Herbst Umwelttechnik GmbH

Herbst Umwelttechnik GmbH (HUT), based in Berlin, Germany, has operated in environmental protection for over 38 years, specializing in the planning, construction, and maintenance of process engineering systems for gas, water, and sludge treatment. The company's flagship technology is the Herbst-Loop-Reactor (Herbst-Schlaufenreaktor), a patented continuous fermentation system that couples mesophilic and thermophilic digesters in a closed-loop process. Operating at atmospheric pressure below 70°C, it achieves biogas yields exceeding 350 Nm³ per tonne of fresh rice or soy straw with methane concentrations above 60%. The process accepts challenging substrates including rice straw, soy straw, elephant grass, and co-substrates like pig and cattle manure, producing zero liquid waste through filtrate water recirculation. Digestate is dewatered to approximately 20% dry residue suitable for use as organic fertilizer, with optional MAP precipitation (magnesium-ammonium-phosphate) for ammonium and phosphate recovery. HUT also offers water treatment technologies including FerroSorp Plus, a high-purity iron hydroxide granulate for arsenic and phosphate removal from drinking water down to WHO limits of 10 µg/l; the H2S-Clean adsorption system for dissolved hydrogen sulfide removal; GoPur 3000 polymer for uranium separation; and the KS-Process for sediment dewatering via dual flocculation and belt filtration exceeding 50% dry matter. The company has participated in BMBF-funded research on bank filtrate water treatment in Vietnam and decentralized small incineration plants for organic mixed waste.