Simultaneous removal of chemical oxygen demand, turbidity and hardness from biologically treated citric acid wastewater by electrochemical oxidation for reuse

2013 ◽  
Vol 107 ◽  
pp. 281-288 ◽  
Author(s):  
Xinyang Li ◽  
Chengwen Wang ◽  
Yi Qian ◽  
Yujue Wang ◽  
Liwei Zhang
Keyword(s):  
Citric Acid ◽  
Chemical Oxygen Demand ◽  
Electrochemical Oxidation ◽  
Oxygen Demand ◽  
Simultaneous Removal

scholarly journals Simultaneous nitrate and organic matter removal from a dairy effluent by biodenitrification

2018 ◽  
Vol 31 (2) ◽  
pp. 97-107
Author(s):  
Ahmed Hamdani ◽  
Mohammed Mountadar ◽  
Omar Assobhei
Keyword(s):  
Organic Matter ◽  
Chemical Oxygen Demand ◽  
Electron Donor ◽  
High Efficiency ◽  
Oxygen Demand ◽  
Nitrite Accumulation ◽  
Simultaneous Removal ◽  
Optimal Conditions ◽  
Dairy Effluent ◽  
Organic Removal

In order to study the simultaneous removal of nitrate and organic matter from a dairy effluent containing 670 mg∙L-1 of nitrate (NO3--N) and 5 760 mg∙L-1 of dissolved chemical oxygen demand (CODd), denitrification in a laboratory scale bioreactor consisting of an immersed bacterial bed colonized by an heterotrophic denitrifying flora (HDF) selected for NO3- reduction, COD consumption and adapted to grow on an effluent produced by a dairy industry was investigated. The obtained results indicated that at the optimal conditions of temperature (30°C), pH (7), COD/NO3--N ratio (5), the operation lasted 108h with total reduction of nitrate in 72h, no nitrite accumulation, and 92% of soluble COD removal in 96h. This indicates that the biodenitrification was accompanied with a high efficiency of matter organic removal as an electron donor, and thereby satisfies the applicable standards.

Electrochemical oxidative degradation of indigo wastewater based on chlorine-containing system

2020 ◽  
Vol 49 (1) ◽  
pp. 46-54 ◽  
Author(s):  
Wei Zhang ◽  
Weiwei Lv ◽  
Xiaoyan Li ◽  
Jiming Yao
Keyword(s):  
Chemical Oxygen Demand ◽  
Response Surface ◽  
Electrochemical Oxidation ◽  
Surface Analysis ◽  
Removal Rate ◽  
Oxidative Degradation ◽  
Oxygen Demand ◽  
Single Factor ◽  
Dyeing Wastewater ◽  
Content Type

Purpose In this study, the oxidative degradation performance of indigo wastewater based on electrochemical systems was explored. The decolourization degrees, removal rate of chemical oxygen demand and biochemical oxygen demand of the indigo wastewater after degradation were evaluated and optimized treatment conditions being obtained. Design/methodology/approach The single factor method was first used to select the electrolyte system and electrode materials. Then the response surface analysis based on Box–Behnken Design was chosen to determine the influence of four independent variables such as FeCl3 concentration, NaCl concentration, decolourization time and voltage on the degradation efficiency. Findings On the basis of single factor experiment, the electrode material of stainless steel was selected in the double cell, and the indigo wastewater was electrolyzed with FeCl3 and NaCl electrolytes. The process conditions of electrochemical degradation of indigo wastewater were optimized by response surface analysis: the concentration of FeCl3 and NaCl was of 16 and 9 g/L, respectively, with a decolourization time of 50 min, voltage of 10 V and decolourization percentage of 98.94. The maximum removal rate of chemical oxygen demand reached 75.46 per cent. The highest ratio of B/C was 3.77, which was considered to be more biodegradable. Research limitations/implications Dyeing wastewater is bringing out more and more pollution problems to the environment. However, there are some shortcomings in traditional technologies such as adsorption and filtration. As a kind of efficient and clean water treatment technology, electrochemical oxidation has been applied to the treatments of various types of wastewater. The decolourization and degradation of indigo wastewater is taken as an example to provide reference for the treatment of wastewater in actual plants. Practical implications The developed method provided a simple and practical solution for efficiently degrading indigo wastewater. Originality/value The method for the electrochemical oxidation technology was novel and could find numerous applications in the degradation of printing and dyeing wastewater.

