Collection and transportation within the system of solid waste management may account more than 60% of the overall budget, most of which is for fuel costs. Furthermore, municipal vehicles have great environmental impact through exhaust gases emissions. The aim of this research was to estimate the potential for reduction of fuel consumption and thus the emission of CO 2 through the communal vehicles route optimization. General methodology for route optimization is also presented. For the area under study, detailed field experimental research in the City of Kragujevac was conducted. Using GIS and GPS technology, whole municipally infrastructure for waste collection was scanned and all paths of communal tracks was recorded and allocated in developed database. Based on experimental and numerical results, one typical municipal vehicle route was analyzed by using ArcGis software. The obtained result indicates 2700 km of possible savings per year concerning one communal vehicle. In addition, the most fuel-economical route was extracted and compared with the original route, and with the routes extracted from criterions concerning the traffic time and shortest distance. According to available information for the City of Kragujevac and the results from this study, it was estimated that the total savings could be 20% in costs and the associated emissions.

This paper explores the impact of concentrate re-circulation, as a product of leachate treated by reverse osmosis plant, on the production of landfill gas at the realscale landfill for municipal solid waste. In an effort to come up with results, experimental measurements were carried out at the landfill in city of Bijeljina, Republic of Srpska, Bosnia and Herzegovina. All performed measurements were divided into three groups. The aims of two groups of measurement were to determine landfill gas and methane yield from concentrate, and leachate in laboratory conditions (1 st group), and to find out concentrations of oxidizing matters (chemical and biochemical oxygen demand) present in leachate and concentrate at different points of treatment as well as its variability over the time (2 nd group), which could be used to calculate the potential of landfill gas and methane generation from concentrate by re-circulation, theoretically. The 3 rd group of measurements, carried out in parallel, has goal to determine the quality and quantity of the collected landfill gas at wells throughout the landfill. The results of analysis carried out in this experimental research show the clear evidence of concentrate re-circulation impact on methane production by increasing the landfill gas flow, as well as its concentration within the landfill gas composition, at the nearby well. Although results indicated relatively high impact of concentrate re-circulation on landfill gas production, comparing to its theoretical potential, the influence on the landfill at whole, is negligible, due to relatively low volumes in re-circulation with respect to its size and objectively low potential given by organic matter present in concentrate.