were 97.6 and 88.6%, respectively. Another alternative of using Na2CO3 as the precipitant was not promising because of its high chemical cost and excessive sludge-settling period (15-20 hours). The MgO precipitation scenario proved to be able to pay back economically within 3 years for the “without-additive” waste stream whereas that of “with-additive” wastewater was not worth the investment. This is because the “with-additive” discharge contains low chromium content whereas it requires high chemical doses.
Characterisation of municipal solid waste and its recyclable contents of Guangzhou
Authors: Chung Shan-Shan , Poon Chi-Sun
Published: April 2009

Waste characteristics are essential data for waste disposal facilities planning and waste management policy formulation. However, waste composition studies are rarely carried out in mainland Chinese cities and even when it does, the methodologies used are not stringent. A year-long field survey on the physical components of waste and the recyclable in the waste stream has been conducted in Guangzhou to fill the information gap and to provide further experience for waste characterization study in mainland China. It was found that the ash content in the waste stream has decreased considerably. But the proportion of plastic materials in the waste stream has increased and is now comparable to its more urbanized cities. Although this lends support to the recent controls on expanded polystyrene food containers implemented by the Guangzhou environmental protection bureau, more detailed analysis shows that the focus should not only be on disposable food containers, but also on film plastic waste. Furthermore, the abundance of composite materials in the waste stream solicits attention from the waste management authority to step up the monitoring of their generation pattern and to consider imposing control measures.
Recycling for all: preliminary criteria for the design of disability-friendly receptacles
Authors: Jensen P. , Nielsen C. Woetmann
Published: April 2009

The design of current waste bins, paper and bottle banks presents barriers for disabled and elderly persons, as pointed out by several Danish studies. In drawing up design criteria for the development of receptacles to be usable by persons with disabilities and senior citizens it is essential to be aware of the problems caused by different types of disability as well as old age. On the basis of general user requirements, preliminary criteria for the design of disability-friendly receptacles are proposed. In collaboration with a collecting agent, current receptacles modified in accordance to the preliminary design criteria will be tested in pilot studies in three selected housing estates in the municipalities of Frederiksberg and Copenhagen. It is the authors’ hope that the testing of the modified receptacles will result in achieving more efficient source separation not only for disabled and elderly persons, but for all user groups.
Utilisation of waste nitrocellulose powders and environmental pollution in their destruction
Authors: Ganev Radi
Published: April 2009

The composition of major types of waste powders and pollution during their long-term storage in military storehouses are shown. An analysis of the powder related problems and the types of their recycling and utilisation is proposed. The gaseous products released from incineration of two major types of powder under atmospheric pressure were measured. It is proposed to utilise the powders through processing in polymer mixtures for the production of paint materials. The coatings made thereof have standard characteristics with self-extinguishing and low-flammability-point properties. A diagram of installation for waste powder processing by wasteless technology is shown.
Optimisation of industrial wastes reuse as construction materials
Authors: Collivignarelli Carlo , Sorlini Sabrina
Published: April 2009

This study concerns the reuse of two inorganic wastes, foundry residues and fly ashes from municipal solid waste incineration, as “recycled aggregate” in concrete production. This kind of reuse was optimised by waste treatment with the following steps: waste washing with water; waste stabilisation-solidification treatment with inorganic reagents; final grinding of the stabilised waste after curing for about 10-20 days. Both the treated wastes were reused in concrete production with different mix-designs. Concrete specimens were characterised by means of conventional physical-mechanical tests (compression, elasticity modulus, shrinkage) and different leaching tests. Experimental results showed that a good structural and environmental quality of “recycled concrete” is due both to a correct waste treatment and to a correct mix-design for concrete mixture.
Utilisation of bottom ash in road construction: evaluation of the environmental impact
Authors: Bruder-Hubscher V. , Lagarde F. , Leroy M. J. F. , Coughanowr C. , Enguehard F.
Published: April 2009

France incinerates about 40% of its municipal solid waste (MSW), producing 2.7 million tons of bottom ash annually. Utilisation of bottom ash (BA) is encouraged in France but strictly regulated. Only bottom ash meeting specific criteria and produced in accordance with a quality assurance plan can be used in roadbeds and embankments. In order to evaluate the environmental impact of BA used in road construction under real conditions, two road sections were built: one containing a sub-layer of BA and the other, constructed using only natural gravel to serve as a reference. Water percolating through each roadbed was collected and sampled periodically over three years. Analysis of the samples shows minimal leaching of pollutants from BA. The results are encouraging and indicate that BA utilisation can be safe and can have an environmental impact no greater than that of natural materials.
Hospital waste management in Brazil: A case study
Authors: Mattoso Valéria D. B. , Schalch Valdir
Published: April 2009