scholarly journals Treatment of a Textile Effluent by Electrochemical Oxidation and Coupled System Electooxidation–Salix babylonica

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Alejandra Sánchez-Sánchez ◽  
Moisés Tejocote-Pérez ◽  
Rosa María Fuentes-Rivas ◽  
Ivonne Linares-Hernández ◽  
Verónica Martínez-Miranda ◽  
...  
Keyword(s):  
Chemical Oxygen Demand ◽  
Electrochemical Oxidation ◽  
Oxygen Demand ◽  
Textile Wastewater ◽  
Coupled System ◽  
Treated Wastewater ◽  
Boron Doped Diamond ◽  
Boron Doped ◽  
Effective Reduction ◽  
Salix Babylonica

The removal of pollutants from textile wastewater via electrochemical oxidation and a coupled system electrooxidation—Salix babylonica, using boron-doped diamond electrodes was evaluated. Under optimal conditions of pH 5.23 and 3.5 mA·cm−2 of current density, the electrochemical method yields an effective reduction of chemical oxygen demand by 41.95%, biochemical oxygen demand by 83.33%, color by 60.83%, and turbidity by 26.53% at 300 minutes of treatment. The raw and treated wastewater was characterized by infrared spectroscopy to confirm the degradation of pollutants. The wastewater was oxidized at 15-minute intervals for one hour and was placed in contact with willow plants for 15 days. The coupled system yielded a reduction of the chemical oxygen demand by 14%, color by 85%, and turbidity by 93%. The best efficiency for the coupled system was achieved at 60 minutes, at which time the plants achieved more biomass and photosynthetic pigments.

Treatment of papermaking tobacco sheet wastewater by electrocoagulation combined with electrochemical oxidation

2015 ◽  
Vol 71 (8) ◽  
pp. 1165-1172 ◽  
Author(s):  
Xiangjuan Ma ◽  
Yang Gao ◽  
Hanping Huang
Keyword(s):  
Chemical Oxygen Demand ◽  
Electrochemical Oxidation ◽  
Biological Treatment ◽  
Carbonic Acid ◽  
Oxygen Demand ◽  
Mixed Metal Oxide ◽  
Promising Alternative ◽  
Main Components ◽  
Final Effluent ◽  
Made In

Attempts were made in this study to examine the efficiency of electrocoagulation (EC) using aluminum (Al) anode and stainless steel net cathode combined with electrochemical oxidation with a β-PbO2 anode or a mixed metal oxide (MMO) anode for treatment of papermaking tobacco sheet wastewater, which has the characteristics of high content of suspended solids (SS), intensive color, and low biodegradability. The wastewater was first subjected to the EC process under 40 mA/cm2 of current density, 2.5 g/L of NaCl, and maintaining the original pH of wastewater. After 6 minutes of EC process, the effluent was further treated by electrochemical oxidation. The results revealed that the removal of SS during the EC process was very beneficial to mass transfer of organics during electrochemical oxidation. After the combined process, 83.9% and 82.8% of chemical oxygen demand (COD) removal could be achieved on the β-PbO2 and MMO anodes, respectively. The main components of the final effluent were biodegradable organic acids, such as acetic acid, propionic acid, butyric acid, valeric acid, and hexahyl carbonic acid; the 5-day biochemical oxygen demand/chemical oxygen demand (BOD5/COD) ratio increased from 0.06 to 0.85 (Al + β-PbO2) or 0.80 (Al + MMO). Therefore, this integrated process is a promising alternative for pretreatment of papermaking tobacco sheet wastewater prior to biological treatment.

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