C.R.O.P. – Combined Regenerative Organic Food Production: waste and wastewater processing by trickling filters.

The DLR Project C.R.O.P. generally aims to combine the utilization of all kinds of organic wastes with soilless plant cultivation for life support purposes. Within the project scientific work is divided into several research areas that are allotted to different groups. Our group is concerned with the waste management system, in which nutrients should be recycled to the highest possible degree. The core of the system is formed by microbial trickling filters in which organic matter is liquefied if needed, and converted into inorganic compounds. The resulting nutrient solution is assigned to fertigation. In our testing facility at DLR the capability of the filters to convert urine into a nitrate containing solution is characterized. Running the filters with diluted synthetic urine to simulate yellow water showed that the process of urea conversion as it occurs in the soil also works in the filters. Ammonia is turned over so quickly that odour nuisance and toxicity are reduced to a minimum. The use of the resulting solution as fertilizer is currently tested experimentally. A C.R.O.P. System combining trickling filters for waste processing with hydroponic or aeroponic plant cultivation facilities could be modified for use in space thus providing the bioregenerative compartment of a modular life support system.