Think of the Harvest-Monrovia (Alabama) Water and Sewer Authority infrastructure as a big wheel.

The Burwell Road and Jeff Road wastewater treatment plants form the hub; two small package plants and 19 recirculating sand filters in residential and commercial developments form the perimeter.

And the spokes? The seven multitalented members of the Harvest-Monrovia wastewater treatment team, who staff and maintain the treatment plants, service the filters, and maintain connections with customers. “Our operators don’t just pass the test; they can take care of everything you can think of,” says Brent Kulavich, chief wastewater operator. “They have a can-do attitude. We’re blessed to have them.”

A novel approach

While centralized treatment is in vogue at many utilities, it’s just the opposite at Harvest-Monrovia, near Huntsville in northern Alabama. There, the most effective approach is a series of small treatment facilities, strategically placed around the sprawling district, anchored by a pair of larger membrane bioreactor plants.

“It’s not ‘one size fits all’ here,” Kulavich says. The district has tailored the treatment plan to fit the rapidly developing community, applying the best and most cost-effective technologies.

After slowing because of the 2008-09 recession, development is speeding up again. The area serves as a bedroom community to Huntsville. “We’re adding rooftops,” says Mike Oliver, P.E., general manager.

Instead of building expensive sewer systems to reach outlying homes and businesses, Harvest-Monrovia uses 1,500-gallon partitioned tanks that developers install at each property. Liquid from the tanks is pumped to the recirculating sand filtration, or RSF, units. The effluent percolates into the groundwater through pressure-compensated drip tubing. Green space for the soil treatment areas is set aside at each filtration site.

Pump and gravity

In these septic tank effluent pump (STEP) and septic tank effluent gravity (STEG) systems, the wastewater is pumped or gravity fed out of the tank based on usage. The solids remain in the tanks, where anaerobic biological processes consume them. “The tanks, solids and all the maintenance of the systems belong to the authority,” Kulavich says. “The customers pay a flat rate for the service. We provide 24/7/365 service calls on all the systems.”

There are 19 RSFs in operation, and another is on the drawing board. They handle an average flow of 15,000 to 70,000 gpd and serve 30 to 200 homes. Backwashed solids from the filters remain in the tanks and are periodically cleaned out by vacuum trucks. Orenco Systems provides the filter controls; Atlantic Ultraviolet supplies the UV disinfection units.

“We have no major river to discharge to, and the community continues to grow with commercial and residential developments popping on the outskirts,” Kulavich says. “It would cost an astronomical amount to connect those developments to the main sewer system.”

The package plants serve two subdivisions and may eventually be tied into the overall system. One at Stoney Creek uses extended air biological treatment technology (McNeill Water & Wastewater) and handles 20,000 gpd. The other, at Hunter’s Crossing, is an STM-Aerotor nutrient-removal unit (WesTech Engineering) with 72,000-gpd average flow.

The heavy lifting

At the center of the system are the Burwell Road and Jeff Road wastewater treatment plants, which use KUBOTA Membrane USA submersible membranes for biological treatment and nutrient removal. The absence of clarifiers helps the process fit into small footprints.

The Burwell Road plant (250,000 gpd design, 150,000 gpd average) has fine screens in the headworks. A flow equalization step includes an anoxic zone, followed by the MBR and a UV disinfection system (TrojanUV). The scheme at Jeff Road is identical except that the flows are larger (500,000 gpd design, 200,000 gpd average). Effluents from both plants discharge to Indian Creek.

Kulavich says the effluents contain essentially no ammonia or CBOD: “We put out the best water we can every day. We don’t have violations.” Biosolids from both plants are trucked at about 3 percent solids to nearby Madison Utilities for dewatering by centrifuge. The cake is land-applied on farms.

The two plants have the only submerged MBRs in Alabama, but that novelty hasn’t kept them from award-winning performance. The Burwell Road plant received an Award of Excellence from the Alabama Water Environment Association in 2014, 2016, and 2017 and the Best Operated Plant Award from the Alabama Water and Pollution Control Association in 2016, 2017, and 2018. The Jeff Road plant won the Alabama Water Environment Association Award of Excellence for 2018.

