Use of Artemia sp. as a Test-Organism to Assess the Toxicity of the Cashew Nut Improvement Industry Effluent Before and After the Treatment by an Experimental Biological Reactor

Abstract

The cashew nut is among the most important products of exportation for the State of Ceará, generating considerable amounts of contaminated wastewater. In this context, the aim of this research was to evaluate the efficiency of a biological reactor inoculated with funghi in the treatment of cashew nut industry wastewater using as end-points: the acute toxicity to the microcrustacean Artemia sp., Total Phenol Content (TPC) and Chemical Oxygen Demand (COD). Results showed that the plant effluent is highly toxic, presenting elevated levels of TPC and COD. In addition, it was demonstrated the efficacy of the biological treatment. The mortality was reduced from 84.7 ± 29.3% to 16.3 ± 25.6%. The reduction of TPC reached a maximum of 98.1%, while the reduction for COD levels reached 95.8%. There was a strong positive correlation between toxicity, TPC and COD. It was clearly concluded that the acute toxicity test using Artemia sp. is an important tool in the monitoring of biological reactors efficiency in the treatment of phenol enriched effluents. In addition, it was possible to observe that the biological treatment greatly improved the quality of wastewater from the cashew nut industry.