Operation and Optimization of a Full-Scale Fixed-Bed Reactor for Anaerobic Digestion of Animal Rendering Waste Water

A description of design, efficiency of purification and operating results of an anaerobic fixed bed reactor, which was set in operation in November 1986 to purify waste water from an animal rendering plant, is given. The main subjects of the project were proving the anaerobic digestibility of rendering waste water as well as process engineering and working conditions. The tests showed that waste water from rendering plants is perfectly suited to anaerobic pretreatment. The treatment can be carried out in a single-stage system as most of the organic compounds are volatile fatty acids. The chosen fixed bed loop reactor proved to be a reliable and efficient system-with high security in process. Under the layout conditions(VL_COD of 8 kg/m³ d; HRT of 27 h) a COD reduction of 75 – 80 % was achieved.