POST TREATMENT OF EFFLUENTS FROM THE BAKERY AND CONFECTIONERY INDUSTRY BY CONSTRUCTED WETLANDS CONSIDERING DIFFERENT HYDRAULIC DETENTION TIMES

Abstract

Phytoremediation with macrophytes is an alternative for recovering environments contaminated with effluents. Thus, Constructed Wetlands Systems (SAC's) were developed, which are designed to reproduce natural wetlands 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 retention, collecting effluents after treatments in anaerobic reactors followed by an aeration lagoon. The activities were separated into two phases: (1) Characterization of the raw effluent, construction of the 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. To evaluate the removal efficiency, the following parameters were considered: chemical oxygen demand (COD) and ammoniacal nitrogen (NH₄⁺). The results showed that the longer hydraulic detention time (> 40 h) were significant and positively influenced the reduction of COD values. Among the species of macrophytes tested, it was observed significance and better efficiency of J. effusus in reducing ammonia nitrogen values, while the species S. podophyllum obtained better results for the variable COD. Therefore, it is possible to conclude that the wetlands system was efficient in reducing NH₄⁺ from the aerated lagoon effluents and COD from the effluents from the anaerobic reactor.