scholarly journals Study on the properties of denitrifying carbon sources from cellulose plants and their nitrogen removal mechanisms

Author(s):  
Liang Qi ◽  
Ling Li ◽  
Lin Yin ◽  
Wen Zhang

Abstract Carbon sources of cellulose plants are the promising materials that enhancing the activities of denitrifying bacteria in the groundwater system. To further verify the denitrification performance of cellulose plants and the main factors of affecting the denitrifying system, six cellulose plants from agricultural wastes (wood chip, corn cob, rice husk, corn straw, wheat straw, and sugar cane) were selected for bioavailable organic matter leaching experiments, carbon denitrification experiments, functional bacteria identification, and analysis experiments. The results show that the extracts of cellulose plants contain a mixed carbon sources system including small molecular organic acids, sugars, nitrogen-containing organic components, and esters. The qPCR results showed that the denitrifying bacteria had obvious advantages compare to anaerobic ammonia-oxidizing bacteria during the stable period; the denitrification experiment showed that each of six cellulose plants removed more than 80% of nitrogen, and the denitrification rates reached 1.00–2.00 mg N cm−3·d−1. The supplement of cellulose plants promotes the metabolism rate of denitrifying bacteria, and the additional denitrifying bacteria have little effect on nitrate removal. In summary, the expected denitrification reaction occurred in the cellulose plant system, which is suitable as a carbon source material for water body nitrogen pollution remediation.

2012 ◽  
Vol 65 (9) ◽  
pp. 1696-1704 ◽  
Author(s):  
Jianmei Zhang ◽  
Chuanping Feng ◽  
Siqi Hong ◽  
Huiling Hao ◽  
Yingnan Yang

The present study was conducted to compare the behavior of wheat straw, sawdust and biodegradable plastic (BP) as potential carbon sources for denitrification in groundwater remediation. The results showed that a greater amount of nitrogen compounds were released from wheat straw and sawdust than from BP in leaching experiments. In batch experiments, BP showed higher nitrate removal efficiency and longer service life than wheat straw and sawdust, which illustrated that BP is the most appropriate carbon source for stimulation of denitrification activity. In column experiments, BP was able to support complete denitrification at influent nitrate concentrations of 50, 60, 70, 80, and 90 mg NO3−-N/L, showing corresponding denitrification rates of 0.12, 0.14, 0.17, 0.19, and 0.22 mg NO3−-N.L−1.d−1.g−1, respectively. These findings indicate that BP is applicable for use as a carbon source for nitrate-polluted groundwater remediation.


Molecules ◽  
2021 ◽  
Vol 26 (11) ◽  
pp. 3390
Author(s):  
Hui Zhang ◽  
Lin Song ◽  
Xiaolin Chen ◽  
Pengcheng Li

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO3−-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO3−-N. More importantly, the increased NH4+-N content could avoid excessive loss of nitrogen, and less NO2−-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.


2020 ◽  
Author(s):  
Mee-Rye Park ◽  
Medini K. Annavajhala ◽  
Kartik Chandran

AbstractThe application of metagenomics and metatranscriptomics to field-scale engineered biological nitrogen removal (BNR) processes revealed a complex N-cycle network (the meta-azotome) therein in terms of microbial structure, potential and extant function. Autotrophic nitrification bore the imprint of well-documented Nitrosomonas and Nitrospira in most systems. However, in select BNR processes, complete ammonia oxidizing bacteria, comammox Nitrospira, unexpectedly contributed more substantially to ammonia oxidation than canonical ammonia oxidizing bacteria, based on metatranscriptomic profiling. Methylotrophic denitrification was distinctly active in methanol-fed reactors but not in glycerol-fed reactors. Interestingly, glycerol metabolism and N-reduction transcript signatures were uncoupled, possibly suggesting the role of other carbon sources in denitrification emanating from glycerol itself or from upstream process reactors. In sum, the meta-azotome of engineered BNR processes revealed both traditional and novel mechanisms of N-cycling. Similar interrogation approaches could potentially inform better design and optimization of wastewater treatment and engineered bioprocesses in general.


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.


PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9457
Author(s):  
Zongjing Kang ◽  
Jie Zou ◽  
Yue Huang ◽  
Xiaoping Zhang ◽  
Lei Ye ◽  
...  

Background NirS-type denitrifying bacteria and ammonia-oxidizing bacteria (AOB) play a key role in the soil nitrogen cycle, which may affect the growth and development of underground truffles. We aimed to investigate nirS-type denitrifying bacterial and AOB community structures in the rhizosphere soils of Carya illinoinensis seedlings inoculated with the black truffle (Tuber melanosporum) during the early symbiotic stage. Methods The C. illinoinensis seedlings inoculated with or without T. melanosporum were cultivated in a greenhouse for six months. Next-generation sequencing (NGS) technology was used to analyze nirS-type denitrifying bacterial and AOB community structures in the rhizosphere soils of these seedlings. Additionally, the soil properties were determined. Results The results indicated that the abundance and diversity of AOB were significantly reduced due to the inoculation of T. melanosporum, while these of nirS-type denitrifying bacteria increased significantly. Proteobacteria were the dominant bacterial groups, and Rhodanobacter, Pseudomonas, Nitrosospira and Nitrosomonas were the dominant classified bacterial genera in all the soil samples. Pseudomonas was the most abundant classified nirS-type denitrifying bacterial genus in ectomycorrhizosphere soils whose relative abundance could significantly increase after T. melanosporum inoculation. A large number of unclassified nirS-type denitrifying bacteria and AOB were observed. Moreover, T. melanosporum inoculation had little effect on the pH, total nitrogen (TN), nitrate-nitrogen (NO${}_{3}^{-}$-N) and ammonium-nitrogen (NH${}_{4}^{+}$-N) contents in ectomycorrhizosphere soils. Overall, our results showed that nirS-type denitrifying bacterial and AOB communities in C. illinoinensis rhizosphere soils were significantly affected by T. melanosporum on the initial stage of ectomycorrhizal symbiosis, without obvious variation of soil N contents.


