mesophilic anaerobic co-digestion of cow manure and biogas crops in full scale german biogas plants: a model for calculating the effect of hydraulic retention time and vs crop proportion in the mixture on methane yield from digester and from digestate storage at different temperatures

data from 24 full scale biogas plants in germany digesting cow manure and crops were evaluated. special emphasis was given to the effect of hydraulic retention time hrt and proportion of crops in the mixture (vs basis) p^inp _vs;crops on the methane yield from the digester y^d;vsinp_ch4 and the storage tank y^s;vsinp_ch4;t at 37 and 22 c. the evaluation has shown model parameters for maximal methane yield of manure and crops y^eff;vsinp_maxch4 at 270 and 420 l kg^-1, respectively. for example, at hrt of 60 days, maximum methane yield result to 249 and 388 l kg^-1 for a crop proportion in the input of 0.0 and 1.0, respectively.