## 3 Results and Discussion
### Discussion  
The pH in the hydrogen BR\({}_{1}\) changes in both directions during the ongoing processes and its continuous adjustment is necessary. For industrial applications, sodium hydroxide and hydrochloric acid might be replaced (because of the high costs) by some industrial waste liquids. After a certain time for adjustments, the pH controller (supply of two normal  
Figure 8: Volume content of H\({}_{2}\) and CO\({}_{2}\) in the biogas from BR\({}_{1}\) in the continuous mode of TPAD of CSL. Figure 10: The profile of pH values for the biohydrogen (BR1) and biomethane (BR2) bioreactors during the continuous mode of TPAD of CSL). Figure 9: Volumetric content of CH\({}_{4}\) and CO\({}_{2}\) in BR\({}_{2}\) biogas in the continuous mode of TPAD of CSL. sodium hydroxide and hydrochloric acid for corrections) performs relatively well and maintains it in the range of 4.9-5.6. The pH in the methane BR\({}_{2}\) is kept practically constant (7.3-7.7) despite the acidity of the substrate introduced by the hydrogen BR\({}_{1}\), which could be explained by the buffer capacity of the medium in the methane BR\({}_{2}\). The yields of biohydrogen in BR\({}_{1}\) from the cascade are variable and in the range from 0.7 to 1.0 dm\({}^{3}\) of biogas from 1 L working volume of the bioreactor. The concentration of hydrogen in the biogas from the hydrogen BR\({}_{1}\) varies greatly in the range of 14-34.7% volumetric. The yields of biomethane in BR\({}_{2}\) from the cascade are variable (depending on the incoming substrate from BR\({}_{1}\)) and vary in the range from 0.4 to 0.85 dm\({}^{3}\) of biogas from 1 L working volume of the bioreactor. The concentration of methane in biogas from BR\({}_{2}\) is high and remains practically constant (in the range of 65-69% volumetric). H\({}_{2}\)S in BR\({}_{1}\) exceeds 1000 ppm (this is the highest measurable value with our instrument) in all measurements, which is explained by the large amount of protein in CSL. H\({}_{2}\)S in BR\({}_{2}\) exceeds 1000 ppm in almost all measurements, which shows that the protein is poorly absorbed in hydrogen BR\({}_{1}\) and is in high concentrations in methane BR\({}_{2}\). CO\({}_{2}\) in BR\({}_{1}\) varies in the range of 21.8-60.6% volumetric, and in BR\({}_{2}\)--28-30% volumetric. The total volatile fatty acids concentration in BR\({}_{1}\) varies in the range 4.02-6.5 g/L, and in BR\({}_{2}\)--always below 1 g/L. The concentration of cellulose in BR\({}_{1}\) varies in the range of 0.163-0.484 g/L, and in BR\({}_{2}\)--in the range 0.972-2.9 g/L with a gradual decrease, which can be explained by the presence of residual cellulose from previous experiments with wheat straw. The concentration of glucose in BR\({}_{1}\) varies in the range 0.686-1.636 g/L, and in BR\({}_{2}\)-in the range 0.916-1.073 g/L. The concentration of protein in BR\({}_{1}\) varies in the range 0.33-3.2 g/L, and in BR\({}_{2}\)--in the range 0.696-3.88 g/L. At a dilution rate D\({}_{1}\) = 0.4 day\({}^{-1}\) and a concentration of the inlet solution of 50 g/L (for BR\({}_{1}\)), respectively, a dilution rate D\({}_{2}\) = 0.04 day\({}^{-1}\) for BR\({}_{2}\), the best results are obtained as follows: For BR\({}_{1}\), the daily yield of biohydrogen is 0,74 dm\({}^{3}\)/L at a concentration of hydrogen in the biogas of 32.6% volumetric, pH = 5.25, concentration of TS = 8.85 g/L, concentration of VS = 5.1 g/L, concentrations of cellulose, glucose, and protein, respectively, 0.29 g/L, 0.97 g/L, and 1.64 g/L; For BR\({}_{2}\), the daily yield of biomethane is 0.587 dm\({}^{3}\)/L at a methane concentration in biogas of 69% volumetric, pH = 7.56, TS concentration = 9.92 g/L, VS concentration = 5.0 g/L, concentrations of cellulose, glucose, and protein, respectively, 1.39 g/L, 1.01 g/L and 1.08 g/L.