Saulmon M M, Reardon K F, Sadeh W Z
Center for Engineering Infrastructure and Sciences in Space, Colorado State University, Fort Collins 80523, USA.
Adv Space Res. 1996;18(1-2):289-92. doi: 10.1016/0273-1177(95)00818-y.
As space missions become longer in duration, the need to recycle waste into useful compounds rises dramatically. This problem can be addressed by the development of Controlled Ecological Life Support Systems (CELSS) (i.e., Engineered Closed/Controlled Eco-Systems (ECCES)), consisting of human and plant modules. One of the waste streams leaving the human module is urine. In addition to the reclamation of water from urine, recovery of the nitrogen is important because it is an essential nutrient for the plant module. A 3-step biological process for the recycling of nitrogenous waste (urea) is proposed. A packed-bed bioreactor system for this purpose was modeled, and the issues of reaction step segregation, reactor type and volume, support particle size, and pressure drop were addressed. Based on minimization of volume, a bioreactor system consisting of a plug flow immobilized urease reactor, a completely mixed flow immobilized cell reactor to convert ammonia to nitrite, and a plug flow immobilized cell reactor to produce nitrate from nitrite is recommended. It is apparent that this 3-step bioprocess meets the requirements for space applications.
随着太空任务的持续时间越来越长，将废物回收为有用化合物的需求急剧增加。这个问题可以通过开发受控生态生命支持系统（CELSS）（即工程化封闭/受控生态系统（ECCES））来解决，该系统由人类和植物模块组成。离开人类模块的废物流之一是尿液。除了从尿液中回收水之外，回收氮也很重要，因为它是植物模块的必需营养素。提出了一种用于回收含氮废物（尿素）的三步生物过程。为此目的对填充床生物反应器系统进行了建模，并解决了反应步骤分离、反应器类型和体积、载体颗粒尺寸和压降等问题。基于体积最小化，推荐一种生物反应器系统，该系统由活塞流固定化脲酶反应器、将氨转化为亚硝酸盐的全混流固定化细胞反应器以及将亚硝酸盐转化为硝酸盐的活塞流固定化细胞反应器组成。显然，这种三步生物过程满足太空应用的要求。
