The coupling of hemin with persistent free radicals induces a nonradical mechanism for oxidation of pollutants

2016 ◽  
Vol 52 (61) ◽  
pp. 9566-9569 ◽  
Author(s):  
Bin Jiang ◽  
Dejun Dai ◽  
Yuyuan Yao ◽  
Tiefeng Xu ◽  
Renhong Li ◽  
...  
Keyword(s):  
Free Radicals ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Pollutant Removal Rate

Herein, we report that persistent free radicals (PFRs) based on MWCNTs significantly accelerate the pollutant removal rate.

Kinetic Analysis of COD Removal from Actual Domestic Wastewater in an Expanded Granular Sludge Bed (EGSB) Reactor

2012 ◽  
Vol 610-613 ◽  
pp. 1691-1695
Author(s):  
Chun Juan Dong ◽  
Qing Ye Pan
Keyword(s):  
Low Temperature ◽  
Removal Efficiency ◽  
Removal Rate ◽  
Experimental Studies ◽  
Domestic Wastewater ◽  
Pollutant Removal ◽  
Cod Removal ◽  
Utilization Rate ◽  
Cod Removal Efficiency ◽  
Pollutant Removal Rate

Treatment of actual domestic wastewater at ambient temperature, even low temperature is considered to be difficult by traditional systems. The present study is related to treatment of actual domestic wastewater in an EGSB reactor. The study showed the effectiveness of biological treatment of actual domestic wastewater involving appropriate microorganism and granules in an EGSB reactor. At 26°C, the reactor was operated at 18.7kg COD.m−3.d−1 of average organic loading and 83% high COD removal efficiency, and even at the highest loading rate of 57.12kgCOD.m−3.d−1, the COD removal efficiency still could attain to 68%. Varied influent flow need to supply varied optimal and thus to ensure the optimal removal effect. Low temperature would cause pollutant removal rate decrease. However, enhancing could optimize the contact of sludge and wastewater and thus strengthen the performance effect. Modified Stover–Kincannon model was applied to data obtained from experimental studies in EGSB reactor. Treatment efficiencies of the reactor were investigated at different hydraulic retention times (0.5-1.3h) and different operation temperature (15°C, 26°C). The modified Stover–Kincannon model was best fitted to the EGSB reactor, and the substrate utilization rate( ), saturation constant value( ), and actual pollutant removal rate( ) were found to be , , and for 26°C, , , and for 15°C( before increasing ), and , , and for 15°C(after increasing ). Low temperature could cause decrease and thus cause distinct decreasing of COD removal efficiency. However, increasing could increase and accordingly increase COD removal efficiency.

Advanced Treatment of Secondary Sewage Effluent by Iron-Carbon Internal Electrolysis

2011 ◽  
Vol 183-185 ◽  
pp. 291-295
Author(s):  
Li Hua Cheng ◽  
Xue Jun Bi ◽  
Chang Qing Liu
Keyword(s):  
Reaction Time ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Advanced Treatment ◽  
Tertiary Treatment ◽  
Dynamic Experiment ◽  
Internal Electrolysis ◽  
Initial Ph ◽  
Degradation Reaction ◽  
Pollutant Removal Rate

Due to increasing water scarcity, appropriate technologies were need for advanced treatment of wastewater to enable reuse. Effect of iron-carbon internal electrolysis in tertiary treatment of wastewater was investigated in this study. Static experiment was adopted to evaluate influence of Fe/C ratio, pH, reaction time and aeration on pollutant removal by iron-carbon internal electrolysis. Then dynamic experiment was conducted to determine removal rate of CODcr, TP, chroma and NO3--N. The results showed that internal electrolysis could remove CODcr, TP and chroma efficiently. The optimal ratio of Fe/C was 1:1. Initial pH could affect removal efficiency. In acid circumstance, the removal rate was higher. Degradation reaction by internal electrolysis was fast. when the reaction time was 10min, the removal rate could be ideal. In the process of internal electrolysis, aeration could increase pollutant removal rate. In aerated system, when the reaction time was only 15min, removal rate of CODcr, TP and chroma could reach 49.2%, 89% and 75%. But in non-aerated system, only when the reaction time was 100min could removal rate of these indexes reach 46.5%, 81% and 85.1%. In dynamic experiment, removal rate of CODcr, TP, chroma and NO3- could reach above 40%, 90%, 75% and 20%, respectively.

