Biomass, grain yield, ethanol production, and energy cogeneration of sweet sorghum irrigated with domestic sewage effluent

The scarcity of fossil fuels and environmental pollution prompted the search on new renewable fuels. Sweet sorghum has succulent stems and broth similar to sugarcane, but studying its energy potential is necessary. We evaluated the biomass, grain yield, ethanol production, and energy cogeneration of sweet sorghum cultivars irrigated with raw and diluted domestic sewage effluent. The experiment was conducted in a randomized block design, with six replicates, in a 3 × 3 factorial scheme, corresponding to three water sources (well water—control, raw sewage effluent and sewage effluent diluted by 50% in well water) and three sorghum cultivars (IPA 2502, BRS 506 and BRS Ponta Negra). The results indicated that irrigation with domestic sewage effluent increases biomass, grains yield, briquettes production, and energy cogeneration. BRS 506 has higher ºBrix and produces more mass of juice, ethanol, and energy involvement compared with other cultivars. We concluded that domestic sewage effluent increases biomass production and energy cogeneration of sweet sorghum. BRS 506 cultivar is viable for the production of biomass, ethanol, and energy cogeneration. BRS Ponta Negra cultivar is viable for the production of biomass, grains, ethanol, and energy cogeneration. IPA 2505 cultivar is only viable for biomass and grain production.