scholarly journals Electrochemical treatment of spent tan bath solution for reuse

2016 ◽  
Vol 8 (1) ◽  
pp. 123-134
Author(s):  
Amel Benhadji ◽  
Mourad Taleb Ahmed ◽  
Hayet Djelal ◽  
Rachida Maachi
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Optimum Operating ◽  
Operational Parameters ◽  
High Concentration ◽  
Leather Processing ◽  
Chromium Salt

Abstract A spent tanning bath contains high concentration of salts, chromium and protein. The treatment system for removal of chlorides or chromium from this effluent is expensive. In this context this waste has to be reused. Our study focuses on the application of advanced oxidation processes for protein removal present in a tanning bath. To improve the quality of the chromium tanning bath, two electrochemical processes (electrooxidation and peroxi-electrocoagulation process, PEP) are investigated in a batch reactor. The effects of operational parameters such as reactor configuration, current density and electrolysis time on chemical oxygen demand (COD) and protein removal efficiency are examined. Results indicated that under the optimum operating range for process, the COD and protein removal efficiency reached 53 and 100%, respectively. The optimum values are determined for the hybrid process (PEP) under 0.13 A·cm−2 over 2 h. The treated tanning bath is used as a tanning solution in leather processing. The influence of chromium salt dose, pH solution, stirring time and contact time on the leather characteristic is evaluated. The hides tanned after the addition of 0.25% of commercial chromium salt, at pH solution, leaving them stirring for 4 h with a contact time of 2 days, and showed good hydrothermal stability and physical characteristics of leather.

scholarly journals Response surface methodology approach for the optimisation of adsorption of hydrolysed polyacrylamide from polymer-flooding wastewater onto steel slag: a good option of waste mitigation

2017 ◽  
Vol 76 (4) ◽  
pp. 776-784 ◽  
Author(s):  
Mijia Zhu ◽  
Jun Yao ◽  
Zhonghai Qin ◽  
Luning Lian ◽  
Chi Zhang
Keyword(s):  
Response Surface Methodology ◽  
Response Surface ◽  
Removal Efficiency ◽  
Contact Time ◽  
Interactive Effect ◽  
Steel Slag ◽  
Oxygen Demand ◽  
Polymer Flooding ◽  
High Concentration ◽  
Adsorbent Dosage

Wastewater produced from polymer flooding in oil production features high viscosity and chemical oxygen demand because of the residue of high-concentration polymer hydrolysed polyacrylamide (HPAM). In this study, steel slag, a waste from steel manufacturing, was studied as a low-cost adsorbent for HPAM in wastewater. Optimisation of HPAM adsorption by steel slag was performed with a central composite design under response surface methodology (RSM). Results showed that the maximum removal efficiency of 89.31% was obtained at an adsorbent dosage of 105.2 g/L, contact time of 95.4 min and pH of 5.6. These data were strongly correlated with the experimental values of the RSM model. Single and interactive effect analysis showed that HPAM removal efficiency increased with increasing adsorbent dosage and contact time. Efficiency increased when pH was increased from 2.6 to 5.6 and subsequently decreased from 5.6 to 9.3. It was observed that removal efficiency significantly increased (from 0% to 86.1%) at the initial stage (from 0 min to 60 min) and increased gradually after 60 min with an adsorbent dosage of 105.2 g/L, pH of 5.6. The adsorption kinetics was well correlated with the pseudo-second-order equation. Removal of HPAM from the studied water samples indicated that steel slag can be utilised for the pre-treatment of polymer-flooding wastewater.

scholarly journals Micro-pressure swirl reactor (MPSR) for efficient COD and nitrogen removal of high-concentration wastewater

2020 ◽  
Vol 82 (9) ◽  
pp. 1795-1807 ◽  
Author(s):  
Dejun Bian ◽  
Zebing Nie ◽  
Fan Wang ◽  
Shengshu Ai ◽  
Suiyi Zhu ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Nitrogen Removal ◽  
Lower Cost ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Swirl Flow ◽  
High Concentration ◽  
Internal Circulation ◽  
Carbon And Nitrogen ◽  
Pressure Swirl

