The Laforge Holstein plant is a biomass system set on 400 hectares (1000 acres) of land that uses organic materials such as potato peels, fries, pizza dough and tomato sauce, mixed with manure and chicken grease residue for biodigestion (anaerobic decomposition).
The system has 2 mixing tanks that hold the organic material: tank 1 is used as an energy source and tank 2 is used as a protein source. These tanks are linked to the biodigester using a regular feeding schedule run by a computer program that is linked to all the machinery.
The ideal pumping ratio of organic material or feed to capture gas and minimize wastage is 4 m3 every hour for tank 1 and 8 m3 every 2 hours for tank 2. The biodigester has an agitator to encourage movement of materials and the creation of gas. The leftover liquid from the biodigester seeps into a holding tank or lagoon which is later used as fertilizer.
Through the digestion process methane is released by bacteria and captured. The gas is then piped to the generator where it is burned for electricity generation.
This installation makes economic sense because the biomass is obtained free of charge. In the case of McCain’s, the company also saves money in transportation costs for their waste.
At the same time, the dairy cows on the farm provide 2200 L of milk per day, which is sold to the Northumberland and Baxter dairy farms. The cow manure is used to speed up the decomposition process in the biodigester tank due to the presence of bacteria.
They expect the system to pay for itself in 10 years.