The evaluation of the current definition, classification and quantification of hospital waste being carried out by hospitals in different countries is extremely important to avoid improper waste management practices. In this work, the waste management from a 400-bed Brazilian hospital which generates about 386 kg per day of hospital waste was studied. The generation rate of just over one kg per bed per day was considered small, although more than 50% of the waste from non-isolation wards consisted of food waste. It was also interesting to note that the highest generation rate per patient per day was found in private rooms and the lowest rate in the public ones. The waste practices used in this hospital are discussed in terms of current Brazilian legislation.
Lateral gas transport in soil adjacent to an old landfill: factors governing emissions and methane oxidation
Authors: Christophersen Mette , Kjeldsen Peter , Holst Helle , Chanton Jeffrey
Published: April 2009

Field investigations of lateral gas transport and subsequent emissions in soil adjacent to an old landfill in Denmark have been conducted during a one-year period. A significant seasonal variation in the emissions with high carbon dioxide and low methane fluxes in the summer (May to October) was observed. This was attributed to methane oxidation. Diurnal measurements during a drop in barometric pressure showed that the fluxes of landfill gas changed dramatically within a very short time. The concentrations and the soil moisture content in the upper part of the soil profile had significant influence on the fluxes, as did the distance from the landfill border, temperature, barometric pressure and the pressure gradient. Statistical analyses proved that soil moisture described the largest part of the variation. No methane at all emitted during the summer. Calculations and isotope analyses showed that very high fractions of the laterally migrating methane were oxidised.
An optimisation model for regional integrated solid waste management I. Model formulation
Authors: Najm M. Abou , El-Fadel M. , Ayoub G. , El-Taha M. , Al-Awar F.
Published: April 2009

Increased environmental concerns and the emphasis on material and energy recovery are gradually changing the orientation of MSW management and planning. In this context, the application of optimisation techniques have been introduced to design the least cost solid waste management systems, considering the variety of management processes. This study presents a model that was developed and applied to serve as a solid waste decision support system for MSW management taking into account both socio-economic and environmental considerations. The model accounts for solid waste generation rates, composition, collection, treatment, disposal as well as potential environmental impacts of various MSW management techniques. The model follows a linear programming formulation with the framework of dynamic optimisation. The model can serve as a tool to evaluate various MSW management alternatives and obtain the optimal combination of technologies for the handling, treatment and disposal of MSW in an economic and environmentally sustainable way. The sensitivity of various waste management policies will be also addressed. The work is presented in a series of two papers: (I) model formulation, and (II) model application and sensitivity analysis.
Vermicomposting of a lignocellulosic waste from olive oil industry: A pilot scale study
Authors: Benítez E. , Sainz H. , Melgar R. , Nogales R.
Published: April 2009

The vermicomposting with Eisenia andrei of dry olive cake, a lignocellulosic waste produced during the extraction of olive oil, either alone or mixed with municipal biosolids, was studied in a nine-month pilot scale experiment. Number and biomass of earthworms and enzyme activities were periodically monitored and relevant properties of the final products were determined. In the assayed substrates, the total biomass of earthworms increased at the end of the experimental period between 9 and 12-fold respectively in comparison with the earthworm biomass initially inoculated. The increase in hydrolytic enzymes and overall microbial activity during the vermicomposting process indicated the biodegradation of the olive cake and resulted in the disappearance of the initial phytotoxicity of the substrate. However, the recalcitrant lignocellulosic nature of the dry olive cake prevented suitable humification during the vermicomposting process. For this reason, in addition to organic amendments, other management procedures should be considered.
Plant available nitrogen from anaerobically digested sludge and septic tank sludge applied to crops grown in the tropics
Authors: Sripanomtanakorn S. , Polprasert C.
Published: April 2009

Agricultural land is an attractive alternative for the disposal of biosolids since it utilises the recyclable nutrients in the production of crops. In Thailand and other tropical regions, limited field-study information exists on the effect of biosolids management strategies on crop N utilisation and plant available N (PAN) of biosolids. A field study was conducted to quantify the PAN of the applied biosolids, and to evaluate the N uptake rates of some tropical crops. Sunflower ( Helianthus annuus) and tomato ( Lycopersicon esculentum) were chosen in this study. Two types of biosolids used were: anaerobically digested sludge and septic tank sludge. The soil is acid sulfate and is classified as Sulfic Tropaquepts with heavy clay in texture. The anaerobically digested sludge applied rates were: 0, 156 and 312 kg N ha-1 for the sunflower plots, and 0, 586, and 1172 kg N ha-1 for the tomato plots. The septic tank sludge applied rates were: 0, 95 and 190 kg N ha-1 for the sunflower plots, and 0, 354 and 708 kg N ha-1 for the tomato plots, respectively. The results indicated the feasibility of applying biosolids to grow tropical crops. The applications of the anaerobically digested sludge and the septic tank sludge resulted in the yields of sunflower seeds and tomato fruits and the plant N uptakes comparable or better than that applied with only the chemical fertiliser. The estimated PAN of the anaerobically digested sludge was about 27-42% of the sludge organic N during the growing season. For the septic tank sludge, the PAN was about 15-58% of the sludge organic N. It is interesting to observe that an increase of the rate of septic tank sludge incorporated into this heavy clay soil under the cropping system resulted in the decrease of N mineralisation rate. This situation could cause the reduction of yield and N uptake of crops.
The concept of a sorption chemical barrier for improving effectiveness of landfill liners
Authors: Voudrias Evangelos A.
Published: April 2009

