Comparison and Analysis of Denitrification Effect and Kinetics Regarding Several New Type Carbon Sources

2011 ◽  
Vol 255-260 ◽  
pp. 2695-2699
Author(s):  
Hao Yan Li ◽  
Dian Hai Yang ◽  
Hai Yan Wu ◽  
Qin Lu ◽  
Xiang Zheng

Three typical external carbon sources (i.e. leachate, hydrolysates from primary sludge and starch solution) with regard to the denitrification process were investigated respectively in sequencing batch reactors (SBR) and their denitrification properties were compared to provide the optimum substrate suited for nitrogen removal processes. The variations of nitrogen were examined and nitrate utility ratio as well as carbon consumption rate was exhibited, denitrification kinetics regarding leachate was also analyzed by use of zero-order kinetic model. The experimental results indicated that the similar denitrification trend was achieved between hydrolysates from primary sludge and starch solution other than leachate as carbon source in denitrification system. The nitrate was not entirely degraded and the nitrite generated permanent accumulation. Compared with other carbon sources, leachate in steady operation showed the highest nitrate removal concentration and rate in phase I with an average of 13 mg/L and 86%, respectively. In phase II, the maximum nitrate and carbon decomposition rates were 0.088 g N/g VSS•d and 0.848 g TOC/g VSS•d respectively occurring at leachate as substrate. Thus, stable leachate was considered as the most suitable carbon source in comparison with other substrates.

2012 ◽  
Vol 518-523 ◽  
pp. 2319-2323 ◽  
Author(s):  
Guang Ying Liu ◽  
Huan Zhen Zhang ◽  
Wei Li ◽  
Xin Zhang

Carbon source used as electron donors is critical to heterotrophic denitrification. Addition of external carbon source is necessary when internal organics are deficient. A review was conducted on the use of external carbon source in denitrification. Traditional carbon sources such as methanol and ethanol, alternative carbon sources such as cellulose-rich materials, biodegradable polymers and primary sludge are included in external carbon sources. Present situation and problems of its biodegradability and effects in denitrification are summarized. Focus in external carbon source includes further study on the biodegradation mechanism of the media, slow release performance and nitrate removal rate of available carbon source and continuous research on new kinds of substrates. Recommendations on further study of carbon source are put forward.


2021 ◽  
Author(s):  
Junzhen Di ◽  
Yangyang Jiang ◽  
Mingjia Wang ◽  
Yanrong Dong

Abstract Aiming at the problems of insufficient supply of carbon source and toxic effect of heavy metal ions in the treatment of acid mine wastewater (AMD) by sulfate reducing bacteria (SRB), immobilized particles were prepared with Rhodopseudomonas spheroides, SRB and lignite as the main raw materials, and the optimal ratio of immobilized particles was determined based on single factor test and orthogonal test. The adsorption experiment of immobilized particles was carried out under the optimal ratio, the reaction kinetic process and adsorption capacity of immobilized particles for different ions were analyzed, and the action mechanism was studied. The results show that lignite not only has good adsorption performance, but also can be used as the carbon source of SRB after degradation by Rhodopseudomonas spheroides, so as to solve the problems of low removal efficiency of AMD by SRB and insufficient supply of carbon source. When the dosage of lignite, Rhodopseudomonas spheroides and SRB is 3%, 10% and 10% respectively, and the particle size of lignite is 200 mesh, the overall treatment effect is the best. The removal rates of SO42-, Zn2+ and Cu2+ are 83.21%, 99.59% and 99.93% respectively, the pH is increased to 7.43, the release of COD is 523 mg/L, and the ORP number is -134 mV. The reduction process of SO42- by immobilized particles conforms to the pseudo first-order kinetics, the isothermal adsorption of Zn2+ more conforms to the Freundlich isothermal adsorption equation, and the adsorption kinetics of Zn2+ more conforms to the pseudo second-order kinetic model.


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.


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.


1992 ◽  
Vol 26 (5-6) ◽  
pp. 1077-1086 ◽  
Author(s):  
U. Nyberg ◽  
H. Aspegren ◽  
B. Andersson ◽  
J. la C. Jansen ◽  
I.S. Villadsen

In Sweden many advanced sewage treatment plants for BOD and phosphorus removal have to be extended with nitrogen removal. Due to existing plant configuration and wastewater composition, denitrification with supply of an external carbon source can be a cost-effective solution in many cases. At the Klagshamn wastewater treatment plant in Malmo investigations for extensive nitrogen removal have been made in a single-sludge system with pre-precipitation and post-denitrification where methanol was added for denitrification. Results from the tests showed that a high level of nitrogen removal can be reached, and that the process was stable and easy to operate. The process application gave less supplementary cost for an extended nitrogen removal than for upgrading the plant with larger basin volumes. In order to examine the purification performance caused by the addition of methanol, the starting period was followed extensively with online nitrate sensors and daily composite samples. The development of the denitrif ication capacity of the sludge with methanol and acetate as carbon sources was followed and microbiological changes were examined microscopically. Complete denitrification was obtained after approximately one month at 10°C. The denitrification capacity of the sludge with methanol reached that of acetate after about the same time. The microscopic examination revealed a growing population of budding and/or appendaged bacteria, presumably Hyphomicrobium spp, reaching a stable maximum at the time when optimal nitrate removal occurred.


