Remediation of Contaminated Surface Water by Permeable Reactive Barriers (PRBs): Lab-Scale Experiments with Four Industrial Wastes as Reactive Media

2013 ◽  
Vol 295-298 ◽  
pp. 1850-1854
Author(s):  
Li Cui ◽  
Rui Gao ◽  
Fang Qin Cheng ◽  
Jian Feng Li ◽  
Xu Ming Wang
Keyword(s):  
Fly Ash ◽  
Removal Efficiency ◽  
Steel Slag ◽  
Cod Removal ◽  
Permeable Reactive Barriers ◽  
Industrial Wastes ◽  
Column Tests ◽  
Cod Removal Efficiency ◽  
Initial Ph ◽  
Reactive Media

Four industrial wastes: iron scraps, ceramsite, fly ash and steel slag were studied as reactive media for COD removal from the Fenhe River. Leaching tests demonstrated that iron scraps and ceramsite were relatively stable compared to steel slag and fly ash. Ca2+ was the main leaching ion. Batch experiment results showed that iron scraps and steel slag had better COD removal efficiency than ceramsite and fly ash. It was also found that the initial pH was important for COD removal and the COD removal efficiency of iron scraps was linearly correlated with the initial pH (R2=0.982). Compared to batch experiments, COD removal was much higher in column tests, which were about 70%, 54%, 46% for iron scraps, steel slag and ceramsite respectively.

Electrocoagulation and nanofiltration integrated process application in purification of bilge water using response surface methodology

2016 ◽  
Vol 74 (3) ◽  
pp. 564-579 ◽  
Author(s):  
Ceyhun Akarsu ◽  
Yasin Ozay ◽  
Nadir Dizge ◽  
H. Elif Gulsen ◽  
Hasan Ates ◽  
...  
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Cod Removal ◽  
Positive Sign ◽  
Aluminum Electrode ◽  
Integrated Process ◽  
Bilge Water ◽  
Cod Removal Efficiency ◽  
Initial Ph

Marine pollution has been considered an increasing problem because of the increase in sea transportation day by day. Therefore, a large volume of bilge water which contains petroleum, oil and hydrocarbons in high concentrations is generated from all types of ships. In this study, treatment of bilge water by electrocoagulation/electroflotation and nanofiltration integrated process is investigated as a function of voltage, time, and initial pH with aluminum electrode as both anode and cathode. Moreover, a commercial NF270 flat-sheet membrane was also used for further purification. Box–Behnken design combined with response surface methodology was used to study the response pattern and determine the optimum conditions for maximum chemical oxygen demand (COD) removal and minimum metal ion contents of bilge water. Three independent variables, namely voltage (5–15 V), initial pH (4.5–8.0) and time (30–90 min) were transformed to coded values. The COD removal percent, UV absorbance at 254 nm, pH value (after treatment), and concentration of metal ions (Ti, As, Cu, Cr, Zn, Sr, Mo) were obtained as responses. Analysis of variance results showed that all the models were significant except for Zn (P > 0.05), because the calculated F values for these models were less than the critical F value for the considered probability (P = 0.05). The obtained R2 and Radj2 values signified the correlation between the experimental data and predicted responses: except for the model of Zn concentration after treatment, the high R2 values showed the goodness of fit of the model. While the increase in the applied voltage showed negative effects, the increases in time and pH showed a positive effect on COD removal efficiency; also the most effective linear term was found as time. A positive sign of the interactive coefficients of the voltage–time and pH–time systems indicated synergistic effect on COD removal efficiency, whereas interaction between voltage and pH showed an antagonistic effect.

scholarly journals Treatment of simulated printing and dyeing wastewater using ozone microbubble

2021 ◽  
Vol 261 ◽  
pp. 04005
Author(s):  
Emmanuel Nkudede ◽  
Husseini Sulemana ◽  
Bo Zhang ◽  
Kaida Zhu ◽  
Shan Hu ◽  
...  
Keyword(s):  
Mass Transfer ◽  
Methylene Blue ◽  
Removal Efficiency ◽  
Human Life ◽  
Cod Removal ◽  
Dyeing Wastewater ◽  
Flow Rates ◽  
Printing And Dyeing Wastewater ◽  
Cod Removal Efficiency ◽  
Initial Ph

