Chemical Oxygen Demand Removal Ratio Research Articles

Application of iron tailings in the coagulation of landfill leachate by bipolar membrane electrodialysis

Landfill leachate contains large amounts of non-biodegradable organic matter. The recalcitrant substances become more concentrated following the treatment using a combination of biological methods and nanofiltration. In this study, the nanofiltration concentrated landfill leachate (NCLL) was subjected to coagulation treatment using the bipolar membrane electrodialysis (BMED) process with iron tailings. The H+ required for metal leaching and OH− for coagulation are supplemented by water dissociation. The pH value of the NCLL played an important role for coagulation and the suitable pH value was 4. As the resource of the coagulant, a certain amount of iron tailing is needed. The energy consumption (EC) for chemical oxygen demand (COD) removal was about 0.70 kW h/g COD with 10 g tailing. Pretreating the tailing with 0.2 mol/L HNO3 could enhance the coagulation process, resulting in a COD removal ratio of 67.3% within 4 h. Increasing the current density improved the COD removal rate, but consumed more electricity. Employing more treatment units is a viable approach to reduce EC. It decreased to 0.045 kW h/g COD when two treatment units connected together. Humic like acids and fulvic like acids present in the NCLL have been effectively removed. This study provides a way of ‘treating the wastes with wastes’ for NCLL treatment.

Advanced treatment of secondary effluent by the integration of heterogeneous catalytic ozonation and biological aerated filter.

The advanced treatment of secondary effluents was investigated by employing heterogeneous catalytic ozonation integrated with a biological aerated filter (BAF) process. The results indicated that catalytic ozonation with the prepared catalyst (MnxCuyOz/γ-Fe2O3) significantly enhanced the performance of pollutant removal and broke up macromolecules into molecular substances by the generated hydroxyl radicals. These molecular substances were easily absorbed by microorganisms in the microbial membrane reactor. In the BAF process, chemical oxygen demand (COD) (chemical oxygen demand) decreased from 54.26 to 32.56 mg/L, while in catalytic ozonation coupled with the BAF, COD could be reduced to 14.65 mg/L (removal ratio 73%). Under the same condition, NH4+-N decreased from 77.43 to 22.69 mg/L and 15.73 mg/L (removal ratio 70%) in the BAF and the catalytic ozonation coupled with BAF, respectively. In addition, the model that highly correlated influent COD to effluent COD and reactor height for filler could predict the removal ratio of COD of the BAF system. Based on the microbial community analysis, ozone in the solution had a certain screening effect on microorganisms, which helped to better adapt to the ozone-containing environment. Therefore, the integrated process with its efficient, economic, and sustainable advantages was suitable for the advanced treatment of secondary effluents.

Efficiency of submerged ceramic flat membrane bioreactor in the treatment of coal chemical wastewater

Coal chemical wastewater inhibits the development of the modern coal chemical industry. This study used a submerged ceramic flat membrane bioreactor to treat coal chemical wastewater. By combining the characteristics of high flux and high strength of ceramic flat membrane with the characteristics of high sludge concentration of Membrane Bio-Reactor (MBR). The treatment effect of ceramic flat membrane bioreactor on coal chemical wastewater and related influencing factors were studied. The Chemical Oxygen Demand (COD) concentration, ammonia nitrogen concentration, total phenol concentration, and turbidity of coal chemical wastewater could be reduced to below 31.4 mg/L, 3.03 mg/L, 3.76 mg/L, and 0.4 NTU. The ceramic flat membrane bioreactor achieved the optimal removal effect on pollutants when Hydraulic Retention Time (HRT) was 21 h, Dissolved Oxygen (DO) concentration was 3.2–4.0 mg/L and pH was 7.1–7.5. Among them, the total phenol removal ratio reached the maximum value of 95.31 %, and the COD removal ratio remained at 93 % ∼ 94 %, ammonia nitrogen removal ratio was stable at 95 % ∼ 97 %. The microorganisms in the mixture and membrane mainly were aerobic bacteria, and the content of organic-degrading bacteria, nitrifying and denitrifying bacteria was high. The addition of a membrane module not only prevented the loss of activated sludge in the reactor but also kept a high sludge concentration. Meanwhile, the addition of a membrane module also improves the biodiversity and stability of sludge treatment system.