In this work, we apply the concept of a “sorption chemical barrier”, as a means of improving landfill liner effectiveness. The sorption barrier is formed by addition of the organoclay hexadecyltrimethylammoniummontmorillonite (HDTMA-montmorillonite) to a fine sand-bentonite liner. Using previously published experimental data and mathematical model simulations, we demonstrate that such a liner retards significantly the transport of landfill leachate components, thus, increasing the useful life of the liner by a factor of 5 to 10, for the cases calculated. The superior HDTMA-liner performance is maintained even when the sorption extent is significantly decreased, as in the case of leachate containing methanol, a cosolvent miscible with water, found in some industrial and hazardous waste sites. The increase of the useful life of the liner results in smaller liner thickness, required to provide equivalent protection, from the point of view of contaminant transport, as compared to the liner containing no organoclay. Clay liner design based on hydraulic conductivity alone neglects the early breakthrough due to hydrodynamic dispersion and, therefore, is not a conservative one.
Recycling ferrous-nickel slag in blast cleaning
Authors: Katsikaris K. , Voutsas E. , Magoulas K. , Andronikos G. , Stamataki S.
Published: April 2009

The aim of this study is the development of a procedure for the recycling of the ferrous-nickel slag that is widely used in open dry blast cleaning operations in Greek shipyards thus annually generating thousands of tons of blast cleaning waste. Laboratory tests were carried out, based on the reclamation of the material fraction with size a distribution within the range -1400+150 μm, in order to determine the number of the effective uses (life cycles) of the abrasive material. It is demonstrated that the reclamation yield in the first three life cycles is more than 80%. Laboratory tests also proved that the recycled ferrous-nickel slag has properties comparable to the fresh material’s ones in terms of particle size distribution, consumption and other physical-chemical properties.

A semi-industrial recycling unit of used ferrous-nickel slag was also designed and installed in a Greek shipyard (Neorion New SA of Syros Shipyards). The operation of the semi-industrial recycling unit verified the conclusions resulting from the laboratory tests, and most important, it was proved profitable for the shipyard.
The effect of various environmental and design parameters on methane oxidation in a model biofilter
Authors: Park Soyoung , Brown Kirk W. , Thomas James C.
Published: April 2009

Methane from landfills built with RCRA (Resource Conservation and Recovery Act) covers is frequently vented directly to the atmosphere. Alternatively, landfill gasses could be vented through a layer of soil that could serve as a biofilter to oxidize CH4 to carbon dioxide and water. Properly designed soil biofilters may reduce atmospheric CH4 emissions from landfills and help reduce the accumulation of greenhouse gasses in the atmosphere. This study was conducted to investigate the performance of a lab-scale model biofilter system using soil as the filter-bed medium in packed columns to measure the effect of a variety of environmental and design factors on the CH4 oxidation capacity of a soil biofilter.

Biofilter performance was tested under a variety of environmental and design conditions. The optimum soil moisture content for CH4 oxidation in a loamy sand was 13% by weight. Addition of NO3-N did not affect the CH4 oxidation rate. Soil depths of 30 cm and 60 cm were equally efficient in CH4 oxidation. When the CH4 loading rate was decreased, the percentage of CH4 oxidized increased. The maximum CH4 oxidation rate was 27.2 mol m-2 d-1 under optimum conditions.
Evaluation of the potentialities to reduce greenhouse gases (GHG) emissions resulting from various treatments of municipal solid wastes (MSW) in moist tropical climates: Application to Yaounde
Authors: Ngnikam Emmanuel , Tanawa Emile , Rousseaux Patrick , Riedacker Arthur , Gourdon Rémy
Published: April 2009

The authors here analyse the emission of greenhouse gases (GHG) resulting from the various treatment of municipal solid waste found in the town of Yaounde. Four management systems have been taken as the basis for analyses. System 1 is the traditional collection and landfill disposal, while in system 2 the biogas produced in the landfill is recuperated to produce electricity. In systems 3 and 4, in addition to the collection, we have introduced a centralised composting or biogas plant before the landfilling disposal of refuse.

A Life Cycle Inventory (LCI) of the four systems was made; this enable us to quantify the flux of matter and of energy, consumed or produced by the systems. Following this, only the greenhouse effect was taken into account to evaluate the ecological consequences of the MSW management systems. The method used to evaluate this impact takes into consideration on the one hand, GHG emissions or avoided emission following the substitution of fuel with methane recovered from landfills or produced in the digesters, and on the other hand, sequestrated carbon in the soil following the regular deposit of compost.

