Autonomous remote gas sensor network platforms with applications in landfill, wastewater treatment and ambient air quality measurement

摘要

Carbon dioxide (CO2) and methane (CH4) are produced by anaerobes on decaying matter. This gas production is present in landfill sites and in anaerobic lagoons in waste water treatment plants (WWTP). Monitoring gas production is important as CO2 can collect in low lying areas and asphyxiates, CH4 is flammable in the 5%-15% v/v gas/air region. Both CO2 and CH4 are greenhouse gases, CH4 having 25 times the global warming potential of CO2. At landfill site perimeters, CO2 and CH4 must not exceed the EPA thresholds of 1.5% and 1.0% respectively. Gas production is infrequently measured on individual wells due to expense and labour-intensity. In WWTPs, the monitoring of gas emissions from anaerobic lagoons can enable the bio-digestion process to be optimised and ensure they remain in safe levels. Gas levels can be reduced by modifying the chemistry of the process and by water agitation. Typically measuring gas emissions requires a handheld device to be brought on site and connected to the gas source at each point of interest. This is expensive, time consuming and results in infrequent data, sometimes as long as one month between samples.ududTo address the issue of infrequent sampling rates and to provide the plant managers with near real time data from multiple points on site autonomous wireless gas sensing platforms have been developed, multiples of which can be deployed across a landfill/WWTP to sample gas and pressure up to 12 times per day. Data is sent via GSM to the cloud and can be accessed via an online portal.