Abstract A micro-pressure swirl reactor (MPSR) was developed for carbon and nitrogen removal of wastewater, in which dissolved oxygen (DO) gradient and internal circulation could be created by setting the aerators along one side of the reactor, and micro-pressure could be realized by sealing most of the top cap and increasing the outlet water level. In this study, velocity and DO distribution in the reactor was measured, removal performance treating high-concentration wastewater was investigated, and the main functional microorganisms were analyzed. The experiment results indicated that there was stable swirl flow and spatial DO gradient in MPSR. Operated in sequencing batch reactor mode, distinct biological environments spatially and temporally were created. Under the average influent condition of chemical oxygen demand (COD) concentration of 2,884 mg/L and total nitrogen (TN) of 184 mg/L, COD removal efficiency and removal loading was 98% and 1.8 kgCOD/(m3·d) respectively, and TN removal efficiency and removal loading reached up to 90% and 0.11 kgTN/(m3·d) respectively. With efficient utilization of DO and simpler configuration for simultaneous nitrification and denitrification, the MPSR has the potential of treating high-concentration wastewater at lower cost.

scholarly journals Removal of biological organics in high-salinity wastewater produced from methylcellulose production and subsequent changes in the microbial community

2020 ◽  
Vol 26 (4) ◽  
pp. 200187-0
Author(s):  
GueSoo Jo ◽  
SeongWan Hong ◽  
HyunGu Kim ◽  
Zhuliping ◽  
DaeHee Ahn
Keyword(s):  
Microbial Community ◽  
Removal Efficiency ◽  
High Salinity ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Community Change ◽  
High Concentration ◽  
Nitrogen And Phosphorus ◽  
Conventional Activated Sludge ◽  
Biological Removal

The wastewater generated in methylcellulose (MC) production is characterized by high salinity and pH due to the residual sodium and chlorine separated from the methyl group. It is difficult to treat wastewater using the conventional activated sludge method because the high concentration of salt interferes with the microbial activity. This study confirms the biological removal of organic matter from MC wastewater using sludge dominated by Halomonas spp., a halophilic microorganism. The influent was mixed with MC wastewater and epichlorohydrin (ECH) wastewater in a 1:9 ratio and operated using a sequencing batch reactor with a hydraulic retention time of 27.8 d based on the MC wastewater. The removal efficiency of chemical oxygen demand (COD) increased from 80.4% to 93.5%, and removal efficiency had improved by adding nutrients such as nitrogen and phosphorus to the wastewater. In terms of microbial community change, Halomonas spp. decreased from 43.26% to 0.11%, whereas Marinobacter spp. and Methylophaga spp. increased from 0.50% to 15.12% and 7.51%, respectively.

scholarly journals Comparison Between the Performance of Activated Carbon and Graphene in Removal of Reactive Red 198

2017 ◽  
Vol 4 (1) ◽  
pp. 6021-6021
Author(s):  
Mohammad Reza Samarghandi ◽  
Ali Poormohammadi ◽  
Samane Shanesaz ◽  
Kazem Godini
Keyword(s):  
Activated Carbon ◽  
Removal Efficiency ◽  
Active Carbon ◽  
Contact Time ◽  
Ph Value ◽  
Batch Reactor ◽  
Industrial Effluents ◽  
Order Kinetic ◽  
Operational Parameters ◽  
Reactive Red 198

The current study aimed at comparing the performances of activated carbon and graphene in the removal of reactive red 198. The experiments were conducted in a batch reactor and the effects of some operational parameters including initial dye concentration, pH, contact time, and different doses of activated carbon and graphene on the removal efficiency of dye were investigated. The results showed that the adsorption efficiency was affected by initial dye concentration. In general, with increasing contact time up to 180 minutes, the removal efficiency increased significantly. The removal efficiency of reactive red 198 increased with increasing contact time, and after 60 minutes of contact time, adsorption phase reached the equilibrium. When activated carbon was used, the maximum removal efficiency happened at pH 3. At this pH value, reactive red 198 was removed completely (100%) after 120 minutes, whereas the minimum efficiency was observed at pH 10. A similar trend was also observed for graphene as an adsorbent. Moreover, the removal efficiency of the dye by both adsorbents increased with the increase of the adsorbent dosage. The experimental data showed that the adsorption of reactive red198 on both active carbon and graphene fitted well into the second-order kinetic model. Active carbon and graphene fitted well Langmuir 1 model. According to the results, graphene acts as suitable adsorbent and can be applied in treating several industrial effluents and contaminated water in greater scales. The main upside of grapheme, in comparison with activated carbon, is that it reaches the equilibrium in a shorter time. Further, grapheme adsorbed the dye nearly completely (98% to 100%).

