As environmental regulations controlling direct land application of livestock waste
increase, farmers search for ways to cost-effectively handle manure from their farms. Farmers’
goals include efficient and effective means to remove the objectionable characteristics of their
manure so that it may be recycled in an environmentally friendly manner. Anaerobic digestion is
one way to control odors, liquefy manure and decrease pathogen loading, while reducing
system costs by selling byproducts from the manure treatment system. Odor control allows
digested effluent to be recycled in an environmentally friendly manner by applying it to cropland.
Economic, nutrient, pathogen, energy production, and mass flows are under an ongoing
quantification process for five integrated manure treatment systems in New York State. Each of
these farms has recently installed an anaerobic digester as a method to control odor. The mass
flow, nutrient flow, pathogen reduction, energy production and use, and economics of these
systems are presented and compared. The systems vary by 1) type of digester: fixed film, plug
flow, or mixed, 2) type of energy conversion: boiler, internal combustion, engine, or micro
turbine, 3) digester feed: scraped manure from freestalls, separated tie stall manure, or manure
with food waste added, and 4) farm size.