Course: BFM 101 Biofuels Fundamentals

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Introduction to Ecological Intensification and Water Use in Ethanol Production

Introduction to Ecological Intensification

Ecological Intensification (EI) is the state-of-the-art management of crop production focused on increasing yield per unit of land. EI seeks to approach the attainable yield of farming systems; ideally, yields within 75-85 percent of their physiological maximum for a given soil and climate. Yield increases are fundamental in feeding a rapidly expanding world population, and meeting increasing biofuel demands. As a result of yield increases from EI, the need to break-out new land for grain production will be reduced. The system promotes less use of marginal and erodible land for crop production, leaving these areas in restored or native conditions. This means more land is available for wildlife habitat, recreation and other purposes. As a consequence of projected population growth, non-agricultural land uses will be in greater demand. Another impact of EI is increased carbon sequestration; which is achieved because of the greater residue biomass that accompanies higher yields. Additional crop residue from this increased production can also provide environmental benefits such as reduced water, sediment, nutrient runoff, and reduced wind erosion—ultimately improving water and air quality [19].

Introduction to Water Use in Ethanol Production

Water use in ethanol production facilities is viewed in two ways: 1) the total facility water use and impact on local water supply, and 2) the water used per gallon of ethanol produced. Total facility water use and impact on local water resources depends on the size of the processing facility and how efficient it is in water used per gallon of ethanol produced. So, in fact, these two views are related.

If a facility is drawing water from a ground or surface water source then it may have a significant impact on local water supply conditions.  Aquifer drawdown may affect neighboring water users. Ethanol production facilities can use significant quantities of water, and for this reason the industry, as it has developed, has emphasized water reuse and recycling. The Zero Liquid Discharge concept focuses on reducing consumptive use of water to a minimum. Co-location of ethanol facilities to share water with other industrial users is an additional efficient water practice to reduce impact on aquifers and water supplies.

In the production life cycle of corn-grain ethanol, water for feedstock growth and processing into ethanol, use the greatest amount of water; and water to grow the feedstock dominates consumptive water use. However, the monetary cost to provide this water, and ultimate “water cost” paid, including redirecting water from alternative uses, depends on whether crops are grown with irrigation or without, and how water is treated in ethanol processing facilities. There are vast differences regionally in how water is used in bioenergy production.

Conclusions

The production and processing of feedstocks for bioenergy will have impacts on water resources. The productive use of water for bioenergy takes place within the confines of the water cycle. Careful management of crop water and production facility water use will be needed to ensure sustainable bioenergy production.

Resources by eXtension, Bioenergy & Sustainability, BIOEN3 CC BY-NC-SA 2.5
www.extension.org/pages/63365/bioenergy-curriculum

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