Summary 27 Manure as valuable commodity – Some technological options Sanders, Prof. J. (Wageningen UR), J. van Kasteren (ed.) InnovationNetwork Report no. 10.2.233, April 2010, Utrecht, The Netherlands Direct manure drying Manure consists of 90-95% water, which makes it difficult to process and reduces its value. The Netherlands has a surplus of low-grade residual heating from industrial facilities, such as power stations. This residual heating can be utilized to dry manure, thereby creating a higher-value product. The drying process can take place centrally near large power stations, such as at Eemshaven or Rotterdam. To make this economically viable, you need about 200 firms jointly supplying about 800,000 tonnes of manure. Alternatively, the manure can be used for gasification to fuel power stations. The dried product or the mineral ash can be shipped to the countries where the minerals originally come from, thus closing the cycle. Drying manure using zeolites The manure can also be dried on a smaller scale using zeolites. Zeolite is a porous, hygroscopic (= water-absorbing) material with a waterabsorbing capacity of roughly a quarter of its volume. The speed of absorption depends on the temperature (30-50 oC) and is a matter of seconds. In principle, it is possible to separate manure and zeolite granules and then regenerate the absorbed water by heating the granules. 103301_Binnen.indd 27 18-05-2010 13:16:16 Pagina 34
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