Cross-trained team

With such a mixture of treatment systems, and with close customer contact through the STEP-STEG units, staffing and communications are critical. Consistency helps. “Except for two, all our people were hired and trained within,” Kulavich says. “We have about a five-year learning curve. Every staff member has been the primary operator for every piece of equipment in the system. They’re cross-trained every couple of years through rotation.”

Bobby Benefield and Eric Edwards, lead operators, are responsible for all the biological treatment operations at Burwell Road and Jeff Road, as well as the package plants. Operators Andrew Sokolik, Adam Smith, and Byron Romine handle the house calls and RSF scheduled maintenance. Shauwn Baker is responsible for collections and lift stations.

“We all come to work at the same time every morning,” Kulavich says. “We talk for about 15 minutes and then get together and talk again in the afternoon. Our two lead operators help to oversee the normal operation and prioritize things. We have highly motivated folks here.

“The team has a good understanding of how everything operates — seeing pressure differentials, for example, and understanding what that number means. Is it a critical problem or something that’s hydraulically induced?” The staff members also understand and appreciate safety; they’ve had no lost-time accidents for the past three years.

Taking care of customers

The decentralized system requires operators to respond to alarms and maintain close contact with customers. “Each operator is on a call schedule,” Kulavich says. “They respond to emergency after-hours calls during the week and during the weekends. Screens need cleaning; pumps require maintenance.”

Customer complaints require attention as well. “We take responsibility at the tank in the customer’s yard,” Kulavich says. “We’re a very visible authority, and to some operators, it’s a culture shock because they’re not used to dealing that closely with customers.”

Each house has an alarm system, and customers have the authority’s phone number. “It rings through to the water plant,” Kulavich explains. “We go back to the house and figure out the problem and resolve any issues. We try to leave a situation where everybody feels good. We appreciate our customers. They’re our boss!”

The authority’s Wonderware (AVEVA) SCADA system plays an important role: “It serves as one central hub. We can see all the operating sites: all of the sand filters and the data at the package plants, as well as the bigger plants. It brings all the information to one point in real time.”

Teamwork and idea-sharing pay off. As an example, Kulavich remembers a few years ago when a large submersible waste activated sludge pump began to act up. Rather than purchase a new one at considerable cost, the staff realized that an air header was available in the mixing tank, so they tapped off it and converted the problem pump into a 4-inch airlift pump. “It’s a simple, old technology,” Kulavich says. “It does the job, saves on power, and cost us about $150, versus $5,000 for a new pump.”

Still growing

Development in the area shows no sign of diminishing; Kulavich says the growth rate could hit 30 percent per year. A proposed automobile plant providing 4,000 jobs would boost the population and create even more “rooftops.”

“Growth is coming, north and south,” Kulavich says. “Our job will be to maintain the water quality in our area.”

Tornado alley

Wastewater treatment is challenging enough without violent weather, like tornadoes. But that’s what the team at the Harvest-Monrovia Water and Sewer Authority has contended with in recent years.

Alabama and the Harvest-Monrovia area have experienced many tornadoes in the last 40 years and have suffered serious damage from some. In April 1974, a pair of F5 tornadoes hit within a half-hour of each other, destroying most of Harvest and claiming 59 lives.

In May 1995, the Anderson Hills subdivision was destroyed by an F4 tornado. The worst storm hit on April 27, 2011, during what weather experts called a “Super Outbreak.” The twister caused significant damage in Harvest and destroyed the Anderson Hills subdivision once again. Seventy-two people died.

On March 2, 2012, Harvest was hit again. Although there was no loss of life, the storms hit the same areas damaged the year before. “Most of my staff was here when those storms happened,” says Brent Kulavich, chief of wastewater operations. “We were blessed in that we all survived, but we had catastrophic problems. There were houses all torn to pieces.”

Mike Oliver, general manager, recalls, “It was a struggle — sheer misery. We didn’t have power in the wastewater system for seven days.” The Burwell Road and Jeff Road treatment plants ran on emergency power. At the recirculating filter sites, power came from generators on trucks connected to the filters.

One sand filter disappeared altogether. “No building, no fencing, just pipes sticking up out of the ground,” Oliver says. “But we rallied. Our customers had service throughout the period.”