Landfilling without recuperation of methane is the most emitting solution for greenhouse gas: it leads to the emission of 1.7 ton of carbon dioxide equivalent (tCO2E) per ton of household waste. Composting and methanisation allow one to have a comparable level of emission reduction, either respectively 1.8 and 2 tCO2E/t of MSW. In order to reduce the emission of GHG in the waste management systems, it is advisable to avoid first of all the emissions of methane coming from the landfills.

System 2 seems to be a solution that would reduce the emissions of GHG at low cost (2.2 to 4 $/tCO2E). System 2 is calculated as the most effective at the environmental and economic level in the context of Yaounde. Therefore traditional collection, landfill disposal and biogas recuperation to produce electricity is preferable in moist tropical climates.
Molecular characterisation of bacteria in a wetland used to remove ammoniacal-N from landfill leachate
Authors: Walsh Kerry A. , Hill Tom C.J. , Moffett Bruce F. , Harris James A. , Shaw Phil J. , Wallace Joanne S.
Published: April 2009

Bacteria associated with leachate from a constructed, surface-flow wetland effective at removing ammonium-N, were characterised using molecular methods which bypass the need for cultivation. DNA was extracted from the sample and bacterial 16S rDNA sequences amplified and cloned. Ninety-six individual clones were re-amplified and analysed by restriction digestion and targeted sequencing. A collector's curve was used to estimate the total number of bacterial groups (operational taxonomic units, OTUs) in the sample at 47. Thirty-six clones representing 28 OTUs were sequenced and characterised by aligning them against published sequences. Of these, 10 were confidently identified, whilst for the remaining 18, the closest match was obtained. The sequences in 64% of the OTUs were similar to those of the Proteobacteria but no classical nitrifying bacteria were identified. However, alkaliphilic Methylomicrobium sp. that oxidise ammonium and bacteria from the genus Alcaligenes, at least one species of which is capable of heterotrophic nitrification, were detected.
Review: Mercury in waste incineration
Authors: van Velzen Daniel , Langenkamp Heinrich , Herb Georg
Published: April 2009

The paper investigates the sources of mercury (Hg) in municipal/industrial waste and the consequences of the presence of this pollutant for the incineration of this waste.

About 1990 the average mercury concentration of the feed stream to incinerators was about 4 mg kg -1. The concentration decreased considerably during the last decade thanks to a considerable reduction of the application of mercury and to the introduction of effective battery return systems. Presently the mercury concentration in municipal SOLID waste is approximately 2 mg kg-1.

During incineration mercury passes practically for 100% in the flue gas. The techniques for mercury removal from flue gases are discussed at the hand of practical examples. It is concluded that there are a number of processes which guarantee mercury concentrations of <50 μg Nm-3 in the clean gas, the present emission limit concentration.

All mercury control processes produce a new solid or liquid waste stream that contains the mercury removed from the flue gas. This stream has to be disposed of as hazardous waste in a qualified landfill.

The flue gas from waste incinerators undergoes very rapid dispersion and dilution after leaving the incinerator stack. It follows that the maximum mercury concentration in the ambient air will remain at least five to six orders of magnitude below the lowest MAC value (=Maximum Admissible Concentration in work spaces) and that public health will not be threatened.
Strategic environmental assessment of alternative sewage sludge management scenarios
Authors: Poulsen Tjalfe G. , Hansen Jens Aa.
Published: April 2009

Strategic environmental assessment (SEA) of sewage sludge management in a Danish municipality (Aalborg), with 160,000 inhabitants using alternative methods for aggregation of environmental impacts was performed. The purpose is to demonstrate the use of SEA in relation to sludge management and to improve SEA methodology. Six different scenarios for management of sewage sludge within the Aalborg municipality involving thermal treatment, composting and landfilling of sludge were evaluated. Environmental impact categories considered were global warming, non-renewable resources (nutrients and fossil fuels) and land use. Impact categories human health, ecotoxicity and soil quality were excluded as methodology for their assessment is not yet fully developed. Thermal sludge treatment with energy utilisation was shown to be a promising option for sewage sludge management in Aalborg. Sensitivity of the relative environmental impacts with respect to calculation methodology and input parameter values were evaluated to identify important parameters and calculation methods. The analysis showed that aggregation procedures, sludge biogas potential and sludge production were very important whereas sludge transport was not.
The use of by-products from metallurgical and mineral industries as filler in cement-based materials
Authors: Moosberg Helena , Lagerblad Björn , Forssberg Eric
Published: April 2009