Kinetic Analysis for COD Removal in Actual Coking Wastewater through an Micro-Aerobic EGSB Reactor

2014 ◽  
Vol 700 ◽  
pp. 455-459 ◽  
Author(s):  
Chun Juan Dong ◽  
Qing Ye Pan
Keyword(s):  
Kinetic Analysis ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Cod Removal ◽  
Utilization Rate ◽  
Coking Wastewater ◽  
Performance Effect ◽  
Dense Granules ◽  
Half Saturation Constant ◽  
Pollutant Removal Rate

Treatment of actual coking wastewater considered to be difficult by traditional systems. The present study is related to treatment of actual coking wastewater through microaerobic EGSB reactor. The study showed the EGSB reactor could attain about 75% high COD removal. IncreasingVupcould strength COD removal. Moreover, high sludge concentration and profound communal synergism existing within the dense granules were very important. As a result of the kinetic analysis of the EGSB reactor treating actual coking wastewater for COD removal using a modified Stover–Kincannon model, the maximum substrate utilization rate,vmax, half saturation constant,KS, inhibitor constant, KI, actual pollutant removal rate, , and the actual inhibition degree,KS/KIwere determined as 2.65×10-3h-1, 39.57mg.L-1, 415.82mg.L-1, 6.7×10-5h-1.mg-1.L and 0.1(before increasingVup), 7.34×10-3h-1, 19.53mg.L-1, 197.76mg.L-1, 3.7×10-4h-1.mg-1.L and 0.1(after increasingVup), and 9.35×10-3h-1, 6.38mg.L-1, 162.81mg.L-1, 1.47×10-3h-1.mg-1.L and 0.04 (after increasingVupand X), respectively. The inhibition of toxic contaminants in the actual coking wastewater would cause the decreasing of pollutant removal rate, however, enhancing and X (simultaneously optimizing sludge aggregate structure) could strengthen the performance effect.

scholarly journals Effect of Different Influent Conditions on Biomass Production and Nutrient Removal by Aeration Microalgae Membrane Bioreactor (ICFB-MMBR) System for Mariculture Wastewater Treatment

Membranes ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 874
Author(s):  
Yi Ding ◽  
Shiyuan Wang ◽  
Hang Ma ◽  
Binyu Ma ◽  
Zhansheng Guo ◽  
...  
Keyword(s):  
Growth Rate ◽  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Biomass Production ◽  
Nutrient Removal ◽  
Membrane Bioreactor ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Average Growth ◽  
Pollutant Removal Rate

The nutrient removal and biomass production of the internal circulating fluidized bed microalgae membrane bioreactor (ICFB-MMBR) was studied under different cultivation modes, influent TOC, influent pH, and influent N/P. Platymonas helgolandica tsingtaoensis was used as the biological source. The growth of P. helgolandica tsingtaoensis and the removal efficiency of pollutants in the mixotrophy culture mode were improved compared with other culture modes. With the increased influent TOC, the average growth rate of P. helgolandica tsingtaoensis increased, and ammonia nitrogen and total phosphorus removal rate were improved. The P. helgolandica tsingtaoensis growth rate and nutrient removal efficiencies at the influent pH of 8 were the best among the different influent pH values. As the influent N/P ratio increased from 5 to 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate increased gradually. When the influent N/P ratio was higher than 20, the P. helgolandica tsingtaoensis growth rate and pollutant removal rate tended to be stable and did not significantly change with the increase of influent N/P ratio. At the proper influent conditions, the high P. helgolandica tsingtaoensis biomass and nutrient removal efficiency could be obtained in the microalgae membrane bioreactor, which could provide a theoretical basis for the application of the system for wastewater treatment.

