Treatment of biologically treated leachate by oxidation and coagulation

2011 ◽  
Vol 64 (7) ◽  
pp. 1413-1418
Author(s):  
H. Y. Zhang ◽  
Y. C. Zhao ◽  
J. Y. Qi
Keyword(s):  
Removal Efficiency ◽  
Combined Treatment ◽  
Ferric Sulfate ◽  
Oxidation Time ◽  
Advanced Treatment ◽  
Experimental Conditions ◽  
Combined Process ◽  
Effective Removal

This work aims to investigate removal efficiency of oxidation and coagulation/flocculation processes, to provide an effective method for the treatment of biologically pre-treated leachate. Leachate containing 985 mg L−1 COD was treated by using three treatment schemes, i.e. oxidation, coagulation/flocculation and the combined process of coagulation/flocculation followed by oxidation. The application of single oxidation resulted in the effective removal of COD and color up to 80.4 and 83.2%, respectively. However, residual COD values lower than 200 mg L−1 could only be achieved under intensive experimental conditions (high dosage of Ca(ClO)2 and prolonged oxidation time). Coagulation/flocculation yielded residual COD values higher than 200 mg L−1 even at the optimum coagulation conditions. The combined treatment by coagulation/flocculation followed by oxidation yielded final COD lower than 100 mg L−1 at the following conditions: pre-coagulation with 250 mg L−1 PFS (poly-ferric sulfate) and over 30-min post-oxidation, or pre-coagulation with 300 mg L−1 PFS and over 20-min post-oxidation. Hence, pre-coagulation with PFS followed by oxidation with Ca(ClO)2 was recommended for advanced treatment of biologically treated leachate.

Study on Removal Efficiency and Fluorescence Characteristics of Humus in Landfill Leachate Treated by Combined Process

2011 ◽  
Vol 233-235 ◽  
pp. 667-672
Author(s):  
Zhi Ping Liu ◽  
Jin Song Guo ◽  
Fang Fang
Keyword(s):  
Removal Efficiency ◽  
Landfill Leachate ◽  
Three Dimensional ◽  
Spectroscopic Characterization ◽  
Excitation Wavelength ◽  
Combined Process ◽  
Effective Removal ◽  
Fluorescence Characteristics ◽  
Fluorescence Peak

The removal efficiency and three-dimensional excitation emission matrix(3DEEM) fluorescence spectroscopic characterization of landfill leachate humus (HA and FA) in the Fenton-SBR process was studied. It was concluded that the combined Fenton-SBR process was available for effective removal of leachate humus, and the removal rates for HA and FA was 87.3% and 88.2%, respectively. The major fluorescence peaks observed in the leachate combined process was protein-like fluorescence peak a (Ex/Em=280nm/345nm), humic-like fluorescence peak b (Ex/Em=295/400nm), short excitation wavelength tryptophan-like fluorescence peak c (Ex/Em= 230nm/340nm) and ultraviolet band fulvic acid-like fluorescence peak d (Ex/Em=235nm/400nm). Types of fluorescence peak of HA and FA reduced and the intensities decreased after combined process treatment. The capability for removal of different components of humus was determined by the process units adopted.

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.

Textile Wastewater Treatment Using Combined Process of Biological Wriggle Bed and Ozone Biological Aerated Filter

2012 ◽  
Vol 441 ◽  
pp. 589-592
Author(s):  
Zhi Min Fu ◽  
Yu Gao Zhang ◽  
Xiao Jun Wang
Keyword(s):  
Wastewater Treatment ◽  
Removal Efficiency ◽  
Textile Wastewater ◽  
Cod Removal ◽  
Biological Aerated Filter ◽  
Combined Process ◽  
Cod Removal Efficiency ◽  
Aerated Filter ◽  
Textile Wastewater Treatment

A combined process of biological wriggle bed and ozone biological aerated filter was utilized to treat textile wastewater. Results showed that COD removal efficiency was almost 90.4%. The average effluent COD was 85.87 mg/L. The effluent colority was 64-32 times. This study indicated that the combined process is potentially useful for treating textile wastewater.