Owing to its widespread and persistent usage, methylene blue (MB) is an environmental substance, mostly found in the printing and dyeing industry that raises concerns in the environment recently by posing significant threat to human life and the ecosystem as a whole. Thus, there is the need to effectively manage and treat the wastewater from these industries before reaching to the available water sources. Ozonation treatment is very efficient in treating printing and dyeing wastewater (MB) and can be greatly improved by using micro-bubble technology. Microbubble dissolution is an effective way to improve the rate of ozone mass transfer. To discover these properties, a method was used to improve the mass transfer of ozone microbubbles, which was used to effectively treat simulated printing and dyeing wastewater. We investigated the effects of pH, water temperature, ozone flow, and other conditions on the dissolution and attenuation properties of ozone in methylene blue microbubble solutions. Treatment of simulated printing and dyeing wastewater (methylene blue) was investigated under various initial pH and ozone flow rates. A catalytic exhibition was performed towards the decolorization of methylene blue (MB) concentrations and the corresponding COD removal efficiency. Ozone depletion and pH levels played key roles in MB degradation. Under high pH level of 11.01, the rate of removal of COD was 93.5%. Ozone dosage also has direct effect on COD removal efficiency and decolorization. Higher ozone flow rates, 0.4 L/min and 0.5 L/min recorded more than 94% degradation of COD thus very effective and efficient. Also, ozone flow rates 0.3 L/min, 0.4 L/min and 0.5 L/min with initial pH, 7.03, 6.63 and 6.36 decreased to 3.43, 3.49 and 3.44 after reaction processes which clearly shows that with high ozone dosage, pH reduces considerably.

scholarly journals Effect of Current and Initial pH on Electrocoagulation in Treating the Distillery Spent Wash with Very High Pollutant Content

Water ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 11
Author(s):  
Iqbal Syaichurrozi ◽  
Sarto Sarto ◽  
Wahyudi Budi Sediawan ◽  
Muslikhin Hidayat
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Kinetic Constants ◽  
Spent Wash ◽  
Distillery Spent Wash ◽  
Removal Process ◽  
Cod Removal Efficiency ◽  
Working Volume ◽  
Initial Ph ◽  
Very High

The distillery spent wash (DSW) from bioethanol industries has a very high chemical oxygen demand (COD). Hence, the goal of this study is to investigate the effect of currents (2.5, 3 and 3.5 A) and initial pHs (4.4, 5.0 and 7.0) on electrocoagulation (EC) to decrease the COD in DSW. The results showed that the EC at the current of 3.5 A enabled a higher COD removal efficiency (74.9%) than those at the currents of 2.5 (35.4%) and 3 A (60.9%). Furthermore, the initial pH of 7.0 resulted in a higher COD removal efficiency than the initial pHs of 4.4 and 5.0. The solution pH and temperature increased throughout the process. The working volume was not constant due to the reactions of water reduction, evaporation and flotation. Scum and sludge productions were also monitored during the process. Then, the measured data (COD, sludge and scum) were used in the modeling. The simple mechanistic models were successfully built and applied to simulate the data in mass units with two different routes of process. Route 1 assumed that the COD was converted to sludge and then the latter was converted to scum. Route 2 assumed that the COD was converted to the sludge and scum at the same time. When the EC was operated at the initial pH of 4.4, the COD removal process followed route 1, but that at the initial pHs of 5.0 and 7.0, the COD removal process followed route 2. The higher the current applied in the EC, the higher the kinetic constants of ka and kb. Additionally, the higher the initial pH set, the higher the kinetic constants were. This showed that the formation rates of sludge and scum at the higher currents or initial pHs were faster than those at the lower values.

Treatment of oil–water emulsion from the machinery industry by Fenton's reagent

2015 ◽  
Vol 71 (12) ◽  
pp. 1884-1892 ◽  
Author(s):  
Chao Feng ◽  
Henghu Sun ◽  
Suqin Li ◽  
Mary Kay Camarillo ◽  
William T. Stringfellow ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Cod Removal ◽  
Oxidation Time ◽  
Single Factor ◽  
Water Emulsion ◽  
Machinery Industry ◽  
Cod Removal Efficiency ◽  
Initial Ph ◽  
Oil Water ◽  
Chinese Standard

An oil–water emulsion from the machinery industry was treated using Fenton's reagent. The objective was to reduce the high chemical oxygen demand (COD) of this waste stream so that it would meet the COD effluent limit of Chinese Standard JS-7740-95. The optimal [H2O2]/[Fe2+] ratio for COD removal was 3. An orthogonal experimental design was developed based on the optimal [H2O2]/[Fe2+] ratio to evaluate the significance of four parameters relevant to the treatment process, namely, H2O2 dosage, initial pH, oxidation time and coagulation pH. The influence of the four parameters on COD removal efficiency decreased as follows: H2O2 dosage > oxidation time > coagulation pH > initial pH. The COD removal efficiency was further investigated based on the most important single-factor parameter, which was H2O2 dosage, as discovered in the orthogonal test. A well-fitted empirical correlation was obtained from the single-factor analysis and up to 98% COD removal was attained using 50 mM H2O2. Using the doses and conditions identified in this study, the treated oil–water emulsion can be discharged according to Chinese Standard JS-7740-95.