Mineral residue accelerant-enhanced anaerobic digestion of cow manure: An evaluation system of comprehensive performance

Anaerobic digestion (AD) is an efficient technology for treating biowaste and generating biogas. A reasonable evaluation of AD performance is crucial to its development. Herein, a comprehensive evaluation system covering five dimensions (energy output, process stability, degradation efficiency, digestate fertility, and digestate safety) was established to assess AD performance. Each dimension in the evaluation system was assigned a specific indicator defined by a threshold or range. Additionally, the proposed evaluation system was applied to assess a case study of batch-mode mesophilic AD that employed three industrial waste residues as mineral accelerants (nickel‑iron slag, steel slag, and fly ash). The mineral accelerants enhanced the energy output (methane yield by 66.55 %–87.54 %) and the feedstock degradation (chemical oxygen demand removal ratio by 11.23 %–32.42 %). The digestates also retained promising safety (heavy metal contents of 190–1260 mg/kg) and fertility (total nutrient contents of 3.71 %–4.69 %). The evaluation system reasonably appraised the comprehensive performance of accelerant-enhanced AD systems with cow manure. This work provides a reliable methodology for evaluating and comparing the performance of different novel accelerants and can be applied to evaluate the comprehensive performance of large-scale biogas projects with cow manure.

Organic Pollutants Removal from Olive Mill Wastewater Using Electrocoagulation Process via Central Composite Design (CCD)

Electrocoagulation (EC) was studied in this study as a potential alternative approach for treating Olive Mill Wastewater (OMW). Aluminum plates were utilized as anode and cathode to evaluate the removal of Chemical Oxygen Demand (COD) from OMW and the aluminum electrode’s weight loss. Central Composite Experimental Design (CCD) and Response Surface Methodology were used to optimize its performance. Anodes were weighed before and after each electrocoagulation experiment, to compare the experimental and the theoretical dissolved aluminum weights calculated using Faraday’s law. We discovered the following EC conditions for CCD: current density = 15 mA/cm2, pH = 4, and electrolysis time of 30 min. Under these conditions, the maximum COD removal ratio was 41%, equating to an Al weight loss of 288.89 g/m3 at an estimated operating cost of 1.60 USD/m3. According to the response optimizer, the most economical operating settings for COD removal efficiency of 58.888% are pH 4, a current density of 18.41 mA/cm2, electrolysis time of 36.82 min, and Al weight loss of 337.33 g/m3, with a projected running cost of 2.00 USD/m3.

Study on heterogeneous catalytic wet air oxidation process of high concentration MDEA-containing wastewater

High concentration N-methyldiethanolamine (MDEA)-containing wastewater with strong alkaline, high chemical oxygen demand (COD), and toxic organics, cannot be directly treated by biochemical process. In this paper, effect of operation parameters (temperature, reaction pressure and residence time) on removal ratio of COD and MDEA was investigated by catalytic wet air oxidation (CWAO) over commercial activated carbon (AC). The degradation pathway of MDEA in the CWAO was proposed. The results showed that the concentration of MDEA, COD, total organic carbon (TOC), and total nitrogen (TN) were 18.92, 61.2, 21.34 and 5.65 g·L−1, respectively. The contribution rate of MDEA concentration to COD in the wastewater reached up to 89.8%. The removal ratio of MDEA and COD exceeded 98% and ∼90% at temperature of 230 °C, reaction pressure of 5.0 MPa and residence time of 90 min for 168 h continuous running, respectively. The surface carboxylic acid groups of AC played a key role in the formation of hydroxyl radicals (·OH), due to the O2 was adsorbed by the carboxyl groups on the surface of AC to form ·OH, and the ·OH then attacked the CN bond of the MDEA to generate other intermediate products, and then these intermediate products was further oxidized to NH4+, CO2 and H2O. This work provides a promising pretreatment technology of high concentration MDEA-containing wastewater.

