Oxygen Demand Carbon Research Articles

Experimental Studies on Continuous Electrocoagulation Treatment of Peat Water in Sarawak with Copper Electrodes

Electrocoagulation is an electrochemical wastewater treatment method, which coagulates impurities particles and ionsby using electrical current. In Sarawak, freshwater peat covers around 1.698 million hectares whereas the other 154,000 hectares are mangrove. Peat water is the water or moisture produced from these peatland or peat soil. Clean water availability in the rural coastal regions are limited due to the high financial cost of distribution of essential clean water resources to sparse population in the remote areas. Therefore, a cost-effective standalone electrocoagulation system for the treatment of peat water in Sarawak is one of the suggested solutions to this water supply problem. The main aim of this research is to develop a continuous electrocoagulation water treatment system by using copper electrodes to treat peat water in Sarawak. The peat water treated is targeted to achieve at least standard quality for domestic usage and the parameters studied to measure the optimal design of the treatment system are the turbidity, total suspended solids (TSS), total organic carbon (TOC), pH and chemical oxygen demand (COD) of the water treated. The experimental results meet the standard for Raw Water Quality and Drinking Water Quality with an optimum parameter of 20 electrodes, 0.7 cm inter electrodes spacing, current density of 5.99A/m2 and treatment time of 100 minutes. The total operating cost for the optimize parameters is RM 0.11 per litre of peat water. Overall, the treatment ofpeat water by using continuous electrocoagulation with copper electrodes is feasible.

Electro-oxidation of a Commercial Formulation of Glyphosate on Boron-Doped Diamond Electrodes in a Pre-pilot-Scale Single-Compartment Cell

Kinetic and environmental aspects related with the mineralization of a commercial glyphosate (GP) formulation in a pre-pilot-scale reactor were assessed. Assays were performed at an acidic pH using Na2SO4 as support electrolyte at five different current densities. GP removal can be achieved in 60 min and is not dependent on the applied current density; however, the reduction of organic carbon (TOC) and chemical oxygen demand (COD) from the sample evidence the impact of the limitations of mass transfer in aspects like energy consumption, effluent quality, and sustainability of the process. Assays at 120 and 240 mg L−1 revealed that it is feasible to improve the biodegradability of the effluent after 300 min of treatment using higher current densities (80 and 100 mA cm−2). At 360 mg L−1, neither the current density nor the time of treatment had an impact on the biodegradability of the effluent at all the assessed current densities. GP removal could have an environmental footprint (1.3 kg CO2 Eqv/kg TOC) in countries where the energy matrix depends on hydropower. In countries where electricity is generated from non-renewable raw materials, like gas or coal, the emissions of greenhouse gasses (GHG) could increase 170% and 439%, respectively. The use of renewable energy sources, like wind power or solar, could reduce the GHG emission to 0.3 kg CO2 Eqv/kg TOC. The cost of treatment ranged between US$ 0.7 and 2.1 g TOC−1 removed; this variability is due to the selected energy source and the subsidies established in each country.

Simultaneous Domestic Wastewater Treatment and Electricity Generation in Microbial Fuel Cell with Mn(IV) Oxide Addition

AbstractCompared to traditional domestic wastewater treatment methods, microbial fuel cells (MFCs) with Manganese(IV) (Mn(IV)) oxide addition were established to promote the degradation efficiency of organics in domestic wastewater and generate electricity simultaneously. Activated sludge consists of various electricigen and Mn(IV) oxide acts as an excellent electron acceptor. Results showed that the MFC with Mn(IV) oxide addition obtained higher total organic carbon and chemical oxygen demand removal efficiencies in domestic wastewater than without Mn(IV) oxide addition and in an open circuit system, and produced a maximum output power density of 0.946 W m−3 with a corresponding maximum voltage density of 0.915 V L−1. Cyclic Voltammograms (CVs) indicated that the current density of the MFC with Mn(IV) oxide addition reached 2.21 mA cm−2 at the peak separation of 0.26 V, whereas the current density of the MFC only was up to 1.15 mA cm−2 at 0.443 V. Linear Sweep Voltammetry (LSV) showed the half‐wave potential and limiting current density of the MFC with Mn(IV) oxide addition as 71 mV and 4.24 mA cm2 respectively, which were higher than corresponding values (36 mV and 3.65 mA cm−2) of the MFC. Tafel curves illustrated the MFC with Mn(IV) oxide addition showed a lower anodic Tafel slope of 6.14±0.393 V−1, confirming the MFC with Mn(IV) oxide addition enabled faster electron‐transfer kinetics as compared to the MFC.

