scholarly journals Application of heterogeneous catalytic ozonation process for treatment of high toxic effluent from a pesticide manufacturing plant

2020 ◽  
Vol 7 (2) ◽  
pp. 79-88
Author(s):  
Mina Ghahrchi ◽  
Edris Bazrafshan ◽  
Behruz Adamiyat Badan ◽  
Yousef Dadban Shahamat ◽  
Fariba Gohari
Keyword(s):  
Reaction Time ◽  
Treatment Process ◽  
Catalyst Concentration ◽  
Oxygen Demand ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Heterogeneous Catalytic ◽  
Removal Efficiencies ◽  
Ozonation Process ◽  
Maximum Removal

Background: The discharge of untreated wastewater containing toxic and resistant compounds into the environment is a serious threat for ecosystems. Therefore, this study was conducted to evaluate the treatment of poison production factory wastewater using heterogeneous catalytic ozonation process (COP). Methods: Magnetic carbon nanocomposite was used as a catalyst at concentrations of 1, 2, and 4 g/L. Its effect on improving the treatment process was evaluated at reaction time of 30, 60, 90, and 120 minutes. At the end of each experiment, parameters including total organic carbon (TOC), chemical oxygen demand (COD), biological oxygen demand (BOD5 ), pH, electrical conductivity (EC), and turbidity were measured. Results: It was revealed that in single ozonation process (SOP), the maximum removal efficiencies of TOC, COD, and BOD5 were achieved at reaction time of 120 minutes as 56%, 40%, and 11.7%, respectively. By adding the catalyst to the wastewater, the treatment process was improved, so that the maximum removal efficiencies of COD (91%), TOC (73%), and BOD5 (74%) were obtained at catalyst concentration of 4 g/L. Under this condition, BOD5 /COD ratio increased from 0.22 to 0.64. Also, the results of analysis of ozone consumption per each mg of reduced COD showed that its amount sharply decreased from 2.1 mgO3 / mg COD removal in the SOP, to 0.34 mgO3 /mg COD removal in the COP. The results of kinetic reaction analysis also revealed that the rate constant increased from 0.007 to 0.02 min-1. Conclusion: According to the results, it can be concluded that the COP at a catalyst concentration of 4 g/L, by decomposing resistant compounds and increasing the biodegradability, can be used as a suitable pretreatment method for biological processes.

Fenton's treatment of actual agriculture runoff water containing herbicides

2016 ◽  
Vol 75 (2) ◽  
pp. 451-461 ◽  
Author(s):  
Sanjeev Sangami ◽  
Basavaraju Manu
Keyword(s):  
Reaction Time ◽  
Treatment Process ◽  
Signal To Noise Ratio ◽  
Oxygen Demand ◽  
Runoff Water ◽  
Independent Variables ◽  
Dependent Variables ◽  
Removal Efficiencies ◽  
Dichlorophenoxy Acetic Acid ◽  
Maximum Removal

This research was to study the efficiency of the Fenton's treatment process for the removal of three herbicides, namely 2,4-dichlorophenoxy acetic acid (2,4-D), ametryn and dicamba from the sugarcane field runoff water. The treatment process was designed with the Taguchi approach by varying the four factors such as H2O2/COD (1–3.5), H2O2/Fe2+ (5–50), pH (2–5) and reaction time (30–240 min) as independent variables. Influence of these parameters on chemical oxygen demand (COD), ametryn, dicamba and 2,4-D removal efficiencies (dependent variables) were investigated by performing signal to noise ratio and other statistical analysis. The optimum conditions were found to be H2O2/COD: 2.125, H2O2/Fe2+: 27.5, pH: 3.5 and reaction time of 135 min for removal efficiencies of 100% for ametryn, 95.42% for dicamba, 88.2% for 2,4-D and with 75% of overall COD removal efficiencies. However, the percentage contribution of H2O2/COD ratio was observed to be significant among all four independent variables and were 44.16%, 67.57%, 51.85% and 50.66% for %COD, ametryn, dicamba and 2,4-D removal efficiencies, respectively. The maximum removal of herbicides was observed with the H2O2 dosage of 5.44 mM and Fe2+ dosage of 0.12 mM at pH 3.5.

scholarly journals Heterogeneous Catalytic Ozonation of p-Chlorobenzoic Acid in Aqueous Solution by FeMnOOH and PET

