Figure 4. To maximize algae biofuel sustainability, nutrients must be recycled.

This is a model of how we expect nutrient utilization to occur as the field matures. Algae will be harvested and the oil will be extracted, the remaining biomass (carbohydrates/proteins) will either be recycled for nutrients through anaerobic digestion or similar means, producing methane gas and a nutrient-rich slurry, which can then be fed back into the algal pond, rather than exogenously produced fertilizers, or used to for high-value co-products, ranging from industrial enzymes, nutraceuticals or animal feed stocks. Some of these nutrients can be recycled through waste water, while others will be lost due to runoff.