Organic matter and nutrient removal in a combined anaerobic–aerobic fixed-bed reactor treating digestate from anaerobic biodigester

Abstract

Anaerobic digestion has become a possible approach for treating organic fraction of urban solid waste. However, the treatment of the digestate is still a matter for technological development. In this work a single anaerobic–aerobic fixed-bed reactor subjected to recirculation was used to treat the effluent from an anaerobic digester fed with organic food waste. The reactor was operated for 100 days, with hydraulic retention time of 24 h. The organic loading rate applied was 1 kg COD m−3 d−1. The efficiency in removing nitrogen, organic matter, and phosphorus were 73%, 83%, and 23%, respectively. This reactor configuration proved to be quite promising to promote simultaneous removal of carbon, nitrogen, and phosphorus from effluents with high nitrogen and organic matter contents.