PRESENTED BY:
VAGISH. H. V

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WHAT IS ANAEROBIC DIGESTION (AD)?
AD is a biological process in which biodegradable organic matters are broken-down by bacteria and to get end product (CH4 , CO2 ,etc), in absence of oxygen.
Anaerobic digestion (AD) - a technology that has traditionally been viewed as simply 'energy-from-waste' - can provide a range of benefits in addition to the valuable renewable energy.
AD can be considered as one of the oldest and most efficient waste and wastewater treatment processes.
SOURCES OF WASTE ORGANIC MATTERS
Food Waste: Fruits, Vegetables, Dairy Products, etc.
Yard Waste: Leaves, Grass, Plant Material, etc.
Fibre Waste: Paper Products, Polycoat, Boxboard, Towels, Napkins, Disposable Diapers,Tissues, Waxed Plates/Cups, etc.
Miscellaneous Waste: Pet Wastes, Hair, Vacuum Cleaner Bags, Sawdust, etc.
Industrial, Commercial & Institutional Waste: Agricultural Waste, Organic Sludges and Slurries, Food Processing Residues,etc.
DIGESTION PROCESS
AD occur in stages, which is a complex process under a controlled manner
A group of microorganisms converts organic material to form organic acids.
Methane-producing anaerobic bacteria utilize these acids and complete the decomposition process to obtain end products.
Dry digestion and Wet digestion
In digestion processes water is an important parameter and is practiced in two different ranges of water content.
Dry digestion-solids content of 25-30%.
Wet digestion-solids content of less than 15%.
Reasons: higher solid contents lead to smaller reactors, lower solids contents (more water) lead to much better mixing possibilities but to a higher energy input (more water to be heated) and a bigger reactor.