scholarly journals Catalytic wet oxidation of high concentration pharmaceutical wastewater with Fe3+ as catalyst

2018 ◽  
Vol 2017 (3) ◽  
pp. 661-666
Author(s):  
Xu Zeng ◽  
Jun Liu ◽  
Jianfu Zhao
Keyword(s):  
Oxygen Pressure ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Kinetic Studies ◽  
Cod Removal ◽  
Wet Oxidation ◽  
Catalytic Wet Oxidation ◽  
Pharmaceutical Wastewater ◽  
High Concentration ◽  
Temperature Time

Abstract Catalytic wet oxidation of high concentration pharmaceutical wastewater with Fe3+ as catalyst was carried out in a batch reactor. Results showed that the degradation of pharmaceutical wastewater was enhanced significantly by Fe3+. The effects of reaction parameters, such as the catalyst dose, reaction temperature, time, and initial oxygen pressure, were discussed. The chemical oxygen demand (COD) removal increased with the increases of catalyst dose, temperature, time and oxygen supply. With the initial COD 34,000–35,000 mg/L, approximately 70% COD removal can be achieved under the conditions of catalyst 1.0 g and oxygen pressure 1.0 MPa at 250 °C after 60 min. The results of kinetic studies showed that two reaction steps existed in this oxidation process, which followed an apparent first-order rate law. This process provides an effective approach for the pretreatment of high concentration pharmaceutical wastewater.

scholarly journals Post-treatment of tannery wastewater using pilot scale horizontal subsurface flow constructed wetlands (polishing)

2017 ◽  
Vol 77 (4) ◽  
pp. 988-998 ◽  
Author(s):  
Tadesse Alemu ◽  
Andualem Mekonnen ◽  
Seyoum Leta
Keyword(s):  
Removal Efficiency ◽  
Batch Reactor ◽  
Subsurface Flow ◽  
Oxygen Demand ◽  
Pilot Scale ◽  
Surface Flow ◽  
Tannery Wastewater ◽  
Treated Effluent ◽  
Horizontal Subsurface Flow ◽  
Pollutants Removal

Abstract In the present study, a pilot scale horizontal subsurface flow constructed wetland (CW) system planted with Phragmites karka; longitudinal profile was studied. The wetland was fed with tannery wastewater, pretreated in a two-stage anaerobic digester followed by a sequence batch reactor. Samples from each CW were taken and analyzed using standard methods. The removal efficiency of the CW system in terms of biological oxygen demand (BOD), chemical oxygen demand (COD), Cr and total coliforms were 91.3%, 90%, 97.3% and 99%, respectively. The removal efficiency for TN, NO3− and NH4+-N were 77.7%, 66.3% and 67.7%, respectively. Similarly, the removal efficiency of SO42−, S2− and total suspended solids (TSS) were 71.8%, 88.7% and 81.2%, respectively. The concentration of COD, BOD, TN, NO3−N, NH4+-N, SO42 and S2− in the final treated effluent were 113.2 ± 52, 56 ± 18, 49.3 ± 13, 22.75 ± 20, 17.1 ± 6.75, 88 ± 120 and 0.4 ± 0.44 mg/L, respectively. Pollutants removal was decreased in the first 12 m and increased along the CW cells. P. karka development in the first cell of CW was poor, small in size and experiencing chlorosis, but clogging was higher in this area due to high organic matter settling, causing a partial surface flow. The performance of the pilot CW as a tertiary treatment showed that the effluent meets the permissible discharge standards.

