The interaction between Pseudomonas C27 and Thiobacillus denitrificans in the integrated autotrophic and heterotrophic denitrification process

Due to the extensive application of artificial nitrogen-based fertilizers on land, groundwater from the central part of Taiwan faces problems of increasing concentrations of nitrate, which were measured to be well above 30 mg/L all year round. For meeting the 10 mg/L nitrate standard, optimal operations for a heterotrophic denitrification pilot plant designed for drinking water treatment was investigated. Ethanol and phosphate were added for bacteria growing on anthracite to convert nitrate to nitrogen gas. Results showed that presence of high dissolved oxygen (around 4 mg/L) in the source water did not have a significantly negative effect on nitrogen removal. When operated under a C/N ratio of 1.88, which was recommended in the literature, nitrate removal efficiency was measured to be around 70%, sometimes up to 90%. However, the reactor often underwent severe clogging problems. When operated under C/N ratio of 1.0, denitrification efficiency decreased significantly to 30%. Finally, when operated under C/N ratio of 1.5, the nitrate content of the influent was almost completely reduced at the first one-third part of the bioreactor with an overall removal efficiency of 89–91%. Another advantage for operating with a C/N ratio of 1.5 is that only one-third of the biosolids was produced compared to a C/N value of 1.88.

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A two-stage soil infiltration system incorporated with heterotrophic denitrification (TSISHD) for urban runoff treatment

Hydrology Research ◽

10.2166/nh.2015.025 ◽

2015 ◽

Vol 47 (1) ◽

pp. 128-136

Author(s):

Lizhu Hou ◽

Xue Xu ◽

Yiran Song ◽

Chuanping Feng

Keyword(s):

Carbon Sources ◽

Oxygen Demand ◽

Urban Runoff ◽

Quality Standard ◽

Soil Infiltration ◽

Class V ◽

National Quality ◽

Removal Efficiencies ◽

Denitrification Process ◽

Heterotrophic Denitrification

To enhance denitrification performance of soil infiltration, a soil infiltration system incorporated with heterotrophic denitrification (TSISHD) for urban runoff treatment was developed. Sawdust and grass powders were added in the anaerobic stage (ANS) to provide organic carbon sources for the denitrification process, and the reduction environment was improved by iron addition in the ANS. Aerobic respiration and nitrification primarily occurred in the upper aerobic stage (AES), which removed 86.68% of the chemical oxygen demand (COD) and 91.80% of the NH+4-N. Moreover, heterotrophic denitrification occurred in the bottom ANS when added sawdust and grass powders were used as a carbon source. Overall, the TSISHD showed remarkable removal efficiencies of 88.29%, 82.50%, 92.05%, and 78.10% for COD, NO−3-N, NH+4-N, and total phosphorus, respectively, and the corresponding effluent concentrations met the national quality standard of China for class V surface water. The removal efficiencies were significantly higher than those of the previous soil infiltration systems without inoculated microbes. The developed system has the potential to treat urban runoff.

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Nitrate Removal from Actual Wastewater by Coupling Sulfur-Based Autotrophic and Heterotrophic Denitrification under Different Influent Concentrations

Water ◽

10.3390/w13202913 ◽

2021 ◽

Vol 13 (20) ◽

pp. 2913

Author(s):

Feng Liu ◽

Suqin Wang ◽

Xuezhi Zhang ◽

Feiyue Qian ◽

Yaobing Wang ◽

...

Keyword(s):

Removal Efficiency ◽

Nitrate Removal ◽

Operating Conditions ◽

Coupled Systems ◽

Polluted Water ◽

Sequencing Analysis ◽

Autotrophic Denitrification ◽

Actual Wastewater ◽

Denitrification Process ◽

Heterotrophic Denitrification

Contamination of wastewater with organic-limited nitrates has become an urgent problem in wastewater treatment. The cooperating heterotrophic with sulfur autotrophic denitrification is an alternative process and the efficiency has been assessed in many studies treating simulated wastewater under different operating conditions. However, due to the complex and diverse nature of actual wastewater, more studies treating actual wastewater are still needed to evaluate the feasibility of collaborative denitrification. In this study, lab-scale experiments were performed with actual nitrate polluted water of two different concentrations, with glucose and sodium thiosulfate introduced as mixed electron donors in the coupling sulfur-based autotrophic and heterotrophic denitrification. Results showed that the optimum denitrification performance was exhibited when the influent substrate mass ratio of C/N/S was 1.3/1/1.9, with a maximum denitrification rate of 3.52 kg NO3−-N/(m3 day) and nitrate removal efficiency of 93% in the coupled systems. Illumina high-throughput sequencing analysis revealed that autotrophic, facultative, and heterotrophic bacteria jointly contributed to high nitrogen removal efficiency. The autotrophic denitrification maintained as the predominant process, while the second most prevalent denitrification process gradually changed from heterotrophic to facultative with the increase of influent concentration at optimum C/N/S ratio conditions. Furthermore, the initiation of dissimilatory nitrate reduction to ammonium (DNRA) was very pivotal in promoting the entire denitrification process. These results suggested that sulfur-based autotrophic coupled with heterotrophic denitrifying process is an alternative and promising method to treat nitrate containing wastewater.

