Abstract

The deposition of waste in a landfill can be a threat to the environment and human health; in spite of their potential pollution, landfill are still of grate use for the residual municipal solid waste, thus efficient and cost effective technologies need to be studied in order to minimize aqueous and gaseous emissions. The present work focuses on the evaluation of the remediation of old landfill sites that pollutes groundwater and on the determination of a new pre-treatment of fresh waste upstream of landfilling. First the biosparging technology has been applied to remediate an aquifer polluted by leachate. The biosparging stimulates the growth of indigenous bacteria able to convert pollutants, such as ammonium nitrogen, in harmless compounds. The technology shows high efficiency in ammonium nitrogen removal via nitrification processes. The biosparging remediation technology prevents the mobilization of metals and removes the nitrates produced in the nitrification process when the organic carbon source is conveniently dosed. The application of the biosparging on site has proven to be feasible. The Solidification/Stabilization (S/S) technology is a pre-landfill waste treatment process, which has been used for different types of hazardous wastes since it has a proved efficiency on heavy metal immobilization. The S/S process uses chemically reactive formulations that, together with the water, form stable solids; it also insolubilizes, immobilizes, encapsulates, destroys, sorbs, or otherwise interacts with selected waste components. The S/S process improves the physical characteristics of the waste and reduces the mobility of the hazardous compounds, thus the waste leaches less contaminants into the environment. The result of this process is a less hazardous solid. The experimental evidences proved that this technology reduces volumes used for landfilling and inhibits the methanogenesis blocking greenhouse gases emissions. The reduced permeability and the leaching test results show that the leachate produced is of a smaller amount and less polluted. The enhanced mechanical properties and the reduced emissions both in bodies of water and atmosphere have proven the worth of this technology. Therefore an alternative waste treatment plant involving S/S pre-treatment is proposed.