© DLR: All rights reserved.
The C.R.O.P.® (Combined Regenerative Organic food Production) process enables liquid farm manure such as cattle slurry and fermentation products from biogas plants to be processed into a fertilizer solution that is directly available to plants.
Originally, C.R.O.P.® was developed at the Institute of Aerospace Medicine of the German Aerospace Center (DLR) as a process for recycling nitrogenous wastewater in closed habitats such as Moon or Mars stations. By converting human urine into a plant fertilizer, astronauts are able to cultivate fresh food in greenhouses. This process can also be transferred to agricultural applications and enables the biological production of high-quality fertilizers in liquid and solid form.
The manure problem
Intensive agriculture and the large number of livestock result in large quantities of manure, which lead to regional nutrient surpluses. The ecosystem’s soil, water and air are extremely polluted by the excessive use of liquid manure and the nitrogen it contains. Regions in Germany that keep livestock are particularly affected by the nitrate problem. The excessive liquid manure is subsequently delivered to livestock-less arable farms or biogas plants. The longer the transport route of the liquid manure, the less economical it becomes, since liquid manure consists of 90 % water. Additionally, greater environmental pollution is caused by the increased transport of liquid manure. In order to sustainably reduce this problem, sustainable solutions are urgently needed.
C.R.O.P.® process in the agricultural cycle © DLR: All rights reserved.
Closed loops with natural resources
The aim is to obtain a higher quality product by processing manure and fermentation products using the C.R.O.P.® technology and to implement an integrated system by natural resources. A liquid fertilizer solution is obtained through the process, which mainly contains nutrients which are directly available to plants, as well as a solid fertilizer with a high content of organic substance. This biologically produced fertilizers contribute towards soil and water protection and prevent the emission of greenhouse gases and pollutants (e.g. ammonia) from arable land. In addition, applying the solution does not result in the usual odor, which greatly increases social acceptance for the use of this type of fertilizer on farms. The C.R.O.P.® process transforms nutrients into stable compounds and thus enables lossless storage or volume reduction.
Function and structure
The C.R.O.P.® technology is designed on the basis of natural metabolic processes. This allows the complete process to be carried out without the use of chemicals or hazardous substances. The organically bound nutrients in the slurry/digestate are converted into nutrients that are directly available to plants, thus enabling precise plant nutrition in line with requirements. The biological fertilizer solution can be applied using conventional slurry technology and does not require any additional technology. The system has a modular design and consists of a reaction chamber and a tank volume. The closed reaction chamber is located above the tank and contains carrier materials on which a large number of microorganisms can settle. Due to the simple process control with few technological components, the plant can be integrated into the existing infrastructure of an agricultural farm and individually adapted. The process is low-maintenance and robust in the face of incidents, so that the system can regenerate independently and quickly after a possible power or pump failure. In addition, the system's energy requirements are low as the process runs at ambient pressure in a low temperature range. Due to the continuous addition of separated slurry/digestate, a C.R.O.P.® treatment plant runs in continuous operation.
Image on the left: Test facility at the DLR site in Cologne; Picture right: C.R.O.P.® fertilizer in liquid and pelletized solid form © DLR: All rights reserved.
Advantages of the C.R.O.P.® process
Contribution to sustainable development in the agricultural sector
The C.R.O.P.® process developed by the DLR Institute of Aerospace Medicine is based on the United Nations Sustainable Development Goals and generates value at economic, ecological and sociopolitical levels. The call for increased climate and environmental protection as well as public health protection require further technological development for the utilization of liquid farm manure and fermentation products. In addition, the C.R.O.P.® process makes a decisive contribution to resource recovery from waste. With the implementation of an almost closed operational cycle, important steps towards the promotion of sustainable agriculture are achieved.
C.R.O.P.® Biological Refinement of Manure - Factsheet
DLR at AGRITECHNICA 2019
Life support system C.R.O.P.® at the Hanover Fair