Treatment of Palm Oil Mill Effluent by Electrocoagulation Process

2012 ◽  
Vol 610-613 ◽  
pp. 363-367
Author(s):  
Tipakorn Suwannarat ◽  
Nipon Pisutpaisal ◽  
Siriorn Boonyawanich
Keyword(s):  
Palm Oil ◽  
Contact Time ◽  
Batch Reactor ◽  
Oxygen Demand ◽  
Total Suspended Solid ◽  
Suspended Solid ◽  
Steel Plates ◽  
Palm Oil Mill Effluent ◽  
Electrocoagulation Process ◽  
Palm Oil Mill

The purpose of current study was to examine the ability of electrocoagulation in decreasing chemical oxygen demand (COD) and total suspended solid (TSS) constituted in palm oil mill effluent. Bench-scale batch reactor containing two aluminum or steel plates (10 cm width × 30 cm height with 0.1 cm thickness) serving as electrodes with the interval distance of 3 cm was set up. The wastewater with COD concentration of 68,425 mg L-1 was treated in the reactor under the varied direct currents (0.3-1.3 A) and contact time (30-120 min). Sodium chloride was added to the wastewater to obtain the final concentration of 2 g L-1 (conductivity of 10 ms) prior to being fed into the reactor. The results showed that higher treatment efficiency when the aluminum was used as electrodes compared to the steel. COD removal efficiency was directly proportional to the contact time. The maximum COD and TSS removal observed at 1.3 A current input and 60 min contact time are 74.1 and 77.0%, respectively.

scholarly journals Continuous flow electrocoagulation system for the treatment of coir industry wastewater

2021 ◽  
Author(s):  
Ayyappan U ◽  
Indu M.S ◽  
Adithya G Murickan ◽  
Balagopal J ◽  
Arun S Kumar ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Continuous Flow ◽  
Electrolyte Concentration ◽  
Oxygen Demand ◽  
Synthetic Dyes ◽  
Operational Parameters ◽  
Colour Removal ◽  
Chemical Reagents ◽  
Secondary Pollutants ◽  
Industry Wastewater

Coir industry, a prominent industry in Kerala, uses huge amount of water and chemical reagents for its functioning. The effluent from these industries has high BOD, COD, toxic chemicals, oils and grease etc. Of the various pollutants, synthetic dyes are the most concerning. Electrocoagulation has advantages over other systems, as it doesn’t produce any secondary pollutants. In this study, a continuous flow electrocoagulation reactor is designed and operational parameters like flow rate, voltage, pH, electrolyte concentration, dye concentration and electrode orientation are optimized. The influence of these parameters are assessed by measuring colour removal efficiency (CRE) and chemical oxygen demand (COD). The optimum flow, voltage, electrolyte concentration, pH and electrode orientation were 1000 mL/hr., 8V, 1000 mg/L, 7 and parallel respectively. The optimized parameters were used for performance evaluation of the system in treating coir industry wastewater. Under these optimized conditions, colour removal efficiency, turbidity, pH, COD removal efficiency and BOD removal efficiency for the treated coir industry wastewater was found as 92.17%, 25 NTU, 8.7, 95.49%, and 92.20% respectively.

scholarly journals Penyisihan Fluoride dan COD Air Limbah Industri Asam Fosfat Menggunakan Kombinasi Presipitasi dan Elektrokoagulasi

METANA ◽  
2020 ◽  
Vol 16 (2) ◽  
pp. 47-54
Author(s):  
Adhi Setiawan ◽  
Nadya Ayu Arianingtyas ◽  
Novi Eka Mayangsari ◽  
Tanti Utami Dewi
Keyword(s):  
Removal Efficiency ◽  
Contact Time ◽  
Supply Voltage ◽  
Oxygen Demand ◽  
Cod Removal ◽  
Precipitation Process ◽  
Fluoride Removal ◽  
Power Supply Voltage ◽  
Fluoride Ions ◽  
Electric Voltage

