Designed and manufactured in Germany, the Awi-Flex multifunctional biogas analyzer is supplied with a small air compressor that regulates air injection into the digester (above the sludge level) to between 0.5 and 1 vol.% for breaking down H2S into elemental sulfur and water. By accurately measuring the O2 and H2S levels in the biogas and using a combination of PI and fuzzy logic control, H2S levels can be reduced by up to 80%, says the company. The Awi-Flex analyzer is designed to measure CH4, CO2, H2S, O2 and H2, with up to five measuring points. It features an integral PC that enables easy access to recorded data, sensor parameters and system diagnostics, with 4–20-mA, Profibus and Ethernet communications. — Allison Engineering, Basildon, U.K.