Carbon monoxide detection in waste mounds
GA2000 now supersdeded by the GA5000 portable landfill gas analyser
National Institute for Environmental Studies
20 million tons of waste from the tsunami has been collected into about 200 mounds, similar to landfill sites. Each site is monitored by inserting a 2cm diameter pipe for measuring temperature. The team, led by Dr. Kazuto Endo of the National Institute for Environmental Studies at Tsukuba, are focusing on 10 sites where they are monitoring every two months, sending the results to government.
The main concern is prevention of fires within the waste sites. Researchers are monitoring carbon monoxide (CO) with a target of less than 50ppm, as well as methane (CH4) and oxygen (O2). The key factor in controlling gases and, most significantly, fire risk is managing the depths of the waste piles, which are ideally no deeper than 5m. CH4 can be around 30%, particularly in areas which had a lot of food or fish. A combination of unsaturated fatty acids and oxygen can cause temperatures to rise to over 100 degrees. Below 70 degrees the reaction is limited, so the priority is to control temperature. 2,000 tons of waste is treated every day. There were 30 fires in 2011 but only 3-4 during 2012. Monitoring of the site is likely to continue until March 2014 which is the end target for the clean-up. Dr. Endo’s team have been using a GA2000 portable gas analyser supplied by Geotech and are now changing to a GA5000.