The IBS system at Montfort was designed to primarily accommodate spent grain from beer breweries, which would otherwise be discharged into the sea, smothering and destroying Fiji's world famous coral reefs. The IBS system can also accept bagasse, a fibrous waste from sugar cane processing, which, like the brewery waste, is a free and readily available raw material. The fibrous raw material forms a substrate for growing commercially desirable shiitake, oyster, and straw mushrooms. The mushrooms break down the lignin-cellulose structure of the substrate, generating a residue that is a high value feed for pigs. The IBS system can support up to 100 pigs, although the Montfort site only has 50 pigs.
Students wash the manure out of the pig house twice a day with a simple garden hose.
Since reinforced concrete is not universally available in Fiji, a new biodigester made from concrete bricks and plaster has been developed. After the effluent is anaerobically treated, it flows downhill through a pipeline to a gravity-fed series of three algae ponds. Aerobic decomposition virtually eliminates the BOD and produces a final effluent stream of nutrient-rich water that fills two 3000 m3 fish ponds. The algae is harvested daily and used as feed for livestock. The nutrient rich waters permeate the soils in the fish pond embankments, creating fertile soil for vegetables and crops without irrigation or chemical fertilizers.