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.
Leachate
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.