Ecovation's Sustainable Alternative for Managing Distillery Co-Products

1. Equalization - Ecovation’s total solution starts with understanding the drivers for treatment and energy recovery from the distillery’s high BOD waste streams. The most appropriate treatment train, equipment sizing, and co-product management start with a complete understanding of current water and energy use. Adequate equalization is essential for balancing the flow and organic load for all downstream treatment and process operations and to maximize conversion of the soluble organics to biogas as an alternative fuel source.

2. Waste Heat Recovery - Recapturing waste heat from the distillery bottoms can be a cost effective way to return heat to the distillery for a variety of purposes: preheating the mash tub/tun, for barley malting, as heat to the fermenters, or other hot water uses. For every 1,000 gallons of distillery bottoms, a distillery could realize $5.00 to $6.00 in avoided hot water heating costs.

3. Solids Separation/ Spent Grain Recovery - Removing the spent grains for reuse as animal feed or as a solid fuel source is the key to optimizing recovery of co-products and performance of the anaerobic treatment of high-strength wastewater from the still bottoms. Ecovation has evaluated both conventional and innovative approaches for removal of spent grains, and will match the method of solids separation to the particular distillery feed stocks and operations.

4. Wastewater Treatment & Energy Recovery - Ecovation’s patented and proprietary anaerobic treatment process is the workhorse of the treatment and co-products recovery process. This efficient and stable high-rate anaerobic process treats the soluble organics in the wastewater and converts them to biogas (methane and CO2). Each pound of COD will be converted to 5.61 cubic feet of methane.

5. Biogas Reuse Options - There are several reuse options for the biogas produced from the treatment system. These options will vary depending on the distillery’s cost of energy and spent grain feed markets. Also, existing assets at the distillery may dictate highest and best use for the recovered biogas. Potential viable options may include conversion of existing boilers to dual fuel burners; use in existing grain dryers; or cogeneration of steam and electricity.

6. Three Options for Spent Grain Co-Products: A New Solid Fuel Option - Distillers wet grain (DWG) or “wet cake” from the solids separation step can be evaluated for three potential reuse scenarios depending on a distillery’s existing assets, local feed markets, and energy costs. Use of spent grains as a solid boiler fuel option, after dewatering and partial drying, may be a viable option. Spent grains are a relatively clean burning fuel with decent BTU value, depending on moisture content. The other options include the more traditional approach of selling the DWG (with or without solubles) or drying wet cake to produce DDG. The protein and crude fat fraction typically recovered in evaporators is now recovered in the very low energy DAF and can be applied to the DWG or DDG to produce a high feed value co-product.

7. Post-Treatment for Direct Discharge - If distillery discharge is direct to a surface water body, Ecovation can incorporate existing wastewater treatment assets or provide additional treatment as part of our “total solution” to meet discharge permit requirements. As water becomes a more scarce and expensive resource, treatment for recycling distillery wastewaters can also be evaluated as an alternative.