An attempt to perform water balance in a Brazilian municipal solid waste landfill

Abstract

This paper presents an attempt to model the water balance in the metropolitan center landfill (MCL) in Salvador, Brazil. Aspects such as the municipal solid waste (MSW) initial water content, mass loss due to decomposition, MSW liquid expelling due to compression and those related to weather conditions, such as the amount of rainfall and evaporation are considered. Superficial flow and infiltration were modeled considering the waste and the hydraulic characteristics (permeability and soil-water retention curves) of the cover layer and simplified uni-dimensional empirical models. In order to validate the modeling procedure, data from one cell at the landfill were used. Monthly waste entry, volume of collected leachate and leachate level inside the cell were monitored. Water balance equations and the compressibility of the MSW were used to calculate the amount of leachate stored in the cell and the corresponding leachate level. Measured and calculated values of the leachate level inside the cell were similar and the model was able to capture the main trends of the water balance behavior during the cell operational period.

A new screening model for leachate production assessment at landfill sites

“…To this end, an useful tool is represented by simulation models based on the water balance method. However, the development of a model which is suitable to different specific landfills contexts is complex Tejero 2007, Han et al 2011) because of the influence on the water balance of local factors, such as meteorological condition, composition and hydro-physical properties of wastes, filling methods, as well as the influence of physical, biological and chemical processes, e.g., generation and migration of gas and fluid, biological and chemical degradation of waste and materials aging (Oni and Okunade 2009;São Mateus et al 2012). All these phenomena and factors are mutually dependent and usually vary in space and time (Oni and Okunade 2009;Sirini et al 2010).…”

“…The most widely used package is the Hydrologic Evaluation of Landfill Performance, HELP (Schroeder et al 1994), even though in the last years its use is questioned as a number of limitations have been detected (Berger 2000;Lobo et al 2003;Murthy et al 2009;Oni 2010;São Mateus et al 2012;Shariatmadari et al 2010). The HELP model has been designed to conduct water balance analyses of open, partially closed and fully closed landfills (Schroeder et al 1994), but actually it does not allow to reproduce the progressive development of a landfill, the aging of materials and other important processes that affect leachate generation (e.g., biodegradation reaction, waste compression and consolidation and change in waste physico-mechanical properties).…”

“…Indeed, the HELP model assumes constant parameters and simulates the leachate transport and generation after all solid wastes are placed and stability conditions of refuse are reached. In order to overcome these limitations, several integrated models have been developed (e.g., De Velásquez et al 2003a;Kindlein et al 2003;White et al 2004;Zacharof and Butler 2004;Lobo and Tejero 2007;São Mateus et al 2012) that consider both leachate and gas generation due to biological transformation of organic matter, simulating jointly hydrological and degradation phenomena. These models differ by the underlying assumptions and the conditions at which they can be applied.…”

Permeabilidade de Solo Laterítico por Diferentes Métodos

“…Os valores de CV encontrados são considerados altos em análises estatísticas (valores maiores que 30%), indicando que a variabilidade em relação à média é alta (FONSECA;MARTINS, 2008). Contudo, valores elevados de coeficiente de variação em ensaios de permeabilidade tanto de campo como de laboratório têm sido reportados na literatura e são esperados (GARCIA-SINOVAS et al, 2001;PAZ GONZALES et al, 2001;SÃO MATEUS;MAVHADO;BARBOSA, 2012). Analisando os valores de CV, pode se dizer que o ensaio com infiltrômetro indicou menor variabilidade que os demais.…”

Quantification of regional leachate variance from municipal solid waste landfills in China

“…However, the HELP model was questioned for leachate quantification in recent years because it neglected the water balance of waste, which was proved to be important processes during leachate generation. For instance, Komilis and Athiniotou (2014), Pantini et al (2014) andSao Mateus et al (2012) established their own water budget models and demonstrated that water which leached out by waste compression and biodegradation contributed to the leachate amounts to a large extent. In China, researchers Yang, 2012b) widely believed that the failure to include water leaching out from waste itself in the Chinese national standard (Ministry of Housing and Urban-Rural Development of the People's Republic of China, 2013) was the main reason for the underestimation of leachate generation amounts in landfills.…”