Diagnóstico da gestão do lodo de uma ETE em escala real

Abstract

Sewage sludge (LE) production is increasing in view of the increase in population and sewage systems. Sludge is considered a waste under federal law 12.305 / 2010 and therefore an appropriate disposal is required. Currently the most used are: agriculture, landfill and composting. The Ministry of Agriculture, Livestock and Supply (MAPA) frames the sludge as an agricultural product. Agricultural disposition has become a very attractive alternative, especially for Brazil, due to the nutritional potential of LE. For its disposal was prepared in 2006 the resolution of CONAMA 375/2006 that gives parameters for the application of this biosolid in the soil, although, before that, there were already normative and manuals prepared by the Environmental Company of the State of São Paulo (CETESB) and Companhia de Sanitation of Paraná (SANEPAR), because they were already using the sludge in agriculture. This paper aims to show the economic viability of the use of biological sludge in agricultural activity to replace the landfill. Then, during the 10-month period (Jan - Oct / 2019), the sludge generated by the Central System Treatment Station (ETE Baldo), located in the city of Natal, Rn, was quantified and the monthly average expenditure on disposal in the landfill of the metropolitan region of Natal, current destination. Then, through the use of indexes available in the literature and studies, the costs were calculated for the new proposal (agricultural use). With the current provision ETE has a monthly expense of R $ 8,624.29. Thus, although there is a 16.9% saving on agricultural recycling, this type of disposal is not economically attractive to the Rio Grande do Norte Water and Sewage Company (CAERN) today. However, considering the construction of two new sewage treatment units, this idea may be interesting in a future scenario.