Separations ◽  
2018 ◽  
Vol 5 (3) ◽  
pp. 42 ◽  
Author(s):  
Savvina Psaltou ◽  
Stylianos Stylianou ◽  
Manasis Mitrakas ◽  
Anastasios Zouboulis
Keyword(s):  
Organic Compound ◽  
Adsorption Capacity ◽  
Treatment Process ◽  
Catalyst Concentration ◽  
Catalytic Ozonation ◽  
Total Removal ◽  
Chlorobenzoic Acid ◽  
Heterogeneous Catalytic ◽  
Hydrophobically Modified ◽  
Typical Model

The oxidation of p-chlorobenzoic acid (p-CBA), used as a typical-model refractory organic compound, in aqueous solutions during the heterogeneous catalytic ozonation treatment process by applying the hydrophilic tetravalent manganese feroxyhyte (TMFx), as well as modified hydrophobic TMFx and the polyethylene terephthalate (PET) as solid (powdered) catalysts was examined in this study. TMFx was hydrophobically modified by using trichloromethylsilane (TriClMS) solutions in toluene at the concentration range 10–1000 mg/L. TMFx catalysts were characterized by the application of scanning electron microscopy (SEM), as well as by Brunauer-Emmet-Teller (BET) and surface charge density determinations. TMFx catalyst, which was modified by 50 mg/L trichloromethylsilane (TriClMS) solution (TMFx-50), was found to present the higher adsorption capacity of studied organic compound (250 μg p-CBA/g) when compared with all the other investigated catalysts, which in turn resulted in the higher removal of p-CBA (>99%) by the subsequent application of ozonation, as compared to hydrophilic TMFx (96.5%) and to single ozonation (96%) applications. PET-catalyst concentration in the range 0.5–10 g/L led to almost total removal of p-CBA within 15 min of reaction/oxidation time at pH 7. Conclusively, the experimental results for both catalysts indicated that hydrophobicity and adsorption capacity are crucial steps for the process of heterogeneous catalytic ozonation of refractory organic compounds.

scholarly journals Calcite Mineral Catalyst Capable of Enhancing Micropollutant Degradation during the Ozonation Process at pH7

2020 ◽  
Vol 2 (1) ◽  
pp. 26
Author(s):  
Savvina Psaltou ◽  
Efthimia Kaprara ◽  
Manassis Mitrakas ◽  
Anastasios Zouboulis
Keyword(s):  
Reaction Time ◽  
Hydroxyl Radicals ◽  
Advanced Oxidation Process ◽  
Oxidation Process ◽  
Catalytic Ozonation ◽  
Batch Mode ◽  
Heterogeneous Catalytic ◽  
Physico Chemical ◽  
Oxidative Species ◽  
Ozonation Process

Catalytic ozonation is an Advanced Oxidation Process (AOPs) based on the production of hydroxyl radicals, which are very reactive oxidative species. The aim of this study is to evaluate the catalytic activity of calcite on the ozonation of four different typical micropollutants (atrazine, benzotriazole, carbamazepine, and p-CBA) at pH 7 and for low initial concentrations (4 μΜ) by performing batch mode experiments. These compounds have different physico-chemical characteristics, as well as different rate constants, when reacting with ozone and hydroxyl radicals (•OH), being in the range of <0.15 − 3 × 105 M−1s−1 and 2.4 − 8.8 × 109 M−1s−1, respectively. It was found that most of these micropollutants can be sufficiently removed by the application of heterogeneous catalytic ozonation, using calcite as the catalyst, except for the case of atrazine, which was the compound that was most difficult to degrade, when compared to the application of single ozonation. Carbamazepine with kO3 = 3 × 105 M−1s−1 can be easily removed even by single ozonation after the first minute of the reaction time, and the addition of the catalyst eliminated the oxidation/reaction time. The application of catalytic ozonation resulted in 50% and 68.2% higher removals of benzotriazole and p-CBA, respectively, in comparison with single ozonation, even during the first 3 min of the reaction/oxidation time, due to the higher production of hydroxyl radicals, caused by the catalytic ozonation. For the case of atrazine, the addition of calcite did not enhance the micropollutant degradation, and its removal reached 83% after a 30 min application of catalytic ozonation, whereas during the single ozonation, the removal under the same reaction time was 90%.

