Question

Name the constituent of bio gas .why is biogass formed in digester doesnt get mix with slurry?what is difference between slurry and sludge

Answer 1

Biogas can be produced from a broad range of feedstocks that are suitable for anaerobic digestion. Current ethanol technology requires feedstocks with high fermentable carbohydrate levels (e.g. corn and sugarcane), while biodiesel production requires feedstocks with high oil content (e.g. waste vegetable oils or virgin vegetable oil from oil seed crops). Both technologies require extensive pre-processes of feedstocks and only yield fuel from a portion of the native biomass material. In contrast, biogas can be made from most biomass and waste materials regardless of the composition and over a large range of moisture contents, with limited feedstock preparation. Feedstocks for biogas production may be solid, slurries, and both concentrated and dilute liquids. In fact, biogas can even be made from the left over organic material from both ethanol and biodiesel production.

Most of the existing installations are processing residual sludge from wastewater treatment plants. Other facilities are processing wastes from chicken processing, juice processing, brewing, and dairy production. However, the range of potential waste feedstocks is much broader including: municipal wastewater, residual sludge, food waste, food processing wastewater, dairy manure, poultry manure, aquaculture wastewater, seafood processing wastewater, yard wastes, and municipal solid wastes. Food processing wastewaters may come from citrus processing, dairy processing, vegetable canning, potato processing, breweries, and sugar production.

There are many potential energy crops, which may be suitable for biogas production including: sugarcane, sorghum, napier grass, as well as, woody crops (tree crops). The best crops should have low fertility requirements, and low energy costs for planting and harvesting. Further, ethanol production from an energy crop will produce large volumes of stillage wastewater, which can be converted to biogas. Also, the production of biodiesel from oil crops produces a glycerol wastewater that also may be converted to biogas.