Dioctyl Phthalate Esters Wastewater Treatment by Fenton Reagent / Fly Ash Combined Process

2013 ◽  
Vol 777 ◽  
pp. 122-126
Author(s):  
Li Ping Wang ◽  
Xin Ying Li ◽  
Xiang Mei Li
Keyword(s):  
Fly Ash ◽  
Removal Efficiency ◽  
Phthalate Esters ◽  
Dioctyl Phthalate ◽  
Cod Removal ◽  
Fenton Reagent ◽  
Combined Process ◽  
Cod Removal Efficiency ◽  
Simulated Wastewater ◽  
Better Than

Used Fenton reagent and fly ash combined process to treat dioctyl phthalate (DOP) simulated wastewater. Influences of pH, concentration of H2O2, Fe2+ concentration, fly ash dosage and other factors effect of COD were studied. The results showed that, under the synergies of the fly ash, Fenton reagent on the COD removal efficiency was better than Fenton reagent used alone. When the pH was 5, H2O2 concentration was 1.2 g/L, Fe2+ concentration was 1.0g/L, fly ash dosage was 4 g, and COD removal efficiency reached 83.21%.

scholarly journals Organic matter removal from mother liquor of gas field wastewater by electro-Fenton process with the addition of H 2 O 2 : effect of initial pH

2019 ◽  
Vol 6 (12) ◽  
pp. 191304 ◽  
Author(s):  
Yan Wang ◽  
Hui-qiang Li ◽  
Li-ming Ren
Keyword(s):  
Organic Matter ◽  
Removal Efficiency ◽  
Mother Liquor ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Gas Field ◽  
System Effect ◽  
Organic Matter Removal ◽  
Cod Removal Efficiency ◽  
Initial Ph

The electro-Fenton (EF) process was applied to treat mother liquor of gas field wastewater (ML-GFW). The Fe-Fe electrodes were used and H 2 O 2 was added to the EF system. Effect of initial pH on chemical oxygen demand (COD) removal efficiency, specific electrical energy consumption (SEEC), specific electrode plate consumption (SEPC) and organic matter removal mechanism was investigated. The results showed that COD removal efficiency reached the maximum (71.9%) at initial pH of 3 after reaction for 3 h. Besides, considering with the SEEC and SEPC, pH of 3 was also the best choice, at which SEEC was 4.7 kW h kg COD −1 , SEPC was 0.82 kgFe kg COD −1 . Organic matter removal was achieved by two ways: oxidation and flocculation, and oxidation played a major role. With the analysis of GC-MS, the possible degradation pathways of the representative contaminants in the ML-GFW were given.

scholarly journals Using BCN nanostructure as anode electrode for photoelectrocatalytic degradation of organics: a statistical approach

2021 ◽  
Author(s):  
Sadegh Ebadi ◽  
Karim Ghasemipanah ◽  
Ebrahim Alaie ◽  
Alimorad Rashidi ◽  
Alireza Khataee
Keyword(s):  
Removal Efficiency ◽  
Residence Time ◽  
Produced Water ◽  
Ph Value ◽  
Copper Wire ◽  
Cod Removal ◽  
Effective Parameters ◽  
Cod Removal Efficiency ◽  
Initial Ph ◽  
Anode Electrode

Abstract In this study, boron carbon nitride (BCN) nanostructures were used as photocatalyst which was synthesized in a chemical vapor deposition reactor. Photoelectrocatalysis was used for degradation organic pollutants from produced water. BCN nanostructures were coated on a coil-type copper wire to be as anode electrode in the photoelectrocatalytic process. The effect of different parameters on chemical oxygen demand (COD) removal efficiency from produced water was investigated by a central composite design (CCD) to maximize photoelectrocatalysis influence as one of the most used methods of wastewater treatment. A 12 run Plackett–Burman design was used for screening of the parameters (initial COD, electrical conductivity, applied cell voltage, UV lamp wavelength, H2O2 concentration, residence time, and initial pH) which led to the selection of residence time and initial pH as effective parameters. Since the core goal of this study was to maximize the COD removal efficiency, the steepest ascent method was used to propel these two parameters to the optimum region. Finally, CCD showed that applying photoelectrocatalysis could lead to 88.79% of the COD removal efficiency which would be an optimum value at a residence time of 15.85 min and a pH value of 3.3. Ultimately, this result was confirmed by experimentation at those conditions.

