The director of the Mid-Atlantic Biosolids Association, Michael Wardell, defended the land application of sewage sludge in "Biosolids not a threat to environment, human health" (April 2010)

Wardell claims that "Biosolids is not a term coined to sell a product."

Yet, when one looks up biosolids on Wikipedia, one finds these quotes: "Biosolids is a term used by the wastewater industry to denote the byproduct of domestic and commercial sewage and wastewater treatment." "The legal term for biosolids by law is sludge."

You can put lipstick on a pig, but a pig is still a pig. Wardell states that treatment of sewage sludge "destroys bacteria." He is correct for "Class A biosolids." But sludge that is land-applied is almost always "Class B," which must legally contain a "fecal coliform density...less than 2 million most probable numbers of colony-forming units per gram at the time of use or disposal," according to EPA regulations.

A typical truck disposes of 20 tons of waste on about one-half acre. In Virginia, bacterial concentrations at the time of disposal are not certified, despite concern that bacterial re-growth may occur during storage and transport. Claiming that the waste that is land-applied is bacteria-free is absolutely false.

Setting aside human and animal health concerns, bacterial pollution-and potential pollution by pharmaceuticals and other industrial substances-it is critical to clearly understand the facts about nutrient pollution caused by using sewage sludge instead of conventional chemical fertilizer.

Wardell's statement: "Much of the nitrogen is in the organic form, which is not subject to leaching from the soil into the groundwater" tries to hide the truth. Microbes slowly decompose the "insoluble" organic material just as a fallen tree slowly rots on the forest floor, and the nitrogen, mostly as nitrate or ammonia, is either taken up by plants or released to the environment. How else could the waste nourish plants?

The last part of his statement, "regulations governing the use of biosolids limit the application rates to the nitrogen needs of the crop, meaning there is little excess nitrogen to leach into groundwater," is absolutely false. He is correct that sludge is applied to meet the "nitrogen needs of the crop" and that is the crux of the nitrogen pollution problem. In Virginia, only 30 percent of the total nitrogen in the waste is assumed to be "plant available." If a crop requires 120 pounds of nitrogen per acre, 400 pounds of nitrogen (30 percent of 400 is 120) is applied in the form of sludge, meaning that 70 percent of the nitrogen is ultimately available "to leach into the groundwater" or contribute to other vectors of pollution once it is released from the organic material by microbes.

In no way can animal waste be characterized as a useful "slow-release" fertilizer. Fertilizer should be completely consumed by the time the crop is mature and drying in the field or else it will cause unnecessary pollution.

According to Virginia regulations, the release of nutrients from sewage sludge continues for years. There is no evidence that Virginia farmers reduce chemical fertilization in years after sludge application, as is recommended. Chemical fertilizer applied in years subsequent to sludge application at normal rates means that at least 70 percent of the nitrogen in the sludge is pollution. A more complete comparison of the inefficiencies caused by nitrogen fertilization practices is presented in "Animal waste causes too great a share of Bay's pollution to ignore," (March 2010).

In Virginia, sludge is applied to meet the nitrogen needs of the crop and whatever phosphorus it contains is disposed along with the waste. This is called "nitrogen-based" land application. There is always more phosphorus disposed of than is needed for crop growth. Virginia recently revised regulations with regard to the land application of poultry litter, but the regulations still allow the application to be "nitrogen-based."

In a letter of 03/22/10, I requested that the new governor and natural resources secretary justify the new poultry litter regulations, stating: "In the case of Phosphorus (P), common sense dictates that the soil should be analyzed and P application should be restricted to the amount required by the crop (the Soil Test P method), as is mandated by [the Virginia Administrative Code] 9VAC25-32-600 'The applied nitrogen and phosphorous content of biosolids shall be limited to amounts established to support crop growth.' Instead, the law is being violated and a permissive method known as the P-Index is used. This is because, according to DCR (Form TH-03, 11/02/05) 'dairy, poultry, swine, and biosolids sectors have all voiced a strong desire to have an option to use the P-index.' and because the Soil Test P method could not 'accommodate the volumes of animal and human waste generated in the watershed,' according to Secretary [of Natural Resources at the time] Tayloe Murphy." The letters are all posted on www.VaBayBlues.org. As long as "nitrogen-based" land application is permitted under the permissive P-index, phosphorus pollution will not be controlled, as Tom Horton points out in "Pretending excess phosphorus doesn't exist won't make it go away," (May 2010).

Wardell is entitled to his opinion that the land application of sewage sludge "pose(s) neither a threat to the health of citizens near the farms nor the Chesapeake Bay." But the science summarized above with regard to nutrient pollution, and numerous people (www.sludgevictims.org) say otherwise.

His primary goal is "to protect and encourage agriculture." Or does the Bay come first? Citizens must never lose sight of the fact that the land application of animal waste causes about one-quarter of Bay nitrogen pollution, as the EPA states.

Should we continue to put the profits of a very small number of farmers ahead of Bay water quality by allowing highly polluting animal waste to be used as fertilizer?

An alternative exists-ban land application and use the waste as biofuel. Nothing will spur waste-to-energy technology more than forcing the producers to find a less environmentally damaging use for the waste. Some waste-to-energy technologies are being used today and are not just "on the horizon" as Wardell asserts. Requiring that land application be phosphorus-based, using realistic crop requirements and not the astronomical caps found in the Virginia P-index, would cause less pollution than is currently the case and at least be a step in the right direction toward a complete ban.

The bottom line is that sewage sludge causes more pollution per acre than any other form of "fertilizer." It is unsatisfactory that the EPA, an active promoter of land application not too many years ago, allows a practice to continue that benefits so few farmers and causes such a disproportionate environmental damage. Sanctioning the land application of animal waste protects the profits of special interests, not the environment.