Energy production from anaerobic co-digestion of swine manure and microalgae Chlorella sp.

Microalgae Chlorella sp. grown in the centrate of anaerobically digested swine manure were harvested for anaerobic digestion and co-digestion with swine manure for energy production. Chlorella had the lowest biogas yield when digested alone. Co-digestion of algae with swine manure improved the biogas yield of algae. Addition of 6-16% (by volatile solids) of algae to swine manure did not affect the biogas yield of swine manure. However, co-digestion of more than 43% (by volatile solids) of algae with swine manure decreased the biogas yield of swine manure. A concentrated animal feeding operation (CAFO) with 7000 pigs with algae production and anaerobic digestion will produce an average net energy of 43kWh per day.