NCD980602163_19971006_Warren County PCB Landfill_SERB C_Monitoring System at the PCB Landfill-OCR

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October 6, 1997
To:
From:
Re:
Bill Meyer, Director, Division of Waste Management
Mike Kelley, Deputy Director, Division of Waste Management /Jl
Ed Mussler, P.E., Solid Waste Section, Division of Waste Manageme~
Monitoring System at the PCB Landfill, Warren County, North Carolina
Gentlemen,
This memorandum provides information on the monitoring equipment which has been installed
at the PCB landfill in Warren County. The system consists of a battery powered data logger
(computer), and instruments which monitor and record rainfall, ambient temperature, ambient
pressure, and water levels within the landfill. Water levels are being monitored in the two new
boreholes which were put in the landfill in February, 1997.
The instruments take measurements once per hour, and the results are stored in the data logger
(rainfall is cumulative and the hourly total is stored). Periodically, division staff go to the landfill
and download the stored data from the data logger into a laptop computer. Reports can be
generated and the data is available in comma delimited ASCII files for import into most common
data base and spreadsheet programs. Currently the data is downloaded every 7-10 days, but the
battery is expected to last for at least 30 days in the winter, more in the summer.
The instruments were installed and the system debugged on September 23 and 24, 1997. Hourly
readings have been recorded since two PM on September 24. Data was last retrieved October 3.
One water level instrument was installed in the south borehole. Additional cable is required to
install the second instrument in the north borehole. The cable has been ordered and it is expected
that it will be installed before the 15th of October.
A summary of the equipment installed at the landfill may be found on the attached specifications
sheet. If there are any further questions, please do not hesitate to contact me.
. ' ' ,
Data Logger
VWP Interface
Battery
VS Piezometer
Software
Pressure Sensor
Rain Gauge
Temperature
PCB Landfill Monitoring Equipment
Specification Sheet
Met One Instruments, Grants Pass, Oregon. Model 457. An enhanced
Campbell Scientific CRl O Data Logger.
Campbell Scientific digital to analog interface. Used to communicate with
the VS Piezometers.
Lowes, 12 volt, 135 amp-hour, rechargeable lawn tractor battery.
Slope Indicator, Vibrating wire strip piezometer. Used to measure
pressure, thus water level elevations and changes in the boreholes. Very
accurate,+/-0.001 feet. The instrument is used to measure water levels in
the landfill. It was zeroed with measurements taken manually with an
electronic water level indicator. The instrument converts water pressure to
a tensional load on a fixed steel strip (similar to a tuning fork). Tension
increases linearly with pressure. 1 magnetic coil excites the strip, which
vibrates at a known frequency. The vibration excites the strip which
vibrates and generates voltage pulses. These pulses are counted, calibrated,
and converted to an elevation of water for the output.
Custom written. Meteorological portion by Met One, VSP by Slope
Indicator, debugged by division consultant.
Met One, Model 090D-solid state barometer. Provides absolute (site
specific) pressure. Monitors and calibrated for 26-32" of Mercury (Hg)
pressure. Temperature rated for -18 to 50 degrees C (-0.4-122 degrees F).
Accurate to +/-0.04" of Hg.
Met One, tipping bucket. Model 370, 8". Measures 0.01" ofrain. Mercury
switch. Accurate to+/-1% at 1 "-3" ofrain per hour, at 70 F.
Campbell Scientific. Model 107 with a model 41301 radiation
shield. Mounted on and 8 foot PVC pole. Range -35-50 degrees C.
Sensitivity of<+/-0.4 C within -24-48 degrees C (-11.2-118.4
degrees F).