"Wetlands construídos" de fluxo vertical com meio suporte de solo natural modificado no tratamento de esgotos domésticos / "Wetlands construídos" de fluxo vertical com meio suporte de solo natural modificado no tratamento de esgotos domésticos / Vertical flow constructed wetlands systems with substract of natural soil for domestic wastewater treatment / Vertical flow constructed wetlands systems with substract of natural soil for domestic wastewater treatment

AUTOR(ES)

Selma Cristina da Silva

DATA DE PUBLICAÇÃO

2007

RESUMO

In Brazil, the municipalities with sewerage system is 52,2% of the total (PNSB, 2000). Therefore, it is low figure and there are regional discrepancies, as the percentage of attendance at the southern and southeastern regions are higher then at the northern northeastern and middle western. The situation is even worse at the rural area, where most localities do not have these services and are insufficient when they do exist. Aiming at contributing for better sanitary condition in this country, we tried to improve our understanding of a natural system, the constructed wetlands, which are technically advanced systems with low costs (Bird, 2004). In this study we evaluated the performances of the treatment processes, that occurs at wetland systems constructed under vertical descendent flux on modified natural soil substrate ( yellow red-latosoil mixed with medium sand), planted with irrigated rice (Oryza sativa L.), as a biological reactor projected for the treatment of domestic sewage after primary treatment. We built three experimental systems and each of them had 3 units of constructed wetlands (planted) and 3 control units (without plants), giving a total of 18 units. Systems were operated on unsaturated flux regimes, with intermittent availability. The sewage loads were done on Mondays, Wednesdays and Fridays. Systems were operated during 10 months and surveys on sewage and effluent quality were done during nine months. The load did not interfere on the efficiency of pollutants removal, as there was no significant difference between treatments. Mean removal efficiency varied from, approximately, 97 to 99% (BOD); 90 a 98% (SS); 90 a 99% (turbity); 9 a 37% (CE); 90 a 99,9999% (faecal coliform); 96 a 100% (P); 88 a 94% (total N); 85 a 95% (ammonia) and increased from 2 to 116% (nitrate). The removal efficiencies between the wetlands and the controls did not differ significantly. However, the positive influence of irrigated rice was perceived on the nitrification and fertilization processes and soil clogging among others.

ASSUNTO(S)

"wetlandas construídos" recursos hidricos tratamento de esgoto qualidade do solo remoção de poluentes

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