Energy and Protein Production from Pulp Mill Wastes. Annual Report,June 15, 1977--June 15, 1978.

摘要

Studies on desugared spent sulfite liquor, DSSL,subjected to ozonation indicate that this complex organic substrate in water solution reacts readily with ozone to produce lower molecular weight organic fragments which can be metabolized by a variety of microorganisms. Ozone uptake is complete up to approximately 15 g/l and results in an increase of 35% BOD and a reduction of 16% COD. The production of BOD is pH dependent with a maximum occurring at aroung pH 3. The production of methane via fermentation of DSSL is greatly enhanced by the ozonation reaction. Methane production on raw DSSL is only 45.3standard cc/1of DSSL. After ozonation of the DSSL during which 15 g/l of ozone are reacted,the resulting product yields 1239standard cc/1. The hypothesis that methane is produced from acetic acid,held by several prior workers,could not be corroborated in this study. Liquor remaining in the fermenter after gas production has essentially ceased in much richer in acetic acid than ozonated DSSL. Continuous fermentation studies operated to optimize gas production produced a fermentate containing 3.96 g/l of acetic acid. The production of protein accomplished through the growth of Torula yeast on DSSL is also enhanced by the ozonation reaction. Two variants show minimal growth on unozonated DSSL but cell densities of 5 g/l were obtained with the rough variant when this substrate has been ozonated. In contrast to the methane fermentation which showed high ozone consumption to be beneficial,the yeast prefer very minimal ozone reaction. Yeast growth was not vigorous on methane fermentate shown to be rich in acetic acid. (ERA citation 04:021925)