LANDFILL SURVEY EQUIPMENT
FIT FOR PURPOSE EQUIPMENT
NEAR SURFACE GAS MONITORING / WALKOVER SURVEYS
Near Surface Gas Monitoring is a method used world over to survey for landfill gas emissions. This method focuses on examining point sources (e.g. cracks in landfill cover) where relatively high concentrations of landfill gases may be identified.
Landfill gas monitors are held as close to the surface of the landfill as possible to obtain readings.
The usefulness of data collected through near surface gas monitoring can be effected by:
- Ability to identify and examine point sources
- Accuracy of surveying instrument
- Responsiveness of surveying instrument
- Operator technique
- Environmental conditions
- Timing – Barometric pressure changes throughout the course of the day and therefore gas emissions may be higher or lower depending on the time of day that surveying is performed
NOTE:
Slow response times, for many portable gas detectors and personal gas detectors can compromise the effectiveness of walkover (Near Surface Gas Monitoring) surveys.
Common T90 response times shown below.
- CH4 < 10 seconds
- CO2 < 10 seconds
- O2 < 20 seconds
- H2S < 30 seconds
- CO < 30 seconds
- NH3 < 90 seconds
- H2 < 90 seconds
Taking these response times into consideration, a landfill surveying instrument will require up to 10 seconds to analyse a sample for Methane CH4. When completing Near Surface Gas Monitoring surveys, the operator must understand these response times and adjust walking pace to suit, to ensure the accurate location of leaks. Walking progress along a survey path must be slow and steady to ensure the effective capture of samples.
Fit for purpose surveying instruments feature rapid response times, high sensitivity and should be calibrated to the appropriate target gas or selective to the target gas.
A wide variety of appropriate landfill surveying devices are available and some offer near immediate response rates. This might include laser gas detectors, methane drones, infrared cameras and gas detectors, thermal gas cameras and even methane/ethane monitoring vehicles. Prices to purchase these devices can vary widely, ranging from low cost e.g. $1k USD to $250k USD.
NOTE:
When selecting fit for purpose surveying equipment, constraints imposed by your budget need not affect quality outcomes. It is possible to hire, lease or even share market leading survey devices. Some progressive suppliers are now offering fractional ownership plans over high end equipment, allowing multiple owners for one piece of equipment.
Some devices offer significant efficiency gains over others and may require little to no maintenance or calibration. Return on investment may be achieved over a relatively short period of time for more expensive devices when taking these two factors into consideration.
Of equal importance, some devices offer improved safety and ergonomics for the operator. Drones, methane/ethane vehicles, laser detectors and telemetry systems all allow for the remote monitoring of emissions reducing potential exposure for operators in the field.
Examples of fit for purpose landfill surveying equipment include:
