Utilisation of the effluent of a plug flow digester
The aims of this project were to design and evaluate of the effectiveness of solid/liquid separation from the digester effluent and to assess the potential value for (partially dried) organic fertilizer in Mali.
Two different systems, a straw filter and a solar dryer, have been designed and tested. The solid content removal of the systems and the composition of the different end products have been studied and are described in this report. The nitrogen and phosphorus content of the different phases were evaluated as well to get an idea of the fertilising effect of these products. Additional works realised during this project are presented in this report as well.
The defined solution to deal with the digester effluent is to use the straw filter to make a first decrease in the volume of the effluent and remove the bigger parts. The filtrate would then be treated by the solar dryer for further volume reduction.
Concerning the fertilising effect of the different products obtained during processing, the nutrient content (N and P) has been defined and would have a positive effect on the crops cultivation. However, further investigation concerning the experimental assessment of the fertilising effect could provide more information about the increase in the crops yield.