Treatment of wastewater from adhesive-producing industries by electrocoagulation and electrochemical oxidation

Adhesive wastewater from adhesive-producing industries is a kind of refractory organic wastewater containing high chemical oxygen demand (COD) and ammonia nitrogen. In this study, the electrocoagulation and electrochemical technology were in series attempted to treat adhesive wastewater from adhesive-producing industries. The effects of operating parameters such as current density and initial pH were investigated to determine the optimum electrocoagulation parameters. The removals of COD and ammonia nitrogen achieved 81.62%, and 50.92%, respectively, under the optimum electrocoagulation conditions (current density of 5 mA/cm2, pH 3, 2 g/L Na2SO4 supporting electrolyte solution, 60 min of electrocoagulation). The effluent of electrocoagulation was subsequently treated by electrochemical oxidation. The effects of operating parameters, such as current density, initial pH, and supporting electrolyte, on the degradation of COD and ammonia nitrogen were investigated. The COD and ammonia nitrogen removal ratios were both as high as nearly 100% after electrolysis of 120 min (current density of 35 mA/cm2, pH 8.4, 2 g/L NaCl supporting electrolyte solution). The results of excitation-emission-matrix (EEM) revealed the changes of different dissolved organic matter after electrocoagulation and electrochemical oxidation treatment. The experimental results proved that the electrocoagulation combined with electrochemical oxidation methods are the potential technologies for treatment of adhesive wastewater.

Study on wet oxidation process and mechanism for ethylene spent caustic

ABSTRACT Ethylene spent caustic with strong alkalinity, high chemical oxygen demand (COD) and toxicity could not be directly discharged without pretreatment. In this paper, the composition of spent caustic from a petrochemical enterprise was analyzed. Effects of oxidants, reaction temperature, pressure and residence time on the removal ratio of COD in the spent caustic were investigated. The oxidation reaction mechanism of main organic sulphides in the spent caustic was discussed. Results show that COD of the ethylene spent caustic is ∼ 24.5 g/L, the main compositions are S2- and disulphides including a small amount of ketones and phenolic organics. The removal ratio of S2- in spent caustic is up to 100%, and the removal ratio of COD is over 83% at 180 °C with the pressure of 2 MPa and residence time of 15 min using oxygen as an oxidant. Taking dimethyl disulphide as an example, dimethyl disulphide with HO• firstly produces methyl thiosulphonate and methyl sulphenic acid, then further oxidized to generate methanesulphonic acid, and the C–S bonds in the methanesulphonic acid were broken to generate sulphuric acid and formic acid. So the oxidative degradation products of organic sulphides are sulphuric acid, formic acid and a small amount of acetic acid.

Advanced treatment of pharmaceutical wastewater with a combined Fe-C micro-electrolysis/EGSB system assisted by microalgae

ABSTRACT An integrated process of iron/carbon micro-electrolysis (ICME)–expanded granular sludge bed (EGSB)–microalgae reactor (MR) was developed for treating pharmaceutical wastewater with initial chemical oxygen demand (COD) of 25000–28500 mg/L. The results show that, under the optimum conditions, the removal ratio of COD, total suspended solids (TSS), color, NH3-N, and total phosphorus were 99.2%, 98.4%, 97.5%, 95.3%, and 78.9%, respectively. The ICME removed a considerable proportion of TSS and color, and improved the biodegradability of the wastewater, while the EGSB played an important role in the removal of residual COD, and finally, post-polish treatment was achieved in the MR.

Biodegradation of Sulfonated Lignite (SL) by fungi from waste drilling mud

In this paper, three indigenous Sulfonated lignite (SL) degrading fungi were isolated from waste drilling mud (WDM) and were identified, and the mechanism of SL degradation and potential of WDM bioremediation was presented. These SL degrading fungi (WNF15, WNF20, and WNF22) were as Pseudallescheria ellipsoidea, Stachybotrys chartarum, and Scopulariopsis brevicaulis by their physiological characteristics and ITS gene sequencing. SL degradation test results showed that all three species can effectively degrade SL but WNF-20 had the highest SL degradation ratio (47.54%). MnP and Lac were the dominant enzymes used by the fungi for SL degradation. Analysis of SO4 2- concentration and degradation products suggested that the fungus firstly breaks the C-SO3 bond and release of sulfite assisted. Subsequently, breaks the branched-chain and crosslink bone of the aromatic rings in desulphurisation by-products, and then the broken crosslink bone were transformed into hydrocarbons and aromatic acids. Inoculation of a mixture of the three fungi into a liquid MS medium containing 5% WDM resulted in a chemical oxygen demand removal ratio of 87.65% after 14 d. All rustles suggest that these three fungi are efficient SL degraders and can be used for bioremediation of WDM in gas drilling fields.