Solar nanophotocatalytic pretreatment of seawater: process optimization and performance evaluation using response surface methodology and genetic algorithm

In reverse osmosis seawater treatment process, membrane fouling can be mitigated by degrading organic pollutants present in the feed seawater. The present study evaluates the effectiveness of employing solar photocatalysis using TiO2/ZnO/H2O2 to pretreat reverse osmosis (RO) feed seawater under solar irradiation. Process optimisation and performance evaluation were undertaken using response surface methodology-desirability function and RSM integrated with genetic algorithm (RSM-GA). Statistical analysis was performed to determine the interactive relationships and main effects of input factors such as TiO2 dosage, H2O2 dosage, pH, reaction time and ZnO dosage. The performance evaluation was determined in terms of percentage removal of total organic carbon (TOC) and chemical oxygen demand (COD). The obtained optimum values using RSM-GA evaluation for TOC and COD removal were found to be 76.5% and 63.9%, respectively. The predicted RSM-GA results correspond well with the experimental results (TOC removal = 73.3%, COD removal = 61.2%). Utilization of renewable solar energy coupled with optimum utilisation of nanophotocatalysts enables this technique to be a unique treatment process for RO pretreatment of seawater and membrane fouling mitigation.

Wastewater COD characterization: RBCOD and SBCOD characterization analysis methods

Wastewater characterization is the basis for process design and operation optimization of wastewater treatment plants (WWTPs). In this work, a comprehensive study of the respirometry method has been performed to evaluate the biodegradable organic matters of wastewater. First, the optimal initial substrate to biomass ratio (S0/X0) was confirmed. Second, under the optimal S0/X0, the degradation curves of wastewater carbon oxygen demand (COD) components rapidly biodegradable COD (RBCOD) and slowly biodegradable COD (SBCOD) were obtained. Third, the Mann–Kendall test was performed to confirm the time point (t2) when endogenous respiration levels were reached, and the hydrolysis model was used to determine the time point (t1) of the SBCOD degradation stage. Considering the results, an adequate wastewater COD characterization method for RBCOD and SBCOD has been proposed. This study provides strong support to carry out effective and feasible process design, process diagnosis and optimization capability, can help achieve refined and stable operational management of WWTPs.

Petroleum-contaminated soil: using sonolysis to improve mineralization and biodegradation potential of Fenton reaction and ozonolysis process

The degradation efficiency of the Fenton reaction or ozonolysis (O3) to treat soil contaminated by crude petroleum was studied in association with the sonolysis process. To quantify oxidation efficiency, total organic carbon (TOC) and chemical oxygen demand (COD) were measured, while biochemical oxygen demand (BOD5) was measured to estimate biodegradation potential. TOC removal efficiency ranged from 9 to 52% to the Fenton reaction without sonolysis, and 18% and 78% with sonolysis for reagent concentrations of 1% H2O2-100 mM Fe2+ and 20% H2O2-1 mM Fe2+, respectively. For ozonolysis (after 10 and 60 min of treatment), the reduction in TOC ranged from 9 to 43% without sonolysis and 15 to 61% with sonolysis. The Fenton reaction without sonolysis increased the biodegradability in relation to the non-oxidized sample by 6% (1% H2O2-100 mM Fe2+) and 26% (20% H2O2-1 mM Fe2+), and with sonolysis the corresponding values were 13% and 42%, respectively. The biodegradation potential under ozonolysis without sonolysis increased from 0.18 (10 min of treatment) to 0.38 (30 min of treatment), and with sonolysis these values were 0.26 and 0.58, respectively. Optimization of the remediation processes is essential to determine sequential treatment order and efficiency.