This investigation has been made in order to make it possible to increase the use of by-products in cement-based materials. Use of by-products requires a screening procedure that will reliably determine their impact on concrete. A test procedure was developed. The most important properties were considered to be strength development, shrinkage, expansion and workability. The methods used were calorimetry, flow table tests, F-shape measurements, measurements of compressive and flexural strength and shrinkage/expansion measurements. Scanning electron microscopy was used to verify some results. Twelve byproducts were collected from Swedish metallurgical and mineral industries and classified according to the test procedure. The investigation showed that the test procedure clearly screened out the materials that can be used in the production of concrete from the unsuitable ones.
Slag from hazardous waste incineration: Reduction of heavy metal leaching
Authors: Reich Jens
Published: April 2009

Hazardous waste incineration (HWI) in rotary kilns and the disposal of the residues on landfills play an important role in German waste treatment. In order to reduce costs by disposal on cheaper landfill sites still applying to landfill regulations the leaching behaviour of HWI-slag should be improved further. In a new process-integrated approach hazardous waste is mixed with limestone, which initiates chemical reactions with heavy metals in the rotary kiln yielding new compounds of different solubility. These reactions were observed after treatment at 1200°C combined with fusion processes, at 930°C they also occurred without fusion to the major part. For that purpose HWI-slag/limestone mixtures are thermally treated and then examined by elution tests. A minimum of overall heavy metal leaching was determined at CaO-contents between 15 and 20% after sintering at the average temperature at HWI.
Carbon mineralisation and plant growth in soil amended with compost samples at different degrees of maturity
Authors: García-Gómez Antonio , Bernal María Pilar , Roig Asunción
Published: April 2009

The carbon and nitrogen mineralisation of a composting mixture of brewing yeast and lemon tree prunings was studied, at different degrees of stabilisation of this matrix, within an incubation experiment in soil. Meanwhile, a growth test in pots with ryegrass ( Lolium perenne L.) was carried out using the selected soil and equal amounts of the composting mixture taken at different maturation steps, in order to evaluate the additions of these organic amendments in terms of fertilising value. Samples of the composting mixture, when poorly transformed through the biostabilisation process, showed high CO2-C releases in the soil, due to the microbial attack on easily degradable organic fractions still present in the mixture, with 24.7% mineralisation of the initial total organic carbon (TOC) after a 70 day incubation. On the other hand, mature compost was the most stable matrix, with only 5.4% of TOC mineralised after 70 days. Furthermore, amendments with the initial composting mixture led to negative net N-mineralisation during 56 days of incubation with soil. Only slight negative values of the net N-mineralisation were detected with fully stabilised compost. Nevertheless, pot experiments with ryegrass revealed that mature compost may promote N mineralisation to certain extents. Moreover, mature compost did not produce any phytotoxic effect, behaving as a slow-action organic fertiliser with N made available through a progressive mineralisation. Thus, the results gained through this study are a confirmation that the fertilising quality of a compost destined for agricultural uses is heavily affected by the complete exhaustion of the maturation reactions.
A preliminary study on zero solid waste generation from pulverised coal combustion (PCC)
Authors: Wang Wenlong , Luo Zhongyang , Shi Zhenglun , Cen Kefa
Published: April 2009

How to completely utilise the solid residues from pulverised coal combustion (PCC) has been a hard problem so far. On the basis of a first feasibility analysis and a preliminary experimental research, this study creates an innovative idea how to realise zero generation of solid waste from PCC. By adding some quick lime as well as some other mineralisers to the coal and grinding together before combustion, the mineral composition and property of ashes could be changed significantly. The formation of some cement minerals, such as Belite, would convert the ashes from solid waste into a kind of product that is similar to cement clinker. And this technology would have great effect on energy utilisation as well as environmental protection.
Siting MSW landfills on Lesvos island with a GIS-based methodology
Authors: Kontos Themistoklis D. , Komilis Dimitrios P. , Halvadakis Constantinos P.
Published: April 2009

The siting of Municipal Solid Waste (MSW) landfills in Greece is a difficult process due to land resource limitations, the country’s mountainous, insular and primarily water permeable terrain as well as an exacerbated public opposition (NIMBY syndrome). A GIS-based methodology is presented here with the goal to identify and rank the candidate landfill sites for the entire island of Lesvos. The initial step of the methodology comprises a GIS-based spatial analysis that uses 10 criteria, by excluding all areas unsuitable for any waste disposal activity. The pre-selected areas are then further assessed by fieldwork and candidate landfill sites are determined. The candidate sites are ranked using 19 criteria with predefined weight coefficients on a 0 to 10 grading scale. The weight coefficients are estimated for each criterion using the Analytic Hierarchy Process (AHP), while the grading scheme is based on pre-defined guidelines. An overall suitability index is produced for each candidate site allowing comparison and best case selection. A case study for the island of Lesvos is presented here, in which eight candidate landfill sites were finally selected and ranked. Social factors highly determined the ultimate selection of the site in Lesvos, since the third rather than the first site suggested by the methodology, was finally approved by local authorities.
Relating landfill gas emissions to atmospheric pressure using numerical modelling and state-space analysis
Authors: Poulsen Tjalfe G. , Christophersen Mette , Moldrup Per , Kjeldsen Peter
Published: April 2009

