Existing and newly built farm-based AD plants in Ontario operate on large farms. The systems are individually designed and engineered to optimize the production of biogas. These systems tend to be on dairy farms because the operation of an AD system with dairy manure is fairly well known and the manure handling systems are already in place. Although it would be economically unfeasible to individually design and engineer AD systems for the numerous smaller farms in operation, if the systems were standardized and designed in a modular fashion, the economics should be favourable for smaller farms.