Tratamento das águas do processamento dos frutos do cafeeiro em filtro anaeróbio seguido por sistema alagado construído: II - remoção de nutrientes e compostos fenólicos

Abstract

Six treatment systems composed of three anaerobic filters with downflow followed by six constructed wetlands (SACs) have been operationally evaluated in the treatment of wastewater from coffee fruit processing (ARC). The filters were made of PVC (1.5 m high and 0.35 m in diameter) and filled with n. 2 crushed stone. SACs were constructed of wood boxes (1.5 m long, 0.4 m high and 0.5 m wide) being sealed with an HDPE geomembrane and filled with “zero” crushed stone. The ARC had the pH adjusted with lime to values close to 7.0 and concentration of nutrients modified to have a relationship BOD/N/P equal to 100/5/1. In half of the SACs was planted ryegrass (Lolium multiflorum Lam.) and in the other half oat (Avena strigosa Schreb). As a result, it was observed that the plant species grown in the SACs have influenced the removal efficiencies of phosphorus by the systems (SAC3 e SAC4; SAC5 e SAC6). The systems that received the lowest loads of nutrients and phenolic compounds showed the highest removal efficiencies, reaching 40% for NT and 50% for PT. The removal of total phenolic compounds was higher than 65% in most systems. Thus, it is considered to be feasible the application of anaerobic filter system followed by constructed wetland system for the treatment of ARC.