Avaliação de sistema RBS de dois estágios com aeração intermitente alimentado por energia solar em região tropical

Abstract

A solar self-sufficient two-stage RBS-AS system submitted to long non-aerated periods (intermittent aeration) was studied to evaluate its performance in removing MO, nitrogen and phosphorus from domestic wastewater. The influence of aeration time on battery life was also evaluated. The system was subjected to daily inflows of 3, 4.5 and 6m³/day, and sludge ages of 32 ± 2 and 21 ± 2 days. The results indicated a high efficiency and stability of the system in the domestic wastewater treatment, reaching efficiencies of 93 ± 2%, 86 ± 4% and 93 ± 6%, in the removal of BOD, N and P, respectively. The biomass of the system is robust in relation to long-term operation with low DO concentration (without aeration for 80% of the batch time). However, the presence of a solids concentration limit (4.3 gSST / l), above which sedimentation is impaired, was evidenced. The durations of the aeration fases can be adjusted as a strategy to extend the life of the photovoltaic system's batteries.