Pretreatment of concentrated leachate by the combination of coagulation and catalytic ozonation with Ce/AC catalyst

2015 ◽  
Vol 73 (3) ◽  
pp. 511-519 ◽  
Author(s):  
Hangdao Qin ◽  
Honglin Chen
Keyword(s):  
Size Distribution ◽  
Membrane Separation ◽  
Oxygen Demand ◽  
Molecular Size ◽  
Apparent Molecular Weight ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Distribution Analysis ◽  
Molecular Size Distribution ◽  
Ozonation Process

A raw concentrated leachate produced from membrane bioreactor-nanofiltration (MBR-NF) was taken from Chengdu Chang'an Waste Landfill Site, China. The major fraction of this concentrated leachate was large refractory humic substances. A coagulation–ozonation process was applied to treat this leachate, aiming at enhancing chemical oxygen demand (COD) removal efficiency and increasing its biodegradability. Meanwhile the molecular size distribution of the leachate, before and after coagulation and ozonation treatment, was analyzed by using ultrafiltration membrane separation. Coagulation pretreatment effectively removed varieties of large molecules in the raw concentrated leachate. The addition of Ce/AC greatly improved the oxidative ability of O3 in COD removal in the ozonation of coagulated leachate. The biochemical oxygen demand (BOD5)/COD ratio increased from 0.011 for the untreated concentrated leachate to 0.30 for the effluent of the coagulation–catalytic ozonation process, which indicated that a subsequent biological treatment could be readily conducted. The stability test demonstrated that the Ce/AC catalyst was effective and stable in the catalytic ozonation process. According to the results of molecular size distribution analysis, a direct correlation was observed between the increase of BOD5/COD and the decrease of apparent molecular weight.

Treatment of Palm Oil Mill Effluent (POME) Supernatants Using Aerobic Attached–Growth System: Trickling Filter as a Case Study

2012 ◽  
Author(s):  
Ahmad Zuhairi Abdullah ◽  
Mohamad Hakimi Ibrahim ◽  
Mohd. Omar Ab. Kadir
Keyword(s):  
Palm Oil ◽  
Colloidal Particles ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Palm Oil Mill Effluent ◽  
Trickling Filter ◽  
Biomass Hydrolysis ◽  
Removal Efficiencies ◽  
Palm Oil Mill ◽  
Hydrolysis Of

Kertas kerja ini membincangkan tentang kecekapan penuras cucur dalam merawat supernatan kumbahan kilang kelapa sawit (POME). Supernatan POME diperoleh menerusi dua jenis perawatan. Dalam perawatan 1, pengendapan graviti digunakan untuk menyingkir pepejal boleh mendak. Perawatan 2 digunakan untuk menyingkir pepejal boleh mendak dan gumpalan partikal dengan menggunakan 350 ppm alum. Influen dialurkan secara titisan pada biojisim yang terlekat pada penyokong pepejal rawak PVC setinggi 1 m. Penuras cucur berupaya menyingkir lebih daripada 90.0% dari keperluan oksigen biologi (BOD) dan keperluan oksigen kimia (COD) di bawah 1 m3/m2–hari. Pada 2.53 m3/m2–hari, influen dengan Perawatan 1 menghasilkan kecekapan penyingkiran COD sebanyak 40.3%, berbanding 83.1% bila Perawatan 2 digunakan. Perkara ini berlaku berikutan penyingkiran bahan organik tak boleh resap semasa Perawatan 2. Kecekapan penyingkiran menurun dengan meningkatnya bebanan hidraulik kerana wujudnya kelemahan dalam hidrolisis bahan tak boleh resap kepada substratum larut. Dengan edaran semula (α=1), penyingkiran BOD dan COD yang lebih tinggi dicapai di bawah 7 m3/m2–hari. Pencapaian ini disebabkan oleh bebanan organik yang lebih rendah serta pergedaran semula enzim dan biojisim yang aktif kepada sistem. Perawatan 2 menghasilkan enap cemar yang lebih tinggi kerana penukaran substratum boleh larut kepada biojisim tak boleh larut. Hidrolisis bahan organik tak boleh resap didapati berlaku secara aktif pada bahagian atas penuras cucur sementara bahagian bawahnya cenderung mengoksidakan substratum organik. Kata kunci: POME, turas cucur, bahan organik bolehresap, penggumpalan, alir semula This paper discusses the efficiency of a trickling filter to treat Palm Oil Mill Effluent (POME) supernatants. POME supernatants were obtained via two treatments. In Treatment 1, gravity sedimentation was used to remove settleable solids. In Treatment 2, both settleable solids and colloidal particles were removed using 350 ppm of alum. The influents were allowed to trickle over biomass attached to 1 m high random PVC solid support. Below 1 m3/m2–day, the filter demonstrated Biological Oxygen Demand (BOD) and Chemical Oxygen Demand (COD) removal efficiencies of more than 90.0%. At 2.53 m3/m2–day, the influent with Treatment 1 gave a COD removal efficiency of 40.3%, but increased to 83.1% when the influent with Treatment 2 was used. This was ascribed to the removal of non–diffusible organics during Treatment 2. The removal efficiencies decreased with an increase in hydraulic loading due to limitations in the hydrolysis of non–diffusibles into soluble substrates. With recirculation (α=1), higher BOD and COD removals were achieved below 7.0 m3/m2–day, attributed to lower organic loading and the recycling of active enzyme and biomass to the system. The influent with Treatment 2 demonstrated higher sludge production due to higher conversion of soluble substrates into insoluble biomass. Hydrolysis of non–diffusible organics mainly took place at upper reaches of the filter column while lower reaches were involved in oxidizing the organic subtrates. Key words: POME, trickling filter, diffusible organic, coagulation, recirculation