Detecting the concentration of aldehydes disinfection by-products formed due to the application of the ozonation process in water treatment plants

The current study presents, in detail, an experimental investigation for detecting four of high risk aldehyde compounds in water (acetaldehyde, formaldehyde, glyoxal, and methyl glyoxal). These compounds are normally formed in water in micrograms per liter, as by-products, after addition of ozone in the water treatment plants. For this study, 114 samples were taken from the raw and directly from the ozonated water of a drinking water treatment plant in Iraq, between August 2020 (54 samples) and September 2020 (60 samples). The samples were analyzed for their constituents — for aldehyde compounds — using a Gas Chromatography-Electron capture detector (GC-ECD) apparatus. In addition, the concentration of organic matters was measured via total organic carbon (TOC) and chemical oxygen demand (COD) tests, which were measured in accordance with the other technique for the checking of water. The results showed that in all analyzed samples there was a significant increase in the formaldehyde and acetaldehyde concentration in the water, after subjecting it to the ozonation process.In addition to that, noticeable concentrations of glyoxal (6.7 and 9.0 µg/L in August and September, respectively) and methyl glyoxal (12.6 and 12.1 µg/L in August and September, respectively, which were not detected in the raw water samples, appeared in those taken from the treated water. The conclusion obtained from this study was that the level of aldehydes formed in the water was dependent on the raw water characteristics and the amount of ozone added for disinfection purposes.

Effect of Commercial Grade Methyl Parathion on the Survival of Pseudomonas at Varying Temperature and pH

The wide-spread use of methyl parathion as an agricultural insecticide has been causing an increased level of contamination in soil, vegetation and groundwater reservoirs and as well as adverse effects on human, flora, fauna and ecosystems. Therefore, eco-friendly and cost-effective bioremediation system are needed to remove these pollutants from the contaminated sites and mitigate its hazardous. For this purpose, a lab scale study was conducted to investigate the effect of high concentrations of commercial grade methyl parathion (50 EC) on growth of indigenous soil Pseudomonas IES-Ps-1 under different environmental conditions such as pH and temperature. To determine the tolerance limit, Pseudomonas IES-Ps-1 was grown in nutrient broth supplemented with methyl parathion (0, 200, 400, 600, 800, 1000 and 1200 mg/l). The detailed pH (6, 7, 9) and temperature (25, 30 and 35 oC) studies were conducted using higher methyl parathion (400 and 800 mg/l). No growth was observed at 1000 and 1200 mg/l of pesticide after 96 hrs of incubation compared to other concentrations of 200, 400, 600 and 800 mg/l. The maximum growth for both 400 and 800 mg/l of pesticide was observed at pH 7 and 30 °C. The maximum removal of total organic carbon and chemical oxygen demand for 400 mg/lof pesticide were found 50 and 52 % while those for 800 mg/l were 46 and 49 % respectively. Hence, this study concluded that indigenous soil bacterium Pseudomonas IES-Ps-1 could serve as an efficient candidate at 30 °C and pH 7 in development of a bioremediation system for the removal of toxic effects of methyl parathion like pesticides from contaminated sites.

