Enhanced nitrate removal and fouling behavior in a denitrifying membrane bioreactor: impacts of carbon source and C/N ratio

2020 ◽  
Vol 207 ◽  
pp. 86-98
Author(s):  
Zhaozhao Wang ◽  
Peng Gao ◽  
Lina Yan ◽  
Chunyu Yin ◽  
Simin Li
2009 ◽  
Vol 60 (2) ◽  
pp. 517-524 ◽  
Author(s):  
S. Kavitha ◽  
R. Selvakumar ◽  
M. Sathishkumar ◽  
K. Swaminathan ◽  
P. Lakshmanaperumalsamy ◽  
...  

Brevundimonas diminuta MTCC 8486, isolated from marine soil of coastal area of Trivandrum, Kerala, was used for biological removal of nitrate from ground water collected from Kar village of Pali district, Rajasthan. The organism was found to be resistance for nitrate up to 10,000 mg L−1. The optimum growth conditions for biological removal of nitrate were established in batch culture. The effect of carbon sources on nitrate removal was investigated using mineral salt medium (MSM) containing 500 mg L−1 of nitrate to select the most effective carbon source. Among glucose and starch as carbon source, glucose at 1% concentration increased the growth (182±8.24 × 104 CFU mL−1) and induced maximum nitrate reduction (86.4%) at 72 h. The ground water collected from Kar village, Pali district of Rajasthan containing 460±5.92 mg L−1 of nitrate was subjected to three different treatment processes in pilot scale (T1 to T3). Higher removal of nitrate was observed in T2 process (88%) supplemented with 1% glucose. The system was scaled up to 10 L pilot scale treatment plant. At 72 h the nitrate removal was observed to be 95% in pilot scale plant. The residual nitrate level (23±0.41 mg L−1) in pilot scale treatment process was found to be below the permissible limit of WHO.


2015 ◽  
Vol 71 (7) ◽  
pp. 1019-1025 ◽  
Author(s):  
Chuanfu Wu ◽  
Danqi Tang ◽  
Qunhui Wang ◽  
Juan Wang ◽  
Jianguo Liu ◽  
...  

A suitable carbon source is significant for biological nitrate removal from groundwater. In this study, slow-release carbon sources containing polylactic acid (PLA) and starch at 8:2, 7:3, 6:4, 5:5, 4:6, and 3:7 ratios were prepared using a blending and fusing technique. The PLA/starch blend was then used as a solid carbon source for biological nitrate removal. The carbon release rate of PLA/starch was found to increase with increased starch content in leaching experiments. PLA/starch at 5:5 mass ratio was found to have the highest denitrification performance and organic carbon consumption efficiency in semi-continuous denitrification experiments, and was also revealed to support complete denitrification at 50 mg-N/L influent nitrate concentration in continuous experiments. The effluent nitrate concentration was <2 mg NO3–-N/L, which met the national standard (GB 14848-93) for groundwater. Scanning electron microscopy results further showed that the surface roughness of PLA/starch increased with prolonged experimental time, which may be conducive to microorganism attachment. Therefore, PLA/starch was a suitable carbon source and biofilm carrier for groundwater remediation.


2005 ◽  
Vol 51 (6-7) ◽  
pp. 357-364 ◽  
Author(s):  
H. Mo ◽  
J.A. Oleszkiewicz ◽  
N. Cicek ◽  
B. Rezania

A hydrogenotrophic denitrification system, comprising a suspended growth membrane bioreactor (MBR) with membrane hydrogen gas diffusion, was developed to remove nitrate from groundwater. A hollow fiber gas permeable membrane module was designed for hydrogen delivery and a commercially available hollow fiber membrane module was used for solid/liquid separation. The MBR was operated at an SRT of 20 days and at room temperature. Four nitrate loading rates of 24, 48, 96 and 192 NO3−-N mg l−1 d−1 were applied to the system. As the nitrate loading was raised, pH increased due to increased denitrification and release of OH− ions. The oxidation reduction potential (ORP) remained fairly stable when full denitrification was achieved, but increased when nitrate loading rates reached 192 NO3−-N mg l−1 d−1 and residual nitrate was present in the reactor. Nitrate removal was complete (100%) in the first three nitrate loadings and 72% in the system with 192 NO3−-N mg l−1 d−1. Nitrate utilization rates of 30.6, 23.4, and 37.7 g NO3−-N m−3 d−1 were achieved in the first three loadings. Average effluent dissolved organic carbon (DOC) concentration of approximately 8 mg l−1 was observed in all four nitrate loading regimes, possibly owing to the generation and release of soluble microbial bi-products (SMP).


