Enhanced Biodegradation of Aniline under Anoxic Condition

2011 ◽  
Vol 356-360 ◽  
pp. 25-30 ◽  
Author(s):  
Jin You Shen ◽  
Chao Zhang ◽  
Xiu Yun Sun ◽  
Jian Sheng Li ◽  
Lian Jun Wang
Keyword(s):  
Performance Analysis ◽  
Benzene Ring ◽  
Organic Pollutants ◽  
Degradation Rate ◽  
Removal Rate ◽  
Degradation Process ◽  
Anoxic Condition ◽  
Aerobic Degradation ◽  
Industrial Wastewaters ◽  
Enhanced Biodegradation

Recalcitrant and toxic organic pollutants such as aniline from numerous industrial wastewaters can not be efficiently removed using the conventional methods. This study reported a concept for mineralization of aniline in an anoxic reactor, where enhanced biodegradation of aniline were achieved under anoxic conditions. The results indicated that with the presence of nitrate, the degradation rate of aniline was greatly improved compared with the absence of nitrate. From the UV-vis adsorption spectra, COD analysis and denitrification performance analysis, it could be inferred that the cleavage of benzene ring of aniline occurred, aniline could be mineralization by microorganisms under the anoxic condition. However, aniline removal rate was lower compared to aerobic degradation process, and thus needs a significant improvement.

Methyl Orange Photoelectrocatalytic Degradation Using Porous TiO2 Film Electrode in NaH2PO4 Solution

2012 ◽  
Vol 433-440 ◽  
pp. 411-415
Author(s):  
Wen Jie Zhang ◽  
Ke Xin Li ◽  
Jia Wei Bai
Keyword(s):  
Methyl Orange ◽  
Degradation Rate ◽  
Removal Rate ◽  
Sol Gel ◽  
Degradation Process ◽  
Film Electrode ◽  
Applied Potential ◽  
Gel Method ◽  
Photoelectrocatalytic Degradation ◽  
Better Than

Porous TiO2 film was prepared by a sol-gel method using PEG1000 as pore forming template. The porous film and normal film were used as electrodes in a photoelectrocatalytic reactor. The functions of applied potential and concentration of NaH2PO4 to the photoelectrocatalytic degradation process of methyl orange were investigated. The results show that methyl orange cannot be degraded solely by the applied potential. Under the applied potential of 2 V, 49.9% of the initial dye can be removed on the normal TiO2 film electrode, which is much better than the 31.1% removal rate on the porous TiO2 film electrode. The normal TiO2 film electrode has better performance than the porous TiO2 film in the whole NaH2PO4 concentration range. After 80 min of reaction, degradation rate is 93.7% on the normal TiO2 film electrode. After 100 min of reaction, degradation rate is 89.7% on the porous TiO2 film electrode.

Use of a sequencing batch biofilter for degradation of azo dyes (acids and bases)

2000 ◽  
Vol 42 (5-6) ◽  
pp. 329-336 ◽  
Author(s):  
M. Quezada ◽  
I. Linares ◽  
G. Buitrón
Keyword(s):  
Azo Dyes ◽  
Azo Dye ◽  
Degradation Rate ◽  
Removal Rate ◽  
Textile Effluent ◽  
Colour Removal ◽  
Substrate Degradation ◽  
Acids And Bases ◽  
Removal Efficiencies ◽  
Basic Red 46

The degradation of azo dyes in an aerobic biofilter operated in an SBR system was studied. The azo dyes studied were Acid Red 151 and a textile effluent containing basic dyes (Basic Blue 41, Basic Red 46 and 16 and Basic Yellow 28 and 19). In the case of Acid Red 151 a maximal substrate degradation rate of 288 mg AR 151/lliquid·d was obtained and degradation efficiencies were between 60 and 99%. Mineralization studies showed that 73% (as carbon) of the initial azo dye was transformed to CO2 by the consortia. The textile effluent was efficiently biodegraded by the reactor. A maximal removal rate of 2.3 kg COD/lliquid·d was obtained with removal efficiencies (as COD) varying from 76 to 97%. In all the cycles the system presented 80% of colour removal.

scholarly journals Enhanced Wastewater Treatment by Immobilized Enzymes

2021 ◽  
Author(s):  
Jakub Zdarta ◽  
Katarzyna Jankowska ◽  
Karolina Bachosz ◽  
Oliwia Degórska ◽  
Karolina Kaźmierczak ◽  
...  
Keyword(s):  
Wastewater Treatment ◽  
Process Optimization ◽  
Organic Pollutants ◽  
Large Scale ◽  
Removal Rate ◽  
Immobilized Enzymes ◽  
Future Research ◽  
Process Conditions ◽  
Removal Rates ◽  
Catalytic Cycles

Abstract Purpose of Review In the presented review, we have summarized recent achievements on the use of immobilized oxidoreductases for biodegradation of hazardous organic pollutants including mainly dyes, pharmaceuticals, phenols, and bisphenols. In order to facilitate process optimization and achievement of high removal rates, effect of various process conditions on biodegradation has been highlighted and discussed. Recent Findings Current reports clearly show that immobilized oxidoreductases are capable of efficient conversion of organic pollutants, usually reaching over 90% of removal rate. Further, immobilized enzymes showed great recyclability potential, allowing their reuse in numerous of catalytic cycles. Summary Collected data clearly indicates immobilized oxidoreductases as an efficient biocatalytic tools for removal of hazardous phenolic compounds, making them a promising option for future water purification. Data shows, however, that both immobilization and biodegradation conditions affect conversion efficiency; therefore, process optimization is required to achieve high removal rates. Nevertheless, we have demonstrated future trends and highlighted several issues that have to be solved in the near-future research, to facilitate large-scale application of the immobilized oxidoreductases in wastewater treatment.

