Operators at the Bosque Farms Wastewater Treatment Plant say their biggest challenge is keeping their microorganisms happy. Their biggest worry is staying ahead of grinder pump rebuilds. Fortunately, they have it all under control.

A dedicated, experienced team keeps the plant and 1,460 grinder pumps humming in this community of 5,000 in the Rio Grande Valley of New Mexico. They also operate and maintain the 1,400 gpm conventional water plant and 1.0 mgd and 0.5 mgd tank wells, install and maintain water or sewer lines, and read the water meters.

“It takes all five employees to properly handle operations and maintenance of the treatment plant and both wells,” says Krista Tays, utilities operator. “We’re on call for emergencies such as line breaks, and we take turns handling after-hours grinder pump failures and water calls.”

The hard work has paid off. The plant won the 2015 Wastewater Treatment System of the Year award from the New Mexico Rural Water Association. Treated effluent more than meets permit standards: The plant removes 99 percent of BOD and 97 percent of TSS.

Household grinders

Built in 1999, the 0.58 mgd (design) Bosque Farms treatment facility is an extended aeration plant with a pressurized collections system. A village ordinance requires installation, maintenance and inspection of grinder pumps, grease traps and sand traps for individual connections. The grinder pumps, equipped with alarms, are connected to each residence and commercial facility in the village. Sand traps are required for car washes, schools, day care facilities, commercial laundries and laundromats.

Influent enters the treatment plant’s covered anaerobic selector system, and the contents are mixed by a horizontal mixer before moving to the aeration basin. The basin is aerated using diffused air in the tank bottom, delivered by one of three blowers, which operate alternately. The basin’s concrete baffles extend aeration time and surround the secondary clarifier. A scum skimmer arm removes floatables from the clarifier and pushes them into a scum pit; the material eventually goes to the sludge storage basin.

Effluent is disinfected with a UV system (WEDECO - a Xylem Brand), then measured with a 6-inch Parshall flume and a secondary ultrasonic flowmeter (AMETEK Drexelbrook). Discharge is to the Rio Grande.

Waste sludge is pumped with a double disc pump (Penn Valley Pump) from the secondary clarifier to an aerated thickener, where it is thickened with a polymer (UGSI Chemical Feed) and allowed to settle by turning off the aeration. Biosolids are trucked to a village-owned 240-acre property for injection into the soil.

Says Tays, “When wasting, we send it to our aerated holding tank. From there, we load it into our vacuum tanker truck and drive about 21 miles to our injection site.” A Big Foot tanker truck injects the material 6 to 8 inches under the surface.

Two Aurora (Pentair) wash water pumps are used for the spray bar in the clarifier and to water the apple, almond and other trees and the grounds. The holding tank biofilter odor control fan is a Nidec Motor Corporation radial fume exhauster with pecan hulls for the top composite cover.

Doing it all

The plant’s operators (referred to as utility workers) do everything from laboratory testing and equipment maintenance to grounds work and cleaning. “There is practically nothing we don’t know or do, and the employees work their tails off keeping the plant spic and span,” says Tays.

Tays holds Level 3 wastewater and water certifications and Level 1 laboratory certification, and has been with the village for 18 years. She reports to Cliff Hibdon, utility director (Level 3 wastewater, Level 2 water, Level 1 lab, 22 years). The other team members are:

Kevin Fryhover, utility worker and field supervisor (Level 1 wastewater, Level 2 water, Level 1 water distribution, two years)

Utility workers Bobby Oglesbee (Level 1 wastewater, Level 2 water, 11 years) and Ralph McClellan Jr. (10 years)

The plant is required to have two Level 3 employees (Level 4 is the highest). Each team member has special skills. Hibdon specializes in permit reporting and oversees the grinder pump contractor installations. Tays keeps the lab and plant operating at peak performance, and specializes in clarifier operation.

Fryhover oversees all the fieldwork and keeps the wastewater and waterlines in good shape. He also works with utility contractors in and around the village. Oglesbee specializes in grinder pump repair, and McClellan, with a background in automotive repair, excels at wastewater plant equipment maintenance.

Operators perform mixed liquor suspended solids, mixed liquor volatile suspended solids, settleability and pH tests. Equipment maintenance includes repairing the aeration system blowers,

UV system and water pump, and cleaning the clarifier and biofilter odor control system.