Application of an artificial neural network for the improvement of agricultural drainage water quality using a submerged biofilter.

Artificial neural network (ANN) mathematical models, such as the radial basis function neural network (RBFNN), have been used successfully in different environmental engineering applications to provide a reasonable match between the measured and predicted concentrations of certain important parameters. In the current study, two RBFNNs (one conventional and one based on particle swarm optimization (PSO)) are employed to accurately predict the removal of chemical oxygen demand (COD) from polluted water streams using submerged biofilter media (plastic and gravel) under the influence of different variables such as temperature (18.00-28.50 °C), flow rate (272.16-768.96 m3/day), and influent COD (55.50-148.90 ppm). The results of the experimental study showed that the COD removal ratio had the highest value (65%) when two plastic biofilter media were used at the minimum flow rate (272.16 m3/day). The mathematical model results showed that the closeness between the measured and obtained COD removal ratios using the RBFNN indicates that the neural network model is valid and accurate. Additionally, the proposed RBFNN trained with the PSO method helped to reduce the difference between the measured and network outputs, leading to a very small relative error compared with that using the conventional RBFNN. The deviation error between the measured value and the output of the conventional RBFNN varied between + 0.20 and - 0.31. However, using PSO, the deviation error varied between + 0.058 and - 0.070. Consequently, the performance of the proposed PSO model is better than that of the conventional RBFNN model, and it is able to reduce the number of iterations and reach the optimum solution in a shorter time. Thus, the proposed PSO model performed well in predicting the removal ratio of COD to improve the drain water quality. Improving drain water quality could help in reducing the contamination of groundwater which could help in protecting water resources in countries suffering from water scarcity such as Egypt.

Removal of Cr(VI) and methyl orange by activated carbon fiber supported nanoscale zero-valent iron in a continuous fixed bed column.

The application of activated carbon fiber supported nanoscale zero-valent iron (ACF-nZVI) in the continuous removal of Cr(VI) and methyl orange (MO) from aqueous solution was studied in depth. The breakthrough curves of Cr(VI) in a fixed bed with ACF-nZVI were measured, and compared with those in the fixed bed with ACF. The catalytic wet peroxide oxidation (CWPO) process for MO was also carried out using ACF-nZVI after reacting with Cr(VI) in the same fixed bed. The results showed that the breakthrough time of ACF-nZVI was significantly longer than that of ACF. Higher pH values were unfavorable for the Cr(VI) removal. The breakthrough time increased with decreasing inlet Cr(VI) concentration or increasing bed height. The Yoon-Nelson and bed depth service time (BDST) models were found to show good agreement with the experimental data. The Cr(VI) removal capacity when using ACF-nZVI was two times higher than that when using ACF. Under the optimal empty bed contact time of 1.256 min, the fixed bed displayed high MO conversion (99.2%) and chemical oxygen demand removal ratio (55.7%) with low Fe leaching concentration (<5 mg/L) after continuous running for 240 min. After three cycles, the conversion of MO remained largely unchanged.

Decomposition of spent radioactive ion‐exchange resin using photo‐Fenton process

AbstractBACKGROUNDThe treatment of spent radioactive ion‐exchange resin is of great importance in reducing total waste volume and minimizing potential environmental hazards. In this study, a comparative investigation of resin decomposition by the Fenton and photo‐Fenton process was performed to address these concerns.RESULTSThe effect of UV energy density and irradiation time on residue chemical oxygen demand (COD) was investigated. With a UV energy density of 6.1 J cm−2 and irradiation time of 120 min, the COD removal ratio reached 97.3%. Under optimized conditions, the residue COD obtained via photo‐Fenton was 47.3% lower than that via Fenton. Scanning electron microscopy (SEM), Fourier transform infrared (FTIR) and ion chromatography (IC) were used to characterize the resin beads and intermediates. Four types of small molecular organic acids were monitored during the reaction. The degradation process of two stages was proposed, involving resin dissolution and mineralization.CONCLUSIONPhoto‐Fenton showed better performance for IRN 77 resin degradation compared to the Fenton process. Both the UV energy density and irradiation time showed significant effects on resin degradation. UV irradiation enhanced the mineralization stage during resin degradation. Oxalic acids showed the highest concentration in all main intermediates. © 2020 Society of Chemical Industry

