Dairyland Power Cooperative has a long history of finding and maximizing beneficial reuses for our coal combustion byproducts. Today, bottom and fly ash are mainly used as road base, anti-skid material and in cement production.

Our record of recycling more than 80 percent of the material from the Genoa No. 3 Station is proof that we prefer and commit to recycling whenever possible.
The implementation of new “scrubber” technology to capture sulfur dioxide will greatly improve air quality. It will also change the composition of our byproduct. Dairyland staff is investigating all possible beneficial reuse technologies and markets for the material and has contacted other utilities, regulatory agencies and trade organizations for guidance on the best methods of beneficial use.

At this time, the opportunities with the highest potential are cement replacement products and agriculture. We are also evaluating other potential beneficial reuse applications, including grout mine backfill, filler in asphalt, engineering applications (soil stabilization as structural fill, road base), daily cover in municipal landfills and plasma thermal destruction.

Cement replacement in pipe or concrete block and aggregate manufacturing seems to be the best opportunity at this time. We have had discussions with companies having some success with this in the United States and Europe. The scrubber material is used in a patented process to produce construction aggregates such as crushed rock. The aggregate can be used in block and concrete manufacturing or to replace natural aggregates. We have also contacted a company that has an innovative brick manufacturing process that may be able to use our dry scrubber material.

The scrubber material is not toxic and has concentrations of metals that are comparable to naturally occurring levels in soil. Therefore, using the material in agriculture as a soil amendment or liming agent is also being researched. We support the Electric Power Research Institute’s research on agricultural test pilots with scrubber material, and we are tracking Ohio State University’s research this growing season. Although the agricultural uses require a great degree of testing and permitting, research data from the U.S. Department of Agriculture indicates that dry scrubber material application to soil is beneficial.

Dairyland’s experience as a recycler of ash demonstrates that we cannot plan on reuse options for all the material. Beneficial reuse options can be inconsistent and depend on several factors, including available markets and demand, environmental regulations, production interruptions, seasonal usage and the feasibility of technologies.

Dairyland’s goal is to find viable recycling options for as much scrubber byproduct as possible. However, the reality is that we will not be able to consistently recycle 100 percent, and a landfill will be necessary to safely store the remaining material.

The decision to install a scrubber was made with thoughtful deliberation and is a responsible solution for our environment. The scrubber will improve air quality and allow Dairyland to meet Wisconsin and new federal air quality regulations.

Donald Huff is director of environmental affairs for Dairyland Power Cooperative.

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