The broader impact/commercial potential of this Small Business Innovation Research (SBIR) project will be in addressing increased economic and environmental concerns associated with increasing amount of food waste commensurate with worldwide economic development and population growth. In the U.S., nearly 40% of food is wasted with $165 billion equivalent loss of food plus associated water, energy, chemicals, and labor used in food production. Disposal of the food waste involves additional costs and causes environmental pollution, e.g. rotting food waste in landfills accounts for a large portion of U.S. methane emissions, a powerful greenhouse gas. Moreover, food waste streams contain substantial amount of chemical energy which is also lost by its disposal. Recovering energy in food waste in the form of biofuel and chemicals, as proposed in this project, will provide efficient management of food waste problem reducing food waste disposal costs while producing useful product. The proposed effort will provide a cost-effective, commercially viable, alternative process of on-site treatment of food waste, avoiding its hauling and accumulation in landfills, to large scale food waste producers such as large food processing plants, large supermarket grocery chains, and large commercial dining facilities such as university dining halls.
This SBIR Phase I project proposes to develop and demonstrate performance of a novel immobilized clostridia cell membrane bioreactor-based continuous process to convert food waste solution to butanol. The conventional stirred-tank fermentation reactor based food waste conversion process exhibits low butanol concentration as well as productivity. The proposed process will address the technical barriers of the conventional process by immobilizing the clostridia culture cells on porous media to dramatically increase culture cell density and consequently butanol productivity and conversion efficiency and by separation of toxic butanol from the reaction media minimizing recycled butanol concentration in the reactor to alleviate butanol toxicity. The membrane fouling issues in biomass separation will be addressed by an “open channel” membrane module design to separate and recycle biomass to the bioreactor. The energy requirement for recovery of butanol from dilute reactor effluent will be reduced by an order of magnitude over the conventional distillation by using a pervaporation membrane. The objective of the proposed effort is to demonstrate a steady state continuous integrated process for converting food waste to butanol after optimizing individual components. A techno-economic analysis will be conducted to determine feasibility of a 1 T/day commercial food waste processing system. A prototype system will be fabricated demonstrating proposed process in a subsequent Phase II of this project.