The biogas fermentation co-digestion Salvinia molesta (SM) and rice straw (RS) was investigated within a wide range of SM:RS of 100:0-0:100 (mass ratio). This study used batch anaerobic digesters in laboratory-scale operated at mesophilic temperature in 30 days. The optimum SM:RS ratio was 60:40 -0:100 (C/N of 29.50-39.17) producing total biogas yield of 103.83-113.92 mL/g VS. The highest biogas yield (113.92 +/- 6.90 mL/g VS) was obtained from SM:RS of 40:60 (C/N of 34.80). The biogas produced from SM:RS of 40:60 contained 60.58% CH4, 38.69% CO2, 0.73% H-2. Fitting error between measured and predicted total biogas yield for 30 days fermentation by using modified Gompertz, Cone, First Order model was 0.96-6.45%, 0.14-3.52%, and 1.97-15.25% respeCtively. Furthermore, Cone model was used to design the anaerobic batch digester volume and develop the kinetic model of VS degradability rate. The fit correlation of measured and predicted VS removal was R-2 = 0.992. (C) 2017 Elsevier Ltd. All rights reserved.