Landfill gas (CO2 and CH4) concentrations and fluxes in soil adjacent to an old, unlined Danish municipal landfill measured over a 48-hour period during the passage of a low-pressure weather system were used to identify processes governing gas fluxes and concentrations. Two different approaches were applied: (I) State-space analysis was used to identify relations between gas flux and short-term (hourly) variations in atmospheric pressure. (II) A numerical gas transport model was fitted to the data and used to quantify short-term impacts of variations in atmospheric pressure, volumetric soil-water content, soil gas permeability, soil gas diffusion coefficients, and biological CH4 degradation rate upon landfill gas concentration and fluxes in the soil.

Fluxes and concentrations were found to be most sensitive to variations in volumetric soil water content, atmospheric pressure variations and gas permeability whereas variations in CH4 oxidation rate and molecular coefficients had less influence. Fluxes appeared to be most sensitive to atmospheric pressure at intermediate distances from the landfill edge. Also overall CH4 fluxes out of the soil over longer periods (years) were largest during periods with rapidly decreasing atmospheric pressures resulting in emission of large amounts of CH4 during short periods of time. This effect, however, was less significant for the CO2 fluxes.
A risk factor analysis of municipal domestic refuse landfills using a reactor with high water input
Authors: Zhou Qixing , Tang Xiangyu , Wu Wenhua , Yang Yuesuo , Sylvester Runyuzi , Yu Jiyu
Published: April 2009

Collapse, explosion and water pollution by leachate have been three major problems in confining the development of sanitary landfilling technology as an economical method for disposal of municipal refuse. Potential risk factors including settlement of landfilled refuse, the generation of methane, carbon dioxide and other gases from landfill, the dynamic changes in temperature within the landfill and its ambient environment, as well as CODCr, BOD5, nutrients (TKN, TP and organic matter), heavy metals (Cu, Pb and Zn) and pH in landfill leachate were simulated using a reactor with high water input. It was indicated that high content of organic components in landfilled refuse is a key risk factor to cause abrupt collapse and accidental explosion in the landfill because they have impact not only on the settlement, but also on the release of methane and other gases. Elevated temperatures coincided with maximum generation of methane and other gases, thus increasing the risk of accidental explosion. Leachate quality was closely related with the release of CODCr and BOD5 and heavy metals such as Cu, Pb and Zn, as well as organic pollutants, there was less release of TKN and TP. The mass balance analysis for the reactor showed that 36% of organic carbon reduction in the refuse during the simulations was discharged into leachate as soluble organic carbon, and 3% was converted to methane and carbon dioxide as gas production. Mixing of refuse with soil and sand particles, the so-called drill-a-hole method and recycling leachate were measures suggested in order to mitigate and avoid potential accidents.
Social and institutional feasibility of recycling nutrients in waste in Southern Thailand
Authors: Schouw Nanette Levanius , Tjell Jens Christian
Published: April 2009

The social and institutional feasibility of recycling plant nutrients in waste in three case study areas, Phattalung, Kuan Lang and Prik, in Southern Thailand has been studied. Three sanitation systems (existing with modifications and alternative) in each area have been evaluated with respect to their acceptance among the local stakeholders and accommodation within the Thai legal framework. Culturally, most proposed recycling methods were accepted by local users, and great interest was expressed towards many of the proposed sanitation systems, except recycling methods involving direct contact with human excreta in Prik (Islamic culture). The three existing systems were assessed to be the most convenient and practical among the nine, due to their low maintenance requirement and the low user fees. The proposed modified and alternative sanitation systems involved higher public participation and thereby a change in the understanding of where the responsibility of managing people’s waste products should be placed. Institutionally all nine sanitation systems were accepted by local administrators and all recycling systems were well accommodated within the Thai legal framework. Thus recycling plant nutrients in waste seem both social and institutionally acceptable in Southern Thailand.
The optimisation of food waste addition as a co-substrate in anaerobic digestion of sewage sludge
Authors: Kim Hyun-Woo , Han Sun-Kee , Shin Hang-Sik
Published: April 2009

