Development of technologies for fabricating environmentally friendly fertilizers from organic wastes is an important factor for establishing environmentally friendly zero-waste production, including agriculture. Implementation of this approach entails problems associated with the treatment of byproducts of such processes. In the present study, the technology of physicochemical purification of gases produced by human waste processing was tested on lettuce plants. It has been shown experimentally that the proposed method of deep purification is able to reduce the inhibitory effect of gas on plants. The results can be used to develop agricultural technologies, closed-loop production technologies in other fields, and scientific principles for constructing life support systems intended for space missions.