Siting MSW landfills with a spatial multiple criteria analysis methodology

The present work describes a spatial methodology which comprises several methods from different scientific fields such as multiple criteria analysis, geographic information systems, spatial analysis and spatial statistics. The final goal of the methodology is to evaluate the suitability of the study region in order to optimally site a landfill. The initial step is the formation of the multiple criteria problem's hierarchical structure. Then the methodology utilizes spatial analysis processes to create the evaluation criteria, which are mainly based on Greek and EU legislation, but are also based on international practice and practical guidelines. The relative importance weights of the evaluation criteria are estimated using the analytic hierarchy process. With the aid of the simple additive weighting method, the suitability for landfill siting of the study region is finally evaluated. The resulting land suitability is reported on a grading scale of 0-10, which is, respectively, from least to most suitable areas. The last step is a spatial clustering process, which is being performed in order to reveal the most suitable areas, allowing an initial ranking and selection of candidate landfill sites. The application of the presented methodology in the island of Lemnos in the North Aegean Sea (Greece) indicated that 9.3% of the study region is suitable for landfill siting with grading values greater than 9.     

A methodology to estimate odors around landfill sites: the use of methane as an odor index and its utility in landfill siting

The estimation of odor production and dispersion from landfill sites is a very complicated task because of the different chemical species that exist in biogas. To site a new landfill, it is necessary to know the distance that odors can travel around the landfill under atmospheric conditions that increase the concentration of pollutants. Although CH4 is an odorless gas, it can be used as an index to determine the dispersion of low-reactivity odorous species around a landfill site. Methane production rates, estimated by biogas production models, were used by an air dispersion model to determine the spatial distribution of CH4 around landfill sites. By utilizing dispersion models under extreme atmospheric conditions, a maximum CH4 concentration around the landfills was determined. Based on the ratio between CH4 and odorous chemical species, the spatial distribution of the concentration of an odorous species was determined for those species with low reactivity in the atmosphere. For odorous species with high reactivity in the atmosphere, a dispersion-reaction model must be used. In this way, the acceptable distance between new landfills and residential areas can be determined. The proposed methodology could be used as a design tool for those who are interested in landfill siting.     

83rd Annual Meeting & Exhibition

Abstract

The estimation of odor production and dispersion from landfill sites is a very complicated task because of the different chemical species that exist in biogas. To site a new landfill, it is necessary to know the distance that odors can travel around the landfill under atmospheric conditions that increase the concentration of pollutants. Although CH₄ is an odorless gas, it can be used as an index to determine the dispersion of low-reactivity odorous species around a landfill site. Methane production rates, estimated by biogas production models, were used by an air dispersion model to determine the spatial distribution of CH₄ around landfill sites. By utilizing dispersion models under extreme atmospheric conditions, a maximum CH₄ concentration around the landfills was determined. Based on the ratio between CH₄ and odorous chemical species, the spatial distribution of the concentration of an odorous species was determined for those species with low reactivity in the atmosphere. For odorous species with high reactivity in the atmosphere, a dispersion-reaction model must be used. In this way, the acceptable distance between new landfills and residential areas can be determined. The proposed methodology could be used as a design tool for those who are interested in landfill siting.     

The effect of olive mill wastewater on seed germination after various pretreatment techniques

Olive mill wastewater (OMW) management has been a major issue of environmental concern for olive oil producing countries. OMW can be a serious nuisance, when disposed of untreated, due to its significantly high organic load, its phytotoxic properties and its relatively low biodegradability. Field and plant irrigation with raw or pretreated OMW is an easy and relatively inexpensive method to treat and dispose of OMW. Typical pretreatment techniques could be comprised of phase separation through a settling basin, dilution with water, aeration to promote biological degradation and pH neutralization. A full factorial experimental design approach was used here to study the main effects and interactions of the above four pretreatment techniques on the germination of tomato and chicory seeds. Results of the study showed that the most statistically significant technique affecting OMW phytotoxicity is water dilution. The next most significant technique was aeration. In particular, phytotoxicity decreased with increased OMW dilution with water, when OMW was aerated and without pH adjustment. pH neutralization resulted in increased phytotoxicity. Settling did not significantly decrease the phytotoxicity of settled OMW and is therefore not considered necessary in an OMW management system in which plant irrigation is the goal. The interaction of aeration and pH was, marginally, the most significant two-way interaction for tomato seeds, while no interactions were significant when chicory seeds were used.     

Radon variations during treatment in thermal spas of Lesvos Island (Greece)

The aim of this paper was to study the variations of radon and daughter nuclei during treatment in the thermal spas of Lesvos Island (Greece). For this purpose, in the thermal spas of Lesvos we have measured the radon concentrations of thermal waters, as well as indoor radon, daughter and coarse particle (>500 nm) concentrations. Various instruments and procedures were employed for measurements. Radon concentrations of thermal waters were found to lie in the range 10 Bq l(-1) and 304 Bq l(-1). Concentration peaks both for radon, radon daughter and coarse particle, were found to appear during filling of baths in the treatment process. The doses delivered to the bathers during treatment were in the range of 0.00670-0.1279 mSv per year, while the doses delivered to personnel were below 20 mSv per year.     

Contribution of (222)Rn-bearing water to the occupational exposure in thermal baths

The present study investigates the short- and long-term effects of radon ((222)Rn) released from water on the progeny exposure in a thermal spa. For the purposes of this work, the Polichnitos spa was used as a case study. The bathroom was supplied with water containing 110-210 kBq m(-3) of (222)Rn. The (222)Rn concentration in air and the short-lived (222)Rn progenies in attached and unattached form were monitored into the bathroom and the surrounding premises. The equilibrium factor (F-factor) and the unattached fraction were estimated. The results of this study show that water flow during bath filling is by far the dominant mechanism by which (222)Rn is released in the air of the bathroom. The progeny exposure was correlated linearly with the (222)Rn concentration in the entering water. The annual effective dose received by a worker was found to be below the lower limit value of 3 mSv recommended by ICRP 65. The dose limit was exceeded only for water containing more than 300 kBq m(-3).     

Radon variations during treatment in thermal spas of Lesvos Island (Greece)

The aim of this paper was to study the variations of radon and daughter nuclei during treatment in the thermal spas of Lesvos Island (Greece). For this purpose, in the thermal spas of Lesvos we have measured the radon concentrations of thermal waters, as well as indoor radon, daughter and coarse particle (>500 nm) concentration. Various instruments and procedures were employed for measurements. Radon concentrations of thermal waters were found to lie in the range 10 and 304 Bq l(-1). Concentration peaks both for radon, radon daughter and coarse particle, were found to appear during filling of baths in the treatment process. The doses delivered to the bathers during treatment were in the range of 0.00670 mSv per year to 0.1279 mSv per year, while the doses delivered to personnel were below 20 mSv per year.