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

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.

2017 ◽  
Vol 20 (1) ◽  
Author(s):  
Xu Zeng ◽  
Jun Liu ◽  
Jianfu Zhao

AbstractWet oxidation of an industrial pharmaceutical wastewater with high concentration organic pollutants using hydrogen peroxide as an oxidant was investigated. Experiments were performed in a batch reactor to discuss the effects of reaction temperature, time, the hydrogen peroxide amount and catalyst with COD removal rate as an evaluation index. Results show that the highest COD removal rate, 81.6 %, was achieved at 240 ºC for 60 min with the addition of H


2011 ◽  
Vol 64 (1) ◽  
pp. 117-121 ◽  
Author(s):  
Y. J. Lei ◽  
X. B. Wang ◽  
C. Song ◽  
F. H. Li ◽  
X. R. Wang

Ruthenium-based catalysts were prepared by a saturation-dip method. Their catalytic activity was evaluated by a catalytic wet oxidation (CWO) process. The ruthenium-based catalysts were used to purify organic pharmaceutical wastewater with high concentration pyridine and pyridine derivatives that have high chemical oxygen demand (COD). In the CWO process, organic pharmaceutical wastewater was continuously pumped into fixed-bed reactors filled with Ru-based catalysts, while the organic components in wastewater were catalytically degraded by oxygen at high temperatures and pressures (temperature, 170–300 °C; pressure, 1.0–10 MPa). The experimental results showed that the prepared catalysts could effectively purify pharmaceutical wastewater with high concentration organic components, which are difficult to degrade biochemically, and that the removal rates of both COD and total nitrogen were over 99%.


Author(s):  
Vijay A. Juwar ◽  
Ajit P. Rathod

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).


2020 ◽  
Vol 82 (9) ◽  
pp. 1795-1807 ◽  
Author(s):  
Dejun Bian ◽  
Zebing Nie ◽  
Fan Wang ◽  
Shengshu Ai ◽  
Suiyi Zhu ◽  
...  

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.


2005 ◽  
Vol 52 (10-11) ◽  
pp. 335-343 ◽  
Author(s):  
M. Inizan ◽  
A. Freval ◽  
J. Cigana ◽  
J. Meinhold

Aerobic granulation seems to be an a attractive process for COD removal from industrial wastewater, characterised by a high content of soluble organic compounds. In order to evaluate the practical aspects of the process, comparative experimental tests are performed on synthetic and on industrial wastewater, originating from pharmaceutical industry. Two pilot plants are operated as sequencing batch bubble columns. Focus was put on the feasibility of the process for high COD removal and on its operational procedure. For both wastewaters, a rapid formation of aerobic granules is observed along with a high COD removal rate. Granule characteristics are quite similar with respect to the two types of wastewater. It seems that filamentous bacteria are part of the granule structure and that phosphorus precipitation can play an important role in granule formation. For both wastewaters similar removal performances for dissolved biodegradable COD are observed (> 95%). However, a relatively high concentration of suspended solids in the outlet deteriorates the performance with regard to total COD removal. Biomass detachment seems to play a non-negligible role in the current set-up. After a stable operational phase the variation of the pharmaceutical wastewater caused a destabilisation and loss of the granules, despite the control for balanced nutrient supply. The first results with real industrial wastewater demonstrate the feasibility of this innovative process. However, special attention has to be paid to the critical aspects such as granule stability as well as the economic competitiveness, which both will need further investigation and evaluation.


