|Branded as polluters: Valley air basin is in non-attainment status. Scientists and dairy owners want more studies. (Photo courtesy of Intrepid Technology and Resources Inc.)|
California dairies could be facing millions of dollars in additional equipment costs since the San Joaquin Valley Air Pollution Control District raised the bovine Emissions Factor used to calculate the amount of smog caused by cow-related activities. The increase from 12.8 lb of volatile organic compounds (VOC) per cow per year to 19.3 lb VOC per cow per year is the first step in meeting a state requirement to end air-quality environmental exemptions for farmers.
The previous factor was based on studies conducted in the 1930s. The new factor was determined in conjunction with a Diary Permitting Advisory Group (DPAG) of interested parties that looked at 15 studies from California and the world to come up with the most accurate measurement of gases emitted by chewing of cud, feed and manure storage. DPAG considered studies of housing, waste lagoons, milking centers and manure land applications. The numbers are being disputed by scientists and dairy operators, who think it should be as low as 3 lb VOC per cow per year, but they will be the basis for mitigation efforts until better studies are conducted.
The increase means that, under the rules of the 2003 law, SB 700, as many as 250 more dairies will have to file Air District Permits. Before, dairies with fewer than 1,954 cattlemore if they were all milking cowswere exempt from the permitting process. Now, that number could be as low as 1,290. Getting the permit is easy and inexpensiveabout $300. Permitting is the first stepthe backbone of enforcement, says Valley Air District Spokesman Kelly Malay.
The Valley air basinwhich is considered a serious non-attainment air quality areais home to 2.5 million dairy cattle with another 400,000 planned for new dairy projects. According to Malay, dairies are the largest source of VOC emissions in the Valley air basin. VOCs combine in the atmosphere with nitrogen oxidesemitted primarily by carsto form smog.
Valley Air District now will work with DPAG to identify cost-effective mitigation best practices by July 1, 2006. Dairy operations will have to file reduction plans six months later and implement the reductions within a year of Valley Air District approval. Possible solutions include lagoon covers, anaerobic aeration treatment and digesters.
Digesters trap the methane, carbon dioxide and trace hydrogen sulfide from the manure and convert it into energy. Equipment prices can range from $600 to $1,000 per cow depending on how efficiently and consistently the manure is fermented. The challenge for dairies, however, is that it is difficult to recoup that investment by selling the energy to utility companies.
Jake Dustin, vice president of operations at Intrepid Technology and Resources Inc., in Idaho Falls, Idaho, which builds digester tanks to harvest the methane, says energy companies are concerned about the logistics of buying small, inconsistent wattages of electricity from lots of different dairies. Even though the Public Utility Regulatory Policy Act requires utilities to buy electricity from farmers, it doesnt regulate the price, says Dustin. If they could consolidate and the power company only had to run one line to get consistent megawatts, then it might make more sense for them.
Frank Mitloehner, an air-quality extension specialist for the Dept. of Animal Science at UC Davis, who contributed one of the studies for the decision, says the impact of dairy VOCs has been exaggerated because the types of chemicals emittedparticularly acedic acidare not very reactive.
He advocates lower-cost surface modifications that ensure complete decomposition. Minimally, that would require sizing lagoons so they are large enough to handle the amount of waste that drains into them, not allowing standing water in milking or food storage areas and not overfeeding cattle. A more expensive fix is true oxygenation of lagoons, which requires infusing at least 2 milligrams per liter of dissolved oxygen using microbubblers to change the composition of microbes present. The problem is that this is almost cost prohibitive because so much horsepower is needed, Mitloehner says.
We will set the stage for the rest of the nation that will soon be passing similar legislation for hogs and dairy, says Manuel Cunha Jr., president of the Fresno-based Nisei Farmers League, who is also a member of the U.S. Dept. of Agriculture Air Quality Task Force. We have to do this right, and that means being flexible if later studies show that the factor is too low or too high.