Not long ago, the AlliedSignal Hopewell Plant in Virginia was the world’s largest supplier of ammonium sulfate fertilizer — and the largest single source of nitrogen discharges into the James River.

Today, the plant — now owned by Honeywell — remains the world’s largest supplier of ammonium sulfate, as well as the producer of a number of other products. But now, the plant stands out as the single largest source of nitrogen reduction in the James watershed.

“As our production has increased over the years, we have put much effort into reducing the impact the Hopewell Plant has on the James River,” said plant manager Rick Higbie.

Since 1988, the plant has slashed the amount of ammonia — a form of nitrogen — going into the river by about 80 percent. That amounts to about 6 million pounds a year — more than a third of the river’s entire nitrogen reduction goal.

The Hopewell Plant is not alone. Since 1985, at least a dozen industries have reduced nitrogen discharges by a total of 17.4 million pounds. That is half of the nitrogen reductions achieved by all “point source” dischargers — those with permits that regulate what comes out of their pipes — in the watershed, according to Bay Program figures.

Those reductions happened despite the fact that few industries, in a strict regulatory sense, are required to control nitrogen discharges.

“They all know something is coming down the pike on this, and some of the pro-active industries know it is good to be out in front,” said Allison Wiedeman, point source coordinator with the EPA’s Bay Program Office. Wiedeman has been visiting all of the major industrial dischargers in the watershed.

Still, the vast majority of point source nitrogen discharges come from municipal wastewater treatment plants because nitrogen is a big part of human waste. Both Maryland and Virginia have grant programs to entice municipal wastewater treatment plants to install nitrogen control technology.

Such grants are not available to private industries.

Nonetheless, of 49 industrial facilities that discharge significant amounts of nitrogen, 12 have reduced nitrogen releases, and four more have plans to do so soon, according to an analysis completed by Wiedeman. (In addition, five of the 49 facilities are state-owned fish hatcheries in Pennsylvania where changes in fish feed are being explored to reduce nitrogen releases.)

“I’d say, by and large around the watershed, the industrial contribution to the nutrient reduction effort has been pretty successful,” said John Kennedy, Chesapeake Bay Program manager with the Virginia Department of Environmental Quality.

Both Virginia and Maryland have programs aimed at encouraging industries to consider making nitrogen reductions.

While Virginia does not require nitrogen reductions from facilities, it does offer a carrot for industrial facilities to explore the possibility: If a facility has to reduce phosphorus as part of its permit, the state will grant an extension for controlling phosphorus if it will also reduce nitrogen in its discharge.

In Maryland, the state includes a requirement in permits that industries develop and submit nitrogen reduction plans. Those plans force facilities to consider operational changes that could reduce discharges that might otherwise not be examined.

The hurdles faced by industries are different from those of municipal wastewater treatment plants. For example, paper mills discharge large amounts of nitrogen, but in very low concentrations, making controls difficult, Wiedeman said. Likewise, some chemical plants use nitric acid, another form of nitrogen, in their cleaning processes.

But, Wiedeman noted, because various nitrogen compounds are often added chemicals at many industrial plants, reductions may be possible by using pollution prevention programs that reduce chemical use or find alternatives.

To encourage that, the Bay Program’s “Businesses for the Bay” initiative is expanding its scope to encourage pollution facilities that discharge nutrients. In the past, the program has focused mainly on toxics.

Finding ways to prevent pollution can not only reap savings, but also a positive image in the public’s eye.

“The positive public relations aspect is something that is very important to them,” Kennedy said. “They also are always looking for ways to improve the bottom line, and that is what a lot of the pollution prevention measures are keyed to.”

Not all of the nutrient control actions were voluntary. An EPA consent decree with Hudson Foods in 1998, aimed at resolving several environmental complaints, required three poultry processors in the watershed to install nitrogen control technology to treat wastewater.

But rather than react to that type of a problem, officials say many companies are willing to look for ways to reduce pollution discharges.

Reductions at the Hopewell Plant took place in part because an ammonia water quality standard was being developed by the state. In the late 1980s, the state attached a condition to its permit requiring an evaluation of possible ways to reduce nitrogen discharges.

Through a combination of pollution prevention activities, and use of new technologies, the facility reduced direct nitrogen discharges from the plant to the river by about 3.6 million pounds a year.

In addition, nitrogen discharges from the plant to the publicly owned Hopewell Regional Wastewater Treatment Facility were curbed by about 2.7 million pounds annually. Altogether, the actions kept more than 6 million pounds of nitrogen out of the James annually. “They fulfilled that permit obligation, I think, in spades,” Kennedy said.