Resumo

RUBIM, MAL; ISOLINO SAMPAIO, PR  e  PAROLIN, P. Biofilter efficiency of Eichhornia crassipes in wastewater treatment of fish farming in Amazonia: Eficiencia de Eichhornia crassipes como biofiltro en el tratamiento de aguas residuales de la piscicultura en el Amazonas. Phyton (B. Aires) [online]. 2015, vol.84, n.1, pp.244-251. ISSN 1851-5657.

Fish is a very important part of the human diet in Amazonia. Near the growing cities, fish populations and individual size have decreased over the past decades. Alternatives to traditional and industrial fishing arise, including fish farming. Strategies to minimize the impact of fish farms on the environment are needed to have a regular and healthy fsh supply. This is to avoid a reduction of biodiversity, a depletion of natural resources, and/or the induction of significant changes in the structure and functioning of adjacent ecosystems. Very little research has been performed on management of efluents as to maintain the quality of water resources. The present study aimed at testing the efficiency of the Amazonian aquatic macrophyte Eichhornia crassipes as a bioflter for the treatment of effluents from fish farming. In three filtering treatments (50%, 75% and 100% plant cover) and a control (0%), physical and chemical properties of the water were measured and analyzed in a nursery with fish after passing the biofilter system, with a hydraulic retention time of 24 hours. The analyzed variables showed no significant differences (p>0.05) among the treatments with 50-100% cover, indicating that 50% cover would be enough for a good efficiency of the biofilter. All parameters were reduced after passage of the biofilter under the presence of E. crassipes: 73.7% for electrical conductivity, 15% for pH, 84.5% for turbidity, 86.8% for nitrite, 69% for total phosphorus, and 77.8% for orthophosphate. The concentrations of total nitrogen, nitrate and ammonium ions were not significantly changed (p>0.05). We conclude that E. crassipes is effective in improving the quality of efluents from fish farming, with less efficiency for nitrogen compounds. Our treatment system can be adopted by small and medium-sized farmers, aiming at a sustainable employment of the activity.

Palavras-chave : Aquaculture; Amazon; Effluent; Fish farming; Biofilters; Aquatic macrophytes; Water hyacinth.

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