Political, regulatory and demographic limitations have posed significant demands on landfill managers' abilities to cope with lea-chate treatment and disposal. Al-though Subtitle D regulations dictate various landfill design, operational and monitoring standards, the actual leachate generation and management is only as good as the operation.
No matter how high-tech or efficiently designed a landfill is, experienced and novice landfill managers all share the common challenges of managing leachate. How you manage it can make or break your landfill's environmental integrity and economic viability.
Can Politics And Leachate Mix? On the eastern shores of North Carolina, officials with the Coastal Regional Solid Waste Management Authority (CRSWMA), New Bern, N.C., never dreamed they'd have such stigmas and political problems associated with the disposal of their not-yet-operational landfill's leachate.
Once an "emergency-only" home was found for the liquid, the landfill's leachate generation rates grew out of control, posing economic and operational hazards to the infant agency.
Created in the early 1990s to manage the solid waste needs of a three-county region, CRSWMA's toughest challenge was not getting a landfill permit from the North Carolina Department of Environment, Health and Natural Resources, but finding a place for its landfill's leachate.
The pristine Carolina coast draws many tourists, but, overall, the region is rural and sparsely populated. Major fish kills four years ago on the Neuse River led to heightened environmental sensitivity among local community leaders and focused the public eye on CRSWMA's landfill and two transfer stations.
"Many of the publicly-owned treatment works (POTW) were afraid of the leachate or had political considerations prohibiting it from their systems," said CRSWMA chief engineer Lori Dietz. "In this area, accepting our leachate was a politically touchy subject, and it was difficult to overcome the perception that leachate is some kind of awful stuff."
With few alternatives, state regulators grudgingly allowed CRSWMA to recirculate leachate, provided it had access to a wastewater treatment facility for emergency situations. With permit in hand, CRSWMA's staff began landfill operations only to fall victim to inexperience and cruel blows from mother nature.
"Up until a month before we opened the landfill, we only had five employees, and they all worked in administration," Dietz recalled. "We opened the landfill and the transfer stations on the same day, and it was a huge learning curve."
After a year of pumping leachate into the new cell, Dietz said the system failed. "We had major problems controlling stormwater, and we had no good way of dividing the cell," she said. "With such a new landfill, we also didn't have enough garbage going into it to absorb the recirculated leachate. In essence, we overloaded the system."
The political climate became in-creasingly volatile when the wastewater treatment plant, owned by a neighboring U.S. Marine Corp base, was forced to accept some 40,000 gallons of leachate daily.
The Solution Following political negotiations to find a permanent home for its leachate and weathering two hurricanes and a tropical storm, CRSWMA finally has its leachate management under control. "One of the local cities wanted relief on its construction and demolition (C&D) disposal costs," Dietz said. "It was a trade off: They take our leachate, and we give them a yearly credit on C&D waste."
Operationally, CRSWMA has incorporated temporary synthetic liners as intermediate cover on unoccupied cells, reducing the facility's leachate generation rates to 5,000 gallons daily. When hurricanes Fran and Bertha hit the coast last year, followed by tropical storm Josephine, the wrath of 18 inches of rain dumped on the site didn't phase the landfill's leachate generation rates, proving CRSWMA's success may have been hard earned, but fruitful.
"We didn't get smart until we moved into the [cell's] final area," Dietz admitted. "We've had a huge learning curve, and we're still climbing."
Wet Versus Dry Landfills According to Rick Watson, chief engineer for the Delaware Solid Waste Authority (DSWA), Dover, who oversees three active landfills and a closed facility, leachate management can incorporate many evolving philosophies.
"The current regulations want you to operate as a dry landfill, whereby you take the moisture out of the facility as quickly as you can, using the landfill's liner and leachate collection system," he said.
Another philosophy, of which N.C. Vasuki, the DSWA's executive director is a chief proponent, is to take a portion of the leachate and return it to the landfill, making it wetter and, "theoretically, helping what's in the landfill biodegrade quicker," Watson said. Deciding on which philosophy works best, however, is a matter of site specifics.
At the DSWA's closed Pigeon Point Landfill, where the facility was capped prior to Subtitle D regulations, access to a wastewater treatment plant is convenient and has minimal impact to the POTW operated by the city of Wilmington.
"A couple hundred thousand gallons per day has minimal impact on the [POTW's] total daily flow capacity of 40 million gallons," Watson said. "The landfill was capped with soil that didn't have a lot of clay, and we still have a substantial quantity of lea-chate."
The DSWA had to decide on how much to spend to reduce the leachate quantity. Incurring a yearly sewer charge of $150,000, DSWA officials didn't think it made economic sense to fund the construction of a geomembrane cap and abandon its POTW options.
However, the cost of operating dry landfills at DWSA's Central and Southern landfills was substantial because both facilities are located remotely and aren't accessed by nearby sewer systems.
"A wet landfill appeared to be a more attractive option, so we began recirculating leachate at the Central Landfill in 1982," Watson explained. "The thought was, we would generate enough leachate for the landfill to take it all back."