Food waste has been regarded as the main source of various environmental pollution in Korea due to the high volatile solids (VS) and moisture content caused by the features of dietary habits. The feasibility of food waste as a co-substrate in anaerobic digestion of sewage sludge was investigated in mesophilic and thermophilic conditions using batch tests. Cumulative methane production, dissolved organic carbon (DOC) and volatile fatty acids (VFA) were monitored to find the optimal mixing ratios of food waste and sewage sludge for the enhanced performance of co-digestion. It was observed that adequately mixed food waste led to the enhanced methane production both at mesophilic and thermophilic conditions. However, a conventional linear regression conducted for the optimisation of co-substrate mixing ratios was not accurate in describing exact methane production trends of co-digestion because of the different biodegradability of substrates. Therefore, a remodified Gompertz equation showing nonlinear relationship between variables was developed to find exact information with the same experimental data obtained at 2g VS/l generally used in biochemical methane potential (BMP) tests. Based on an influential parameter, methane production rate (MPR), the optimal mixing ratios of food waste were 39.3% and 50.1% in mesophilic and thermophilic conditions, respectively. To confirm the application of the remodified Gompertz equation, secondary batch tests were conducted with the substrate concentrations of 1-4g VS/l. In overall range tested, the confident mixing ratios of food waste was adjusted to 30-40% and 40% in mesophilic and thermophilic conditions, respectively. The most significant factor for enhanced performance was the improved organic carbon content provided by additional food waste.
Effectiveness of leachate disposal by the young willow sprouts Salix amygdalina
Authors: Białowiec Andrzej , Wojnowska-Baryła Irena , Hasso-Agopsowicz Marek
Published: April 2009

The lysimeter experiment was conducted at the laboratory scale. Different water and leachate dilutions (0%, 25%, 50%, 100% of leachate) were supplied to the lysimeters to achieve the variation in pollutants concentration. The measure of leachate disposal effectiveness was the amount of evaporated leachate solution in evapotranspiration and transpiration. Analysis of evaporation dynamics and the impact of the plants on the leachate disposal effectiveness were determined. Correlation between biomass increase, transpiration and leachate concentration was observed. The highest evapotranspiration was obtained in the lysimeter with leachate concentration 25% and was on the level of 2.3 mm/day and for transpiration, 2.21 mm/day. The lowest values of evapotranspiration (0.55 mm/day) and transpiration (0.39 mm/day) were observed in the lysimeters supplied only by concentrated leachate. The highest leachate treatment efficiency 0.78 mm leachate/day was achieved in lysimeter K3-50% leachate concentration. There was an increase in transpiration participation in evapotranspiration in time. In the lysimeters supplied by the solutions with leachate concentrations, 25% and 50% transpiration participation in evapotranspiration ranged from 80% to 90%, in case of concentrated leachate from 60% to 70%. Evapotranspiration in all lysimeters was 3, 5-14 times higher than evaporation. It seems to be the result of plant impact on evaporation and confirms the possibility of this method being used for leachate treatment. Willows in lysimeter (K3-50% of leachate) had the most effective physiological fit to landfill leachate treatment.
New technique for in-situ measurement of ammonia distribution in industrial combustion systems
Authors: Ming Chen , Tian-Tong Tang , Cheng-Lao Li
Published: April 2009

A new technique of a laser gas monitoring system with a linear Charge-Coupled Device (CCD) has been developed to measure in-situ distribution of ammonia concentrations at various temperatures. The concentration is determined by measuring absorption with a tunable 13CO2 waveguide laser that is frequency modulated between two adjacent emission lines. One line coincides with a strong ammonia absorption line, while the other is used as a reference. By its referencing the system is auto-calibrated continuously. The high spectral resolution of the laser suppresses interference by other species. Multi-light path is used to achieve distribution of ammonia concentration in the flue gas channel, which is inhomogeneous. The linear CCD is used to replace detectors, which can avoid errors caused by parameter inconsistency of multi-detector and enable lower cost, fast and exact data acquisition and processing with computer by video interface. The measuring technique presented in this paper can be used to protect industrial environment against pollution in the chemical industry, several power plants and waste incinerators.
Involvement of the period Gene in Developmental Time-Memory: Effect of the perShort Mutation on Phase Shifts Induced by Light Pulses Delivered to Drosophila Larvae
Authors: Kaneko Maki , Hamblen Melanie J. , Hall Jeffrey C.
Published: April 2009

Phases of circadian locomotor activity rhythms of adult Drosophilareared in constant darkness have been shown to be set by a light stimulus delivered as early as the first-instar larval stage. This implies that a circadian clock functions continuously throughout postembryonic development. The clock genes period ( per) and timeless ( tim) are expressed cyclically in the larval central nervous system of Drosophila, and daily oscillations of per expression persist throughout metamorphosis in a group of cells, which gives rise to the pacemaker cells underlying locomotor activity rhythms of adults. Therefore, PER and TIM cyclings in these neurons may be responsible for the phenomenon of “larval time-memory.” In the absence of any evidence for the involvement of these genes in such a developmental clock, and because circadian-pacemaker functions are underanalyzed in terms of the functions during development, the authors tested the time-memory of a fast-clock period mutant. They show that dark-reared per Smutant individuals as well as wild-type flies can be entrained as larvae and that a brief light pulse given to such entrained larvae can induce phase shifts in animals of either genotype. However, the direction and magnitude of phase shifts were different between wild type and per S, suggesting that a clock under the control of period gene participates in the regulation of developmental time-memory. The authors show that the relevant clock can be entrained by two light input pathways, one involving the phospholipase C encoded by the norpA gene, the other mediated by the blue-light receptor cryptochrome. Phase shifts of molecular oscillations during the larval stage were smaller than those measured by adult behavior, suggesting molecularly transient responses during development.
Exogenous Melatonin Reduces the Resynchronization Time after Phase Shifts of a Nonphotic Zeitgeber in the House Sparrow (Passer domesticus)
Authors: Abraham U. , Gwinner E. , Van't Hof T. J.
Published: April 2009

