Rehab for the Rehabilitators

A site-specific alternate replacement system enables a rehabilitation center in Pennsylvania to continue operations

The undersized, two-part onsite system at White Deer Run at Blue Mountain, a 20-bed rehabilitation center in Kempton, Pa., had effluent ponding in the conventional drainfield and leaking out the berm surrounding the sand mound.

Christman’s Septic Service in Fogelsville, Pa., went from pumping the three septic tanks every six months to twice a month. When the business expanded into onsite installations, operations manager Dave Hummel contacted the center’s regional director with replacement solutions.

To calculate the flow, the company installed a water meter at the facility and a cycle counter on the lift station to the sand mound. “State code specifies that sites must have room for a secondary system, but there was barely room for the primary,” says designer Joshua Hummel. “Using chambers instead of crushed stone reduced the size of the sand mounds, and biofiltration reduced the amount of sand, enabling everything to fit in the area we had.”

The replacement system uses peat moss biofilters and alternate modified at-grade sand mounds. Because of the mountainous terrain and the lack of space for a secondary system, the state Department of Environmental Protection classified it as a site-specific alternate system.

Site conditions

Soils are silt loam/silty clay loam with subangular blocking structure and stones up to 10 inches in diameter. Absorption rates are 104 to 140 minutes per inch with soil mottling at 23 to 28 inches. The 7-acre property in mountainous terrain has slopes of 2 to 12 percent slopes and a potable water well.

System components

Hummel designed the system to handle 3,000 gpd. Its major components are:

• 28-gallon Schier PEC-35 interior grease trap.

• Two 3,000-gallon single-compartment septic tanks in series. Second tank has an A300 Zabel effluent filter (Polylok Inc.). All precast concrete tanks made by Monarch Precast Corp., Allentown, Pa.

• Two 1,500-gallon lift stations with duplex alternating Model WE20H 2 hp pumps from Goulds Pumps-ITT.

• Six Ecoflo STB-650 textile-peat biofilters with six-way flow equalizer from Premier Tech Aqua, supplied by Ecoflo and Fallen Spring Technologies, Newburg, Pa.

• 56 laterals of 1.5-inch Schedule 40 PVC pipe.

• 524 Quick4 chambers from Infiltrator Systems Inc.

• 594 tons of recycled glass from Cougle’s Recycling Inc., Hamburg, Pa.

• Custom control panels from Boulay Fabrication Inc., LaFayette, N.Y.

System operation

Three 3-inch lines leave the center and connect to a 4-inch PVC pipe. Wastewater gravity flows to the septic tanks and into the first lift station. On demand, a 60- to 90-gallon dose is pumped in one to two minutes through a 2-inch PVC line to the flow equalizer. At the end of a cycle, water drains back to the lift station to prevent freezing.

The flow equalizer divides the dose among the biofilters, arranged three per row. Effluent enters the tops of the units and runs into a bucket that tips back and forth, evenly dispersing the liquid onto distribution plates. After passing through 3/4-inch holes in the plates, the liquid percolates down through 32 inches of peat moss in about 24 hours. Each unit’s capacity is 500 gpd.

The water continues through 3/4-inch washed stone, then enters the drainage pipe in the center of the biofilter. The pipe connects to a 4-inch PVC gravity line running to the second lift station. Each time the “on” float rises, a different pump operates in sequence, sending 600 gallons to its dedicated mound. At the end of the cycle, water drains back to the lift station.

Installation

The original building on the site was a four-bedroom home on a septic system with a 900-gallon septic tank. When the owner enlarged the residence to a 20-room rehabilitation center, the contractor added two 1,000-gallon septic tanks and a sand mound. The onsite system was not expanded after White Deer Run at Blue Mountain purchased the facility.

Since the facility prepares meals, the DEP asked Hummel to upgrade the kitchen. “It didn’t have a grease trap, and that contributed to the system’s demise, as did the overuse of water,” he says. “We moved the dishwasher and sinks, then hooked them to the grease trap.”

To avoid interrupting service, Hummel and his three men installed the mounds, biofilters, and the second lift station first. These components, built on a terrace in the side of the mountain, are at a higher elevation than the tanks, which are below the facility.

Workers installed one mound at a time. Absorption area A is 3,989 square feet, area B is 3,807 square feet, and area C is 3,249 square feet. The men scarified the soil using a chisel plow on a mini track-loader, then leveled the area with 12 inches of DEP-approved recycled glass on the high side and up to 5 feet on the low end.

The pressurized drip lines, supplied by 3-inch PVC pipe and covered by chambers, have 1/4-inch holes 6 feet apart on center with the orifices up. Each lateral has an observation port. The entire job required 1 mile of piping.

Ecoflo representative Don Jones helped assemble the fiberglass biofilter shells, which arrived in halves. The units have 70 square feet of peat filtration area, covered by 12 inches of 3/4-inch washed aggregate.

“Subcontractor Mark Schoemaker of Mars Excavating hit huge rocks while digging the hole for the biofilters,” says Hummel. “We set the rocks around the perimeter of the berms to help tie in the soil and make the area resemble the rest of the mountain.” The hole was backfilled with washed 3/4-inch gravel and topped with river stone, which also created the lower berm surrounding the filters. Finally, the men ran the 2-inch flow equalizer supply line down the mountain to the bottom terrace.

During the four days it took to set the septic tanks and first lift station and run new sewer lines, the crew pumped the three existing tanks morning and evening, as the flows had nowhere to go. A 3,500-gallon vacuum truck remained on-site and off-loaded into a 5,000-gallon tanker that hauled the waste away.

To reconnect the system, workers saw-cut the macadam driveway and parking lot, trenched, and laid 4-inch Schedule 80 PVC pipe. They broke out the inlets and outlets in the existing tanks to create a level passage for the lines, cracked the tank floors, then backfilled with 3/4-inch washed stone. The existing sand mound now maintains the caretaker’s residence. The replacement system works as designed.

Maintenance

Christman’s Septic has the one-year maintenance contract. Every three months, a technician checks and tests the control panels, float controls, pumps, and levels in absorption beds and tanks. He cleans the effluent filter and pumps the grease trap as needed. Annual maintenance includes pumping of the septic tanks and lift stations and flushing of the laterals.

At the yearly biofilter inspection, the technician fluffs and levels the peat moss and adds more as needed. Under normal conditions, the filter bed lasts 10 years. When the media is due for replacement, a vacuum truck removes it, and fresh peat moss is added.



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