Study on Improving Biodegradability of Straw Pulp Papermaking Wastewater by Coagu-Flocculation and Nuclear-Flocculation

2014 ◽  
Vol 926-930 ◽  
pp. 4361-4364
Author(s):  
Xiao Qiao Song
Keyword(s):  
Molecular Weight ◽  
Organic Pollutants ◽  
Aromatic Hydrocarbons ◽  
Removal Rate ◽  
Activated Sludge Process ◽  
Test Results ◽  
Combination Process ◽  
Coagulation And Flocculation ◽  
Flocculation Process ◽  
Papermaking Wastewater

When straw pulp papermaking wastewater was treated by the process of coagu-flocculation and nuclear-flocculation, there were still high CODCr. UV254 can reflect organic pollutants and organic pollutants of unsaturated aromatic ring, carbon-carbon double bond. With the decrease of molecular weight of organic pollutants, absorption of ultraviolet light will decrease. Indirectly, it reflectd that the combination process had a good removal effect on high molecular aromatic hydrocarbons difficult to be biodegraded. Meanwhile it can improve the the biodegradability. It used the activated sludge process as subsequent process of coagulation and-flocculation process. The test results showed that the removal rate of CODCr was 24.1%, CODCr was the 88.1mg/L. It reached effluent standard.

Natural Aerobic Degradation of Polylactic Acid (Composites) with Natural Fiber Additives

2018 ◽  
Vol 919 ◽  
pp. 167-174 ◽  
Author(s):  
Jan Prusek ◽  
Martin Boruvka ◽  
Petr Lenfeld
Keyword(s):  
Composite Material ◽  
Polylactic Acid ◽  
Natural Fiber ◽  
Fiber Reinforcement ◽  
Degradation Process ◽  
Composite Sample ◽  
Aerobic Degradation ◽  
Different Types ◽  
Natural Degradation

This paper deals with natural degradation of PLA (polylactic acid) composites with natural fiber reinforcement in non-simulated conditions. Composite material was made of PLA and 6 different types of biodegradable fibers. Fibers made from pulp, wool, bamboo, soya, flax and hemp. All samples had 20% volume of fibers. Three of each composite sample were placed in compost (aerobic surrounding) for 72 weeks. All samples were examined at the beginning every 2 weeks to observe if the degradation process occurred and all samples were examined at the end of 72 weeks period to observe results of degradation of each composite material.

Efficient Mineralization of Organic Pollutants Using Visible-light-induced PTCDA Anions Electronic Reservoir and Photogenerated Holes

2021 ◽  
Author(s):  
Yan Guo ◽  
Qixin Zhou ◽  
Jun Nan ◽  
Yongfa Zhu
Keyword(s):  
Visible Light ◽  
Organic Pollutants ◽  
Advanced Oxidation Processes ◽  
Degradation Rate ◽  
Organic Molecules ◽  
Flow Reactor ◽  
Oxygen Species ◽  
Continuous Flow Reactor ◽  
Light Excitation ◽  
Visible Light Degradation

Abstract Introducing the anion intermediate found with PTCDA into advanced oxidation processes (AOPs) overcomes the limitation of visible-light degradation. Stabilized PTCDA anionic intermediates act as electron reservoir to activate PMS to generate reactive oxygen species, thus improving the degradation rate of organic pollutants driven by visible light. At the same time, the photogenerated holes of PDI induce α and β scission with the unshared electron in organic molecules, and realize the deep mineralization of converting organic molecules to CO2. The BPA degradation rate of PTCDA /PMS is over 125.8 and 2.8 times as high as PTCDA photocatalysis and Co3O4/PMS, respectively. The BPA mineralization of PTCDA /PMS reaching ~ 88% outclasses Co3O4/PMS (~ 25%). In continuous flow reactor, it has a ~ 100% degradation and ~ 80% mineralization of BPA. The outstanding degradation in real water under solar light excitation indicates that PTCDA/PMS would be an intriguing system for non-toxic and harmless elimination of organic pollutants.

Diverting electron fluxes towards sulfate reduction using linoleic acid in a mixed anaerobic culturePaper submitted to the Journal of Environmental Engineering and Science.

