Qualidade dos Efluentes de Sistemas de Tratamento Biológico UASB e UCT para Reúso Agrícola

Abstract

RESUMO:O presente trabalho avaliou as condições de reúso dos efluentes finais de dois sistemas de tratamento biológico de esgotos: um reator UASB e um sistema de lodo ativado frente aos padrões recomendados da Organização Mundial de Saúde (OMS) e os critérios de qualidade de água para irrigação. As variáveis avaliadas foram pH; CE; Ca 2+ ; Mg 2+ ; Na + ; Cl -; NTK; Fósforo total; DQO; Turbidez; SST; amônia; coliformes termotolerantes e ovos de helmintos; RAS; e salinidade. Os resultados demonstraram que os sistemas só cumprem parcialmente os requisitos para reúso agrícola. O sistema UASB apresentou SST e turbidez como limitantes na irrigação localizada, concentração de coliformes apenas para irrigação restrita em subsuperfície, NTK acima de 30 mg.L -1 e a contagem > 1,0 ovo.L -1 de helmintos que inviabiliza o reúso. O sistema UCT apresentou menos limitações de acordo com os parâmetros avaliados, com inviabilidade de reúso direto principalmente devido à turbidez, coliformes e ovos de helmintos. PALAVRAS-CHAVE:Lodo Ativado; Reatores; Reúso Agrícola; UASB. QUALIT Y OF EFFLUENTS FROM UASB AND UCT BIOLOGICAL TREATMENT SYSTEMS FOR AGRICULTURAL REUSEABSTRACT: The reuse of affluents from two biological sewage treatment systems is assessed. The study comprised a Upflow Anaerobic Sludge Blanket (UASB) reactor and an activated sludge system according to standards recommended by the World

Wastewater Use in Agriculture: Analytical Limits of Sewage for Impact Control in Brazil

“…High concentrations of sodium and potassium can cause poor soil water infiltration and soil salinization, as well as chlorides, which are harmful to various crops at concentrations above 350 mg L -1 (SILVA et al, 2011). The electric conductivity of the solution allows a preliminary diagnosis of restriction and consequences on crop yield, according to the crops to be irrigated (TRANI; TIVELLI; CARRIJO, 2011;ROLIM et al, 2016). Trani, Tivelli, Carrijo (2011).…”

“…Guiding documents, such as the Resolution No. 54/200554/ (BRASIL, 2006, establish modalities, guidelines, and general criteria for water reuse; however, they do not describe requirements and limits for sewage quality regulation, causing insecurity to the population and compromising the progress of this practice (ROLIM et al, 2016). The Normative NBR 13969 (ABNT, 1997) presents recommendations for water reuse in agriculture (class 4), but they are limited to the concentrations of thermotolerant coliforms (TC) and dissolved oxygen, which are insufficient for a proper evaluation of the impacts involved.…”

“…Acid water with pH below 6 directly affects irrigated crops and soil, with increasing effect in medium and long terms (SILVA et al, 2018). The pH values commonly found for domestic sewage are neutral to slightly alkaline, offering no risks, as evidenced by Queiroz, Queiroz, Aragão (2015); Silva et al (2015), and Rolim et al (2016), who found pHs of 6.50 to 8.40. Regarding the nutrients, the phosphorus contents found in sewage treatment systems for subsequent agricultural use were 3.00 to 12.80 mg L -1 ; these contents are relevant for plant growth (FREITAS et al, 2012;QUEIROZ;QUEIROZ;ARAGÃO, 2015).…”

“…Currently, it is more intense in the northeastern states, mainly involving family farming and animal feed. However, the lack of regulations and monitoring of wastewater quality and its use results in exposure of plants to organic compounds, heavy metals, pathogens, and emerging pollutants (drugs, cosmetics, endocrine disruptors and their metabolites, and nanoparticles) that are harmful to human health and to the environment (HESPANHOL, 2015b;ROLIM et al, 2016).…”

Aplicação da metodologia de análise de perigo e pontos críticos de controle na disposição de efluentes tratados em solos tropicais e seu potencial uso agrícola

“…Os primeiros estudos para aplicação de efluentes de esgoto tratado na irrigação realizados através do PROSAB (Programa de Pesquisa em Saneamento Básico), ocorreram no ano 2000 (PIVELI et al, 2009). e embora os resultados tenham indicado viabilidade e eficiência (MENDONÇA e PIVELI, 2004) a aplicação praticamente limita-se a experiências controladas em sistemas pilotos (DE SOUSA et al, 2006;FONSECA et al, 2007;HERPIN et al, 2007;BERTONCINI, 2008;DE OLIVEIRA et al, 2012;ROLIM et al, 2016).…”