High ammonia concentration in anaerobic reactors can seriously inhibit the anaerobic digestion process. In this study, a submersible microbial desalination cell (SMDC) was developed as an innovative method to lower the ammonia level in a continuous stirred tank reactor (CSTR) by in situ ammonia recovery and electricity production. In batch experiment, the ammonia concentration in the CSTR decreased from 6 to 0.7g-N/L during 30days, resulting in an average recovery rate of 80g-N/m2/d. Meanwhile, a maximum power density of 0.71±0.5W/m2 was generated at 2.85A/m2. Both current driven NH4+ migration and free NH3 diffusion were identified as the mechanisms responsible for the ammonia transportation. With an increase in initial ammonia concentration and a decrease in external resistance, the SMDC performance was enhanced. In addition, the coexistence of other cations in CSTR or cathode had no negative effect on the ammonia transportation.
Bioresource Technology, 2015, Vol 177, p. 233-239
Ammonia recovery; Anaerobic digestion; CSTR reactor; Power generation; Submersible microbial desalination cell; Ammonia; Desalination; Electric power generation; Molecular biology; Recovery; Submersibles; Ammonia concentrations; Anaerobic digestion process; Average recovery rate; Continuous stirred tank reactor; Electricity production; Maximum power density; Microbial desalination cells