Conversion characteristics of lignite and petroleum coke in chemical looping combustion coupled with an annular carbon stripper

Chemical looping combustion (CLC) of solid fuels was studied in a 30 kW dual fluidized-bed system coupled with an annular carbon stripper for char separation by using a kaolin-promoted manganese ore oxygen carrier. Two solid fuels, a lignite and a petroleum coke, were tested in the CLC unit. The CLC unit was operated continuously for more than 160 h. The effects of the fuel size and residence time in the fuel reactor on the carbon capture efficiency and oxygen demand were investigated. The char separation efficiency of the annular carbon stripper reached 90%, and a maximum carbon capture efficiency of 97% was achieved for the 106–212 μm lignite. The carbon capture efficiency was affected by the fuel particle size and residence time. When >212 μm lignite particles were used, there was a ~ 12% oxygen demand. The carbon capture efficiency in the experiment with petroleum coke was only 45% due to the slow gasification rate. A model was applied to analyze the influence of key factors on the carbon capture efficiency. The redox kinetics of the tested oxygen carrier were studied by a micro-fluidized bed thermogravimetric analysis method.

Performance of acid mine drainage sludge as an innovative catalytic oxidation source for treating vehicle-washing wastewater

This study introduces iron sludge recovered from acid mine drainage (AMD) waste, as advanced oxidation processes, that is, AMD/H2O2 (Fenton’s reagent) to treat vehicle-washing wastewater. Vehicle-washing wastewater was collected from car washing facility in West Virginia, USA, and subjected for laboratory-scale batch experiments. Response surface methodological analysis was chosen to optimize the parametric conditions of the Fenton’s system. A 15-level of quadratic Box-Behnken design model was applied via response surface methodology to evaluate the effects and interactions of the system variables. The optimized system variables were attained at pH 4.0 using 92 and 354 mg/L of AMD and H2O2 concentrations, respectively, to achieve the maximum predicted organics removals of 91.4%. Analysis of variance, which was applied for statistical data analysis, showed the significant of the quadratic models for treatment. The linear correlation between the total organic carbon (TOC) and chemical oxygen demand (COD), with sufficient accuracy, is providing the possibility of estimating COD from TOC values. Finally, the results showed that the reaction is endothermic, non-spontaneous in nature and follows the second-order reaction kinetics rate. The results of this work signify the importance of using iron from waste effluents for treating wastewater.

Evaluation of ozone-based oxidation and solar advanced oxidation treatment of greywater

Reclaiming non-conventional water sources such as greywater is gaining more attention in the light of current and expected water shortage due to the global trend of continued population growth, urbanization, and the impact of climate change. In this work, the degradation of organic matter measured as total organic carbon (TOC) and biochemical oxygen demand (BOD5) in real greywater samples using different ozone-based oxidation and solar advanced oxidation treatments was investigated in a custom-built glass tube reactor combined with a concentrated parabolic collector (CPC). The evaluated processes included ozonation (O3), solar ozonation (O3/solar irradiation), hydrogen peroxide oxidation (H2O2), hydrogen peroxide under solar irradiation (H2O2/solar irradiation), peroxonation (H2O2/O3), and solar peroxonation (H2O2/O3/solar irradiation). Combining different treatment methods with/without exposure to solar irradiation enhanced overall treatment efficiency. The efficiency of the examined processes followed the order: solar peroxonation > solar ozonation > peroxonation > ozonation, while the other processes showed a negligible effect. The highest TOC reduction (58.6 %) was observed using solar peroxonation at 41.7 mg O3/min and 0.2 H2O2/O3 molar ratio; the highest BOD5 reduction (29.4 %) was observed using solar peroxonation at 41.7 mg O3/min and 0.4 H2O2/O3 molar ratio. We conclude that low-cost advanced oxidation technologies can be effective to remove organic materials providing efficient greywater remediation for reuse applications.

