Every lined landfill runs on a simple control loop: a submersible level transmitter in the leachate sump or riser tells a control panel when to run the pump. When that transmitter dies — and at many sites they die yearly — the loop goes blind, the sump overfills against the liner, and the site is suddenly managing a compliance problem instead of a maintenance item. The transmitters aren’t failing because submersible level is exotic technology. They’re failing because leachate service combines three killers that a standard “water” transmitter was never built for, and the fix is almost entirely in how the instrument is specified.
Killer #1: Leachate chemistry
Leachate is rainwater that has percolated through decades of municipal waste, picking up chlorides, organic acids, ammonia, dissolved metals, and whatever solvents arrived in the waste stream. Chlorides in particular attack 316 stainless steel over time, and the standard polyethylene-jacketed cable intended for clean water service degrades in organic-laden liquid. The specification answer: titanium construction (or 316L where chemistry is mild and replacement-cycle economics favor it), and — critically — upgrading the cable jacket and seal materials from the standard water configuration to Tefzel jacket with Viton or EPDM sealing matched to the chemistry. The cable is the most commonly overlooked wetted component, and it’s frequently the first thing leachate destroys.
Killer #2: Lightning
A landfill is a tall, exposed mound — often the highest ground for miles — with hundreds of feet of transmitter cable running down riser pipes acting as antennas. In Southeast storm country, induced surges from nearby strikes are the leading electrical killer of sump instrumentation, taking out the transmitter, the panel input, or both. The specification answer: integral surge protection in the transmitter itself, properly bonded to earth ground through the cable shield, supplemented by a panel-end surge protector for a two-stage defense. Keller America’s 4-20mA submersibles include guaranteed lightning protection at no added cost, backed by a lifetime warranty against surge damage — at lightning-prone sites, that warranty alone has paid for the instrument several times over.
Killer #3: Vent-tube condensation
Gauge-type submersibles reference atmospheric pressure through a small vent tube in the cable. In Southeast humidity, moist air breathes in and out of that tube as barometric pressure changes; when the leachate is cooler than the air, water vapor condenses inside the tube and eventually inside the transmitter, corroding the electronics from within. Failures from this cause are routinely misdiagnosed as “bad sensor.” The specification answer: a desiccant-filled drying tube or an aneroid bellows assembly at the cable termination — a small accessory that, in this climate, should be considered standard equipment rather than an option.
One more thing: it’s a gas environment
Leachate risers and sumps sit inside a methane-generating waste mass. Depending on the site’s area classification, the instrument in that riser may be required to carry Class I Division 1 intrinsically safe approval — and many commodity submersibles don’t. Verify the classification with the engineer of record, and when in doubt, specify the IS-approved version; the cost difference is small against a compliance finding.
Sizing and ordering details
Specify level range from the riser/sump geometry (transmitter ranges are available from a few feet to several hundred feet of water column); confirm cable length to the panel or junction box with margin for routing; state the liquid’s specific gravity if meaningfully different from water; choose output (4-20mA remains the standard for pump panels); and consider keeping a configured spare on the shelf — when a sump transmitter fails, the replacement clock is measured in hours, not weeks.
Local application support
George Grant Co. represents Keller America level and pressure instrumentation across Tennessee, Georgia, Alabama, and the Florida Panhandle. Keller’s Levelgage and Acculevel submersibles are a national standard for landfill leachate service, with leachate-hardened configurations, custom calibration at no charge, and a 3-day standard lead time. We help sites and engineers specify the configuration that survives — and we answer the phone when one doesn’t.
George Grant Co. — Hixson (Chattanooga), TN | 423-875-3241 | sales@georgegrantco.com | www.georgegrantco.com