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 Optimization and Modeling of Microcystin-LR Degradation by TiO2 Photocatalyst Using Response Surface Methodology

2020 ◽  
Author(s):  
Negar Jafari ◽  
Afshin Ebrahimi ◽  
Karim Ebrahimpour ◽  
Ali Abdolahnejad
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Contact Time ◽  
High Performance ◽  
Operating Variables ◽  
Effective Removal ◽  
Positive Effect ◽  
Harmful Effects ◽  
Maximum Removal

Introduction: Microcystin-leucine arginine (MC-LR) is a toxin with harmful effects on the liver, kidney, heart, and gastrointestinal tract. So, effective removal of MC-LR from water resources is of great importance. The aim of this study was to remove microcystin-LR (MC-LR) from aqueous solution by Titanium Dioxide (TiO2). Materials and Methods: In the present study, TiO2, as a semiconductor, was used for photodegradation of MC-LR under ultraviolet light (UV). The Response Surface Methodology was applied to investigate the effects of operating variables such as pH (A), contact time (B), and catalyst dose (B) on the removal of MC-LR. The MC-LR concentration was measured by high-performance liquid chromatography (HPLC). Results: The results showed that single variables such as A, B, and C had significant effects on MC-LR removal (pvalue < 0.05). In other words, increase of the contact time and catalyst dose had a positive effect on enhancing the removal efficiency of MC-LR, but the effect of pH was negative. The analysis of variance showed that BC, A2, and C2 variables had a significant effect on the MC-LR removal (pvalue < 0.05). Finally, the maximum removal efficiency of MC-LR was 95.1%, which occurred at pH = 5, contact time = 30 minutes, and catalyst dose = 1 g/l. Conclusion: According to the findings, TiO2, as a photocatalyst, had an appropriate effect on degradation of the MC-LR.

scholarly journals One-step removal of lead from water using an electricity-free and sustainable membrane filtration

2021 ◽  
Vol 27 (4) ◽  
pp. 166-172
Author(s):  
Junwei Zhang ◽  
Yan Tung Lo ◽  
Hao Guo ◽  
Chuyang Tang
Keyword(s):  
Drinking Water ◽  
Removal Efficiency ◽  
Membrane Filtration ◽  
High Water ◽  
Water Safety ◽  
Drinking Water Contamination ◽  
Emergency Situations ◽  
Drinking Water Safety ◽  
Effective Removal ◽  
Volumetric Loading

Lead (Pb) is a typical contaminant in water with adverse effects on human health. Hong Kong’s incident of drinking water contamination by Pb in 2015 caused severe public concerns regarding drinking water safety. Conventional treatment methods for Pb removal generally require electricity, chemical dosage, and considerable time and space, which significantly restrict their use for rapid water purification under emergency situations. In this study, a polyvinyl alcohol/polyacrylic acid (PVA/PAA) composite nanofibrous membrane was developed for the rapid and effective removal of Pb from water. The PVA/PAA membrane had a high water permeability of 550 L/m2/h/kPa - 710 L/m2/h/kPa, which allowed the filtration to be driven by gravity (e.g. with a water height of 10.0 cm). The membrane showed consistently high removal efficiency of Pb (> 95%) with a volumetric loading up to 3000 L/m2. This high removal efficiency was attributed to the combined effects of complexing and electrostatic attraction between Pb and PAA. An esculent citric acid was used to regenerate the exhausted PVA/PAA membrane. The regenerated membrane maintained its removal efficiency of Pb over a five-cycle filtration. These results imply that the PVA/PAA composite membrane can be repeatedly used in electricity-free filtration devices for rapid elimination of Pb under emergency situations.

scholarly journals Effect of electrode material on removal efficiency regarding single discharges in wire EDM

2021 ◽  
Author(s):  
Lukas Welschof ◽  
Niklas Schäfer ◽  
Tim Herrig ◽  
Andreas Klink ◽  
Thomas Bergs
Keyword(s):  
Removal Efficiency ◽  
Electrical Discharge Machining ◽  
Removal Rate ◽  
Continuous Process ◽  
Wire Edm ◽  
Procedural Understanding ◽  
Decisive Importance ◽  
Effective Removal ◽  
Coated Wires ◽  
The Individual

AbstractFor the precise machining of demanding materials, wire electrical discharge machining (WEDM) is a flexible and often irreplaceable manufacturing process. In order to enhance productivity as the main focus of the wire EDM process, the advancement of the fundamental procedural understanding is of decisive importance. In order to be able to energetically evaluate the removal process, the individual energetic contributors of the process hence the individual discharges need to be understood in terms of their contribution to material removal. In this paper, an experimental setup is presented, which permits the generation of individual discharges on a modern industrial wire EDM machine tool. For three different wire electrodes, the correlation of the discharge energy and the individual removal volume is quantitatively described, showing that coated wires achieve a significantly higher energy-specific removal. Furthermore the removal efficiency is defined as a key figure to transfer the findings to the continuous process and compare theoretical and effective removal rate.