Real herbicide wastewater treatment by combined means of electrocatalysis application and biological treatment

ABSTRACTIn this study, the real herbicide wastewater was degraded by electrocatalysis oxidation followed by subsequent biological treatment. The influence of several process variables of electrocatalysis oxidation, such as current density, pH and electrode gap on chemical oxygen demand (COD) removal ratio, was investigated and the optimum conditions were determined. The results indicated that COD removal ratio reached 87.0%, and the COD decreased from 7519 mg L−1 to 980 mg L−1 after 120 min electrolysis under the degradation parameters of the current density of 4 a dm−2, pH value of 4 and the plate spacing of 1.0 cm. The electrocatalysis degradation of real herbicide wastewater followed pseudo-first-order kinetics. The BOD5/COD increased from 0.18 to 0.43 after 120 min electrolysis. Then, the biological contact oxidation process was performed on the effluent of the electrochemical process. The results showed that the final COD removal ratio reached 95.8% after biological contact oxidation on the following condition: hydraulic residence time was 12 h and the aeration quantity was 0.6 m3 h−1. Conclusively, it can be proved that electrocatalysis is feasible as a pre-treatment technology to treat real herbicide wastewater.

Electrochemical oxidation treatment of coal tar wastewater with lead dioxide anodes.

In this study, coal tar wastewater was treated by electrochemical oxidation technology using lead dioxide anodes. The influence of operating parameters, including applied current density, electrode gap and initial pH value, on the removal ratio of chemical oxygen demand (COD) was investigated. The results demonstrated that the COD removal ratio reached 90.5% after 3.5 h electrolysis with the current density at 3 A dm-2 and electrode gap at 1.0 cm. Correspondingly, the COD decreased from 5,125 mg L-1 to 487 mg L-1, which fitted the wastewater discharge standards of China, and the specific energy consumption (SECCOD) was 35.3 kWh kgCOD -1. Not only was the COD removal ratio only 77.1% after 2 h electrolysis but the BOD5/COD ratio of the wastewater reached 0.44, which could be biochemically treated, and the SECCOD decreased by 34.3%. Moreover, the main composition of pristine wastewater before and after 2 h electrolysis was analyzed by GC-MS, and the disappearance of macromolecules (such as ethyl-2-pyrenemethanol) and the production of small molecules (such as propane-1,3-diol) could improve the biodegradability of the wastewater. Therefore, electrochemical oxidation for 2 h is a promising alternative for pretreatment of coal tar wastewater prior to biological treatment.

Economic optimization of stacked microbial fuel cells to maximize power generation and treatment of wastewater with minimal operating costs

This study proposes an optimization-based strategy to select the best electrical stacking configuration of microbial fuel cells to achieve the highest power output and chemical oxygen demand removal under the lowest operating costs. Three similar wastewater-fed continuous flow microbial fuel cells are electrically connected in four different modes and concentrations of fuel substrate and buffer in anolyte, as main operating cost items, are optimized using two-level factorial design with the dual objective of maximizing power density and minimizing operating costs. In series connection the lowest ratio of operating costs to maximum power $0.048.mW−1.d−1 is achieved that is comparable to the ratio of $0.046.mW−1.d−1 for an individual unit as control. Optimization reduces operating costs 61% with only 37% reduction in maximum power compared to maximum attainable power. At the optimized concentrations, the lowest operating costs to chemical oxygen demand removal ratio $2.01.COD−1 is observed in series connection. This suggests that the cheapest way to stack microbial fuel cells to gain the highest power output and chemical oxygen demand removal is serial electrical connection.

Cover: Industrial Wastewater COD Degradation Technology – Taiwan Solar Cell Plant

CLEAN – Soil, Air, WaterVolume 44, Issue 4 Cover PictureFree Access Cover: Industrial Wastewater COD Degradation Technology – Taiwan Solar Cell Plant First published: 13 April 2016 https://doi.org/10.1002/clen.201670040AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Graphical Abstract Kun-Cheng Lai, Jet-Chau Wen, Wei-Ting Chen, Chiou-Mei Chen, Shao-Yang Huang, Shu-Min Shen, Chi-Min Shu Clean - Soil, Air, Water 2016, 44 (4), 333–338 DOI: 10.1002/clen.201400403 A biotreatment system is integrated with anaerobic and aerobic biotreatments, which are not only capable of treating high chemical oxygen demand (COD) concentrations in influents but can also remove NO3–N. This study successfully establishes an in situ pilot plant capable of treating influent COD concentrations of 3000 mg L‒1 with a COD removal ratio of 70–85%. Volume44, Issue4April 2016 RelatedInformation