Author(s):  
Qinglin Fang ◽  
Wenlai Xu ◽  
Zhijiao Yan ◽  
Lei Qian

Constructed rapid infiltration system (CRI) is a new type of sewage biofilm treatment technology, but due to its anaerobic zone lacks of the carbon sources and the condition for nitrate retention, its nitrogen removal perfomance is very poor; However, shortcut nitrification-denitrification process presents distinctive advantages, as it saves oxygen, requires less organic matter and needs less time for denitrification compared to conventional nitrogen removal method. Thus, if the shortcut nitrification-denitrification process could be applied to CRI system properly, the simpler, more economic and efficient nitrogen removal method will be obtained. But, as its reaction process shows that the first and the most important step of achieving shortcut nitrification-denitrification is to achieve shortcut nitrification. Thus, in this study, we explored the feasibility to achieve shortcut nitrification, which produces nitrite as the dominant nitrogen species in effluent, by addition of potassium chlorate (KClO3) to the influent. In an experimental CRI model system, the effects on nitrogen removal, nitrate inhibition and nitrite accumulation were studied, and the advantages of achieving shortcut nitrification-denitrification were also analysed. The results showed that shortcut nitrification was successfully achieved and maintained in a CRI system by adding 5 mM KClO3 to the influent at a constant pH of 8.4. Under these conditions nitrite accumulation rate was increased, while a lower concentration of 3 mM KClO3 had no obvious effect. The addition of 5 mM KClO3 in influent presumably allowed sufficient activity of ammonia-oxidizing bacteria (AOB) but inhibited nitrite-oxidizing bacteria (NOB) strongly enough to result in a maximum nitrite accumulation rate of up to over 80%. As a result, nitrite became the dominant nitrogen product in the effluent. Moreover, if the shortcut denitrification will be achieved in the subsequent research, it could save 60.27 mg carbon source (CH3OH) consumption when treatment of per liter sewage in CRI system compared with full denitrification process.


2020 ◽  
Vol 158 ◽  
pp. 04002
Author(s):  
Jinxiang Fu ◽  
Zhe Zhang ◽  
Jinghai Zhu

Aiming at the problem of the low removal efficiency of biological nitrogen-removing of low temperature waste-water, using Polyurethane Porous Gel Carrier (PPGC)-SBMBBR treated low temperature sewage, in compared with conventional SBR,and viaing Miseq high-throughput sequencing technology in analysis of the differences of microbial diversity and abundance of structure on the two reactors of activated sludge, revealed dominant nitrogen-removing bacterium improving the treatment efficiency of low temperature sewage. The results shows that the removal efficiency of the effluent nitrogen and the sludge sedimentation rate of (PPGC)-SBMBBR reactor are significantly improved under the water temperature (6.5±1℃). Adding the filler can contribute to improvement of bacterial diversity and relative abundance of nitrification and denitrification bacterium in the activated sludge system. The main relative abundance of ammonia oxidizing bacteria (AOB),nitrite oxidizing bacteria (NOB),anaerobic denitrifying bacteria, and aerobic denitrifying bacteria in (PPGC)-SBMBBR(R2) are significantly better than SBR (R1),and the R2 reactor can independently enrich the nitrifying bacteria and the aerobic denitrifying bacteria, such as Nitrospira, Hydrogens, Pseudomonas, and Zoogloea. The total relative abundance of dominant and nitrifying denitrifying bacterium increases from 28.65% of R1 to 60.23% of R2, providing a microbiological reference for improving the efficiency of biological nitrogen removal in low temperature waste-water.


1998 ◽  
Vol 38 (6) ◽  
pp. 237-243 ◽  
Author(s):  
A. Mohseni-Bandpi ◽  
D. J. Elliott

A pilot scale rotating biological contactor (RBC) was used to investigate the removal of nitrate-nitrogen from groundwater using three different carbon sources, i.e., methanol, ethanol and acetic acid. Optimum carbon sources to influent nitrate-nitrogen ratio were established by varying the influent concentration of carbon sources. The optimum ratio of methanol, ethanol and acetic acid to nitrate-nitrogen ratios were found to be 2.9, 2.35 and 4.3 respectively. The nitrate-nitrogen removal efficiency averaged 93, 91 and 98 for methanol, ethanol and acetic acid respectively at a loading rate of 76 mg/m2.h. The results of this study show that the acetic acid is the most efficient carbon source for removal of nitrate-nitrogen. Effluent nitrite-nitrogen concentration was minimum for acetic acid as compared with ethanol and methanol. The effluent contained minimum suspended solids and turbidity for methanol as a carbon source. The results of this study indicate that biological nitrate removal using a RBC is a reliable and stable system under all the three carbon sources. The denitrified water in all cases requires some post treatment to oxidise the residual carbon source and remove biomass before distribution.


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