2004 ◽  
Vol 48 (11-12) ◽  
pp. 489-495 ◽  
Author(s):  
S. Aslan ◽  
A. Türkman

Denitrification of drinking water was studied using various natural organic solid substrates (NOSS) such as poplar, hornbeam, pine shavings and wheat straw as a carbon source in a batch unit. The highest nitrate removal efficiency was observed with the wheat straw, so it was chosen as the carbon source for biodenitrification in an upflow laboratory reactor. In order to remove solid particles from the effluent water, a sand filter unit was placed after the denitrification reactor. The soluble DOC contents in the reactor affected the efficiency of nitrate elimination and nitrate concentration of the effluent water remained below acceptable values (50 mg/l NO3-). In order to remove colour, DOC and nitrate from the water, powdered activated carbon adsorption studies were performed in the batch unit.


1994 ◽  
Vol 30 (11) ◽  
pp. 69-78 ◽  
Author(s):  
Yongwoo Hwang ◽  
Hiroshi Sakuma ◽  
Toshihiro Tanaka

Several batch tests and pilot-scale investigations on biological denitrification with isopropanol were performed. Isopropanol was converted to acetone by microbial oxidation during denitrification. Isopropanol itself little contributed to denitrification in practice while the converted acetone played a role of a main hydrogen donor. A larger quantity of nitrite intermediate was formed by using methanol compared to the case of isopropanol. The measured requirement of isopropanol was 2.0 mg mg−1 NO3-N, and was 2/3 of methanol. The oxygen equivalent of isopropanol for nitrate removal was almost the same as that of methanol. The denitrifier net growth yield for isopropanol was greater than for methanol. In order to maximize the denitrification rate, it is essential to convert isopropanol to acetone rapidly by accurate dosing for nitrogen load because the denitrification rate was accelerated by using acetone only. Excessive dose of isopropanol can cause a decrease in the denitrification rate as well as an increase of BOD in the effluent.


2002 ◽  
Vol 93 (3) ◽  
pp. 303-308 ◽  
Author(s):  
Yong-Seok Kim ◽  
Kazunori Nakano ◽  
Tae-Jong Lee ◽  
Sunthorn Kanchanatawee ◽  
Masatoshi Matsumura

2016 ◽  
Vol 74 (2) ◽  
pp. 416-423 ◽  
Author(s):  
Junjun Chang ◽  
Luyao Ma ◽  
Yuanyang Zhou ◽  
Shenghua Zhang ◽  
Weilu Wang

Straws of four ornamental flowers (carnation, rose, lily, and violet) were added into denitrification biofilters using gravel as matrix through vertically installed perforated polyvinylchloride pipes to provide organic carbon for the treatment of nitrate-contaminated wastewater operating in batch mode. Removal efficiencies of nitrate and phosphate, as well as temporal variations of nitrogen and carbon during batches 10 and 19, were investigated and assessed. Nitrate removal was efficiently enhanced by the addition of flower straws, but decreased gradually as the organic substances were consumed. Phosphate removal was also improved, although this very limited. High nitrate removal rates were achieved during the initial 12 h in the two batches each lasting for 3 days, along with the depletion of influent dissolved oxygen due to aerobic degradation of the organic compounds. NO2−-N of 0.01–2.83 mg/L and NH4+-N of 0.02–1.69 mg/L were formed and both positively correlated to the nitrate reduced. Inorganic carbon (IC) concentrations increased during the batches and varied conversely with the nitrate contents, and could be indicative of nitrate removal due to the highly significant positive correlation between NO3−-N removed and IC concentration (r2 = 0.881, p < 0.0001). It is feasible and economical to use the denitrification biofilter to treat nitrate-contaminated wastewater, although further optimization of carbon source addition is still required.


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