Farming Magazine - June, 2011
Letter to the Editor: Biosolids are Not a Fertilizer
This is a response to your featured February article, titled "From Sludge to Fertilizer," which describes the yield increases a Northwood, N.H., landowner experienced after two years of using biosolids on his pastures.
Sewage treatment plants were not designed to produce fertilizers or soil amendments. They are designed to REMOVE hazardous and contaminated industrial and domestic waste from sewage, so the treated wastewater can be returned to the environment. The pollutants removed from sewage CONCENTRATE, by necessity, in the resulting sludge or biosolids. Every month, every business, institution and industry in the country is permitted to discharge 33 pounds of hazardous waste into sewage treatment plants. The Federal Clean Water Act defines sewage sludge as a pollutant.
According to soil scientists of the internationally renown Cornell Waste Management Institute, the federal 503 sludge rule does not protect agriculture, human health or the environment. Only eight toxic metals are monitored and regulated. Some states require monitoring for a few additional pollutants, but the latest National Academies of Sciences biosolids report warns that sludge is such a complex and unpredictable mixture of chemical compounds - most of the 90,000 chemical compounds in commerce today can end up in wastewater - that chemical-by-chemical risk assessment does not adequately protect human health, even if additional pollutants are monitored and regulated. The report concludes that current sludge regulations are outdated and not based on recent science.
The U.S. regulations assume that the same site can be sludged repeatedly, i.e. cumulatively loaded with persistent pollutants, until the treated land has been turned into a low-level hazardous waste site and yields reduced by 50 percent. In some New England regions yield reduction can occur much earlier, especially if lime-stabilized sludges are applied to calcareous soils.
Exceptional Quality (EQ) Class A sludge is a misnomer. Legally, EQ sludge can contain 41 mg/kg of arsenic, 39 mg/kg of cadmium, 1,500 mg/kg of copper, 300 mg/kg of lead, 17 mg/kg of mercury, 420 mg/kg of nickel and 2,800 mg/kg of zinc, plus disease-causing pathogens that regrow in cool and moist climates, and thousands of unregulated toxic organic compounds. Since application rates are determined by nitrogen levels, and since Class A biosolids do not contain much nitrogen, it can be applied in very large amounts, any place, anywhere, resulting in high pollutant loading per acre.
Deaths, illnesses and groundwater contamination have been linked to biosolids use. In Augusta, Ga., two prize-winning dairy herds were virtually wiped out when cows ingesting forage grown on biosolids died by the hundreds. Recently, a federal judge ordered the agriculture department (USDA) to compensate one of these farmers because his land was so poisoned by sludge that it was no longer capable of growing crops.
Farmers contemplating using biosolids should not be misled by the deceptive promotional literature of the biosolids industry. For example, in a biosolids ad appearing in the March/April issue of the N.H. Farm Bureau Federation's "The Communicator," the Northwood landowner describes his sludge-grown crop as "the most beautiful alfalfa anyone could ask for." Most farmers know that alfalfa and clover are legumes that have the unique ability to fix atmospheric nitrogen through symbiotic bacteria within their root systems and don't need a lot of extra nitrogen. For centuries, farmers have used not only animal manures, but also legumes and other green manure as cover crops to maintain the fertility of their soils. What today's farmers might not know is that after repeated sludge applications, this natural way of maintaining soil fertility is suppressed. Thus, biosolids use does not "improve soil naturally," as the Communicator ad claims. Instead, it gradually degrades soil with an array of synthetic industrial chemicals that don't break down and don't belong on farmland.
University of New Hampshire Cooperative Extension scientist John Potter supports the use of biosolids. Cooperative extension research is funded by the USDA, and USDA biosolids policy is determined by soil scientist Rufus Chaney, an aggressive promoter of sludge use, who co-authored the 503 sludge rule. Other UNH Cooperative Extension scientists, however, have been neutral on this issue, some warning that land application of sewage sludge is not a long-term option because of the state's lack of suitable sites and shallow water tables. Climate change weather patterns - unprecedented flooding, droughts, stronger winds, winter thaws - all add to the risks of land application in New England.
Farmers have a choice between using proven farming practices that produce stable yields while maintaining healthy and productive soils, or using toxics-containing waste that may increase short-term yields, but ultimately contaminates their land.
Sewage sludge is produced every day and something needs to be done with it. Sludge contains valuable BTUs. Many industrialized countries that want to protect their soil for future generations do not land apply biosolids. Instead, biosolids are used as a renewable nonfossil source of energy.
For recent and reliable information about the serious risks associated with land application, visit www.sludgefacts.org and http://cwmi.css.cornell.edu/case.pdf.
Caroline Snyder Ph.D.
Citizens for Sludge-Free Land
Rochester Institute of Technology