Photon Control”sFocus Probe optical flowmeters are currently being used to measureflowratesof biogas at sewage digesters in Vancouver. The methane-richbiogas posed a problem for conventional flowmeters, which could notcope with the low flowrates, low pressure, and high humidity specificto biogas. Using optical laser beams to measure the velocity ofnaturally-occurring particulates, the Focus Probe enables accurate flowdetermination despite pipe vibration, acoustic noise, andgas condensation. Featuring a high turndown ratio of 1000-to-1, theFocus Probe provides sewage treatment authorities with a source of datato optimize sewage digestion processes,control biogas production, and reduce greenhouse gas emissions.