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Use of permeable reactive barrier to mitigate groundwater nitrate contamination from on-site sanitation

Journal of Water Sanitation and Hygiene for Development ◽

10.2166/washdev.2015.159 ◽

2015 ◽

Vol 5 (2) ◽

pp. 336-340 ◽

Cited By ~ 3

Author(s):

Sudhakar M. Rao ◽

R. Malini

Keyword(s):

Potable Water ◽

Environmental Concern ◽

Nitrate Contamination ◽

Permeable Reactive Barrier ◽

Human Waste ◽

Reactive Barrier ◽

Laboratory Results ◽

Groundwater Nitrate Contamination ◽

Denitrification Process ◽

Heterotrophic Denitrification

Nearly 50% of India's population depends on variants of pit-toilet systems for human waste disposal. Nitrate contamination of groundwater by pit-toilet leachate is a major environmental concern in the country as it sources a major proportion (50–80%) of potable water from aquifers. Therefore, minimizing nitrate contamination of groundwater due to leachate infiltration from pit-toilet systems is essential. Batch and column experiments demonstrated the capability of bentonite-enhanced sand (BES) specimens to reduce nitrate concentrations in synthetic solutions (initial NO3-N concentration = 22.7 mg/L, C/N = 3) by about 85–90% in 10 to 24 hour by a heterotrophic denitrification process. Based on the laboratory results, it is recommended that use of a BES-permeable reactive barrier layer at the base of pit-toilets will facilitate heterotrophic denitrification and mitigate nitrate contamination of the underlying aquifer.

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Compared microbiology of granular sludge under autotrophic, mixotrophic and heterotrophic denitrification conditions

Water Science & Technology ◽

10.2166/wst.2009.092 ◽

2009 ◽

Vol 59 (6) ◽

pp. 1227-1236 ◽

Cited By ~ 14

Author(s):

N. Fernández ◽

R. Sierra-Alvarez ◽

R. Amils ◽

J. A. Field ◽

J. L. Sanz

Keyword(s):

Electron Donor ◽

Water Contamination ◽

Granular Sludge ◽

Electron Donors ◽

Thiobacillus Denitrificans ◽

Microbial Biodiversity ◽

Real Potential ◽

Terminal Electron Acceptor ◽

Uasb Reactors ◽

Heterotrophic Denitrification

Water contamination by nitrate is a wideworld extended phenomena. Biological autotrophic denitrification has a real potential to face this problem and presents less drawbacks than the most extended heterotrophic denitrification. Three bench-scale UASB reactors were operated under autotrophic (R1, H2S as electron donor), mixotrophic (R2, H2S plus p-cresol as electron donors) and heterotrophic (R3, p-cresol as electron donor) conditions using nitrate as terminal electron acceptor. 16S rDNA genetic libraries were built up to compare their microbial biodiversity. Six different bacteria phyla and three archaeal classes were observed. Proteobacteria was the main phyla in all reactors standing out the presence of denitrifiers. Microorganisms similar to Thiobacillus denitrificans and Acidovorax sp. performed the autotrophic denitification. These OTUs were displaced by chemoheterotrophic denitrifiers, especially by Limnobacter-like and Ottowia-like OTUs. Other phyla were Bacteroidetes, Chloroflexi, Firmicutes and Actinobacteria that - as well as Archaea members - were implicated in the degradation of organic matter, as substrate added as coming from endogenous sludge decay under autotrophic conditions. Archaea diversity remained low in all the reactors being Methanosaeta concilii the most abundant one.

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Sulfate reduction and mixotrophic sulfide-utilization denitrification integrated biofilm process for sulfate-laden wastewater treatment and sulfur recovery

Water Science & Technology ◽

10.2166/wst.2015.162 ◽

2015 ◽

Vol 71 (12) ◽

pp. 1852-1858 ◽

Cited By ~ 5

Author(s):

Wei Li ◽

Xiao Liang ◽

Jianguo Lin ◽

Binxia Cao ◽

Ping Guo ◽

...

