The use of lagoon of treatment is a technology thoroughly known and used for organic residues. But, in the specific case of liquid residues from the cassava industrialization, the experiences are reduced. The objective of this study was evaluating the efficiency in the reduction of the pollutant load of lagoons of treatment of liquid residues of cassava industry. Thus samples were collected in the entrance of the system and in each of the seven lagoons of the Fecularia Horizonte, in Marechal Cândido Rondon - PR, Brazil, from May to September of 2004. The following parameters were appraised: Biochemical Oxygen Demand (BOD), Chemical Oxygen Demand (COD), Total Solids (TS), Fixed Solids (FS), Volatile Solids (VS), N-NH + 4, Electric Conductivity (EC), Phosphorus (P), Clorets (Cl-) and pH. The system promoted reduction of 96.3% of COD and 96.4% of BOD, and phosphorus and solids presented similar behavior. However, N-NH+4, CL- and EC oscillated during the system with reduction, mainly in the polishing ponds.
manipueira; effluent; cassava
