Being small is no reason to cut corners. That’s a reason the Mechanic Falls (Maine) Sanitary District has a formal biosolids management plan, even though it serves just 3,100 people and moves just 23 dry tons of material per year.

“It’s about saying what you do and doing what you say,” says Nicholas “Nick” Konstantoulakis, district director. “It’s a booklet that tells exactly what we do, where we do it and how we do it. When regulators know that you have a program in writing for anybody to see and you have a history of following it, you’re fine.”

The plan is built in the model of the National Biosolids Partnership Environmental Management System (EMS) program. The district land-applies liquid, lime-stabilized biosolids on a farm 6 miles from its 490,000 gpd (design) clean-water plant. The management plan spells out every detail of procedures. All land application takes place in October. The entire process — lime addition, hauling, spreading, testing, recordkeeping — costs about $15,000 a year.

Homegrown talent

Konstantoulakis, a Maine native, has been with the district for 10 years and director for two. He served in the U.S. Air Force for four years after high school, lived in Texas for nine years working and attending Sam Houston State University, then returned to Maine, where he put his industrial technology studies to work in laboratory positions with electronics manufacturers.

His quality assurance experience from those jobs helped him make a career change. “I was bored with what I was doing,” he recalls. “When you work in a lab, you pretty much do the same thing day in, day out.”

He and 11 others applied for an opening at the Mechanic Falls district. Then-director Tom Schultz chose Konstantoulakis largely because he was familiar with the ISO 9000 international quality standard, similar in character to National Biosolids Partnership’s EMS: “Tom wanted to do the EMS, and I was a perfect fit.”

Efficient treatment

Mechanic Falls, in southern Maine, has a 33-year-old activated sludge treatment facility using a racetrack-style oxidation ditch. The community is all residential and light commercial, which means flows rates and influent quality are consistent year-round.

Wastewater (250,000 gpd average flow) passes through a Worthington comminutor for preliminary treatment and then directly into the 288,000-gallon oxidation ditch (Lakeside Equipment). A set of grooved, motor-driven, rotating paddles beat air into the mixed liquor. Konstantoulakis and assistant Brian Ahlquist achieve optimum removal of volatile solids by holding dissolved oxygen in the ditch at 0.8 mg/L, with help from oxygen sensors (ABB Automation).

“We can control it manually, but generally we use our SCADA system,” Konstantoulakis says. “If it starts raining heavily or if the DO starts dropping for any reason, the paddles kick in automatically. Our SCADA pretty much takes care of it all.”

Water from the aeration process passes to two final clarifiers (Lakeside Equipment). After chlorine disinfection, final effluent averaging about 8 mg/L BOD and TSS is discharged to the Little Androscoggin River. “If you put a glass of drinking water beside a glass of our effluent, you couldn’t tell the difference,” Konstantoulakis says.

To the fields

On the solids side, waste activated sludge is pumped to a pair of 150,000-gallon storage tanks, where it accumulates until land application season in October. Two Sutorbilt blowers (Gardner Denver) mix the material; there is no digestion. Material enters the tanks at about 3 percent solids, and periodic decanting raises the solids content to 4 percent.

Just before land application the tank contents are lime stabilized. After an initial pH reading on the material, lime slurry is delivered to the tanks by a trash pump until the pH reaches 12, a process that takes about 30 minutes. The pH is held at that level for two hours and rechecked the next day. A year’s biosolids production is typically about 140,000 gallons.

A contractor delivers biosolids to the farm in a 4,000-gallon tank truck and surface-applies it to the field as directed by the landowner. The farm has 109 acres of corn and hay land permitted by the state Department of Environmental Protection. The lime-stabilized material, applied in cool autumn conditions, presents no odor issues.

“We don’t use all 109 acres,” Konstantoulakis says. “We apply about 600 pounds per acre. We do a chemical analysis on the material we spread, and about a month to six weeks later we take a soil sample and send it to the University of Maine for laboratory analysis.”

The biosolids are tested for 25 parameters, including pH and nutrients, as well as heavy metals, which are nearly nonexistent. The contractor, at the district staff’s direction, observes required setbacks from roads (100 feet) and the farmer’s well (300 feet). No other homes are nearby.

“Our farmer loves the material,” Konstantoulakis says. “A brick cheese that was made from milk he supplied recently won an award. The cheesemakers were so impressed with the product that they put a picture of his farm on one of the packages.”

According to plan

The district’s process is fully documented in the biosolids management plan. The district joined the National Biosolids Partnership EMS program in 2007 and is also a member of the North East Biosolids and Residuals Association.

An EMS is a management framework that helps treatment facilities constantly improve in key areas, such as quality management, regulatory compliance, environmental performance and relations with interested parties.   

“Our plan tells who the director is and who the helper is,” Konstantoulakis says. “It has sections on roles and responsibilities for each one of us. It describes our public participation plan, our process controls, our internal audits. There’s a section on management review and a section on chemical analysis. If we encounter a problem, we’re required to describe it in writing and tell what we plan to do about it.”

To Konstantoulakis, the plan is helpful on various levels: “Because we have our procedures in writing, if I get hit by a bus tomorrow, the person I work with could easily take over. When we’re inspected by the DEP, they can look at our plan and see putting it into practice.”

The plan also helps the district run a consistent, clean operation and avoid alarming the public:

“It’s a win-win program that benefits us all. It helps us continue to ensure that our biosolids are of the highest quality and that our recycling program remains cost-efficient. There are a handful of people who are against land application, but they tend to be the same people who will go to a hardware store and buy fertilizer from another country, not even knowing where it comes from. We don’t look over our shoulder when we do this, but we do understand that members of the public who don’t understand it or have been misinformed might raise concerns.”

Running smoothly

For now, Konstantoulakis, Ahlquist and office manager Carrie White are keeping the biosolids program and the treatment plant running smoothly. “Our goal right now is to keep things as they are, business as usual,” Konstantoulakis says. “Our No. 1 goals are to continue with preventive maintenance and to make our community more knowledgeable about us.

“My colleagues are in their 40s. They’re computer-smart, they have positive energy and it’s great. I plan to work until I’m 70. I really like what I’m doing. This is the first time in my life where I don’t need an alarm clock to get up and go to work.”