Solid-state anaerobic digestion of livestock manure and reuse of digested dried manure solids as bedding for dairy cows

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Bio-Terre Systems Inc. (BTS) aims to develop energy efficient solutions for livestock sectors and preserve the quality of our environment by reducing greenhouse gas (GHG) emissions, and recover nutrients to produce organic fertilizer. It is evident that good livestock bedding sources have become harder for farms to secure. Due to the growing demand for biofuels, these sources have started to disappear; consequently, price of the existing sources has increased. Hence, in addition to the renewable energy production, BTS is investigating an alternate economical bedding source that has no adverse effects on the environment. Cow manure with bedding is renewable organic biomass, available around the year on dairy farms. Developing efficient and cost-effective psychrophilic dry anaerobic digestion (PDAD) processes could resolve the farm-related environmental, energy, and manure management problems in cold-climate regions such as Canada. Solid-state AD at psychrophilic temperature (~20oC) is proposed in this project as it results in exportable dry organic fertilizer in addition to the green energy production. At the same time, there is still plenty of manure on farms that might serve the purpose of bedding if processed by separation, digestion/compositing. Some dairies have implemented separated or dried digested manure solids as an alternate source of bedding. However, re-using bedding that may carry a pathogen and other bacterial count load is significant for the herd health and milk quality. Research has shown that liquid AD systems have the potential to reduce pathogens entering the environment. Thus, this proposed project aims to validate the feasibility of using digested dried manure solids as dairy cow bedding in terms of pathogen and odor free material. Accordingly, the outcomes of this project will benefit BTS and the Canadian agricultural sectors as well.