Pilot-scale fermentation of office paper and chicken manure to carboxylic acids
This project focused on scaling up the laboratory fermentation of biomass to
carboxylic acids. Four 1050-gallon tanks were used to simulate four-stage
countercurrent fermentation. Most laboratory fermentations have been performed with
1-L fermentors. The purpose of the pilot plant was to show that the process is scalable.
The inocula were marine and terrestrial microorganisms. Office paper was used
as an energy source, and chicken manure provided the necessary nutrients. The substrate
was 80 wt% office paper and 20 wt% chicken manure. Calcium carbonate was used as a
neutralizing agent and iodoform served as a methane inhibitor. The fermentor
temperature was 40 oC and the pH was 6.0.
The highest total acid concentration obtained was 32.4 g/L, operating with a
volatile solids loading rate (VSLR) of 1 g/(L liq Â·d) and a liquid residence time (LRT) of
80 days. Typical laboratory VSLRs and LRTs are 3 to 10 g/(L liq Â·d) and 10 to 30 days,
respectively. Similar VSLRs and LRTs were not achieved at the pilot scale because the
design was limited by the ability to effectively separate large amounts of solids and
liquids. The bulk of the effort was concentrated on overcoming temperature control and
solids-handling issues. Design modifications included a redesigned temperature control
system and a new material transfer method.
Advisor:Holtzapple, Mark T.; Engler, Cady R.; Glover, Charles J.
School:Texas A&M University
School Location:USA - Texas
Source Type:Master's Thesis
Keywords:fermentation carboxylic acids
Date of Publication:05/01/2005