Electrocatalytic valorization into H2 and hydrocarbons of an aqueous stream derived from hydrothermal liquefaction

Electrocatalytic oxidation is an attractive process for valorizing the organic compounds and removing the nitrogen in aqueous waste streams at ambient conditions. We evaluated the electrocatalytic oxidation reaction as a function of applied potential over Pt electrodes of an aqueous stream generated via hydrothermal liquefaction. We quantified the conversion of particular organic compounds (e.g., carboxylic acids, alpha hydroxyacids, alcohols, ketones, and amides) and the removal of carbon, nitrogen, sulfur, and chemical oxygen demand. Organic nitrogen and sulfur were oxidized to nitrates and sulfates. The main reaction products from the electrocatalytic oxidation at the anode were short chain volatile hydrocarbons (i.e., olefins, and paraffins) and CO2, while H2 was generated at the cathode. Unidentified compounds were converted to short chain carboxylic acids, alcohol and ketones, while ammonia was oxidized into N2. Studies with model compounds showed that amides and alpha hydroxyacids yielded carboxylic acids that convert further via (non-)Kolbe chemistry. Simultaneous denitrification, valorization of organic compounds, and H2 generation from the aqueous stream can potentially simplify the unit operations currently used in a hydrothermal process. The cost of the electricity required to drive the electrocatalytic operation can be partially mitigated by selling the excess H2 produced.

A Comparison of the Mechanism of TOC and COD Degradation in Rhodamine B Wastewater by a Recycling-Flow Two- and Three-dimensional Electro-Reactor System

Dye wastewater, as a kind of refractory wastewater (with a ratio of biochemical oxygen demand (BOD) and chemical oxygen demand (COD) of less than 0.3), still needs advanced treatments in order to reach the discharge standard. In this work, the recycling-flow three-dimensional (3D) electro-reactor system was designed for degrading synthetic rhodamine B (RhB) wastewater as dye wastewater (100 mg/L). After 180 min of degradation, the removal of total organic carbon (TOC) and chemical oxygen demand (COD) of RhB wastewater were both approximately double the corresponding values in the recycling-flow two-dimensional (2D) electro-reactor system. Columnar granular activated carbon (CGAC), as micro-electrodes packed between anodic and cathodic electrodes in the recycling-flow 3D electro-reactor system, generated an obviously characteristic peak of anodic catalytic oxidation, increased the mass transfer rate and electrochemically active surface area (EASA) by 40%, and rapidly produced 1.52 times more hydroxyl radicals (·OH) on the surface of CGAC electrodes, in comparison to the recycling-flow 2D electro-reactor system. Additionally, the recycling-flow 3D electro-reactor system can maintain higher current efficiency (CE) and lower energy consumption (Es).

Removal of tetracycline and ciprofloxacin from wastewater by vetiver grass (Chrysopogon zizanioides (L.) Roberty) as a function of nutrient concentrations.

Antibiotics have been widely used not only for the treatment and prevention of human infectious diseases but also to promote growth and prevent infections in farm animals. These antibiotics enter the environment via wastewater treatment plants, most of which cannot remove them. In addition to antibiotics, nutrients such as nitrogen (N) and phosphorus (P) also create major environmental pollution problems in surface water. Previously, we reported that vetiver grass [Chrysopogon zizanioides (L.) Roberty] successfully removed antibiotics from secondary wastewater effluent. In this study, our objective was to evaluate the potential of vetiver grass to remove two antibiotics, ciprofloxacin (CIP) and tetracycline (TTC), from wastewater in the presence of high N and P. Our results show that vetiver grass significantly (p < 0.05) removed antibiotics (60-94% CIP and 89-100% TTC) and nutrients (78-89% N and 71-97% P) from the secondary wastewater effluent. The removal of antibiotics dropped with increasing nutrient concentrations. The removal efficiency was mainly affected by the presence of N rather than P in the secondary wastewater effluent. The presence of CIP induced more stress on vetiver grass compared to TTC. Vetiver also removed total organic carbon (48-73%) and chemical oxygen demand (73-82%), but their removal was also affected by the nutrient content in the secondary wastewater effluent.

