The evaluation of the meteorological factors affecting landfill gas generation in landfills

The quantity of domestic solid waste increases with increasing development. Mostly preferred method for the disposal of solid waste is constructing landfills. One of the most important final products of landfills is the gas which is produced during anaerobic decay. Landfill gas (LFG) containing methane, carbon dioxide and some other trace gases is known to induce global climate change and cause some health problems. Collection and reclamation of LFG is meant both to eliminate the detrimental effects and to get economic support for the field. With the analysis of landfill gas amount, its formation mechanisms, and the factors affecting the LFG, which has high calorific value, the energy conversion efficiency can be increased and an efficient and environment friendly way of recycling of the LFG can be provided.In this study, a group of one year landfill gas data that is taken from a full-scale landfill is evaluated with meteorological factors. The area of interest is involved the meteorological station located in Kireçburnu, Sarıyer and the landfill site located in Odayeri, Eyüp that are both in European side of İstanbul. The study is divided into two group of analysis, one of them is data analysis and the other is modeling of data. Data analysis is made with self-organizing maps (SOM) algorithm; modeling is made with artificial neural networks (ANN) algorithm.SOM algorithm is used for the visualization of the data by means of a map configuration. It is seen that LFG and most of meteorological data is related to each other seeing as the same color in the same hexagon. The proposed ANN model estimates methane gas percent with all input variables with the accuracy (correlation coefficient, R) of 64 %. However when the inputs includes soil temperatures, the prediction percent increases. For instance, when inputs includes soil and air temperatures together to 70 %, but when soil temperatures took out of the inputs, it is predicted not accurately, showing 30 % correlation. This dictates that the soil temperatures play an important role in landfill gas generation. There are lots of parameters that are affecting landfill gas generation on the literature but this finding by ANN model is the first. With studied model, the effect of change in LFG formation amount is investigated with meteorological factors.Present LFG projection models depend on the operation of landfill area, the sort of waste landfilled, and some natural factors. These factors can change from region to region that affect the efficiency and the projection of energy recovery plants. For this reason, landfill gas guess models can be improved by considering the inputs that are special to the landfill. In this study, meteorological factors are chosen as the special input for this landfill and an estimation model is developed.The results obtained showed that meteorological factors are very important on the formation, content, and amount of landfill gas. In addition to this, it can be stated that meteorological factors are an important input for the feasibility studies and planning of energy recovery plants. With this estimation model, it can be supposed that a special model is developed for the projection and the efficiency of energy recovery plants.By making some post-grade studies; LFG amount can be predicted on-site, an automation system can be created. And by online controlling gas pressure on gas wells, energy recovery plants can recover electricity more efficiently.