Shenandoah treatment plant to use wastewater for irrigation
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A new wastewater treatment plant on the Shenandoah River has the potential, if all goes according to plan, to achieve a goal of the original 1972 Clean Water Act: zero discharge.
Instead of pouring wastewater into the river, the facility, which handles waste from two towns and two poultry processors, is using treated water to irrigate crops. It should keep at least 200,000 pounds of nutrients a year out of the Shenandoah.
Sheaffer International, an Illinois-based firm that designed and operates the plant, touts it as a “whole new paradigm in wastewater treatment” because it is using the water as a resource, rather than a waste.
Before, the two towns, Timberville and Broadway, and two poultry processors, Rocco Inc., and Wampler Foods, each had their own treatment plants which pumped about 1.6 million gallons of wastewater a day into the river.
The new facility takes wastewater from all four places and pipes it into a series of large cells designed to spur the growth of bacteria that break down the wastes, nearly eliminating any sludge. Besides removing solids and other contaminants, the bacteria remove a large amount of nitrogen. After 30 days, the water is moved into a massive 230-million-gallon reservoir, which can hold up to four months of flow.
Then, nearly 8 miles of pipeline transport the water — along with the remaining nutrients — to more than 500 acres of farmland, which will use it for irrigation. The water is supplied free, but farmers must have nutrient management plans and commit to keeping their land in agriculture for at least 25 years.
“We’re dealing with serious, long-term farmers; they aren’t thinking about building houses in the next five years,” said John Johnson, of Sheaffer International. “We’re tying up land for a long-term basis in agriculture and preserving green space.”
In addition, some of the water will be reused by one of the poultry processors for washing parking lots and other non-potable uses.
William Guidos, president of the Friends of the North Fork of the Shenandoah, said the system almost “sounds too good to be true” but predicted it would result in a “benefit for everyone.”
The new facility is not without concern. The system is so big that some wonder whether enough land is available to absorb all of the water.
“It’s got real potential in the sense of keeping nutrients out of the river and doing something else with them,” said Jeff Corbin, of the Chesapeake Bay Foundation. “I’m a little skeptical of how much potential it has in Virginia’s Shenandoah Valley given the fact that it takes a lot of land to apply this, and we already have an overabundance of nutrients out there.”
State officials, too, have concerns.
While such a system could help some areas recharge aquifers, the local groundwater has too many nitrates, and state environmental and health officials don’t want to risk any more being added. So the permit issued by the Virginia Department of Environmental Quality requires extensive monitoring to ensure that no water from the application reaches the water table.
Because that could mean the plant won’t be able to fully use all of the water during wet years, the state also required a discharge permit. In very dry years, the plant may also be required to discharge into the river to replace water drawn by the poultry plants and the towns.
Exactly how well the treatment facility does in keeping nutrients out of the river, and ultimately the Bay, depends on whether — or how often — it discharges into the river.
The treatment process removes a large amount of nitrogen — more than was happening at the four wastewater treatment plants being replaced. But it does not remove as much nitrogen as the biological nutrient removal (BNR) systems being increasingly used at wastewater treatment plants.
About $2.5 million of the $11 million project came from grants from the state’s Water Quality Improvement Fund. That money usually helps to fund BNR upgrades at plants, so officials want the Sheaffer facility — on average — to discharge no more nutrients than what would have reached the river if a conventional wastewater treatment plant with BNR had been built.
“If they are successful in land applying the entire effluent, there is basically no discharge to the river in terms of nutrient loads,” said John Kennedy, of the Virginia Department of Environmental Quality. “If they discharge all the treated effluent, it would probably be a reduction from previous values, but it wouldn’t be as high as we expected if all those old plants were actually operating BNR.”
Similar systems have been used to handle wastewater, but they typically are much smaller in size, serving only an apartment complex or a ski resort. The Shenandoah spray irrigation system is the largest in the region, and the second largest in the country.
State officials, who took nearly two years in crafting a permit for the facility, are concerned that water and nutrients be placed at no greater rate than is needed by the crops so that the treated water is actually used for land application — not land disposal. “We don’t think land disposal is the answer for anything,” said Dwight Sours, senior environmental engineer with DEQ’s Valley Office, who wrote the permit.
As a result, he said 530 acres of farmland may not be enough to prevent a discharge into the river. “I’m anticipating that they are going to be discharging half the time, and land applying half the time,” Sours said.
Still, he said the plant is a potential environmental plus — if it can avoid discharges without affecting groundwater. “We’re interested in seeing what happens, ourselves,” Sours said. “I don’t have a problem with the system being built. I’m glad to see these four dischargers taken off line. Some of them were quite old.”
Johnson, of Sheaffer International, said he believes the system will avoid discharges the “vast majority” of the time, and that groundwater will be protected as well. “We are spoonfeeding those nutrients to it.” He said the facility’s 120-day storage capacity should help it get through most wet and dry spells.
Johnson said he hopes the system will be adopted by other communities as well, arguing that it makes more sense to recycle treated water over a dispersed area than to discharge a massive amount out a single pipe. “Instead of using infrastructure to carry it to a central point, take it all and pipe it out and recycle it on the land.”
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