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Slurry with a Golden Edge (2016-2018)

In the context of the R&D cooperation project 2016 EFRO OP-Oost 2014-2020, at the end of 2016 we started the investigation project "Slurry with a Golden Edge" together with Wopereis Staalbouw B.V. en HoSt Biogas B.V.

The reduction of the CO2 footprint from farming among other things, is a very important spearhead of the Dutch goverment and the European Union. To reduce emissions from stables, air purifiers for example are placed to get the released gasses out of the air. But these air purifiers also have there own CO2 footprint and it's an end-of-pipe solution, which means that the air quality inside the stable doesn't improve. Beside being a spearhead of the Dutch goverment and the European Union, the community also keeps screaming for a solution for the emissions from farming. Beside the emissions, also the large amount of slurry is a big problem. The slurry that is produced costs the farmers a lot of money at the moment, because there isn't enough storage room and/or there aren't enough transport possibilities and processing possibilities. There is a surplus of phosphate in the Netherlands and the N-P-K-ratio of the slurry is unfavorable for the Dutch market. The slurry is stored in cellars until they are full and someone wants to pick it up. During a study, VIC Sterksel find out that the biogas potential of pig slurry reduced from 47m3 gas/m3 slurry in 3 day old slurry to 6,6m3 gas/m3 slurry in slurry that had been in the cellar for 120 days. Click here for the report of this study (in Dutch). By looking at the biogas potential of different kinds of slurry that have been removed from the stables in different kinds of ways, during this new project, we can better determine the value of the slurry (the Golden Edge). Slurry from stables with a fast removal of the slurry will have more value (or less negative value) than old slurry. The farmer not only pays for the export of the slurry, but also for the phosphate in the slurry. When the slurry can be separated at the source, that would be essential for processing the slurry.

By removing the slurry out of the stable as fast as possible, both problems can be solved almost completely. For many years slurry trays are installed in pig stables. These slurry trays reduce the emitting surface under the slats and because they are sucked empty, (almost) no slurry stays behind. Because of that, slurry trays give a reduction of the emissions, but not nearly enough. To reduce the emissions even further, the slurry trays need to be combined with (new) systems that make sure that the slurry can removed from the slurry trays moren often or that make sure that only urine gets into the trays and remove the slurry in an other way.  

By abolish the milk quota the cattle farms have become a lot bigger. And this caused the slurry to become an important spearhead in cattle farming also. The farms produce to much slurry and with that to much phosphate, that untouched is worth nothing or very little and therefore won't be picked up any more. Because of this, the CO2 footprint of the cattle farms is becoming bigger and bigger and thus a hot item for the goverment, European Union and the community. Therefore we also have to find a way to remove the slurry out of the cattle stable as fast as possible, so the value after processing goes up.  

In cattle farming the use of slurry trays is completely new and we want to do a study to see if the they have the same positive effect as in pig farming. With Wopereis we did an orientational research and that showed that the thick cattle slurry can be removed pretty good with slurry trays combined with a vacuum system.       
Main objective
To develop a technically as optimal as possible system that removes pig and/or cattle slurry from the stable as fast as possible in the direction of a fermenter, so we can reduce the emissions in the stable and can get an higher rendement out of the slurry, so the CO2 footprint will also go down.

To accomplish this main objective, we've put ourselves a few sub-objectives.
Sub-objective 1: Optimize the vacuum system with slurry trays to get the slurry out of the stable fast and more often.
Sub-objective 2: Develop a system with a slurry belt that, by sliding over the slats, already separates the slurry and urine in the stable and removes the slurry out of the stable directly.
Sub-objective 3: Study the possibilities of extending the vacuum system with slurry trays with for examle a slurry belt system just outside the stable.  
Sub-objective 4: Study the characteristics and the biogas potential of the different kinds of slurry that have been removed from the stable in different kind of ways and with those results determine which slurry is the most optimal to use in a fermenter.
Sub-objective 5: Investigate if the developed methods can widely be rolled out in both cattle and pig farming and if the method can be used in a cooperation between cattle farmer and pig farmer. 

Extra objective 1
Develop a slat for pigs that can be turned around to remove the slurry from the slat during the round, so the animals don't have to step on it to "break down" the slurry.

Extra objective 2
Develop a suction installation that can suck the slurry of the floors instead of smeering it out over the floor. 

This project is made possible by
OP Oostmetondertitel en EU logo NIEUW D04

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