Keyword(s):

Sulfate Reduction ◽

Nitrogen Compound ◽

Electron Acceptors ◽

Sulfur Recovery ◽

Nitrogen Gas ◽

Removal Efficiencies ◽

Biofilm Process ◽

Nitrate And Nitrite ◽

Denitrification Process ◽

Heterotrophic Denitrification

A novel and integrated biofilm process – the sulfate reduction (SR) and mixotrophic (MR) sulfide-utilization denitrification process (SMSD) – was recently proposed for sulfate treatment and sulfur recovery. The process consisted of two bioreactors: a 5.1 L anaerobic upflow reactor for SR, and a 3.5 L anaerobic upflow reactor for MR desulfurization–denitrification. The experiment was conducted for 370 days to evaluate the performance of SMSD at various sulfate concentrations and hydraulic retention times. The process successfully achieved sulfate, organics and nitrogen compound removal efficiencies of 94.1, 97.7 and 99.1%, respectively. Sulfate was predominantly converted to element sulfur, while nitrate and nitrite were finally converted to nitrogen gas. In SR, with the help of high pH and sponge cubes with various bacteria, 97.5% of sulfide conversion efficiency and 540 mgS/L of sulfide were obtained. In MR, sulfide was removed up to 100% and was partially oxidized to sulfur. The extent of heterotrophic denitrification, which ranged from 35.8 to 59.8%, depended on the categories of electron acceptors.

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Nitrogen removal capacity of simultaneously autotrophic and heterotrophic denitrification in a sewer receiving nitrified source-separated urine

Water Practice & Technology ◽

10.2166/wpt.2013.005 ◽

2013 ◽

Vol 8 (1) ◽

pp. 33-40 ◽

Cited By ~ 4

Author(s):

Feng Jiang ◽

Zhen-Sheng Liang ◽

Guo-Liang Peng ◽

Jin Qian ◽

Guang-Hao Chen

Keyword(s):

Field Study ◽

Nitrogen Removal ◽

Removal Rate ◽

Sewage Treatment ◽

Calcium Nitrate ◽

Denitrification Rate ◽

Batch Tests ◽

Denitrification Process ◽

Heterotrophic Denitrification

Discharging source-separated and nitrified urine into sewer helps to save cost and space in biological nitrogen treatment as in-sewer denitrification is induced. This unique denitrification process may become complicated in sewers with sulfide contamination as simultaneously autotrophic and heterotrophic denitrification possibly occur but may compete each other for nitrate in oxidation of sulfide and organics. The objective of this study is to estimate the mixed denitrification rate in a sulfide-contaminated sewer when nitrified urine (mainly nitrite and nitrate) is discharged. In this study two investigations were conducted: (1) determination of the autotrophic, heterotrophic and mixed denitrification rates via lab batch tests and (2) determination of the total nitrogen removal rate in a 6.5-km long force main sewer via field study with calcium nitrate dosed at an average influent rate of 15.6 mg N/L. The lab tests determined the rates of autotrophic, heterotrophic and mixed denitrification at 0.36 ± 0.06, 6.54 ± 0.04 and 1.99 ± 0.1 mg N/L/h, respectively, while the field study estimated the total in-sewer denitrification rate at 2.32 mg N/L/h in the sewer when sulfide was present. Simultaneously autotrophic and heterotrophic denitrification was found when sewage was contaminated with sulfide. However, nitrogen removal rate of heterotrophic denitrification was 3.3 times higher that of the mixed denitrification process. The results indicate that discharging source-separated and nitrified urine into sewer is meaningful to decentralized sewage treatment, especially when sulfide is absent in the sewer.

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The heterotrophic-combined-with-autotrophic denitrification process: performance and interaction mechanisms

Water Science & Technology ◽

10.2166/wst.2015.097 ◽

2015 ◽

Vol 71 (8) ◽

pp. 1212-1218 ◽

Cited By ~ 5

Author(s):

Guihua Xu ◽

Cuijie Feng ◽

Fang Fang ◽

Shaohua Chen ◽

Yuanjian Xu ◽

...

Keyword(s):

Chemical Oxygen Demand ◽

Reduction Rate ◽

Oxygen Demand ◽

Process Performance ◽

Autotrophic Denitrification ◽

N Accumulation ◽

Interaction Mechanisms ◽

Molar Ratios ◽

Denitrification Process ◽

Heterotrophic Denitrification

In this work, the interaction mechanisms between an autotrophic denitrification (AD) and heterotrophic denitrification (HD) process in a heterotrophic-autotrophic denitrification (HAD) system were investigated, and the performance of the HAD system under different S/Ac− molar ratios was also evaluated. The results demonstrated that the heterotrophic-combined-with-autotrophic denitrification process is a promising technology which can remove chemical oxygen demand (COD), sulfide and nitrate simultaneously. The reduction rate of NO3− to NO2− by the HD process was much faster than that of reducing NO2− to N2, while the reduction rate of NO3− to NO2− by the AD process was slower than that of NO2− to N2. Therefore, the AD process could use the surplus NO2− produced by the HD process. This could alleviate the NO2−–N accumulation and increase the denitrification rate. In addition, the inhibition effects of acetate on AD bacteria and sulfide on HD were observed, and the inhibition was compensated by the promotion effects on NO2−. Therefore, the processes of AD and HD seem to react in parallel, without disturbing each other, in our HAD system.

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