Pb-Based Perovskite Solar Cells and the Underlying Pollution behind Clean Energy: Dynamic Leaching of Toxic Substances from Discarded Perovskite Solar Cells.

Toxicants like Pb in lead-based perovskite solar cells (PSCs) may become available to humans through leaching and transport through water, air, and soil. Here, we summarize the potential toxicity of different substances in PSCs and determine the leaching concentration of typical heavy metals used in PSCs through dynamic leaching tests (DLTs). Extraction fluids for the standard toxicity characteristic leaching procedure, synthetic precipitation leaching procedure, and deionized water were used as the DLT leaching solutions. Results indicated that the leaching concentration of Pb exceeded the hazardous waste limit of 5 mg/L. In addition, Pb was found to continuously leach out in the leaching cycles of water extraction. The findings confirmed that discarded PSCs may release Pb when subjected to water, rain, and landfill leachate. Total organic carbon and chemical oxygen demand analyses indicated that discarded PSCs could increase the oxygen consumption and may release CO2 into the environment.

High selectivity and effectiveness for removal of tetracycline and its related drug resistance in food wastewater through schwertmannite/graphene oxide catalyzed photo-Fenton-like oxidation

Selectively and effectively for removal of tetracycline (TC) and its related antibiotic resistance gene from food wastewater matrix with high-salt and high COD characteristics is highly desirable. In this work, novel schwertmannite/graphene oxide (SCH/GO) nanocomposites were synthesized through a facile oxidation-coprecipitation method. The SCH/GO nanocomposites were characterized by TEM, XRD, BET, PL, DRS, XPS and FTIR. In the presence of 1 mM H2O2, the SCH/GO catalyzed Fenton-like oxidation can thoroughly degrade TC under visible light irradiation, even under nature sunlight, whose second-order kinetic rate constant was about 15 times higher than that of pure SCH. SCH/GO was capable of highly selectively capturing and effectively degrading TC in the presence of similar concentration of Cl−, NO3-, SO42- and PO43- with that of food wastewater, even at organic matters concentration of 12.5 times than that of TC. At the same time, the removal of total organic carbon (TOC) and chemical oxygen demand (COD) in aforementioned food wastewater in SCH/GO+H2O2+Vis system reached 27.3 % and 34.5 % after 60 min, respectively. The inhibition zone experiments authenticated that the removal of drug resistance of bacteria by TC degradation intermediates can be achieved very well without producing secondary contamination in this system.

A Z-scheme WO3 loaded-hexagonal rod-like ZnO/Zn photocatalytic fuel cell for chemical energy recuperation from food wastewater treatment

An anodic WO3-loaded on hexagonal rod-like ZnO/Zn (WO3/ZnO/Zn) with the Z-scheme structure was first developed, and employed in a sunlight-powered photocatalytic fuel cell (PFC). Incorporation of WO3 can extend the optical response range and boosted electrical conductivity of composite. Both the photoelectric and mineralization performance in degrading sunset yellow (SSY) and phenol as food wastewaters have been systematically tested under sunlight irradiation. The maximum power density (Pmax) of the WO3/ZnO/Zn PFC was 0.1052 μW cm−2 and 0.0574 μW cm−2, which was 1.86 times and 1.85 times that of the pristine ZnO/Zn PFC in degrading SSY and phenol, respectively over 240 min period. The carbon oxygen demand (COD) removal of SSY and phenol using the WO3/ZnO/Zn PFC was 84.6% and 67.5%, respectively. The enhanced Z-scheme WO3/ZnO/Zn PFC could be ascribed to improved electron transfer via the hexagonal rod-like structure and efficient charge separation, and thereby maintained high redox ability for photoelectrochemical activity. Additionally, active species trapping and hydroxyl radical generation assays supported the Z-scheme photocatalytic mechanism. Intermediates identification results showed an obvious decomposition effect towards both organic molecules. The WO3/ZnO/Zn PFC performance had also investigated in treating actual food wastewater, 63.6% COD was removed and generated 0.498 μW cm−2Pmax output.

