Replacing A Cottage Septic System

A small lot and numerous obstacles create challenges to an effective onsite upgrade on Georgia’s Blackshear Lake.
Replacing A Cottage Septic System
An IHI compact excavator just fit into this space for removing soil at the home on Blackshear Lake in Georgia. Near the bucket is the home’s old septic tank, which was retained as part of the new treatment system. A pipe from it now runs toward the left rear of the picture where an additional tank was installed beside the house. (Photos courtesy of Debbie Coarsey)

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When Matt Vinson was brought in to design a new system at Blackshear Lake in Georgia, the job requirements were clear although the system’s history was not. “The health inspector had been there with a contractor, and they couldn’t find the old drainfield. It could have been under the driveway, or it could have been the gravel pit they found near the end of the old septic tank,” Vinson says.

As a former health inspector, Vinson understands the challenges of dealing with old systems and older properties. Many lakes in southern Georgia became sites for weekend homes in the 1950s and 1960s, and the basic systems of that era were never intended to handle the water flows of full-time occupancy with people taking regular showers and doing laundry often. This property near Cordele, about 150 miles south of Atlanta, was a part-time residence, but its system was past the end of its life.

“The original tank was in good shape. It was structurally sound, so we repurposed it. Anytime we can salvage and continue to use existing tankage the system is better off because there are more points to control and treat the flow of water,” Vinson says.

The property was tight: a narrow cottage lot with a circular drive, and about 20 feet from the front wall of the house to the lakeshore. The land is also sloped from the road down to the home on the shore. Vinson designed a solution that made the most of the land without creating unnecessary expense for the owner.

THE NEW SYSTEM

Wastewater runs a few feet away from the front wall of the house and empties into the old 750-gallon concrete septic tank. A 4-inch PVC pipe exits the tank and makes a sharp turn to avoid the concrete retaining wall about 20 feet from the front wall of the house. After a run of about 30 feet along the front of the house and past one corner, water flowing under gravity reaches a new 1,500-gallon concrete tank.

This is a three-compartment tank, and the interconnections are at the tops of compartments so the tank can hold its full rated volume. In the first compartment is an Aquaworx Remediator to provide aerobic digestion of organic waste. Water then flows into the second compartment, which acts as a clarifier. The third compartment is a 500-gallon pump chamber.

A STA-RITE pump, controlled by an Aquaworx IPC control panel for time dosing, sends effluent through a 50-foot-long 2-inch pipe that rises about 30 feet to the drainfield. Fortunately, a previous owner had installed a sleeve beneath the driveway. The pipe went through the sleeve, eliminating the need for excavating or horizontal boring.

COMPACT DRAINFIELD

Vinson put the drainfield into a D-shaped space between the home’s circular driveway and the public road. He could not use the entire space because the road right of way intruded into the area.

“We didn’t want to go to the expense of digging up the asphalt. The homeowner had a limited area, and we didn’t want vehicles driving over the drainfield and compacting the soil. That was basically the only place where we could have good, undisturbed soil,” he says. “Part of the challenge here was the space was irregularly shaped.”

In configuring low-pressure pipe systems, it’s easier to make hydraulic load calculations if all laterals are the same length, Vinson says. But in this case, using different lateral lengths covered more soil area and allowed for more water absorption. Vinson settled on five laterals – a total of 144 linear feet composed of 1 1/4-inch pipe running inside Infiltrator chambers. Two of the laterals are 32 feet long, two are 28 feet and one is 24 feet. Orifices are spaced every 4 feet. “I would like them every 2 feet, but the hydraulics didn’t work out because of the non-uniform shape of the bed,” he says.

PIECE BY PIECE

The project went smoothly, but the real challenge was working in front of the house, says installer Ronnie Lewis. With his brother, Leon, he owns Warwick Septic Tank Inc. in Cordele. The company utilized an IHI compact excavator and Zaxis 35U mini excavator from Hitachi to do the digging work.

“It was a real tight area,” Lewis says. In front of the house was a retaining wall, and this left a space about 30 feet by 20 feet to work in. There was less when the crew finished excavating 100 to 150 cubic yards of dirt to gain access to the old septic tank and new outflow pipe that went to the new tank beside the house. “We had about a 4-foot area to get our mini excavator into.”

Another notable feature of the job was the traffic-rated risers on the new tank beside the house. The crew handled the riser work themselves, Lewis says. Steel bases for the manholes were cast into the tank, then the crew built up the sidewalls using brick. On top are regular street-grade steel lids. There isn’t much call for this type of construction on noncommercial jobs, but the owner wanted to be able to drive beside the house and on top of the new tank, Lewis says.

“The time-dosing system we put in there, it’s really about one of the best systems we have on that lake,” Lewis says. He should know. The business he and his brother run was started by their father in the late 1950s. They have worked on systems all around the area and have seen everything from 12-inch terra cotta drain tiles to modern Infiltrator systems. And there was the flood.

“The lake flooded in 1994. There were a lot of houses that were torn down, and the owners rebuilt with completely new construction. This home was an old cottage from the early 1900s. It was damaged in the flood, but the owner chose not to tear it down. Instead she did extensive remodeling to restore the home,” he says.

With a new, advanced wastewater system in place, the Georgia lake home will be welcoming the owner and visitors for years to come.



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