The largest job is maintaining the grinder pumps. “When one fails, we either repair it in the field or replace it,” says Tays. “We take the old one back to our shop at the plant and clean and rebuild it.”

Dealing with mop heads

Tays says one of the most important tasks is educating the public about the effects of grease and lard: “It builds up inside the grinder tanks that the pumps sit in. The motor will burn up from continually running, or the tanks will flood because the motors don’t know when to come on.”

Baby wipes are also a problem: “They get caught in the grinder pumps, so we tell customers no baby wipes or diapers,” says Tays. “Mop heads” are another headache. “Small fibers come off clothes when people wash them, and the fibers find each other and eventually build up,” says Tays. “All this tumbling and spinning in the aeration basin ends up creating humongous mop heads.” Four times a year, McClellan uses a giant pitchfork to reach into the aeration teeth and pull out the fibers.

Perhaps the biggest overall challenge is keeping up with the enormous workload. During the day, the staff goes back and forth between the wastewater plant and the water plant a half mile away. “Whoever is on call for that week will check the tank wells, which are about a mile apart, in the morning and each evening before quitting time to make sure everything is OK,” says Tays.

Like a family

A recent high point was winning the System of the Year award, which was based on the plant’s consistent quality control and monitoring of effluent released to the Rio Grande. “We were proud that we won,” says Tays. “People in the village called and congratulated us, and Mayor Bob Knowlton presented the award to all of us at the village council meeting. It was very nice.”

The plant was nominated by the village’s New Mexico Rural Water representative, Susan Maupin. “We thanked her for nominating us, and then we thanked each other for working so hard at keeping the plant operating and looking so well,” says Tays.

It’s a close-knit group. “We are so small that we’re more like family,” Tays says. “We have our ups and downs like a family, but we communicate well. Every morning as people check in, we talk. If we have a new project, we have a meeting and discuss it.” The team has barbecues at the plant several times a year, and the village does the same for all its employees.

Plant staff members give back to the community. “We give plant tours to elementary, junior high and senior high school kids, and we also take them to visit one of the wells,” says Tays.

“We show videos of what our microorganisms look like under a microscope. Our favorite is a six-legged one that we call the water bear.”

Future goals

Staff members hope to maintain the plant’s efficiency now that the town of Peralta is tied into the system. “We added them in January 2016,” says Tays. “They’re about the same size as Bosque Farms, but they have more room to expand their population.”

The plant may add a primary clarifier at some point to provide a backup if the secondary clarifier is taken offline for maintenance. A SCADA system and staff additions are also on the wish list. “Sometimes we feel short-staffed, but over the years we’ve learned to work smarter so that everything flows,” says Tays.

She cites efficiency as the team’s greatest accomplishment: “When one thing works, the next thing works, and when the numbers look good and the water looks good, everything seems to fall into place.”

Hibdon agrees: “The water is flowing and the toilets are flushing, so we’re in great shape!”

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Training challenges

When the Bosque Farms Wastewater Treatment Plant was built in 1999, the village hired a team of six to operate and maintain it. Only one had wastewater treatment experience.

“Kurt Moffatt, who had been working for the village water department, became our utility director at the wastewater plant,” recalls Krista Tays, utilities operator. “He had Level 4 wastewater certification, and he trained the rest of us.” On-site classes in grinder pump connection, operation, maintenance and electrical wiring also helped the team come up to speed.

They relied on manuals for specific plant equipment operation.

Tays, a former village animal control officer for the village, and her new co-workers attended wastewater treatment classes offered by the State of New Mexico. Tays had worked in a veterinary office laboratory and so was no stranger to the lab environment. She took classes in lab procedures through the New Mexico Water and Wastewater Association, and helped train her colleagues at the plant.

The polymer process posed a challenge. “Operator Cliff Hibdon and I had never worked with wastewater systems before,” Tays says. “We had to learn the polymer-to-sludge ratio when wasting in order to get the best product and keep the food and microorganisms in balance.”

Tays recalls that it took about five years for the plant to come up to speed. Today, operators continually train on grinder pump control board upgrades and pump wiring, troubleshooting and repair. Says Tays, “We have a pressurized system for the grinder pumps, and the alarm system for the pumps is tied into our electrical box, so we have to make sure the voltage is correct and that the box is receiving all the information it’s supposed to.”