Coupling of Anaerobic Waste Treatment to Produce Protein- and Lipid-Rich Bacterial Biomass

Publication date: Available online 20 July 2017 Source:Life Sciences in Space Research Author(s): Lisa M. Steinberg, Rachel E. Kronyak, Christopher H. House Future long-term manned space missions will require effective recycling of water and nutrients as part of a life support system. Biological waste treatment is less energy intensive than physicochemical treatment methods, yet anaerobic methanogenic waste treatment has been largely avoided due to slow treatment rates and safety issues concerning methane production. However, methane is generated during atmosphere regeneration on the ISS. Here we propose waste treatment via anaerobic digestion followed by methanotrophic growth of Methylococcus capsulatus to produce a protein- and lipid-rich biomass that can be directly consumed, or used to produce other high-protein food sources such as fish. To achieve more rapid methanogenic waste treatment, we built and tested a fixed-film, flow-through, anaerobic reactor to treat an ersatz wastewater. During steady-state operation, the reactor achieved a 97% chemical oxygen demand (COD) removal rate with an organic loading rate of 1740 g*d−1m−3 and a hydraulic retention time of 12.25 d. The reactor was also tested on three occasions by feeding ca. 500 g COD in less than 12 hours, representing 50x the daily feeding rate, with COD removal rates ranging from 56-70%, demonstrating the ability of the reactor to respond to overfeeding events. While investigating the storage of treated ...
Source: Life Sciences in Space Research - Category: Biology Source Type: research