ewage backing up in a three-bedroom home on LakeCarmel in Carmel, N.Y., had

created a hazardous mold condi-tion under a bathroom floor.

The homeowners summoned PatTyndall of Tyndall Septic SystemsInc. in Brewster, N.Y. He pumpedthe concrete block septic tank andput the people in touch with ChrisDellaripa, project coordinator forthe Putnam County Septic RepairProgram.

Dellaripa immediately stoppedthe homeowners from using thebathrooms. Because the home waswithin a 500-foot radius of LakeCarmel’s high-water mark, the onsitesystem qualified for free replace-ment under the county program.

“This was one of the most chal-lenging jobs I’ve done in awhile,”

says John Kalin, P.E., of DesignConcepts Engineering in Pawling,N.Y. “The only place for the second-ary treatment system was a 9- by 24-foot area at the back of the house. Itwas like working in a planter box.”

Tyndall won the bid. He faced a2:1 grade change from the road tothe bottom of the 60- by 90-footlot, and had no clear access. At theheart of the system are three peatfiber biofilter systems.

Site conditionsSoils are well-drained brown

sandy loam with no groundwater,mottling or rocks. A failing dry wellnext to the house was within 25feet of the lot’s potable well, andwithin 65 feet of potable wells tothe east and west. Half the septictank extended into the neighbor’s

backyard, where the system’s claytile drainfield was ponding.

System componentsKalin designed the system to

handle 450 gpd. Its major compo-nents are:

• 1,000-gallon Fralo Plastechdual-compartment septic tankfrom Roth Global Plastics.

• A300 effluent filter, ZabelEnvironmental, a division ofPolylok

• 1,000-gallon single-compart-ment pump tank

• 1/3-hp low-head PE31MHydromatic pump

• Three 150-gallon pre-engi-neered Puraflo peat fiberbiofilters, Bord na Mona Corp.

• Installer Friendly Series single-phase timed dose/alarm panel,SJE-Rhombus.

System operationWastewater gravity flows through

a 4-inch PVC Schedule SDR-35 lateral to the septic tank, then into the pump tank. The pumpruns 75 seconds every two hours,sending 30 gallons of effluentthrough a 2-inch PVC line tied tothe biofilters.

A spray manifold in each moduleevenly doses the peat. Purificationoccurs as the liquid percolates throughthe media over 36 to 48 hours. Thepeat also suppresses odors.

Weep holes topped with cleanstone on either side of the modulesdisperse effluent to the groundthrough 7- by 24-foot by 6-inchdeep beds of washed gravel.

The units produce effluent aver-aging less than 10 mg/l TSS andBOD, and a 99 percent reductionin fecal coliforms with no pathogens.

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Peat fiber biofilters provide a treatment solution for a tiny lakeside lot in New York state where an old septic system had failedBy Scottie Dayton

Mighty Tight Squeeze

systemprofile

System ProfileLocation: Carmel, N.Y.

Facility served: Three-bedroom home

Designer: John Kalin, P.E., Design Concepts Engineering, Pawling, N.Y.

Installer: Pat Tyndall, Tyndall Septic Systems Inc., Brewster, N.Y.

Site conditions: Brown sandy loam with no groundwater, mottling or rocks

Type of system: Puraflo peat fiber biofilters, Bord na Mona Corp.

Hydraulic capacity: 450 gpd

An excavator operator places a 1,000-gallon dual-compartment FraloPlastech septic tank from Roth Global Plastics within the 500-foot distancefrom the high-water mark of Lake Carmel. (Photo courtesy of Pat Tyndall)

InstallationThe front of the house faces a

road. A flight of 20 steps leadsdown to a patio, from which anidentical stairway goes to the back-yard. To get the Komatsu PC35zero-tail-swing compact excavatorto the foot of the property, Tyndalland his two men cut a road. Theyused the smaller machine to build aplatform halfway down the hill,then parked the bigger VolvoEC55B Pro compact excavator onthe platform.

