Vegetables in the bioremediation of nitrogen compounds from biofloc effluents

Abstract

Our work aims to evaluate the changes in the water quality parameters of the effluent of a biofloc system (BFT) after the insertion of vegetables. Vegetable seedlings of three species were used: lettuce (Lactuca sativa), arugula (Eruca sativa), and green onion (Allium schoenoprasum). Twelve polyethylene terephthalate bottles were used, divided into four groups (three different vegetables and control), in triplicate, equipped with an aeration system (individually) to avoid BFT sedimentation. The bottles were kept in a polyethylene box (180L). The bottles were filled with 1 L of BFT water used as the initial sample (zero time). The pH, total ammonia, nitrite and nitrate were measured at time zero, 24 hours and 72 hours after the insertion of the different vegetables in the experimental system. It was possible to observe improvements in the ammonia levels 24 h after the insertion of vegetables, as the treatments (Lettuce, Chives and Arugula) reduced the amount of ammonia when compared to the control group. However, there was little influence on pH, nitrite and nitrate. Therefore, we can conclude that the insertion of vegetables in the effluent reduces ammonia levels, improving water quality parameters and, therefore, can reduce the environmental impact or act as bioremediators of the cultivation environment.