Staff PhD
Development of techniques for the separation of plant nutrients of manure
Maibritt Hjorth
| University | University of Southern Denmark, Odense |
| Department |
Department of Agricultural Engineering |
| Supervisor | Associate Professor, Ph.D., Henning S. Jensen, University of Southern Denmark, Odense |
| Local Supervisor | Senior Scientist, Sven G. Sommer |
| Project term | 12/09 2005 - 11/09 2008 |
| Masters degree | M. Sc. Chemistry, Aarhus University, Aarhus |
Background
With the aim of reducing the nutrient loss to the environment, the Aquatic Environment Plan III (Denmark) includes demands of harmony between livestock manure production and the nitrogen and phosphorus requirements of the crops. This will increase the demands for technical solutions to surplus problems. There is a need for the separation of the manure into: a liquid fraction with a low nutrient load for local use and one-to-several fractions with large nutrients loads, to be transported to distant fields. An effective separation system can be designed only if several facts are known including: 1) the desired final products, 2) the potential separation processes and technologies, and 3) the chemical and physical characteristics of the manure.
Aim
Development of techniques for the separation of the plant nutrients from manure; specifically nitrogen, phosphorus and potassium. The new techniques for manure separation should assure an accurate administration of the nutrients equal to the requirements of the crops, and hence contribute to a reduction of the nutrient loss to the environment.
Research Outline
Analysis techniques for rapid/simple determination of the chemical and physical characteristics of manure, such as the content of phosphorus and nitrogen content as well as the surface properties of colloids, will be examined. Potential techniques to be utilized are e.g. near infrared spectroscopy, measurement of the zeta-potential and acid-base titrations.
Separation of manure will be optimized against controlling the final products’ chemical and physical characteristics. Separation of phosphorus and dry matter can be optimized by adding additves; coagulants and flocculants. Electro-oxidation has the potential to be used in the removal of ammonia from the manure. pH affects the evaporation of ammonia upon the field application of manure, and this effect will be included in the overall evaluation of the environmental impact of the separation.
The optimal separation strategy will, in pilot scale tests, be determined for several types of manure, e.g. manure from several livestock species and at several age levels, and further of anaerobically digested and non-digested manure.