The crew first abandoned the20-foot-deep hand-dug well andoriginal septic tank. “I ordered 8cubic yards of concrete, and whenthe mixer arrived, the driver dumpedit into the excavator bucket a loadat a time,” says Tyndall.

The Volvo excavator transferredthe concrete to the Komatsu wait-ing below. Then that operator tookit down the hill to the well. Mostmaterials were handled this way.The men removed a chain-link fencealong the east property line, thenfilled the septic tank with concrete.

A foundation drain pipe pro-truded from the walk-out base-ment, and 3 feet of soil was pushedagainst the wall. The crew removedthe pipe and soil, using the latter tobackfill the well and septic tank.

It took two days to excavate thethree 24- by 7- by 4-foot-deep holesfor the biofilters, which fit next tothe basement and paralleled theeast property line. “We’d extractand move a bucket of soil to a posi-tion the Volvo could reach,” saysTyndall. “That driver piled it on the

road. When the hole was dug, theKomatsu went up the hill to loadthe soil into our dump container.”

Workers shoveled gravel into

wheelbarrows from a pile midwaydown the hill, then transported it tothe holes. Moving and setting the1,800-pound biofilters taxed thesmaller excavator to its limit. Afterinstalling and plumbing a module,the men erected a 4-foot-highretention wall along the propertyline behind it.

“We couldn’t set all three biofil-ters at once because we had an areaonly 2 feet wide in which to installthe 2-inch inflow and outflowpipes,” says Tyndall. The Volvo low-ered five pallets of Unilock blocks,and the men carried each 50-poundblock down the stairs or movedthem in wheelbarrows.

After covering the basementwall and retention wall behind thefirst biofilter with rubber mem-brane, they repeated the process forthe second and third modules. Theliner prevents water from leaching

horizontally. “We laid plywood sheets on top

of the biofilters, then ran over themwith the wheelbarrows and dumpedgravel into the holes,” says Tyndall.“We also used the wheelbarrows tobackfill with spoil.”

Excavating the two 9- by 5- by4-foot-deep holes for the fiberglasstanks along the side of the housewas easier, as there was more roomfor the machine to maneuver. Thepump tank sat 15 feet from the firstbiofilter. The tanks, installed one ata time and side-by-side on a 6-inch-deep gravel bed, were backfilledwith more spoil, only this timeusing the Komatsu excavator.

Because the biofilters were soclose together, the pump could dosethem in 40 seconds, but the manu-facturer recommends running it forat least a minute. Tyndall installed avalve and throttled back the pumpto 75 seconds. A weep hole drainseffluent into the pump tank, pre-venting the liquid from freezing inthe line. “A normal installation ofthese components takes three days,”says Tyndall. “This one took twoweeks.”

MaintenanceUnder the Septic Repair Program,

the system’s installer is responsiblefor maintaining it for the first twoyears. Twice per year, Tyndall observesthe float, pump and lids. He checksthe sludge level in the septic tankand cleans the effluent filter. At theend of two years, he draws an efflu-ent sample and sends it to a lab foranalysis. The system is operating asdesigned. !

“The only place for the secondary treatment system was a 9- by 24-foot area at the back of the house. It was like workingin a planter box.”John Kalin, P.E.

The septic tank is ready to install at the lakeside lot to serve a three-bed-room home in Carmel, N.Y. (Photo courtesy of John Kalin)

Workers backfill around thePuraflo peat biofilter systemfrom Bord na Mona. (Photocourtesy of Pat Tyndall)

MORE INFO: Bord na Mona336/547-9338www.BNM-US.comHydromatic419/289-3042www.hydromatic.com

Roth Global Plastics Inc.866/943-7256www.roth-global.netSJE-Rhombus218/847-1317www.sjerhombus.comZabel Environmental,a division of Polylok800/701-3946www.polylok.com

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