2010 ◽  
Vol 37 (11) ◽  
pp. 1492-1504
Author(s):  
Mamata Sharma ◽  
Nihar Biswas
Keyword(s):  
Linoleic Acid ◽  
Sulfate Reduction ◽  
Degradation Rate ◽  
Volatile Fatty Acids ◽  
Removal Rate ◽  
Electron Flow ◽  
Methane Formation ◽  
Sulfate Removal ◽  
Degradation Rates ◽  
High Concentrations

Sulfate (1500 mg/L) reduction and glucose (1870 mg/L) degradation was examined in the presence of five varying linoleic acid (LA) levels (100–1000 mg/L) at 37 ± 2 °C and pH 7.0–7.2. The sulfate reduction and methane formation data suggest that LA selectively inhibited methane producing bacteria (MPB). The quantity of sulfate removed increased with increasing LA dosage. Approximately 1375 mg/L (92%) sulfate was removed in cultures fed with high concentrations of LA (1000 mg/L), which was 68% more than that removed in glucose and sulfate controls. The quantity of sulfate removed in cultures fed with 100, 300, 500 and 700 mg/L LA were 62%, 66%, 77%, and 84%, respectively. Initial sulfate degradation rates increased with increasing LA levels in the cultures. High LA levels (1000 mg/L) attributed to approximately a sevenfold increase in the initial sulfate degradation rates compared to cultures containing sulfate plus glucose. The highest initial sulfate removal rate (0.19 µg/(mgVSS min)) was observed in cultures receiving 1000 mg/L LA. Initial glucose degradation rates decreased with increasing LA concentrations. The rates for the cultures receiving 1000 mg/L LA were 2.53 µg/(mgVSS min) while the degradation rate for cultures containing 100 mg/L LA was 5.40 µg/(mgVSS min). Methane formation decreased when sulfate and LA were added. Methane formation was lowest in cultures receiving elevated LA concentrations. The percent electron flow fluxes increased towards sulfidogenesis and decreased towards methanogenesis with increasing LA levels. Less than 0.6% electron flow was diverted to methanogenesis in cultures containing high levels of LA (≥700 mg/L) while ≤ 45% was diverted to sulfidogenesis. Acetate and propionate were the major volatile fatty acids (VFAs) detected during glucose degradation. The amount of sulfate reduced in the cultures receiving only LA or sulfate and no other carbon source was comparable (approximately 10%), which suggests that LA did not contribute to electrons during the course of experiment for sulfate reduction.

scholarly journals Combined Application of UV Photolysis and Ozonation with Biological Aerating Filter in Tertiary Wastewater Treatment

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Zhaoqian Jing ◽  
Shiwei Cao
Keyword(s):  
Molecular Weight ◽  
Wastewater Treatment ◽  
Organic Pollutants ◽  
Wastewater Treatment Plants ◽  
Removal Rate ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Secondary Effluent ◽  
Uv Photolysis ◽  
Combined Application

To enhance the biodegradability of residual organic pollutants in secondary effluent of wastewater treatment plants, UV photolysis and ozonation were used in combination as pretreatment before a biological aerating filter (BAF). The results indicated that UV photolysis could not remove much COD (chemical oxygen demand), and the performance of ozonation was better than the former. With UV photolysis combined with ozonation (UV/O3), COD removal was much higher than the sum of that with UV photolysis and ozonation alone, which indicated that UV photolysis could efficiently promote COD removal during ozonation. This pretreatment also improved molecular weight distribution (MWD) and biodegradability greatly. Proportion of organic compounds with molecular weight (MW) <3 kDalton was increased from 51.9% to 85.9%. COD removal rates with BAF and O3/BAF were only about 25% and 38%, respectively. When UV/O3oxidation was combined with BAF, the average COD removal rate reached above 61%, which was about 2.5 times of that with BAF alone. With influent COD ranging from 65 to 84 mg/L, the effluent COD was stably in the scope of 23–31 mg/L. The combination of UV/O3oxidation with BAF was quite efficient in organic pollutants removal for tertiary wastewater treatment.

Synergetic Degradation of Zidovudine Wastewater by Ultrasonic and Iron-Carbon Micro-Electrolysis

2011 ◽  
Vol 347-353 ◽  
pp. 1949-1952 ◽  
Author(s):  
Liang Li ◽  
Bing Zhe Xu ◽  
Chang Yu Lin ◽  
Xiao Min Hu
Keyword(s):  
Reaction Time ◽  
Degradation Rate ◽  
Removal Rate ◽  
Cod Removal ◽  
Mass Ratio ◽  
Initial Ph ◽  
Cod Removal Rate

Zidovudine wastewater is difficult to biodegradation due to high COD and toxicity. The synergetic treatment of Zidovudine wastewater by Ultrasonic and iron-carbon micro-electrolysis technology was studied. The influence of initial pH, reaction time, mass ratio of iron and carbon and mass ratio of iron and water on degradation rate of COD was researched. The result showed that the COD removal rate was only about 54.3% and the degradation speed is very slow when iron-carbon micro-electrolysis treated Zidovudine wastewater　separately. However, when ultrasonic synergy micro-electrolysis to treat Zidovudine wastewater, the COD removal rate could was up to 85% and the reaction time was also decreased. Moreover, the BOD5 / COD rose from 0.15 to 0.35, which meant the wastewater became easily biodegradable.

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