ABSTRACT
A novel heterotrophic nitrification-aerobic denitrification bacterium, identified as Janthinobacterium sp. M-11, was isolated from the Songhua River. When the initial ammonium concentration was 5â¯mg·L-1, 98% of ammonium was removed under cold condition (2⯰C) with the C/N ratio of 5 at initial pH 7 and aerobic condition, which demonstrated the significant ammonium removal capacity of M-11 with low nutrient consumption at cold temperature. Denitrification processes under aerobic and anaerobic conditions were also investigated. 89% of nitrite and 89% of nitrate were removed under aerobic condition. Under anaerobic condition, 93% of nitrite and 98% of nitrate were removed. Interestingly, a high amount of nitrite accumulation was observed in the mid-stage of anaerobic denitrification for nitrate. This special phenomenon was probably because of the existence of narG gene amplified in the strain M-11, which would encode membrane-bound nitrate reductase and accelerate the nitrate conversion rate of M-11 under anaerobic condition.
Subject(s)
Denitrification , Nitrates , Aerobiosis , Ammonium Compounds , Heterotrophic Processes , Nitrification , Nitrites , NitrogenABSTRACT
An upflow anaerobic sludge bed (UASB) system with sludge immobilized on granular activated carbon was developed for fermentative hydrogen production continuously from herbal medicine wastewater at various organic loading rates (8-40 g chemical oxygen demand (COD) L(-1) d(-1)). The maximum hydrogen production rate reached 10.0 (±0.17) mmol L(-1) hr(-1) at organic loading rate of 24 g COD L(-1) d(-1), which was 19.9% higher than that of suspended sludge system. The effluents of hydrogen fermentation were used for continuous methane production in the subsequent UASB system. At hydraulic retention time of 15 h, the maximum methane production rate of 5.49 (±0.03) mmol L(-1) hr(-1) was obtained. The total energy recovery rate by co-production of hydrogen and methane was evaluated to be 7.26 kJ L(-1) hr(-1).
