Estudo físico-químico da água em sistemas de aquaponia com tambaqui (Colossoma macropomum) e alface (Latuca sativa): implicações para a produção sustentável

Abstract

The objective of this work is to evaluate the reuse of water for the cultivation of lettuce (Lactuca sativa) through hydroponics using eutrophic water from intensive tambaqui (Colossoma macropomum) farming. A pilot system was constructed, consisting of a 1000 L tank, four 200 L tanks, pipes and connectors, and a water pump. The water where C. macropomum is raised is sprayed through the roots of L. sativa in a closed cycle of the tanks. To assess water quality, the eutrophication level of the fish tank was initially established; in this stage, the fish farming water did not come into contact with L. sativa roots, and samples were collected every 24 hours over a week. In the second phase, the system operated for the same period with the same sampling interval, but with the water passing through L. sativa roots over 4 weeks. Throughout the experiments, the following recommended physico- chemical variables were measured to assess water quality in fish farming systems: pH, temperature, turbidity, conductivity, BOD, COD, nitrogen, and phosphorus in eutrophic water. The interpretation of the results will be based on the reduction rates of key variables, mainly ammoniacal nitrogen, nitrite, nitrate, and phosphorus. To ensure the experiments' validity, they will be conducted in quadruplicate, and the effect of using L. sativa on water quality will be evaluated using descriptive statistics and the Tukey method. The results obtained allowed us to conclude that using residual water from fish farming is a promising and sustainable alternative for lettuce cultivation in hydroponic systems, provided that treatment and physico-chemical variables are monitored and implemented. This study contributes to expanding knowledge on water reuse in agricultural systems, highlighting its importance in the pursuit of more sustainable agricultural practices.