Comparison of Floating Chamber and Diffusion Model Methods for Measuring Methane Emissions from Inland Fish-Aquaculture Ponds

Freshwater aquaculture ponds collectively cover a large area in southeast China. They are an important anthropogenic source of CH4 emissions, however current knowledge of CH4 emissions from aquaculture ponds is limited. During September 2017 and August 2018, two independent sampling campaigns of CH4 flux measurements over annual cycles were carried out in a fish-aquaculture pond in southeast China using a floating chamber and diffusion model methods for comparison. The purpose of this study is to investigate the variation of CH4 fluxes obtained from the fish-aquaculture pond, analyze the emission mechanisms, and amplify the CH4 emissions inventory. The diffusion model method can further quantify the contribution of diffusion transmission to CH4 emissions. The seasonal variations of CH4 fluxes measured by the two methods were similar, with higher CH4 fluxes appearing in summer and fall and lower CH4 fluxes appearing in spring and winter. CH4 fluxes measured by the floating chamber method and diffusion model method ranged from 0.14-3.13 mg·(m2·h)-1 and 0.04-1.41 mg·(m2·h)-1, respectively, and the respective average values were (0.86±0.30) mg·(m2·h)-1and (0.45±0.08) mg·(m2·h)-1. The CH4 fluxes were positively related to water temperature, dissolved organic carbon (DOC) and chemical oxygen demand (COD), but negatively related to the water dissolved oxygen (DO) concentration in the fish-aquaculture pond. CH4 fluxes calculated by diffusion model methods were 45% lower than those determined by the floating chamber methods over annual cycles. The result suggested that the floating chamber method is more suitable than the diffusion model method for measurements of CH4 fluxes in freshwater aquaculture ecosystems.

The correlation analysis of TOC, CODCr and fluorescence characteristics in MPR

Water samples from different biochemical reaction time in one reactor period in Micro-Pressure Inner-Loop Bioreactor (MPR) were measured respectively with adopt Excitation-emission matrix (EEM) fluorescence spectroscopy, Total organic carbon (TOC) and chemical oxygen demand (CODCr),analyzed the correlation among the fluorescence integrates volume, TOC and CODCr.Results showed that with the increase of biochemical treatment time, sewage fluorescence integrates volume declined significantly, known fluorescence integrates volume, CODCr and TOC value better correlation, by fluorescence spectrometry analyzed fluorescence characteristics of sewage to determine the organic wastewater degradation effect, can be simpler and more rapid the judgment of the sewage treatment effect.

ADVANCED PHOTOCATALYTIC DEGRADATION OF RED WATER FROM TNT MANUFACTURING

ABSTRACT The disposal of waste water (red water) that produced during the production of TNT in an environmental acceptable manner posses serious difficulties. For many years this red water were disposed of by the method open burning but the method is not acceptable today owing to the effect of particulates, nitrogen oxide and other harmful products which pollute the air. Some other methods of incineration are available which overcome part of these difficulties, but they are very costly. Preliminary experiments using the method of adsorption on the locally produced activated carbon have demonstrated that adsorption alone is not enough to fulfill the lowest possible levels of total organic carbon (TOC) and chemical oxygen demand (COD) for red water treatment. In the experimental work the measure of extent of treatment, is the percentage removal at wavelength 200nm, also TOC and COD before and after treatment were measured. Pre-treatment by adsorption demonstrated that, the percentage removal at wavelength 200nm is 76%, 70% TOC and 78% COD. The aim of this work is the usage of advanced oxidation process (AOP) by UV/H2O2 to fulfill the lowest possible levels of TOC and COD. The treated water after manipulation of the proposed technique of advanced oxidation process (AOP) was 95.7% TOC and 97% COD. The preceding results reflect that the used technique is promising and the red water after treatment can be discharged safety.