Starch Mills
Starch mills produce valuable biogas substrates like mash and pulp from soybeans, corn, potatoes, and tapioca. Converting these into biogas offers an efficient alternative to natural gas or electricity. Mash with 20-25% solid content is ideal for high-load reactor technology. Biogas plants save on capital costs and turn waste into energy, with a three-year payback period. Benefits include economic savings and environmental advantages.
Biogas yield varies based on processing methods and waste composition. Soybeans and corn mash enhance biogas production. Potato pulp, rich in starch, offers excellent methane potential. Tapioca pulp, similar to potato pulp, shows promise for significant biogas output.
Maximizing biogas production involves maintaining optimal digestion conditions, applying pretreatment for increased biodegradability, and balancing microbial nutrition through feedstock mixing.
Sugar Mills
Sugar beet mills produce beet pulp, an effective biogas substrate in anaerobic digestion. The pulp varies in compression:
- Primary-pressed pulp at 8% solids;
- Half-pressed pulp at 16-18% solids;
- Deep-pressed pulp at 25-30% solids.
The lighter pulps are stored in lagoons, becoming acidic and losing organic content, which challenges biogas reactor efficiency due to their high moisture. They necessitate larger reactors for processing. In contrast, deep-pressed pulp is stored in concrete silos, compacted and sealed for enhanced preservation, optimizing space and processing efficiency in biogas production.
