Text Box: The purpose of these experiments was to evaluate some factors that would influence the CH4 generation potential and solids quality of anaerobically digested yard waste feedstock and yard waste combined with food.   Specifically, experiments were designed to analyze the CH4 production potential from both a well-characterized yard waste mix and from a yard waste plus food mix. A second objective was to evaluate CH4 production success in the absence of external heating. One operating mode that was being considered by the system designers was to allow digestion to occur at the ambient temperatures of the Piedmont North Carolina climate. Finally, a trial was conducted where initial supplemental alkalinity was provided in the absence of manure inoculant to stabilize the pH until a natural methanogen population could become established.   The latter trial was conducted because a proposed start-up plan for the facility did not allow for gradual filling of the digester; the reactor was to be completely filled at the onset of digestion. Manure addition was proposed to provide a methanogen population at start-up to prevent early instability from rapid acidification and volatile fatty acid accumulation. Since the manure was only to be used for good start-up, and since it would elevate the pathogen load of the digested solids, some experiments were directed at assessing whether good digester start-up could be achieved without manure addition.    

                                                                     

                                                                                       

 

                                                                             

Text Box: The team at work   Lead   Text Box: 50 gal pilot digester   Lead Text Box: Feedstock Grass, leaves, wood Lead