Research on Low Concentration Municipal Wastewater Removal Rate with Chemical-Biological Flocculation and Suspended Medium Process

2012 ◽  
Vol 599 ◽  
pp. 387-390
Author(s):  
Xing Yu Bian ◽  
Xing Sheng Kang ◽  
Yi Li ◽  
Yu Lin Sun ◽  
Min Kong ◽  
...  
Keyword(s):  
Municipal Wastewater ◽  
Removal Rate ◽  
Pilot Scale ◽  
Pollutant Removal ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Optimal Operating ◽  
Operational Parameter ◽  
Low Concentration ◽  
Scale Test

In this paper, chemical and biological flocculation and suspended medium process was applied to treat low concentration municipal wastewater in a pilot scale test in order to find the optimum operational parameter. The results showed that: system on pollutant removal mainly on chemical and biological flocculation reaction pool, Under the optimal operating condition, CODCr, TP and SS removal efficiencies reached 75.5％, 76％and 90.5％ respectively, and the CODCr, TP, SS concentrations of effluent meet the National Wastewater Integrated Discharge Standard. The optimum operating conditions according to the local actual situation, running for more than half a year, for the optimization of control parameters for the contrast obtained.

Filtration Treatment of Pollutants in Urban Runoff Using Expanded Polypropylene Media

2007 ◽  
Vol 544-545 ◽  
pp. 573-576
Author(s):  
Sung Won Kang ◽  
Byung Cheol Lee ◽  
Young Im Kim ◽  
Sang Leen Yun ◽  
Yong Jin Park ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Best Management Practices ◽  
Urban Areas ◽  
Management Practices ◽  
Removal Rate ◽  
Stormwater Runoff ◽  
Expansion Ratio ◽  
Pollutant Removal ◽  
Polynuclear Aromatic Hydrocarbons ◽  
Filter Media

Pollutants such as heavy metals and PAHs (Polynuclear Aromatic Hydrocarbons) in stormwater runoff are a major problem in urban areas because these pollutants are discharged directly, in most cases without any treatment, into the receiving environments like river and lake. Since many of the pollutants are associated with suspended particulate materials in stormwater, SS (suspended solids) is of acknowledged importance in stormwater runoff treatment by BMPs (best management practices). Filtration, which is commonly used for removing particulate matter in stormwater structural BMPs, depends on various factors (e.g., filter media size, flow rate, bed depth, filter surface properties, etc). Especially, the characteristics of filter media are important factor affecting removal efficiency of pollutants and replacement period of filter media in filtration performance. In this study, EPM (expanded polypropylene media) as a filter media was manufactured at different expansion ratios (i.e., 5, 10, 15 times) and tested in the up-flow filtration for removing pollutants in urban stormwater runoff. The specific surface area of EPM10, EPM15, EPM30, EPM54 was 0.760 m2/g, 0.799 m2/g, 0.812 m2/g, 0.845 m2/g, respectively. The SS removal efficiency (64.1%) by EPM media was higher than that (44.2%) by sand media. In case of EPM10 media, it took 175min of removal rate of filtration system to be approached under 50% and EPM15 media was spent 110min. However, the SS removal efficiency of EPM15 was over 10% higher than that of EPM10. The CODCr removal efficiency of EPM media was also increased with increasing expansion rate. The experimental results in this work show that pollutant removal efficiency by EPM media was increased with increasing expansion ratio but replacement period of media was decreased. EPM media are expected to adsorb non-biological organics like PAHs owing to its hydrophobicity.

scholarly journals Porous Multifunctional Phenylcarbamoylated-β-Cyclodextrin Polymers for Rapid Removal of Organic Pollutants

