Alternative mechanisms of charging for use of water resources in wastewater assimilation

ABSTRACT Nowadays in most hydrological basins in Brazil, the charging mechanism of water use for effluents assimilation in inland surface water bodies is based on the emitted organic load parameter quantified in terms of Biochemical Oxygen Demand (BOD). This method is insufficient given the broad variety and compositions of discharges. Therefore, the objectives of the study are to propose alternative charging mechanisms for the qualitative use of water resources, aiming to insert, beside BOD, other parameters as calculation criteria; and to evaluate the charging potential for the Doce River hydrological basin. Two methods were proposed: the Limiting Population Equivalent (LPE) and the Compromised/Committed Volume (CV). Five water quality parameters were established: Biochemical Oxygen Demand, Chemical Oxygen Demand, Total Suspended Solids, Ammonia Nitrogen, and Phosphorus. The proposed mechanisms contemplated, from a broader perspective, the real problem concerning water quality in the Doce River basin. Simulations showed that phosphorus was a problem of concern for managing water resources in the specific basin. The method of Limiting Population Equivalent was considered of easiest application and understanding by its users.