STUDIES ON THE TREATMENT OF BLACK LIQUOR FROM WHEAT STRAW SODA―AQ PULPING PROCESS BY PHOTOSYNTHETIC BACTERIUM

摘要

Photosynthetic Bacterium (PSB) was the name of a group Bacterium, which the Bacterium performance photosynthetic and not release the Oxygen in anaerobic condition. It includes the rhodospirillum Bacterium and the other species. They widely distributed in the rice field, marsh, lakes and rivers. The body of this Bacterium contains rich protein, vitamin as so on, which can promote the growing of the animals and water living things. Photosynthetic Bacterium has the potential to clean the wastewater. Since 1967, the researchers have been confirming that the COD and BOD of the wastewater can be reduced by Photosynthetic Bacterium. Using Photosynthetic Bacterium to treat the high concentrate organic wastewater was taken more interest in the peoples. The characteristics and biodegradability of the black liquor from wheat straw Soda-AQ pulping process was analyzed firstly in this study. The content of the wheat straw black liquor is high in the lignin, its CODcr reached 89838mg/L and BOD_5 reached 20850mg/L, so that it must be pretreated to suit for bacterial treatment. The treatment of wheat straw black liquor by Photosynthetic Bacterium (PSB) was researched, at the same time, a process of the acid pretreatment and PSB treatment was advanced for treating the black liquor. The factors which affect the PSB treatment are treating temperature, time, illumination strength, effluent concentration and inoculation dose. The i better condition for PSB treatment are 30℃ aerobic, darken lightly aerobic or illuminating anaerobic treatment by mixed culture. The process proposed in this paper can be used for treating wheat straw black liquor. The advantages are performed well under high loads and good stability. The removal rates of CODcr and BOD_5 were found to be 70%, 14% respectively after acid pretreatment and 65%, 82% after PSB treatment.