Proses produksi asam fosfat menghasilkan air limbah dengan kandungan fluoride dan Chemical Oxygen Demand (COD) yang berpotensi mencemari lingkungan jika tidak diolah secara tepat. Kandungan ion fluoride di dalam air dapat menjadi ancaman serius bagi kesehatan manusia karena menyebabkan kerusakan pada gigi dan tulang. Kombinasi presipitasi dan elektrokoagulasi merupakan salah satu alternatif yang efektif untuk menurunkan kandungan fluoride dan COD. Penelitian ini bertujuan menganalisis pengaruh pH presipitasi, tegangan, dan waktu kontak terhadap penyisihan fluoride dan COD pada limbah industri fosfat menggunakan metode presipitasi dan elektrokoagulasi. Proses presipitasi dan elektrokoagulasi dilakukan secara batch. Presipitan menggunakan bahan berupa Ca(OH)2 sedangkan proses elektrokoagulasi menggunakan elektroda aluminium yang tersusun secara monopolar. Pengaturan pH presipitasi menggunakan pH 5, 7, dan 9. Elektrokoagulasi menggunakan variasi waktu kontak 40, 50, dan 60 menit. Variasi tegangan listrik 17, 22, dan 27 V. Hasil penelitian menunjukkan bahwa peningkatan pH meningkatkan efisiensi penyisihan pada proses presipitasi. Peningkatan nilai tegangan listrik dan waktu kontak menyebabkan peningkatan efisiensi penyisihan fluoride dan COD. Efisiensi tertinggi pada proses penyisihan fluoride dan COD diperoleh pada kondisi pH 9, waktu kontak 60 menit dan tegangan 27 volt dengan nilai efisiensi penyisihan fluoride sebesar 99,84% dan efisiensi penyisihan COD sebesar 56,35%. The production process of phosphoric acid produces wastewater containing fluoride and COD which has the potential to pollute the environment if not treated properly. The content of fluoride ions in water can be a serious threat to human health because it causes damage to teeth and bones. The combination of precipitation and electrocoagulation is an effective alternative to reduce fluoride and COD content. This study aims to analyze the effect of pH of precipitation, voltage, and contact time on fluoride and COD removal in industrial phosphate waste using precipitation and electrocoagulation methods. The precipitation and electrocoagulation processes are carried out in batches. Precipitant uses a material in the form of Ca (OH) 2, while the electrocoagulation process uses aluminum electrodes that are arranged monopolarly. Setting the pH of the precipitation using pH 5, 7, and 9. Electrocoagulation using a variation of contact time 40, 50, and 60 minutes. Electric voltage variations 17, 22, and 27 V. The results showed that increasing pH increased the removal efficiency in the precipitation process. Increasing the value of the power supply voltage and contact time led to an increase in the efficiency of fluoride and COD removal. The highest efficiency in fluoride and COD removal process was obtained at conditions of pH 9, contact time of 60 minutes and a voltage of 27 volts with a fluoride removal efficiency value of 99.84% and COD removal efficiency of 56.35%.

scholarly journals Electrochemical Degradation of Crystal Violet Using Ti/Pt/SnO2 Electrode

2021 ◽  
Vol 11 (18) ◽  
pp. 8401
Author(s):  
Rachid El Brychy ◽  
Mohamed Moutie Rguiti ◽  
Nadia Rhazzane ◽  
Moulay Driss Mellaoui ◽  
Khalid Abbiche ◽  
...  
Keyword(s):  
Removal Efficiency ◽  
Crystal Violet ◽  
Current Density ◽  
Ph Value ◽  
Supporting Electrolyte ◽  
Chloride Concentration ◽  
Oxygen Demand ◽  
Electrochemical Treatment ◽  
Electrochemical Process ◽  
Initial Ph

Today, organic wastes (paints, pigments, etc.) are considered to be a major concern for the pollution of aqueous environments. Therefore, it is essential to find new methods to solve this problem. This research was conducted to study the use of electrochemical processes to remove organic pollutants (e.g., crystal violet (CV)) from aqueous solutions. The galvanostatic electrolysis of CV by the use of Ti/Pt/SnO2 anode, were conducted in an electrochemical cell with 100 mL of solution using Na2SO4 and NaCl as supporting electrolyte, the effect of the important electrochemical parameters: current density (20–60 mA cm−2), CV concentration (10–50 mg L−1), sodium chloride concentration (0.01–0.1 g L−1) and initial pH (2 to 10) on the efficiency of the electrochemical process was evaluated and optimized. The electrochemical treatment process of CV was monitored by the UV-visible spectrometry and the chemical oxygen demand (COD). After only 120 min, in a 0.01mol L−1 NaCl solution with a current density of 50 mA cm−2 and a pH value of 7 containing 10 mg L−1 CV, the CV removal efficiency can reach 100%, the COD removal efficiency is up to 80%. The process can therefore be considered as a suitable process for removing CV from coloured wastewater in the textile industries.

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