Solid waste

The wet cake has the total solid around 20-30% and contains a mixed component of cassava feedstock since no fractionation of cassava components is employed in dry milling process. The wet cake can be used to produce Dry Distillers Grains With Solubles or DDGS as developed in corn ethanol industry. However, cassava roots do not contain a high protein content as corn grains, cassava DDGS contains less protein contents (around 11-14% and 30% dry basis for cassava and corn DDGS; Sriroth et al., 2006). Though the solid waste from cassava chips is not as valuable as corn DDGS, it can be utilized in many ways:

— To produce biogas: this waste treatment has been practiced in China. The solid waste in the thick slop is sent to Biomethylation process. The results are successfully reported by Dai et al. (2006).

— To feed the burner: Another alternative design for Thai factories is that the solid waste from the thick slop is separated by a decanter so that the moisture content is around 50% of total solids (50% H2O). This semi-dry solid is then used as the feedstock for fuel production by direct burning.

— To supplement in animal feed: The solid waste contains some fibers, proteins and ash and can be used as animal feed fillers.