DSWA officials pursued a series of recirculation efforts, including perforated concrete wells, ponds on top of the landfill and a traveling spray irrigation system.
"It had its problems," Wat-son recalled. "In the winter, [leachate] would freeze, and in the summer, when it was windy, it would travel to the working face and smell like hell."
In the mid-to-late 1980s, when the U.S. Environmental Protection Agency (EPA), Washington, D.C., began considering Subtitle D regulations, Vasuki petitioned agency officials and asked them to reconsider the dry landfill option.
"They allowed us to conduct a one-year test, filling two one-acre cells," Watson said. "One cell was operated as a dry landfill, the other as a wet."
Today, partially funded by the EPA, the DSWA is conducting a study of the cells. Both cells are being excavated, and during the next several months, a waste characterization analysis will provide the DSWA with telling results of both operations.
Green Leachate Or Green Budgets? Aside from the political and regulatory issues concerning leachate, management treatment and disposal costs are dictated by operational practices. Rob Burnette, vice president of engineering for Santek En-vironmental Inc., Cleveland, Tenn., heads the engineering efforts at the company's five publicly-owned landfills.
How green are you? "From an environmental standpoint, you don't want to negligently produce more leachate than you have to, but, sometimes, the cost to prevent leachate generation can be many times more the cost of disposing of it," Burnette said.
And, while Subtitle D regulations govern current landfill practices, economics probably will dictate future trends.
"Leachate management is more of a best-management practice," Burnette said. "The regulations don't specifically address the generation rate of leachate.
"Under the Subtitle D theory, leachate isn't going to be leaking into the groundwater so it really doesn't matter how much leachate you're generating from a purely regulatory perspective."
And, for current practices and trends to change, Watson believes it will be regulatory-driven, pushing disposal costs higher or making alternative options more competitive.
"Pretreatment is coming, basically because of the nature of regulations," he said. "As the clean water regulations become more stringent on rivers and streams, there's bound to be a domino effect on the wastewater treatment standards which will eventually hit landfills."
Regardless of future technologies and regulations, Dietz said economics is the fundamental challenge associated with leachate disposal.
"It would have to take absolutely no available [leachate disposal] facility, or a drastic raise in disposal rates for another alternative to be more attractive than using our local POTW," Dietz said. "For my authority, it's definitely a dollar issue."
Leachate Controls, Part II will feature examples of the latest advancements in collecting and treating leachate.
* Aeromix Systems Inc. Surface aspirating aerators. Contact: Linda MacFarlane, 2611 N. Second St., Minneapolis, Minn. 55411. (612) 521-8519. Fax: (612) 521-1455.
* Agru America Inc. Thermoplastic HDPE and LLDPE geomembranes and drainage geomembranes. Contact: Robert John-son, 300 West Davis, Ste. 520, Conroe, Texas 77305. (800) 373-2478. (409) 539-6162.
* Blackhawk Environmental Co. Leachate and methane gas pumps and flare ignition systems. Contact: Dennis Thorton, Z1W159 Hill Ave., Glen Ellyn, Ill. 60137. (630) 469-4916. Fax: (630) 469-4896.
* Central Plastics Company. Complete line of polyethylene fittings and connecting equipment for joining leachate piping systems; electrofusion fittings, equipment and accessories. Contact: Tammy Jones, 1901 W. Independence St., Shawnee, Okla. 74801. (800) 654-3872. Fax: (405) 273-5993.
* EPG Companies Inc. Leachate pumps and controls. Contact: Duncan Bosley, P.O. Box 410, Rogers, Minn. 55374. (800) 443-7426. Fax: (612) 493-4812.
* John Zink Company. Enclosed and open flare systems, condensate vaporization systems, complete blower/flare skid systems. Contact: Tim Locke, 11920 East Apache, Tulsa, Okla. 74116. (918) 234-2783.
* Landfill Gas & Environmental. Landfill gas and recovery equipment. Contact: Manuel Palma, 9855 Prospect Ave., Santee, Calif. 92071. (888) 533-5343. Fax: (619) 596-9088.
* Osmotek Inc. Leachate treatment technology. Contact: Keith Lampi, P.O. Box 1882, Corvallis, Ore. 97339. (541) 753-0281.
* Plexco. Plyethylene pipe for dual containment systems, leachate recovery and methane recovery systems. Contact: Jim Stilling, 1050 Il Route 83, Bensenville, Ill. 60106. (630) 350-3700. Fax: (630) 350-2704. E-Mail: [email protected]
* Protec. Down-well leachate recovery pump.Contact: Mark Patton, 7136 South Yale, Ste. 200, Tulsa, Okla. (918) 493-6101. Fax: (918) 493-2050.
* QED Environmental Systems Inc. LFG condensate and leachate pumps. Contact: QED, P.O. Box 3726, Ann Arbor, Mich. 48106. (800) 624-2026. Fax: (313) 995-1170. E-Mail: [email protected]
*Rochem. Leachate treatment systems. Contact: David LaMonica, 3904 Del Amo Blvd., Ste. 801, Torrance, Calif. 90503. (310) 370-3160. Fax: (310) 370-4988.