Environmental Applications for PIDs
Photoionisation detectors (PIDs) are commonly used to monitor hazardous compounds during remediation works, but as Rockall Safety explains, PIDs have a diverse range of applications.
PIDs are continuous, broad-spectrum monitors capable of detecting most volatile organic compounds (VOCs), ranging from simple compounds like methylene chloride (CH2 Cl2 ) to complex ones, such as diesel fuel.
Environmental contractors and consultants frequently use these devices to monitor the remediation of industrial waste sites and decommissioned military bases.
The detection ranges of these devices vary. For example, the MiniRAE 3000+ offers detection in the range of 0.1 to 15,000 ppm, while the ppbRAE 3000+ measures from below 1 ppb to 10,000 ppm, and fixed RAEGuard PIDs have a detection range of 0.01 to 100 ppm, 0.1 to 1000 ppm, or 1 to 1000 ppm.
Soil remediation and monitoring for underground storage leaks
0.1 to 15,000 ppm range PIDs are ideal for detecting BTEX compounds (benzene, toluene, ethyl benzene, xylene) and Total Petroleum Hydrocarbons (TPH) found in gasoline, diesel, and jet fuel. This makes it an excellent tool for headspace analysis to identify soil contamination from leaking underground storage tanks. Environmental engineers and professionals in the petroleum industry can deploy this instrument to monitor contamination at gas stations, industrial sites, commercial transportation refuelling areas, and defence facilities.
Environmental soil contamination monitoring
Environmental engineers and consultants often use these larger range PIDs for monitoring soil contamination at industrial real estate sites and former military bases. These devices help determine whether soil contains VOCs, providing critical information before the sale of land. Conducting due diligence and environmental impact assessments ensures that land can be safely rezoned for homes, shops, or parks.
Environmental remediation process control
0.01 to 100 ppm range, fixed photoionisation detectors are commonly used at remediation sites to monitor effluent levels and assess the efficiency of treatments such as soil vapor extraction, incineration, and bioremediation. The RAEGuard PIDs, for example, provide 4-20 mA outputs for continuous data recording and feature two dry contacts for process control if concentrations exceed alarm thresholds. The MiniRAE 3000+, which can run continuously and stores up to 15,000 datalogging points, is suited for monitoring treatment effluent levels.
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Headspace screening
Leading PIDs are highly effective for determining VOC levels in drinking water. Hydrologists and environmental engineers use it to monitor chlorinated solvents (e.g., carbon tetrachloride) and VOCs (e.g., toluene) in groundwater at drilling sites, closed industrial plants, military bases, and nuclear facilities.
Soil and water headspace screening
Headspace analysis can help determine contamination levels in soil or water. Samples are collected in jars, which are partially filled and sealed with aluminium foil and a lid ring. After the contents reach room temperature, PIDs can be used to measure VOC concentration by inserting the probe through the foil to assess contamination levels.
Hazardous waste monitoring
For hazardous waste monitoring, PIDs assist contractors, engineers, and industrial hygienists in detecting toxic vapours and VOCs. PIDs are particularly useful for identifying hazardous areas at old disposal sites, disused industrial plants, and former military bases, as well as during the transport of hazardous waste. They also help determine the appropriate personal protective equipment (PPE), such as SelfContained Breathing Apparatus (SCBA), required for worker safety.
Conclusion
Photoionisation Detectors (PIDs), such as the MiniRAE 3000+, UltraRAE 3000+, and RAEGuard models provided by Rockall Safety, play a vital role in environmental applications by detecting volatile organic compounds (VOCs) in a wide range of settings. Whether it’s identifying underground storage leaks, performing headspace screening for water and soil contamination, or ensuring safety at hazardous waste sites, PIDs offer a robust solution for environmental monitoring, ensuring accurate, continuous detection and reliable data for process control and safety assessments.