 The Environmental Protection Agency (EPA) requires all landfills in the United States be lined so that they are self-contained. This is to prevent contaminants from being absorbed as rainwater passes through the refuse and reaching ground water and fresh water aquifers. This liquid, called leachate, must be drained periodically and treated as hazardous waste.
Many of Pressure Systems’ customers perform this leachate drainage and treatment service for various municipalities throughout the United States. Our KPSI™ submersible transducers are used to monitor the depth of the leachate substance at the bottom of the landfill liner so that drainage pumps may be turned on and off.
In its simplest application, a pipe is run into a landfill and directly into a basin at the bottom of the liner. At that point, a drainage pump is deployed. The KPSI transducer is attached to the pump and all of the wiring is bundled together and run to the surface. When the water level reaches a pre-set point, the pump turns on and pumps the leachate into a truck for transporting or directly into a holding tank or pond where it is treated, neutralized, and returned to a disposable condition. The pump is then turned off when the leachate reaches another pre-set point, taking care that the pre-set point does not allow the pump to run dry.
This is one of the simplest and least expensive of all of our applications. The wiring from both the leachate pump and the KPSI submersible transducer are wired into a control box at the surface of the landfill. The control box measures the linear output voltage of the transducer and translates that into a predetermined feet-of-water measurement for turning the leachate pump on and off.
Pressure Systems, Inc., offers a variety of analog inputs, connections, pressure ranges, and alternative materials of construction. However, the standard 316 stainless steel transducer housing with an output of 4-20mA, set to a customer-specified pressure range, seems to work best with this particular application.
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