Continuous melatonin administration via silastic implants accelerates the resynchronization of the circadian locomotor activity rhythm in house sparrows (Passer domesticus) after exposure to phase shifts of a weak light-dark cycle. Constant melatonin might induce this effect either by increasing the sensitivity of the visual system to a light zeitgeber or by reducing the degree of selfsustainment of the circadian pacemaker. To distinguish between these two possible mechanisms, two groups of house sparrows, one carrying melatonin implants and the other empty implants, were kept in constant dim light and subjected to advance and delay shifts of a 12-h feeding phase. The resynchronization times of their circadian feeding rhythm following the phase shifts were significantly shorter when the birds carried melatonin implants than when they carried empty implants. In a second experiment, melatonin-implanted and control birds were released into food ad libitum conditions 2 days after either a delay or an advance phase shift. The number of hours by which the activity rhythms had been shifted on the second day in food ad libitum conditions was assessed. Melatonin-implanted house sparrows had significantly larger phase shifts in their circadian feeding rhythm than control birds. This is in accordance with the first experiment since a larger phase shift at a given time reflects accelerated resynchronization. Additionally, the second experiment also excludes any possible masking effects of the nonphotic zeitgeber. In conclusion, constant melatonin accelerates resynchronization even after phase shifts of a nonphotic zeitgeber, indicating that constant high levels of melatonin can reduce the degree of selfsustainment of the circadian pacemaker independent of any effects on the photoreceptive system.
Retinal Innervation of Calbindin-D28K Cells in the Hamster Suprachiasmatic Nucleus: Ultrastructural Characterization
Authors: Bryant Damani N. , LeSauter Joseph , Silver Rae , Romero Maria-Teresa
Published: April 2009

The authors have described a subregion of the hamster hypothalamic suprachiasmatic nucleus (SCN) containing cells that are immunopositive for the cytosolic calcium-binding protein, Calbindin-D28K (CaBP). Several lines of evidence indicate that this region may constitute the site of the pacemaker cells that are responsible for the regulation of circadian locomotor rhythms. First, 79% of the CaBP-immunoreactive (ir) neurons express Fos in response to photic stimulation, indicating that they are close to or part of the input pathway to pacemakers. Second, at the light microscopy level, retinal terminals innervate the CaBP subnucleus. Finally, destruction of this subnucleus renders animals arrhythmic in locomotor activity. In this study, the authors examined the ultrastructural relationship between cholera toxin (CT[.beta]) labeled retinal fibers and the CaBP-ir subregion within the hamster SCN. CT[.beta]-ir retinal terminals make primarily axo-somatic, symmetric, synaptic contacts with CaBP-ir perikarya. In addition, retinal terminals form synapses with CaBPprocesses as well as with unidentified profiles. There are also complex interactions between retinal terminals, CaBP perikarya, and unidentified profiles. Given that axo-somatic synaptic input has a more potent influence on a cell's electrical activity than does axo-dendritic synaptic input, cells of the CaBP subregion of the SCN are ideally suited to respond rapidly to photic stimulation to reset circadian pacemakers.
Direct Innervation of GnRH Neurons by Encephalic Photoreceptors in Birds
Authors: Saldanha Colin J. , Silverman Ann-Judith , Silver Rae
Published: April 2009

In nonmammalian vertebrates, photic cues that regulate the timing of seasonal reproductive cyclicity are detected by nonretinal, nonpineal deep brain photoreceptors. It has long been assumed that the underlying mechanism involves the transmission of photic information from the photoreceptor to a circadian system, and thence to the reproductive axis. An alternative hypothesis is that there is direct communication between the brain photoreceptor and the reproductive axis. In the present study, light and confocal microscopy reveal that gonadotropin releasing hormone (GnRH) neurons and processes are scattered among photoreceptor cells (identified by their opsin-immunoreactivity) in the lateral septum (SL). In the median eminence (ME), opsin and GnRH immunoreactive fibers overlap extensively. Single and double label ultrastructural immunocytochemistry indicate that in the SL and preoptic area (POA), opsin positive terminals form axo-dendritic synapses onto GnRH dendrites. In the ME, opsin and GnRH terminals lie adjacent to each other, make contact with tanycytes, or terminate on the hypophyseal portal capillaries. These results reveal that brain photoreceptors communicate directly with GnRH-neurons; this represents a means by which photoperiodic information reaches the reproductive axis.