Development of the technology for mineralization of fish waste in the “wet” combustion reactor for the CES intended for space flights

By using technologies of organic waste processing within Closed Ecological Systems (CES) intended for space flights, waste material can be involved in the CES material cycling, enabling life support of the crew. An integrated technology, which includes fish waste processing and involvement in the mass exchange in the system, seems a promis- ing process. Fish is considered as one of the potential sources of animal protein for the CES crew. Thus, this paper reports the results of developing the technology for mineralization of organic waste, including fish waste. Such a tech- nology must meet the following requirements: the resultant products must be environmentally friendly, processing must take a reasonable period of time (the average time of processing of the daily waste is no longer than 24 h), the process- ing facility must be easy to handle and compact, the products must be readily incorporated into the food chain of the CES biological components, and the technology must be suitable for simultaneous processing of various types of or- ganic waste typical of the CES (human solid and liquid wastes, inedible plant biomass, and waste products and inedible biomass of other biological components of the CES). The method of “wet” combustion in hydrogen peroxide developed at the Institute of Biophysics SB RAS fulfills the above requirements, and, thus, it was used as the basis for the fish waste processing technology. The process of oxidation of fish waste together with human solid and liquid waste devel- oped in this study enables both burning the sediment in the “wet” combustion reactor and mineralizing fish waste to products that can be used as a source of mineral nutrients for the plant component of the CES. The total duration of the technological processes is about 14 h. More than 90 % of mineral macro elements are present in the resultant products in the form available to plants. The process dynamics achieved in this study suggests that, in the future, the reactor can be controlled automatically, based on the running time data, with the emergency shutdown based on indicators of pres- sure, temperature, and current intensity. The present study offers the opportunity to develop a compartment of physico- chemical processing of various organic waste types for the CES intended for space flights.