Industrial Wastewater COD Degradation Technology – Taiwan Solar Cell Plant

The energy crisis has led to continuous cost increases for petroleum, and global climate change has exacerbated the environmental crisis. To cope with the energy crisis, many industrially developed countries have promoted photovoltaic cells as the most promising green energy alternative. However, their manufacture produces enormous amounts of pollutants that significantly impact the environment. To balance green energy and the environment, the manufacturing processes of photovoltaic cells should be environmentally benign. Therefore, a proper pollution prevention management strategy and control technologies should be developed accordingly. To adapt the growth of photovoltaic cell industries in Asia to the global green trend and contribute to environmental protection, we focused on the treatment of wastewater from plants producing photovoltaic cells. A biotechnology process was used to culture microorganisms based on wastewater characteristics from photovoltaic industries. This biotreatment system was integrated with anerobic and aerobic biotreatments, which not only are capable of treating high chemical oxygen demand (COD) concentrations in influents but also can remove nitrate nitrogen. This process is able to remove more than 85% of the COD from influent streams. The advantages are that less sludge produced, less space required, and operating costs are lower. This study successfully established an in situ pilot plant capable of treating influent COD concentrations of 3000 mg L−1 and producing effluent COD concentrations of 100–400 mg L−1. The COD removal ratio was about 70–85% and can serve as a model reference for practical industrial treatment.

Treatment of hydraulic fracturing wastewater by wet air oxidation.

Wastewater produced by hydraulic fracturing for oil and gas production is characterized by high salinity and high chemical oxygen demand (COD). We applied a combination of flocculation and wet air oxidation technology to optimize the reduction of COD in the treatment of hydraulic fracturing wastewater. The experiments used different values of flocculant, coagulant, and oxidizing agent added to the wastewater, as well as different reaction times and treatment temperatures. The use of flocculants for the pretreatment of fracturing wastewater was shown to improve treatment efficiency. The addition of 500 mg/L of polyaluminum chloride (PAC) and 20 mg/L of anionic polyacrylamide (APAM) during pretreatment resulted in a COD removal ratio of 8.2% and reduced the suspended solid concentration of fracturing wastewater to 150 mg/L. For a solution of pretreated fracturing wastewater with 12 mL of added H2O2, the COD was reduced to 104 mg/L when reacted at 300 °C for 75 min, and reduced to 127 mg/L when reacted at the same temperature for 45 min while using a 1 L autoclave. An optimal combination of these parameters produced treated wastewater that met the GB 8978-1996 'Integrated Wastewater Discharge Standard' level I emission standard.

4-Nitroaniline Degradation by TiO2Catalyst Doping with Manganese

Stainless steel anode covered with layer film of TiO2doped with manganese was utilized to decompose 4-nitroaniline in rectangular borosilicate glass reactor, while stainless steel mesh was chosen as cathode; the anode and cathode were connected to the direct-current power; meantime two 60 W (λmax= 365 nm) UV lamps were used as light source. The microstructures on TiO2before and after being doped with manganese were analyzed by energy disperse X-ray (EDX) and X-ray diffraction (XRD). The performance of degradation of 4-nitroaniline was evaluated by analyzing cracking ratio of 4-nitroaniline ring, the chemical oxygen demand (COD), and total organic carbon (TOC) in remaining solution. Monitored parameters during all the photocatalytic reaction including dissolved oxygen, direct voltage, and radiation dosage of ultraviolet rays were investigated. When dissolved oxygen concentration, direct voltage, and radiation dosage of ultraviolet rays were, respectively, equivalent to 9 mg/L, 24 V, and 1200 μW/cm2, the degradation ratio of 4-nitroaniline reached maximum. The experimental results indicated that cracking ratio of 4-nitroaniline ring and the removal ratio of COD and TOC were, respectively, more than 99%, 85%, and 80% when reaction was run for 10 hours. The values of COD and TOC were, respectively, less than 16 mg/L and 8 mg/L while the experiment was finished.