Assessment of carbon recovery from solid organic wastes by supercritical water oxidation for a regenerative life support system

• Published in: Environmental science and pollution research international 2020-03, Vol.27 (8), p.8260-8270
• Main Authors: Zhang, Dongdong, Luther, Amanda K., Clauwaert, Peter, Ciccioli, Paolo, Ronsse, Frederik
• Format: Article
• Language: English
• Subjects: Aquatic Pollution; Atmospheric Protection/Air Quality Control/Air Pollution; Batch reactors; Carbon; Carbon - analysis; Carbon - chemistry; Carbon dioxide; Earth and Environmental Science; Ecotoxicology; Energy conversion efficiency; Energy efficiency; Environment; Environmental Chemistry; Environmental Health; Environmental science; Life Support Systems; Organic wastes; Oxidation; Oxidation-Reduction; Particulate matter; Performance assessment; Reactors; Research Article; Resource recovery; Solid Waste - analysis; Solid waste treatment; Solid wastes; Space applications; Supercritical water oxidation; Waste disposal; Waste Disposal, Fluid; Waste treatment; Waste Water Technology; Water; Water Management; Water Pollution Control
• ISSN: 0944-1344; 1614-7499
• DOI: 10.1007/s11356-019-07527-3

The carbon recovery from organic space waste by supercritical water oxidation (SCWO) was studied to support resource recovery in a regenerative life support system. Resource recovery is of utmost importance in such systems which only have a limited total amount of mass. However, the practical waste treatment strategies for solid space wastes employed today are only storing and disposal without further recovery. This work assesses the performance of SCWO at recovering organic wastes as CO 2 and water, to discuss the superiority of SCWO over most present strategies, and to evaluate the different SCWO reactor systems for space application. Experiments were carried out with a batch and a continuous reactor at different reaction conditions. The liquid and gas products distribution were analyzed to understand the conversion of organics in SCWO. Up to 97% and 93% of the feed carbon were recovered as CO 2 in the continuous and the batch reactor, respectively. Residual carbon was mostly found as soluble organics in the effluent. Compared with the batch reactor, the continuous reactor system demonstrated a ten times higher capacity within the same reactor volume, while the batch reactor system was capable of handling feeds that contained particulate matter though suffering from poor heat integration (hence low-energy efficiency) and inter-batch variability. It was concluded that SCWO could be a promising technology to treat solid wastes for space applications. A continuous reactor would be more suitable for a regenerative life support system.