Daily photos by Gary Lloyd|
A worker loads sludge onto a truck at Decatur’s wastewater plant on Alabama 20. Some 10 to 12 trucks holding 16 tons of sludge are loaded at the plant daily and sent to area farms that use the waste as fertilizer.
Out Of Decatur’s
Sewers And Onto Fields Of Green
City’s wastewater sludge being put to use on farms
By Catherine Godbey
With concerns about global warming increasing, industries are responding by creating environmentally friendly products.
Automobile companies produce hybrid cars, food companies market organic foods and Decatur’s wastewater plant manufactures fertilizer.
Yes, the plant that treats wastewater received from households, businesses and industries creates a compound that aids in crop growth.
Eighteen million gallons of wastewater go through the treatment process at the plant on Alabama 20 daily.
The wastewater enters the plant as a murky black liquid filled with unidentifiable solids.
After passing through the primary, secondary and final clarifiers — machines that cleanse the water — DU returns the treated water to the Tennessee River. As the wastewater undergoes clarification, so do the solids.
Travis Wilson, the plant’s maintenance supervisor, said the solids, which include particles and floatables, are broken down to their nutrient values and concentrated. Environmental experts refer to the concentrated substance as sludge and biosolids.
“Once dewatered, the sludge is taken out to state-regulated and permitted farmland and used as fertilizer,” Wilson said. “Usually 10 to 12 trucks holding 16 tons of sludge each leave the plant daily.”
DU’s gas, water and wastewater manager, Gary Borden, said Synagro, the country’s largest contractor of residuals, disperses the sludge to four or five farms in Morgan and Lawrence counties.
“The sludge we distribute is applied to agricultural farms that produce pasture hay and row crops that include hay and cotton,” said Chuck Simmons, Synagro’s senior technical services manager.
DU does not receive any monetary profit from the farms receiving the sludge.
“We actually benefit by giving the sludge away,” Borden said, “because then we don’t have to dispose of the sludge ourselves.”
For DU, two places exist to dispose of the sludge — farms and landfills. Stanley Keenum, DU’s interim general manager, touts the economic benefits of using the sludge as fertilizer.
“Land applying sludge is greener for the economy because farmers can use it to regenerate their crops,” Keenum said. “Imagine the amount of space we would fill up if we dumped the sludge in a landfill.”
Before Synagro transports the sludge, DU analyzes the levels of chemicals and nutrients.
“An in-house lab and Eversolv handle the lab work. They make sure all of the samples follow the guidelines set by the Environmental Protection Agency and the Alabama Department of Environmental Management,” said Wilson.
A debate among scientists exists concerning the safety of using sludge as fertilizer. While some researchers question the allowed levels of heavy metals in the sludge, Charles Mitchell lauds EPA’s standards.
Satisfied customer: Jerry Campbell, owner of Triple J Farms at Danville, says the application of sludge yields greener hayfields.
Mitchell said EPA classifies biosolids in two categories, Class A, which meet EPA standards and Class B, which exceed EPA’s permitted pathogen levels. The EPA labels DU’s wastewater plant as Class B.
“As a Class B land-applying plant that means the biosolids are monitored at a higher level. They can only be applied in certain circumstances and in specific places,” Mitchell said. “I am definitely a proponent of land applying, as long as it (biosolids) meet the criteria.”
Local farmers Jerry Campbell and Judy Ramos also support the use of biosolids as fertilizer. Farming for 40 years, Campbell began applying biosolids to his hay five years ago. Along with the biosolids, Campbell treats his farm with Triple 19 fertilizer.
“I can look out over the farm and tell you where the biosolids were used,” Campbell said. “Compared to the Triple 19, the land where biosolids were applied is a lot more green.”
Ramos, a cattle raiser who applies the biosolids to her farm’s hay and grass, added that she uses biosolids for monetary reasons.
“It saves me money to use biosolids because I don’t have to pay for the fertilizer,” Ramos said. “The only drawback is that I have to keep the cattle off the land for 30 days.”
Federal biosolid regulations requires farmers keep people and animals off of the farmland for at least 30 days after the applications of Class B biosolids. The EPA believes that is enough time for the sun to burn off any extra pathogens.
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