Land suitability for final waste disposal with emphasis on septic systems installation in southern Minas Gerais, Brazil

Abstract

Environmental pollution is a problem that has been noted due to changes in the environment, affecting natural resources. Regarding the soil, it may offer great potential for waste disposal. Thus, this study aims to propose criteria for evaluating local suitability for waste disposal, according to soil and terrain attributes for southern Minas Gerais State, and to apply those criteria to define the most appropriate locations for installation of septic systems in a pilot watershed. Literature and the authors' experience were used to propose the more important criteria regarding the suitability of sites for waste disposal. The set of attributes taken into account was grouped into four suitability classes: Adequate, Regular, Restricted and Inadequate. The defined criteria and considered limiting were: soil depth, texture, textural gradient, structure, natural drainage, water infiltration, type of surface horizon, water table depth, depth of perched water table, distance from water bodies, relief, stoniness, rockiness and risk of flooding. From these, soil depth, natural drainage, water table depth, relief and distance from water bodies were adopted for the installation of septic systems. From the total area of the watershed, 5.29% fit in the Adequate suitability class. The Regular, Restricted, and Inadequate sites accounted for, respectively, 19.72%, 41.99% and 33% of the wathershed. Factors such as soil and terrain attributes provide a basis for defining more appropriate places for waste disposal. Future work should involve the refinement of these propositions, since there are rare studies in this research line in Brazil.

Land Suitability Assessment for Olive Mill Wastewater Disposal by Integrating Multicriteria Decision Support Tools

“…Soil Units: Vertisols are soils with high content of clay (montmorillonite) that forms deep cracks in drier seasons or years. They are considered a limiting factor, due to their shrink and swell properties that depend on the moisture content, making the management very difficult (Oliveira et al, 2016).…”

Septic Systems

“…Wastewater retention capacity in soil absorption systems may also be associated with the vertical velocity of the tank effluent, depending on the site gradient, hydraulic conductivity, and porosity of the subsurface media. Factors such as the distance with unsaturated flow from the septic system to the groundwater table, the type of soil (which in turn determines the rate of percolation), and site topography all influence pathogen transport (Wolf et al, 2006;de Oliveira et al, 2016) (see also chapter on Waterless Onsite Systems: Pit Toilets (Latrines)).…”