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Program Overview

Table 3-1 Monitoring Parameters and Frequencies

Parameter Frequency
Leak Detection Quantity Quarterly
Leak Detection Quality Quarterly
Leachate Quality Quarterly
Leachate Quantity Weekly
Leachate Recirculation Quantity Ongoing
Gas Composition Ongoing
Gas Volume and Flow Rates Ongoing
Settlement Quarterly
Waste Density Quarterly
Waste Temperature Ongoing

The monitoring program was developed with assistance from the project academic advisors, Dr. Debra Reinhart and Dr. Morton Barlaz. Table 3-1 shows the monitoring parameters and frequency of data collection for the project.

As part of facility operation, Buncombe County performs semi-annual testing of the leak detection zones (LDZ), groundwater monitoring wells, leachate pond, and stormwater collection points for the 2L groundwater standards established by North Carolina Department of Environment and Natural Resources. This data is also being used in assessment of the alternative liner system performance.

Leak Detection

The landfill cells and leachate pond are equipped with a leak detection zone (LDZ) located beneath the leachate collection system sumps. For Cells 3-6, liquid captured in the LDZ is pumped out through vertical stand pipes located along the perimeter berm. Cells 1 and 2 drain liquid through gravity pipes that protrude from the outer slope of the landfill perimeter access road. The drain pipes are equipped with gate valves that the operator opens to check for liquid. Quantity data is not recorded for Cells 1 as it appears to be impacted by a steady supply of groundwater from an underground spring. Further investigation of flow from the Cell 1 LDZ was discussed at the stakeholders meeting held on September 20th, 2012.

If liquid is present in the LDZ, samples are tested onsite using a Horiba U-22 water quality meter for:

  • ORP (oxidation reduction potential)

In addition, liquid samples are collected in sample bottles and sent to Pace Analytical for analysis of:

The sampling process is dated and recorded in a monitoring log by the Bioreactor Manager.


The quantity of leachate collected is also tracked separately for each cell on a weekly basis. Each cell has a dedicated leachate pump system equipped with a flowmeter that allows the Bioreactor Manager to monitor the number of operating hours for the pumps, the quantity of leachate pumped, and the leachate level in the sumps at the time of monitoring. This data is recorded onto a field form by the Bioreactor Manager.

Leachate quality sampling occurs every quarter. Samples are collected from the leachate pond and from Cells 1-6. The samples are taken from sampling ports located in the valve vaults of the leachate pump stations. Leachate samples are collected in sample bottles and sent to Pace Analytical for analysis of:

On-site analysis of the leachate is also performed using a Horiba U-22 water quality meter. The Horiba unit tests for:

The sampling process is dated and recorded in a monitoring log by the Bioreactor Manager.

Leachate Recirculation

The quantity of leachate recirculated is recorded for each injection event using the magnetic flow meter installed at the leachate pond pump station. The Bioreactor Manager records the quantity of leachate injected and identifies the specific HIT/SGT used for the injection event.

Landfill Gas

The gas collection component of the Retrofit System has been replaced with a gas to energy system and has been in operation since November 2011. Gas composition and flow data is being continually monitored and recorded.

Landfill Settlement

Settlement plates were installed in 10 locations within the retrofit area. The plates are surveyed quarterly to monitor the rate of waste settlement.

Landfill Temperature

To date, no leachate below 50?F has been allowed to be recirculated for fear of impacting decomposition. Some colder leachate will be injected into Cell 6 HIT to see if it causes any significant drop in temperature. If the results are favorable then the project team will consider allowing leachate colder than 50?F to be used on a regularly basis. Temperature is being monitored in Cell 6 since July 2012 to a get background data prior to leachate recirculation.

Effective Waste Density

Since settlement plates are difficult to maintain in active cells, effective waste density is being added to the monitoring program for Cell 6 to assess the impact of wetting on landfill capacity. A topographic survey of Cell 6 is used to compute the volume of waste and cover soil in Cell 6 on a quarterly basis. Waste tonnage records are used to calculate the effective density of the waste which is defined as: the weight of disposed waste/the combined volume of waste and cover soil. Effective density is not the actual density since cover soils are not weighed prior to placement.