Energy costs
Drying wheat distillers grain and solubles has a high energy cost since the drying process may consume 35% of the thermal energy used in an ethanol plant. However, wet distillers grain spoils quickly and the dried form is preferable despite the energy cost (Murphy et al., 2008).
Volatile organic compounds
Drying distillers grain produces volatile organic compounds that may cause serious health problems. These emissions can be reduced by low temperature drying units in ethanol plants (Bühler, 2013).
Industrial waste reduction
Wheat distillers grain fed to livestock removes huge amounts of by-products that would otherwise have to be eliminated by other means (Lyons, 2003).
Reduction of methane emissions
Maize distillers grain has been shown to decrease methane emissions produced from enteric fermentation by 3.2 g CO2eq/MJ ethanol per head of cattle (US EPA, 2010). This reduction is mainly due to the high fat content of maize distillers grain (Grainger et al., 2011). Because wheat DDGS is lower in fat content (only 4-5 % DM), the reductions of CH4 emissions are likely to be lower for wheat DDGS than for maize DDGS (Grainger et al., 2011).