Potencial de remoção de nutrientes de efluente doméstico por plantas aquáticas flutuantes

Abstract

The study investigated the action of three species of aquatic plants called Eichhornia crassipes, Pistia stratiotes and Salvinia auriculata in removing chemicals from the effluent in the treatment of domestic sewage (ETE) station, district of Montalvão, Presidente Prudente / SP. The treatments used effluent distributed in a box of 250 dm3 as follows : (T1) = Raw wastewater without the presence of aquatic plants (control), (T2) = Raw wastewater with Eichhornia crassipes, (T3) = Raw wastewater with the presence of Pistia stratiotes, (T4) = Raw wastewater with the presence of Salvinia auriculata. The weekly samples of effluent were collected monthly for three months (April, May and June 2013), featuring the three phases of experimentation. After collecting the samples were sent to the analytical chemistry laboratory of plant tissue UNOESTE / Campus II, for the determination of Ec (electrical conductivity - µS cm- 1), in addition to the available concentrations of NH4+, NO3-, P, S, K and Na. At the end of each cycle, after twenty-eight days of the experiment, the plants were collected and sent to the same laboratory where it was determined the contents of NH4+ , NO3-, P, S, K, Na (mg L-1) and mass of plant dry matter. It was found that the removal of chemical elements by plants studied was different for each species, between periods of collection and evaluation cycles, there was removal of NH4 and P by plants compared to control, with more significant reduction of NH4 provided by S. auriculata and P by E. crassipes during the evaluation cycles; P. stratiotes showed higher removal rate K, Na, and S in almost all cycles; absorption elements provided a reduction of Ec in the effluent in the presence of P. stratiotes in the three evaluation cycles; P. stratiotes and S. auriculata showed higher content of K in the first cycle of evaluation, a S. auriculata and P. stratiotes were able to absorb more S than E. crassipes during evaluation cycles, the studied aquatic plants, mainly P. stratiotes, can be allies for polishing sewage wastewater treated.