Use of aquatic plants in the treatment of effluents from fish farms in water recirculation systems

Abstract

The growth of aquaculture activities for food production in small farms leads to an increase in
the volume of wastewater discharged, often without adequate treatment, which can lead to eutrophication
of rivers and lakes. The integration of fish farming with aquatic plants can enable
the treatment of effluents, avoiding impacts on the environment and, as a consequence, allow
the use of plants removed from the system in fertilization of beds, composts and also as animal
feed, such as pigs and chickens. The objective of this research was to evaluate the influence
and efficiency of aquatic plants in the treatment of effluents from fish farms. The research was
developed in a small property in the urban area of Sobradinho 2 (DF/Brazil), with six fish ponds
with recirculation of water and covered with aquatic plants of the ecological type floating: Pistia
stratiotes L. and Eichhornia crassipes (Mart.), aiming the treatment of excreta of tilapia (Oreochromis
niloticus L), carp (Cyprinus carpio L.) and Pintado-da-Amazônia (Pseudoplatystoma
punctifer e Leiarius marmoratus). Water samples from the fish tanks were analyzed at the site.
In the study, it was verified that in the tanks with greater coverage of the water mirror by plants, mainly Pistia stratiotes, there was reduction of the ammonia concentrations and greater transparency
of the water, being the quality of the water more suitable for the fish culture