Biomedical subjects

Qifang Luo

Publications and source records attributed to Qifang Luo.

5 recordsLinked to original sources

PubMed2003

[Study on denitrification using different carbon sources].

In this study, bench scale tests were conducted to study the potentials of immobilized denitrifier to reduce nitrate in the presence of 4 different carbon sources: glucose, cane sugar, methanol and acetic acid. The results showed that the carbon sources can be used by the immobilized bacteria as exogenous carbon sources. While using methanol, the average denitrifying velocity was lower than the others. Dissimilatory reduction to ammonium was not significant and accounted for less than 5% of reduced nitrate. By a 6-hour hydraulic residence time, the denitrification rates were higher than 96%. The nitrate enriched water of S lake was also treated by the immobilized denitrifier to study the character of denitrification, especially on the using of natural carbon sources as electron donotor. The results showed that more than 90% of the nitrate in the water could be reduced by the immobilized bacteria, and more than 20% of the natural carbon sources in the water could be used by the immobilized cells.

Acetic Acid↗

PubMed2003

[Study on biodegraded characteristics of endocrine disruptor di-n-butyl phthalate].

The biodegraded Characteristics of di-n-butyl Phthalate (DBP), endocrine disruptor were studied. The activated sludge was acclimated using DBP as the only carbon in the culture medium. DBP concentration was increased progressively from 0.05 g/L to 0.5 g/L. The degradation tests were carried out on the constant temperature table using the acclimated sludge at different PH, temperature, DBP concentration and hydraulic residence time. The results showed that DBP could be rapidly degraded-nearly 90% in 48 hours. The appropriate condition for DBP degradation was pH 6.0-8.0, temperature 25 degrees C-35 degrees C, DBP concentration no more than 300 mg/L, and hydraulic residence time 12 h-24 h. The form of biodegradation of DBP can be described as the first-order reaction model.

Biodegradation, Environmental↗

PubMed2002

[Distribution and role of denitrifying, nitrifying, nitrosation and ammonifying bacteria in east lake].

The most probable number (MPN) method was employed to determine the distribution and role of four nitrogen cycle bacteria, including ammonifying bacteria, denitrifying bacteria, nitrosobacteria and nitrobacteria, in East Lake, Wuhan. The results showed that the n(MPN) of nitrosobacteria in water was most in rainy season and least in dry season, while the number in common season between them. The n(MPN) of water nitrobacteria in rainy season was less than in the other two seasons. The n(MPN) of water ammonifying and denitrifying bacteria were most in common season, least in dry season. The n(MPN) of nitrosobacteria in sediment in rainy season was more than that in other seasons. The n(MPN) of sediment nitrobacteria was most in dry season while denitrifying bacteria was more in dry season than in other seasons. The n(MPN) of ammonifying bacteria had no difference among three seasons. Compared with water phase, the n(MPN) of nitrosobacteria in sediment phase was more in rainy and dry season (p < 0.01), while nitrobacteria's number was prevailing in water phase during common and rainy season while denitrifying bacteria's was prevailing only in common season(p < 0.01). The ammonifying bacteria had no difference in water and sediment. The results demonstrated that the difference in distribution of four nitrogen cycle bacteria in two phase and three season played a significant role in nitrogen removal, which promoted ammoniation, nitrification, nitrosification and denitrification in lake. The study also found that the lg[n(MPN)] of denitrifying and ammonifying bacteria in water and sediment had significant correlation with the catching gas volume(p < 0.001). Furthermore, different season had different gas volume (p < 0.01), which showed that ammoniation and denitrification could convert organic nitrogen and nitrate into gas nitrogen(NH3, N2O, N2) and also varied greatly with different season.

Ammonia↗

PubMed2002

[Variations and transformations of nitrogen pollutants in source and tap water of D-lake].

Ammonia, nitrite and nitrate pollutions and variations in source water and tap water of D-Lake are investigated. The removal effects of nitrogen in routine proceeding of water production and the transformations of the different forms of nitrogen in natural condition with simulated test are studied at the same time. The results show that the nitrogen pollutions in source and tap water of D-waterworks are higher than T-waterworks', although both waterworks have same resource. Compared with D-waterworks, the nitrogen pollutions of source and tap water in Z-waterworks are lower than D-waterworks' and they have different variation and distribution. The forms of nitrogen could be partly transformed during the routine production, but the total percentage of nitrogen removal efficiency is not significant (just about 20%). The simulate test shows that NH4+(-)N could change into NO2-(-)N, while No2-(-)N into NO3-(-)N, which is partly transformed into nitrogen gas by microorganism and majority of which are remained in tap water by form of NO3-(-)N.

Ammonia↗

PubMed2002

[Study on the denitrification of drinking water with upflow anaerobic sludge blanket reactor].

The characteristics of denitrification was investigated with a pilot scale upflow anaerobic sludge blanket (UASB) reactor at room temperature. The results showed that when brewery waste degrading sludge was used as seed, the starting process was completed within 7 weeks, with hydraulic residence time shortened from 11.1 h to 4.7 h, COD/N/P = 200/5/1 and influent NO3-(-)N concentration increased from 5 mg/L to 100 mg/L. After the process starting, the most probable number [n(MPN)] of denitrifying bacteria was 60 folds and the maximum velocity of CH4 produced was 10 folds higher than before. The removal efficiency of No3-(-)N was 99%, C/N ratio and pH value were investigated as effect factors. When C/N > = or 1.0, the NO3(-)-N removal efficiencies were not different from those of C/N < 1.0 groups significantly. The pH value could meet the discharge standards.

Nitrates↗