PÓS TRATAMENTO DE EFLUENTES DA INDÚSTRIA DE PANIFICAÇÃO E CONFEITARIA POR WETLANDS CONSTRUÍDAS CONSIDERANDO DIFERENTES TEMPOS DE DETENÇÃO HIDRÁULICA

Abstract

Phytoremediation with macrophytes is a good alternative for the recovery of environments contaminated with effluents, thus, Constructed Wetlands Systems (SAC's) were developed, which are classified to reproduce natural wet systems. The objective of this work was to evaluate the performance of Wetlands built on a pilot scale, as post-treatment of effluents from the Bakery and Confectionery Industry, operated at different times of hydraulic detention, collecting effluents after treatments in anaerobic and aeration reactors. The activities were separated into two phases: 1. Characterization of raw effluent, construction of SAC's pilot units, period for bed stabilization and application of aquatic macrophyte seedlings (Juncus effusus and Syngonium podophyllum). 2. Application of liquid effluents in pilot beds, collection of the final effluent to evaluate the removal efficiency of specific parameters according to pre-stipulated hydraulic detention periods of 5, 10, 15, 20, 25, 40 and 45 hours. Two application modules were carried out on the beds according to the hydraulic detention times, separated in Batch 01 and Batch 02, that is, the effluent was released into the beds in two phases, respecting the detention periods and thus the collection of the final effluent was carried out. It used two beds (singonio and reed) for effluent from the anaerobic reactor and two beds (singonio and reed) for effluent from the aerated lagoon. To evaluate the removal efficiency, the following parameters were considered: true color (uH), chemical oxygen demand (COD), total phosphorus (PT), nephelometric turbidity unit (NTU - Nephelometric Turbidity Unity), ammonia nitrogen (NH4+) and nitrite (NO2-). The results showed that the longest hours of hydraulic detention time (TDH) (> 40 h) were significant and positively influenced the reduction of true color values, COD and turbidity. Among the species of macrophytes tested, it was observed significance and better efficiency of J. effusus in reducing values of the variables total phosphorus and turbidity, while the species S. podophyllum obtained better results for the variable COD. Thus, it is possible to conclude that the wetlands system was efficient in reducing the parameters of true color and NH4+ of the effluents from the aerated lagoon, COD of effluents from the anaerobic reactor and turbidity in both effluents.