New Landfill Gas Collection System Installed

Published on August 13, 2014 with No Comments

Santa Rosa County recently installed a landfill gas, or LFG, collection and control system along with a blower/flare station consisting of 14,048 feet of high density polyethylene piping and 30 vertical extraction wells with 923 feet of LFG collection piping at the Central Landfill located in Milton.

When organic waste decomposes, landfill gas, or LFG, is created. Instead of the gas escaping into the air, LFG can be used as an energy source after it is captured and converted using the gas collection and control system located at the landfill. This gas is about 50 percent methane, 50 percent carbon dioxide and less than 1 percent non-methane organic compounds. By using LFG, the landfill helps reduce odors as well as other hazards associated with LFG emissions.

The total cost of this project was $1,275,547.

Landfill gas is collected through a number of vertical extraction wells drilled into the surface of the landfill. A vacuum is applied to each well to pull the gas out of the landfill and into a series of horizontal collection pipes called laterals and headers that vary in size from four inches for laterals and up to 14 inches for LFG headers. The LFG is pulled through the headers to a LFG blower/flare station where the LFG is destroyed by burning it in a candle stick flare.

In addition to the process described above, the LFG collection system and blower/flare are controlled by a programmable logic controller, or PLC, and a software program that monitors and controls an assortment of sensors, switches, flow meters and gauges that provide feedback to the PLC. The PLC monitors various components in the LFG including the flow of LFG in standard cubic feet per minute, the percentage of methane, oxygen and carbon dioxide, temperature of the flare and inlet vacuum levels. The PLC also monitors a number of safety sensors that will shut down the system if any LFG component gas exceeds reference levels, the temperature or amperage of the blower or electric motor exceed system parameters or the flow of LFG exceeds or falls below system capabilities.

If a safety fault is activated, the system automatically shuts down the flare and closes isolation valves to prevent the escape of LFG to the atmosphere. The PLC will activate an auto-dialer to notify the LFG technician that a fault and system shutdown has occurred.

The end use of the collected LFG is still being studied. However, the three primary end uses are electrical generation, conversion of LFG to compressed natural gas, or CNG, or insertion of the LFG into a natural gas pipeline. Each of these end uses have unique requirements and cost for the beneficial reuse of LFG. Some of those costs include the cost of electrical generators, installation of new transmission lines, support equipment to purify the gas, a dispensing system for CNG and various control and safety systems.

Posted in Community, News

No Comments

There are currently no comments on New Landfill Gas Collection System Installed. Perhaps you would like to add one of your own?

Leave a Comment