Enhanced phosphorus removal in the DAF process by flotation scum recycling for advanced treatment of municipal wastewater

2015 ◽  
Vol 72 (4) ◽  
pp. 600-607 ◽  
Author(s):  
Dong-Heui Kwak ◽  
Ki-Cheol Lee
Keyword(s):  
Removal Efficiency ◽  
Municipal Wastewater ◽  
Wastewater Treatment Plants ◽  
Advanced Treatment ◽  
Municipal Wastewater Treatment ◽  
Application Process ◽  
Additive Process ◽  
Dissolved Air Flotation ◽  
Equilibrium Control ◽  
P Removal

To remove phosphorus (P) from municipal wastewater, various types of advanced treatment processes are being actively applied. However, there is commonly a space limit in municipal wastewater treatment plants (MWTPs). For that reason, the dissolved air flotation (DAF), which is well known for small space and flexible application process, is preferred as an additive process to enhance the removal of P. A series of experiments were conducted to investigate the feasibility of flotation scum recycling for effective P removal from a MWTP using a DAF pilot plant over 1 year. The average increases in the removal efficiencies due to flotation scum recycling were 22.6% for total phosphorus (T-P) and 18.3% for PO4-P. A higher removal efficiency of T-P was induced by recycling the flotation scum because a significant amount of Al components remained in the flotation scum. The increase in T-P removal efficiency, due to the recycling of flotation scum, shifted from the boundary of the stoichiometric precipitate to the equilibrium control region. Flotation scum recycling may contribute to improving the quality of treated water and reducing treatment costs by minimizing the coagulant dosage required.

A Novel Experimental Method for Mudcake Removal Efficiency of Spacer

2021 ◽  
pp. 1-10
Author(s):  
Rui Zheng ◽  
Yong Li ◽  
Jian-Zhou Jin ◽  
Zi-Shuai Liu
Keyword(s):  
Experimental Method ◽  
Removal Efficiency ◽  
Influence Factors ◽  
Effective Removal

Summary Effective removal of mudcake from the wellbore before cementing is critical to developing an excellent bond between cement and formation. The application of spacer can remove mudcake effectively. The evaluation of mudcake removal efficiency is significant to the design of spacer. The methods proposed by scholars have limits on the development of mudcake and the simulation of the flushing process. For this paper, a novel apparatus used to test mudcake removal efficiency was designed. A novel experimental method for mudcake removal efficiency of spacer was proposed. The influence factors of mudcake removal efficiency are discussed. The method can evaluate the flushing efficiency quantitatively and provide guidance for designing of spacer.

Integrated Leachate Treatment Technology

2020 ◽  
pp. 204-220
Author(s):  
Zawawi Daud ◽  
Halizah Awang
Keyword(s):  
Organic Compounds ◽  
Landfill Leachate ◽  
Combined Treatment ◽  
Treatment Technology ◽  
Leachate Treatment ◽  
Chemical Treatments ◽  
Physico Chemical ◽  
Effective Removal ◽  
Removal Of Heavy Metals ◽  
Pre Treatment

In this chapter, the performance of combined treatment of municipal landfill leachate is reviewed. Although individual physico-chemical treatments are suitable for the removal of heavy metals and hydrolyzation of some organic compounds, a combination of two physico-chemical treatments or physico-chemical and biological is required for optimum treatment of stabilized landfill leachate. A combination of two physico-chemical treatments can give optimum results in removal of recalcitrant organic compounds from stabilized leachate, as reflected by a significant decrease of the COD values after treatment. On the other hand, a combination of physico-chemical and biological treatments is required to achieve effective removal of NH3-N and COD with a substantial amount of biodegradable organic matter. In many cases, physico-chemical treatments are suitable for pre-treatment of stabilized leachate. The objective of this paper is to highlight various types of integrated leachate treatments as it has been difficult to get optimum efficiency from single approached treatment.

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