scholarly journals Investigation of Heavy Metal Effects on the Anaerobic Co-Digestion Process of Waste Activated Sludge and Septic Tank Sludge

2019 ◽  
Vol 2019 ◽  
pp. 1-9
Author(s):  
Quang-Minh Nguyen ◽  
Duy-Cam Bui ◽  
Thao Phuong ◽  
Van-Huong Doan ◽  
Thi-Nham Nguyen ◽  
...  
Keyword(s):  
Heavy Metals ◽  
Heavy Metal ◽  
Activated Sludge ◽  
Removal Efficiency ◽  
Biogas Production ◽  
Cod Removal ◽  
Septic Tank ◽  
Waste Activated Sludge ◽  
Digestion Process ◽  
Cod Removal Efficiency

The effect of copper, zinc, chromium, and lead on the anaerobic co-digestion of waste activated sludge and septic tank sludge in Hanoi was studied in the fermentation tests by investigating the substrate degradation, biogas production, and process stability at the mesophilic fermentation. The tested heavy metals were in a range of concentrations between 19 and 80 ppm. After the anaerobic tests, the TS, VS, and COD removal efficiency was 4.12%, 9.01%, and 23.78% for the Cu(II) added sample. Similarly, the efficiencies of the Zn(II) sample were 1.71%, 13.87%, and 16.1% and Cr(VI) efficiencies were 15.28%, 6.6%, and 18.65%, while the TS, VS, and COD removal efficiency of the Pb(II) added sample was recorded at 16.1%, 17.66%, and 16.03% at the concentration of 80 ppm, respectively. Therefore, the biogas yield also decreased by 36.33%, 31.64%, 31.64%, and 30.60% for Cu(II), Zn(II), Cr(VI), and Pb(II) at the concentration of 80 ppm, compared to the raw sample, respectively. These results indicated that Cu(II) had more inhibiting effect on the anaerobic digestion of the sludge mixture than Zn(II), Cr(VI), and Pb(II). The relative toxicity of these heavy metals to the co-digestion process was as follows: Cu (the most toxic) > Zn > Cr > Pb (the least toxic). The anaerobic co-digestion process was inhibited at high heavy metal concentration, which resulted in decreased removal of organic substances and produced biogas.

scholarly journals Combined treatment of hydroxypropyl guar gum in oilfield fracturing wastewater by coagulation and the UV/H2O2/ferrioxalate complexes process

2017 ◽  
Vol 77 (3) ◽  
pp. 565-575 ◽  
Author(s):  
Zhenchao Zhang
Keyword(s):  
Removal Efficiency ◽  
Guar Gum ◽  
Combined Treatment ◽  
Cod Removal ◽  
Treated Wastewater ◽  
Spectra Analysis ◽  
Hydroxypropyl Guar ◽  
Coagulation Process ◽  
Cod Removal Efficiency ◽  
Hydroxypropyl Guar Gum

Abstract Hydroxypropyl guar gum is considered to be a main component of oilfield fracturing wastewater (OFW). This work is intended to optimize the experimental conditions for the maximum oxidative degradation of hydroxypropyl guar gum by the coagulation and UV/H2O2/ferrioxalate complexes process. Optimal reaction conditions were proposed based on the chemical oxygen demand (COD) removal efficiency and UV_vis spectra analysis. The overall removal efficiency of COD reached 83.8% for a dilution ratio of raw wastewater of 1:2, pH of 4 and FeCl3 loading of 1,000 mg/L in the coagulation process; the dosage of H2O2 (30%,v/v) was 0.6% (v/v) and added in three steps, the n(H2O2)/n(Fe2+) was 2:1, n(Fe2+)/n(C2O42−) was 3:1 and pH was 4 in the UV/H2O2/ferrioxalate complexes process; pH was adjusted to 8.5–9 by NaOH and then cationic polyacrylamide (CPAM) of 2 mg/L was added in the neutralization and flocculation process. The decrease in COD during the coagulation process reduced the required H2O2 dosage and improved efficiency in the subsequent UV/H2O2/ferrioxalate complexes process. Furthermore, COD removal efficiency significantly increased by more than 13.4% with the introduction of oxalate compared with UV/Fenton. The UV_vis spectra analysis results indicated that the coagulation and UV/H2O2/ferrioxalate complexes process could efficiently remove the hydroxypropyl guar gum dissolved in OFW. An optimal combination of these parameters produced treated wastewater that met the GB8978-1996 Integrated Wastewater Discharge Standard level III emission standard.

Sign in / Sign up

Export Citation Format

Share Document