2010 ◽  
Vol 62 (11) ◽  
pp. 2669-2677 ◽  
Author(s):  
Lizhang Wang ◽  
Yuemin Zhao

Experiments were performed to reduce chemical oxygen demand (COD) from 4,4′-diaminostilbene-2,2′-disulfonic (DSD) acid manufacturing wastewater using electrochemical oxidation coupled with adsorption by granular activated carbon. The COD removal is affected by the residence time and applied voltage. When the residence time is increased, lower value of COD effluent could be obtained, however, the average current efficiency (ACE) decreased rapidly, and so does the applied voltage. In addition, aeration could effectively enhance COD removal efficiency and protect anodes from corrosion. Furthermore, the acidic condition is beneficial to the rapid decrease of COD and the values of pH effluent are independent of the initial solution pH. The optimization conditions obtained from these experiments are applied voltage of 4.8 V, residence time of 180 min and air–liquid ratio of 4.2 with the COD effluent of about 690 mg L−1. In these cases, the ACE and energy consumption are 388% and 4.144 kW h kg−1 COD, respectively. These perfect results from the experiments illustrate that the combined process is a considerable alternative for the treatment of industrial wastewater containing high concentration of organic pollutants and salinity.


RSC Advances ◽  
2017 ◽  
Vol 7 (16) ◽  
pp. 9754-9763 ◽  
Author(s):  
Bholu Ram Yadav ◽  
Anurag Garg

The present study reports the performance of catalytic wet oxidation (CWO) for the treatment of simulated pulping effluents (with chemical oxygen demand (COD) = 15 000 and 17 000 mg L−1) from large and small scale pulp and paper mills, respectively.


2021 ◽  
Vol 18 (4) ◽  
pp. 135-140
Author(s):  
Sanju Sreedharan

Zero energy technologies and sustainable energy production are the two major concerns of present day researches. Microbial fuel cells (MFCs) are bioreactors that extract chemical energy stored in organic compounds, into electric potential, through bio-degradation. The core reason for the high strength of effluent generated from slaughterhouses is animal blood. The current study evaluates the potential of MFC technology to reduce the pollution strength of cattle blood in terms of chemical oxygen demand (COD). The current study was piloted in three stages using lab scale two chambered MFC: The first stage was to determine the best oxidising agent as compared to natural aeration from three accessible options, KMnO4, diffused aeration and tape grass aquatic plant. KMnO4 was found to be the superlative with a 30% reduction in COD in 100 hrs batch reactor and a maximum power of 0.97 mW using 125 mL livestock blood. The second stage of the study optimised the concentration of KMnO4. At 500 mg/L KMnO4 concentration, 50% COD removal efficiency was acquired in a batch reactor of 60 hrs with an average energy output of 1.3 mW. In the final stage on the addition of coconut shell activated carbon with an Anolyte at a rate of 40 mL/125 mL of substrate COD removal efficiency increased to 74.9%.


Water ◽  
2020 ◽  
Vol 12 (10) ◽  
pp. 2771
Author(s):  
Jian Wang ◽  
Cong Du ◽  
Feng Qian ◽  
Yonghui Song ◽  
Liancheng Xiang

A pilot-scale experiment is carried out for treating mixed wastewater containing pharmaceutical wastewater (PW) and domestic wastewater (DW), by a process that is a combination of hydrolysis acidification-ozone-modified anaerobic–anoxic–aerobic-ozone (A2/O) (pre-ozone) or hydrolysis acidification-modified A2/O-ozone (post-ozone). The effects of different mixing ratios of PW and DW and pre-ozone treatment or post-ozone treatment on the removal of nitrogen and phosphorus and chemical oxygen demand (COD) are compared and studied. The optimal ratio of PW in mixing wastewater is 30%, which has the optimal COD removal efficiency and minimum biotoxicity to biological treatment. The pre-ozone treatment shows more advantages in removing nitrogen and phosphate but the post-ozone treatment shows more advantages in COD removal. Analysis of dissolved organic matter (DOM) demonstrates that post-ozone treatment has a more significant effect on the removal of fulvic acid and humic acid than the effect from the pre-ozone treatment, so the COD removal is better. Overall DOM degradation efficiency by post-ozone treatment is 55%, which is much higher than the pre-ozone treatment efficiency of 38%. Microbial community analysis reveals that the genus Thauera and the genus Parasegetibacter take great responsibility for the degradation of phenolics in this process. All the results show that the post-ozone treatment is more efficient for the mixed wastewater treatment in refractory organics removal.


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