Optimization and statistical analysis of sono-Fenton treated wastewater of food industry using reactor by response surface method

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod
Keyword(s):  
Reaction Time ◽  
Response Surface ◽  
Food Industry ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Volume Ratio ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Experimental Result ◽  
Molar Ratio

Abstract The present study deals with the treatment of complex waste (WW) treated for removal of chemical oxygen demand (COD) of the food industry by a sono-Fenton process using a batch reactor. The response surface methodology (RSM) was employed to investigate the five independent variables, such as reaction time, the molar ratio of H2O2/Fe2+, volume ratio of H2O2/WW, pH of waste, and ultrasonic density on COD removal. The experimental data was optimized. The optimization yields the conditions: Reaction time of 24 min, HP:Fe molar ratio of 2.8, HP:WW volume ratio of 1.9 ml/L, pH of 3.6 and an ultrasonic density of 1.8 W/L. The predicted value of COD was 91% and the experimental result was 90%. The composite desirability value (D) of the predicted percent of COD removal at the optimized level of variables was close to one (D = 0.991).

scholarly journals Treatment of oilfield wastewater by combined process of micro-electrolysis, Fenton oxidation and coagulation

2017 ◽  
Vol 76 (12) ◽  
pp. 3278-3288 ◽  
Author(s):  
Zhenchao Zhang
Keyword(s):  
Reaction Time ◽  
Removal Efficiency ◽  
Treatment Process ◽  
Cod Removal ◽  
Fenton Oxidation ◽  
Oily Wastewater ◽  
Optimum Conditions ◽  
Combined Process ◽  
Cod Removal Efficiency ◽  
Optimized Conditions

Abstract In this study, a combined process was developed that included micro-electrolysis, Fenton oxidation and coagulation to treat oilfield fracturing wastewater. Micro-electrolysis and Fenton oxidation were applied to reduce chemical oxygen demand (COD) organic load and to enhance organic components gradability, respectively. Orthogonal experiment were employed to investigate the influence factors of micro-electrolysis and Fenton oxidation on COD removal efficiency. For micro-electrolysis, the optimum conditions were: pH, 3; iron-carbon dosage, 50 mg/L; mass ratio of iron-carbon, 2:3; reaction time, 60 min. For Fenton oxidation, a total reaction time of 90 min, a H2O2 dosage of 12 mg/L, with a H2O2/Fe2+ mole ratio of 30, pH of 3 were selected to achieve optimum oxidation. The optimum conditions in coagulation process: pH, cationic polyacrylamide dosage, mixing speed and time is 4.3, 2 mg/L, 150 rpm and 30 s, respectively. In the continuous treatment process under optimized conditions, the COD of oily wastewater fell 56.95%, 46.23%, 30.67%, respectively, from last stage and the total COD removal efficiency reached 83.94% (from 4,314 to 693 mg/L). In the overall treatment process under optimized conditions, the COD of oily wastewater was reduced from 4,314 to 637 mg/L, and the COD removal efficiency reached 85.23%. The contribution of each stage is 68.45% (micro-electrolysis), 24.07% (Fenton oxidation), 7.48% (coagulation), respectively. Micro-electrolysis is the uppermost influencing process on COD removal. Compared with the COD removal efficiency of three processes on raw wastewater under optimized conditions: the COD removal efficiency of single micro-electrolysis, single Fenton oxidation, single coagulation is 58.34%, 44.88% and 39.72%, respectively. Experiments proved the effect of combined process is marvelous and the overall water quality of the final effluent could meet the class III national wastewater discharge standard of petrochemical industry of China (GB8978-1996).

