Results 1 - 10 of 625
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[en] The discussion following presentations on financing landfill gas projects for power generation and the quality of landfill gas for utilisation in internal combustion engines is reported. Topics covered include the use of landfill gas in external combustion engines, the use of oil-free engines, such as gas turbines, and guarantees required by financiers. (UK)
[en] An alternative method is presented which couples a simplified model of waste degradation with a stochastic hydrological and contaminant transport model through the use of travel time distributions. This allows the complex effects of spatial heterogeneity within the landfill to be represented, along with other key variables such as moisture flow, waste composition and microbial activity. Illustrative examples o( the model's output are presented to demonstrate the effects of heterogeneity on leachate and gas generation
[en] In 1987 the Regional Autonomous Corporation of Risaralda, CARDER and the Risaralda Government, they signed a cooperation agreement, in order to endowing from sanitary landfill to the municipalities of the department. In the mark of this agreement it was carried out the design of Santa Rosa's sanitary landfill, that with near 50.000 inhabitants it is constituted in the third city of the department. This city generates some 25 tons/day of garbage that at the present time are heady directly to the waters of San Eugenio River. The present work contains the most important methodological aspects in the design of the sanitary landfill and some comments about the approaches ideal Vs real approaches of selection of places
[en] This paper studies the feasibility of using peat as a pre-treatment medium for landfill leachate and focuses on its capacity to treat boron and BTEX. The properties of three types of peat were investigated to determine which peat properties are best suited for adsorption. Alfred peat had the best performance in the batch adsorption tests and was studied further in a continuous flow column experiment using leachate from the City of Ottawa's Trail Road Landfill. Saturated and unsaturated conditions were studied to determine their effect on peat adsorption capacity. Excellent removal of BTEX (86 to 99%) was observed in all columns regardless of their saturation condition. Saturation conditions did not appear to have an effect on boron removal with both saturated and unsaturated columns exhibited an average removal efficiency of approximately 0.1 mg boron per gram of dry peat. (author)
[en] The cultivation of energy crops on landfills represents an important challenge for the near future, as the possibility to use devalued sites for energy production is very attractive. In this study, four scenarios have been assessed and compared with respect to a reference case defined for northern Italy. The scenarios were defined taking into consideration current energy crops issues. In particular, the first three scenarios were based on energy maximisation, phytotreatment ability, and environmental impact, respectively. The fourth scenario was a combination of these characteristics emphasised by the previous scenarios. A multi-criteria analysis, based on economic, energetic, and environmental aspects, was performed. From the analysis, the best scenario resulted to be the fourth, with its ability to pursue several objectives simultaneously and obtain the best score relatively to both environmental and energetic criteria. On the contrary, the economic criterion emerges as weak, as all the considered scenarios showed some limits from this point of view. Important indications for future designs can be derived. The decrease of leachate production due to the presence of energy crops on the top cover, which enhances evapotranspiration, represents a favourable but critical aspect in the definition of the results.
[en] This study investigates the hydraulic performance and the fouling characteristics of a bench-scale membrane sequencing batch reactor (MSBR), treating mature landfill leachate under various time-based operating conditions. The MSBR system operated initially under a high-flux condition (Period 1) which resulted in a rapid trans-membrane pressure (TMP) rise due to intense fouling. Following the characterization of Period 1 as super-critical, the system was subsequently operated under a near-critical condition (Period 2). The overall filtration resistance analysis showed that cake layer formation was the dominant fouling mechanism during Period 1, contributing to 85.5% of the total resistance. However, regarding the MSBR operation during Period 2, adsorption was found to also be a dominant fouling mechanism (Days 1 to 47), contributing to 29.1% of the total resistance. Additionally, the irregular total resistance variation, which was observed during the subsequent operation (Days 48 to 75), and the respective filtration resistance analysis suggested also the formation of an initial sludge cake layer on the membrane surface, contributing to the 47.7% of the total resistance.
[en] In article an evaluation is made of emissions of landfill gas and complex analyses to evaluate the influence of specific sources like the landfills of solid wastes. For the evaluation of the emissions by emission factor and quantity valuation of potential environmental pollutions after burning the landfill gas we offer a general equation
[en] The use of landfills as an in situ biological treatment system represents an alternative for source area remediation with a significant cost saving. The specific objective of this research is to investigate the intrinsic bioattenuation capacity of the landfill ecosystem for chlorinated aliphatic hydrocarbons (CAHs). The research was conducted in two complementary systems: simulated landfill bioreactors and batch degradation experiment in serum bottles. Refuse samples excavated from a landfill were tested in laboratory bioreactors designed and operated to facilitate refuse decomposition under landfilling conditions. Each bioreactor was operated with leachate recirculation and gas collection. Target CAHs, tetrachloroethene (PCE) and trichloroethene (TCE), were added to selected reactors and maintained at 20 μM each in leachate to simulate the effect of long-term exposure of refuse microorganisms to CAHs on the degradation potential of these chemicals in landfills. At two different stages of refuse decomposition, active refuse decomposition representing young landfills and maturation phase representing aged landfills, anaerobic microbial cultures were derived from selected bioreactors and tested in serum bottles for their abilities to biodegrade target CAHs. Results of this study suggest that landfills have an intrinsic reductive dechlorination capacity for PCE and TCE. The decomposition of refuse, a source of complex organics, enhances reductive dechlorination by the refuse cultures tested in this study. In addition, the test results suggest that it may be possible to develop engineering strategies to promote both CAHs degradation and refuse decomposition in landfills. (author)
[en] This paper provides a summary of a project carried out by Organics on behalf of ETSU concerning an evaluation of the use of landfill gas as a source of fuel for raising heat. Thirteen direct-use schemes were identified in the United Kingdom. Site surveys were completed for twelve of these schemes. From the data collected an analysis was made to identify the principal technical and non-technical barriers to the direct-use of landfill gas. One of the principal conclusions to emerge is that many of the schemes studied would be viewed as commercially attractive if the additional cost of equipment for utilisation were considered as the capital investment, as opposed to the full cost of a complete gas extraction scheme. The paper reviews the key aspects of the schemes studied, discusses the technical and non-technical barriers identified and provides a view of future opportunities that may exist for commercial gain through the direct-use of landfill gas. (Author)