The solid waste landfills as source of atmosphere contamination
The municipal solid waste landfills are often considered as important sources of atmosphere contamination due to diffusive emissions of landfill gas (LFG) from the cover. As known LFG is composed by greenhouse gases, i.e. CH4 and CO2, and other compounds present in trace with toxic and malodorous characteristics. In order to evaluate the health consequences and the contribution to the greenhouse effect, the D.Lgs. 152/2006, acknowledging the EU Directive 96/61/CE, imposes to monitor and to evaluate the LFG diffused from landfill soil cover.
Techniques to quantify the flux released from soil
The numerous techniques to quantify the flux released from soil (landfill) can be divided in three main categories:
- Measurements of the gas concentration gradient
- Micro-meteorological techniques (e.g. eddy correlation)
- Enclosure based techniques (static and dynamic accumulation)
How to intervene: the portable fluxmeter monitoring solution
The Flux-Meter is an integrated instrument, based on accumulation chamber, for the measurement of the diffuse degassing phenomena. Why a static non-stationary technique?
- It is the least affected by environmental and meteorological parameters (Trègourés et al., 1999)
- It allows soil gas flux measurements without any information about soils characteristics and flux conditions or ranges
- These methods are much faster in respect to other techniques
The most important advantage of FLUX-meter is represented in the integration of high performance detectors, able to measure very low CH4, CO2, H2S and VOC concentrations, in a portable instrumentation characterized by manageability, simple use and fast flux measurements. All these characteristics respond to the needs of scientists and engineers engaged in the determination of gas exchange at the soil-air interface linked to the gas escape from the landfill cover, from agricultural soil, from volcanic area and from geothermal exploration.
The West Systems Portable Fluxmeter technical features
The integrated instrument realized by West Systems consists of: an accumulation chamber with specific shape; detectors for the measurements of CH4, CO2, H2S and VOC; a pneumatic system; battery; GPS and a Personal Digital Assistant (PDA). In particular, to meet the needs of the market, WEST Systems has developed a specific CH4 detector, with the sensitivity, selectivity and stability necessary to measure diffuse flux down to extremely low levels. The new CH4 detector is based on Infrared Tunable Diode Laser Absorption Spectroscopy (TDLAS) combined with a Herriot multi pass cell in order to augment the length of the optical path. Therefore very low detection limits are achieved, i.e. 0.1 ppm, allowing to measure low CH4 concentration till to atmospheric levels (around 1.7 ppm). All the sensors with electronic interface, pump, pneumatic filters and light NiMH battery are installed in the backpack. In that way the instrument is easily moved and its total weight, including accumulation chamber, is less than 10 Kg. The entire instrument is managed by a small handheld computer, the PDA, based on MS Windows Mobile, which receives and exchanges information with the instrument via a Bluetooth wireless connection. A specific software allows the acquisition of specific
The entire instrument is managed by a small handheld computer, the PDA, based on MS Windows Mobile, which receives and exchanges information with the instrument via a Bluetooth wireless connection. A specific software allows the acquisition of specific specie (CO2, CH4, H2S, VOC) concentration data vs time, of the position (GPS data) and other, such as pressure and temperature of the measuring cells of the detectors and the voltage of the battery of the whole system. Then the concentration data are represented in function of time, the flow curves acquired are visualized in real time and can be checked and validated by the operator, interacting via the touch screen. Therefore the portable FLUX-meter permits to carried out speedy (2-3 minutes time for a measurement) and reliable punctual measurements. The flux data can also be processed by Sichel software, developed by WEST Systems, in order to estimate the total amount of LFG discharged into the atmosphere and consequently lost by
The flux data can also be processed by Sichel software, developed by WEST Systems, in order to estimate the total amount of LFG discharged into the atmosphere and consequently lost by captured system. Besides, the elaboration of isoflux maps allow an easy visualization of zone of high fluxes.
All the sensors with electronic interface, pump, pneumatic filters and light NiMH battery are installed in the backpack. In that way the instrument is easily moved and its total weight, including accumulation chamber, is less than 10 Kg. The entire instrument is managed by a small handheld computer, the PDA, based on MS Windows Mobile, which receives and exchanges information with the instrument via a Bluetooth wireless connection.
A specific software allows the acquisition of specific specie (CO2, CH4, H2S, VOC) concentration data vs time, of the position (GPS data) and other, such as pressure and temperature of the measuring cells of the detectors and the voltage of the battery of the whole system. Then the concentration data are represented in function of time, the flow curves acquired are visualized in real time and can be checked and validated by the operator, interacting via the touch screen. Therefore the portable FLUX-meter permits to carried out speedy (2-3 minutes time for a measurement) and reliable punctual measurements. The flux data can also be processed by Sichel software, developed by WEST Systems, in order to estimate the total amount of LFG discharged into the atmosphere and consequently lost by captured system. Besides, the elaboration of isoflux maps allow an easy visualization of zone of high fluxes.
The West Systems Portable Fluxmeter Brochure – download here
NOTE.
The “Flux-Meter: implementation of a Portable Integrated Instrumentation for the measurement of CO2 and CO4 diffuse flux from landfill soil cover“ is a study of E. GIOVENALI*, L. COPPO*, G. VIRGILI*, D. CONTINANZA*, I. MINARDI*, B. RACO**
Full research available: download here
See also the Slides Presentation : The FluxMeter: Implementation of a portable integrated instrumentation for the measurement of CO2 and CH4 diffuse flux from landfill soil cover.
For Further information:
www.portablefluxmeter.com
Patricia Vergara, Commercial Dept.
mail: p.vergara@westsystems.com