2021 ◽  
Author(s):  
He Wang ◽  
Congzhi Liu ◽  
Xiaofei Ma ◽  
Yong Wang
Keyword(s):  
Organic Contaminants ◽  
Adsorption Process ◽  
Removal Rate ◽  
Pollutant Removal ◽  
Maximum Adsorption Capacity ◽  
Order Kinetic ◽  
Monolayer Adsorption ◽  
Pseudo Second Order ◽  
Rapid Removal ◽  
Cyclodextrin Polymers

Abstract In this work, a series of porous multifunctional cyclodextrin (CD) polymers were fabricated using tetrafluoroterephthalonitrile (TFTPN) as the rigid crosslinker for the condensation of different functional phenylcarbamoylated-β-cyclodextrin derivatives to afford three preliminary polymerized adsorption materials such as poly nitrophenylcarbamoylated-β-cyclodextrin (NO2-CDP), poly trifluoromethylphenylcarbamoylated-β-cyclodextrin (F-CDP), poly chlorophenylcarbamoylated-β-cyclodextrin polymers (Cl-CDP) and a mix β- cyclodextrin polymer (X-CDP) prepared via a secondary crosslinking procedure of the above three materials. The X-CDP preparation process connects the `pre-formed nanoparticles and increases the presence of linkers inside the particles. At the same time, X-CDP exhibited porous structure with various functional groups such as nitro, chlorine, fluorine and hydroxyl. Those special characteristics render this material with good adsorption ability towards various pollutants in water, including tetracycline, ibuprofen, dichlorophenol, norfloxacin, bisphenol A, naphthol. Especially the maximum adsorption capacity for tetracycline at equilibrium reached 230.15 mg·g− 1, which is competitive with the adsorption capacities of other polysaccharides adsorbents. X-CDP removed organic contaminants much more quickly than other adsorbents, reaching almost ~ 95% of its equilibrium in only 30 s. The main adsorption process of the pollutants by X-CDP fitted the pseudo-second-order kinetic and Langmuir isotherm well, indicating that the adsorption process is monolayer adsorption. Moreover, X-CDP possessed the good reusability where the pollutant removal rate was only reduced 8.3% after five cycles.

scholarly journals Pollutant Removal from Wastewater at Different Stages of the Tanning Process by Electrocoagulation

2019 ◽  
Vol 2019 ◽  
pp. 1-9 ◽  
Author(s):  
Alejandra de la Luz-Pedro ◽  
Efraín F. Martínez Prior ◽  
M. H. López-Araiza ◽  
S. Jaime-Ferrer ◽  
A. Estrada-Monje ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Current Density ◽  
Chromium Content ◽  
Removal Rate ◽  
Minimum Energy ◽  
Pollutant Removal ◽  
Tannery Wastewater ◽  
Wastewater Sample ◽  
Initial Ph ◽  
Tanning Process

The removal of chemical oxygen demand (COD), total organic carbon (TOC), turbidity, and chromium content from tannery wastewater at different stages of the process was experimentally investigated using electrocoagulation (EC) with iron and aluminium electrodes. In the EC of the beamhouse wastewater (S1), the effects of initial pH and current density were analyzed and electrical energy consumption was determined. The COD and TOC in the solution were effectively removed, with an initial pH 7.0, using either metallic electrode. With a current density of 28 mA/cm2 for an electrolysis procedure of 60 minutes, the removal efficiency of COD and TOC was 72% and 57% with aluminium electrodes and 69% and 60% with iron electrodes, respectively. The minimum energy consumption for the highest COD and TOC removal was 0.37 and 0.69 kWh/m3 when employing iron or aluminium electrodes, respectively. At the optimal conditions, removal efficiencies close to 100% for turbidity and chromium content for wastewaters S1-beamhouse, S2-tanning, S3-retanning, and S4-a mixture 1 : 1 : 1 (v/v/v) were achieved. Results show that a pseudosecond-order rate equation provides a good correlation for the removal rate of the parameters. Finally, the results indicate that for tannery wastewater, the EC process does not depend noticeably on the electrode material, but that the stage of the tanning process of wastewater sample has the principal effect on treatment efficiency.

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