2014 ◽  
Vol 1073-1076 ◽  
pp. 779-783
Author(s):  
Patience Awhavbera ◽  
Lian Fang Zhao

External carbon sources provide additional nutrients that improve the efficiency of nitrate removal in constructed wetlands. Typha angustifolia L. were planted in four vertical subsurface-flow constructed wetlands. Different external carbon sources were fed into the columns, to investigate and compare their treatment of nitrate in synthetic wastewater, with initial influent C/N ratio of 1:1. Wetland A (WA) with 50g wheat straw as external carbon source, wetland B (WB) with 50g woodchips, wetland C (WC) with additional 10mg/L glucose and wetland D (WD) without external carbon source to serve as the control, were used in the lab-scale experimental study. WA, WB, WC and WD within a period of 24 days, cumulatively removed 109.38mg/L, 93.75mg/L, 85.14mg/L, and 64.01mg/L nitrate, respectively, from the influent. The nitrate-nitrogen (NO3–N) removal efficiency as aided by the external carbon sources was in the order: wheat straw > woodchips > glucose > control. Wheat straw treated 93% NO3–N, woodchips 78%, glucose 72% and the control 53%. The results indicate that WA, WB and WC outperformed the control system, due to the additional carbon sources. In general, the wheat straw had a better performance than wood chips and glucose. Thus, wheat straw as low cost biological waste product is recommended for the treatment of nitrate in wetlands.


2020 ◽  
Vol 14 (4) ◽  
pp. 2417-2424
Author(s):  
Essam J. Alyamani ◽  
Rayan Y. Booq ◽  
Ali H. Bahkali ◽  
Sulaiman A. Alharbi

Denitrification based on immobilized microbial cellulose may offer an economical replacement for conventional treatment for nitrate removal. The environmental and bacterial biomass may influence the rate of biological denitrification processes. This study aimed to investigate the factors that affect denitrification rates, including carbon sources, pH, and bacterial inoculum. Different inoculum biomass of Pseudomonas aeruginosa and various carbon sources of glucose, sucrose, and cellulose with different concentrations were tested to assimilate 100 mg/L of KNO3 as nitrate source. Additionally, five additional inoculations, five different incubation time, and seven different pH levels were studied. The Pseudomonas aeruginosa isolates used different mineral media with three carbon sources, glucose, sucrose, and cellulose, with different concentrations at different rates to denitrify nitrate. The highest denitrification rate was with glucose after 18 hrs and was after 24 hrs when sucrose and cellulose were used, respectively. The bacterial biomass denitrification level was the highest, between 0.8% and 1% of OD600=1. Nitrate removal by Pseudomonas aeruginosa was the highest at pH 7, 8, and 9. This report suggests that when glucose is used as a carbon source, at neutral to alkaline pH, and 1% of denitrifying bacterial biomass, the highest level of biological denitrification process may be achieved.


2004 ◽  
Vol 50 (8) ◽  
pp. 15-22 ◽  
Author(s):  
Y. Otani ◽  
K. Hasegawa ◽  
K. Hanaki

Abilities of three aerobic denitrifiers such as Alcaligenes faecalis, Microvirgula aerodenitrificans and Paracoccus pantotrophus were compared from the viewpoints of nitrate removal efficiency and organic matter utilization. First, the effect of carbon source was investigated. Although nitrate reduction was observed in all strains under aerobic conditions, a change of carbon source considerably affected the denitrification ability. In the case of P. pantotrophus, nitrate and nitrite were completely removed in three days under sodium acetate or leucine as a carbon source. In the case of A. faecalis, sufficient nitrate removal was observed only when sodium acetate or ethanol was added. P. pantotrophus and A. faecalis showed a higher ability of nitrate removal than that of M. aerodenitrificans. Therefore, P. pantotrophus was selected in order to investigate the effects of concentration and repetitive addition of carbon. Sodium acetate was used as a sole carbon source. Nitrate was not reduced when the carbon concentration was below 500 mgC/L. However, when carbon source was added repeatedly, nitrate was reduced under 100 mgC/L after the optical density of the bacterium reached above 1.0. This result indicated that a high enough level of bacterial density was necessary to express aerobic denitrification activity.


Author(s):  
Gopal P. Naik ◽  
Anil K. Poonia ◽  
Parmesh K. Chaudhari

Abstract Biogas production can supplement the renewable energy target of the world. For this abundantly available agricultural waste like wheat and rice straw can be used. Biogas generation using this waste will curb the stubble burning incidences, reduce greenhouse gases, enhance farmer’s income, and strengthen the energy security of many countries. The recalcitrant nature of rice straw is a barrier to its hydrolysis, which is a prerequisite of the anaerobic digestion (AD) process. Alkaline, electro-hydrolysis, and a combination of both pretreatment (alkaline electrohydrolysis) methods are undertaken in the present study. Batch reactors at ambient temperature were used for AD of rice straw at different inoculums to substrate ratios (ISR) of 0.5, 0.75, and 1.0 to observe the effect on biogas/methane yield. Among these, a higher amount of biogas was obtained for ISR of 0.5 in all sets of experiments. The combined pretreatment method yielded biogas of 315.9 mL/gVS (equivalent to methane of 167.4 mL/gVS). For pretreat-ed rice straw by electro-hydrolysis, alkaline, and combined (alkaline and electro-hydrolysis) respectively, the methane yields were 7.03, 18.13, and 49.82% higher than untreated rice straw. The biogas had approximately 53% of methane content. The use of rice straw for biogas production may prove a viable alternative for clean and sustainable energy. In the studies, a first-order kinetic model is found to fit better the experimental results.


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