Pós-tratamento de efluente suinícola utilizando as macrófitas aquáticas Hedychium coronarium J. Koenig e Lemna minuta Kunth

Abstract

The present work aimed to evaluate the performance of two aquatic macrophytes in the treatment of residual water from the swine activity submitted to the simulation of treatment through dilutions. The crude effluent was obtained from a storage and stabilization pond and transported to the experiment site, where, under a greenhouse with air circulation control, was arranged in the 18 bioreactors, configuring nine treatments, all in duplicates. The dilutions used were 10, 30 and 50% effluent, made with distilled water, and the concentrations and species used were defined from a senescence pre-test. The analyzed parameters were turbidity, electrical conductivity, pH, concentrations of total phosphorus, orthophosphates, organic matter and ammoniacal nitrogen, in addition to macrophytes growth. In order to evaluate the reduction of the quality parameters, the analyzes were repeated every five days after the initial characterization, totalizing a period of 20 days of experiment, being in each day of analysis, before the aliquot removal, the evapotranspiration volume by the addition of distilled water. The results obtained from the senescence test indicated that the species Hedychium coronarium (HC) and Lemna minuta (LM) were the plants that survived the conditions of the swine effluent, and could therefore be applied in the post-treatment of residues of the same origin . The characterization of the effluent submitted to the dilutions demonstrated that this practice is an alternative for the simulation of conventional pretreatment for experimental purposes. For the removal of turbidity, satisfactory results were obtained with the use of aquatic plants when the 30% dilution was used. There were no differences between treatments with different species, in which a mean removal efficiency of 79.76% was obtained. In contrast, none of the two species tested showed significant results for the reduction of electrical conductivity or ammoniacal nitrogen. As for the organic matter removal, it was observed that HC diluted in 50% presented removal efficiency of 85.47% and for total phosphorus and orthophosphates, LM, presented significant removal results in 10 and 30% dilutions of swine effluent . In general, for the parameters in which the macrophytes presented significant results (turbidity, organic matter, total phosphorus and orthophosphates), the ideal holding time varied only between 5 and 10 days and for the growth, in the treatment using LM, the cultivation doubled in size with only 20 days of growth. HC presented the highest sprouting rate (approximately 10 per bioreactor) with the treatment using the effluent at 50%, and its growth amplitude was directly related to the removal of organic matter from the effluent. Finally, it is concluded that HC and LM are macrophytes that can be used in post-treatment of swine effluent. In addition to turbidity, each species acts to remove specific parameters, since in this bias the use of a consortium with the two species would allow the removal of both the different forms of phosphorus, organic matter and turbidity present in this type of residue.