scholarly journals USING METAL WASTE SLAGS AS THE HETEROGENEOUS CATALYSTS OF OZONE FOR TREATMENT OF PULP WASTEWATER

2020 ◽  
Vol 58 (3A) ◽  
pp. 1
Author(s):  
Hu Tap Van
Keyword(s):  
Organic Compounds ◽  
Removal Efficiency ◽  
Heterogeneous Catalysts ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Color Removal ◽  
Order Kinetic ◽  
First Order ◽  
Iron Slag ◽  
Ozonation Process

Catalytic ozonation is one of the promising treatment methods for removal of persistent organic compounds from water and wastewater. In this study, some metal slags such as: iron slag, lead slag, zinc slag, cadmium slag and copper slag originated from solid waste of Thai Nguyen Non-ferrous Metals Limited Company, Vietnam were used as heterogeneous catalysts for ozonation process to remove organic compounds from pulp wastewater. The effects of the initial pH (pHi) of pulp wastewater and the metal slag dosage on efficiency of decolorization and mineralization of pulp wastewater, in term of COD were investigated. The results indicated that iron slag was the most suitable catalyst for treatment of pulp wastewater by ozonation process with the highest removal efficiency of COD, namely, after 120 min of ozonation (with flowrate of O3 of 3.038 g/h) of the pulp wastewater (initial COD 1809 mg/L), COD removal efficiency, respectively, reached 91,16%; 84%; 83,83 %; 83,91%; 83,41% and 83,14% in the presence of iron, copper, zinc, lead, cadmium slag and ozone alone. Simultaneously, the color was almost completely removed (95.55 – 98.79%) by ozonation processes with using all before-mentioned metal slags as heterogeneous catalysts and ozone alone. Maximum COD and color removal efficiency obtained at pH 7 for ozonation alone and its combinations with iron slag. Moreover, an increase in the iron slag dosage from 0.125 g/L to 2.0 g/L for O3/iron slag could enhance COD and color removal of pulp wastewater. The K values (apparent first-order rate constant values) showed that the COD removal rate followed the pseudo-first-order kinetic model. This study also indicated that the main constituent FeO presence in iron slag reaction with O3 in heterogeneous catalytic ozonation system enhances removal efficiency of color and COD of pulp wastewater.

scholarly journals Treatment of Bio-Treated Coking Wastewater by Catalytic Ozonation with Semi-Batch and Continuous Flow Reactors

Water ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2532
Author(s):  
Can He ◽  
Jianbing Wang ◽  
Heng Xu ◽  
Xiangyu Ji ◽  
Weiyi Wang ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Continuous Flow ◽  
Oxygen Demand ◽  
Catalytic Ozonation ◽  
Cod Removal ◽  
Utilization Efficiency ◽  
Coking Wastewater ◽  
Ozone Absorption ◽  
Flow Reactors ◽  
Continuous Flow Reactors

In this work, the treatment of bio-treated coking wastewater (BCW) by catalytic ozonation was conducted in semi-batch and continuous flow reactors. The kinetics of chemical oxygen demand (COD) removal were analyzed using BCWs from five coking plants. An integral reactor with catalytic ozonation stacked by ozone absorption (IR) was developed, and its efficiency was studied. The catalyst of MnxCe1-xO2/γ-Al2O3 was efficient in the catalytic ozonation process for the treatment of various BCWs. The chemical oxygen demand (COD) removal efficiencies after 120 min reaction were 64–74%. The overall apparent reaction rate constants were 0.0101–0.0117 min−1, which has no obvious relationship with the initial COD of BCW and pre-treatment biological process. The IR demonstrated the highest efficiency due to the enhancement of mass transfer and the utilization efficiency of ozone. Bypass internal circulation can further improve the reactor efficiency. The optimal results were obtained with the ozone absorption section accounting for 19% of the valid water depth in the reactor and 250% of circulation flow ratio. The long-term and full-scale application of the novel reactor in a continuous mode indicated stable removal of COD and polycyclic aromatic hydrocarbons (PAHs). The results showed that the system of IR is a promising reactor type for tertiary treatment of coking wastewater by catalytic ozonation.

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