chemical oxygen demand Articles
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Improving the simultaneous removal of chemical oxygen demand and terephthalic acid in a cross-flow aerobic sludge reactor by using response surface methodology
Central composite design and response surface methodology (RSM) were implemented to optimize the operational parameters for a cross-flow aerobic sludge reactor (CFASR) in remedying mixed printing and dyeing wastewater (MPDW). The individual and interactive effects of three variables, hydraulic retention time (HRT), pH and sludge loading rate (SLR), on chemical oxygen demand (COD) and ...
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Effect of Na2CO3 on the pretreatment of oily sludge using wet air oxidation
In this study, pretreatment of oily sludge, was carried out by Wet Air Oxidation (WAO) process. Experiments were conducted to see the effects of temperature, the initial COD, residence time, concentration of catalyst and OE (O2 excess) on the oxidation of the oily sludge. The results showed that in the WAO 88.4% Chemical Oxygen Demand (COD) was achieved after 9min. COD removal was 92.7% in the ...
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A simplified method for estimating chemical oxygen demand (COD) fractions
A simplified method is presented for estimating chemical oxygen demand (COD) fractions. Its effectiveness was assessed by comparing different values found in literature. This case study considered two main sanitary sewer collection systems in Bogotá, Colombia. The results showed important differences in COD fractions between the sewer collection systems and the reference data. The method ...
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Degradation of wine distillery wastewaters by the combination
ABSTRACTThe degradation of wine distillery wastewaters by aerobic biological treatment has been investigated in a batch reactor. The evolution of the chemical oxygen demand, biomass and total contents of polyphenolic and aromatic compounds was followed through each experiment. According to the Contois model, a kinetic expression for the substrate utilization rate is derived, and its biokinetic ...
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Application of chemical oxygen demand to drinking water
“This study investigated the use of a photoelectrochemical chemical oxygen demand (peCOD) analyzer for the detection of model organic compounds and natural organic matter (NOM) from four drinking water treatment plants in Nova Scotia, Canada. Most model organic compounds showed reasonable correlation between peCOD and theoretical oxygen demand (ThOD), indicating that peCOD was a reasonable ...
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Improved UV/O3 method for measuring the chemical oxygen demand
We improved the ultraviolet (UV)/O3-based method for measuring chemical oxygen demand (COD) in water. An on-line COD monitoring device was developed and the UV/O3 method was used to oxidize sample solutions. A model was established by using support vector machines (SVM) algorithm to estimate dissolved oxygen and CO2 in solutions. Based on the measured data by each sensor during the oxidation ...
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Removing organic matter from sulfate-rich wastewater via sulfidogenic and methanogenic pathways
The simultaneous organic matter removal and sulfate reduction in synthetic sulfate-rich wastewater was evaluated for various chemical oxygen demand (COD)/sulfate ratios applied in a horizontal-flow anaerobic immobilized sludge (HAIS) reactor. At higher COD/sulfate ratios (12.5 and 7.5), the removal of organic matter was stable, likely due to methanogenesis. A combination of sulfate reduction ...
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Research experiences in microwave-assisted chemical oxygen demand determination
The conventional COD determination through reflux method, although still much in experimental practice for water and wastewater analysis, is time consuming, complex and prone to a number of errors. A simpler, more rapid, environmentally benign but still precise method would hence be more attractive and is, in point of fact, a pressing need. Contextualised within the concept of Green Chemistry, ...
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Performance evaluation of an aerobic biofilter with high organics containing synthetic wastewater
The organics removal performance of a lab-scale aerobic biofilter of volume 0.6 L was studied using synthetic wastewater and waste automobile tyre-tube beads as media. The column study was performed under Chemical Oxygen Demand (COD) in the range of 500-1500 mg/L at an empty bed contact time (EBCT) of 2 h. The treatability constant at 27°C was found to be 41.963. A maximum COD removal efficiency ...
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Load limit of a UASB fed septic tank-treated domestic wastewater
Performance of a 250 L pilot-scale up-flow anaerobic sludge blanket (UASB) reactor, operated at ambient temperatures, fed septic tank effluents intermittently, was monitored for hydraulic retention time (HRT) from 18 h to 4 h. The total suspended solids (TSS), total chemical oxygen demand (CODT), dissolved chemical oxygen demand (CODdis) and suspended chemical oxygen demand (CODss) removal ...
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Statistical optimisation for biological decolourisation and COD removal of screen–printing wastewater using Trametes versicolor
The conventional treatment methods employed in decolourisation of industrial wastewater are not effective and lead to generation of hazardous sludge. In the present investigation, a systematic study of three important process variables (concentration of initial colour, glucose and ammonium chloride) influencing the decolourisation and Chemical Oxygen Demand (COD) removal in screen–printing ...
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Effect of Sulfate Reduction on Chemical Oxygen Demand Removal in an Anaerobic Baffled Reactor
Laboratory studies were conducted to investigate the effect of sulfate reduction on chemical oxygen demand (COD) removal in an eight-compartment anaerobic baffled reactor (ABR) at two COD to-sulfate (SO4 2-) ratios (40 [corresponding to 100 mg/L SO4 2-] and 8 [500 mg/L SO4 22]) with an influent COD concentration of 4000 mg/L.The COD was composed of a carbohydrate (sucrose) and protein (peptone) ...
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Phenol degradation kinetic property in coking wastewater with pulse corona
The degradation kinetics of phenol in coking wastewater and the effect of electrode parameters on phenol's removal ratio in pulse corona discharge were investigated with experiments and theoretical analysis. The result showed that Chemical Oxygen Demand (COD) and Biochemical Oxygen Demand after five days (BOD5) in the wastewater increased in the initial step, and decreased later. Conductivity ...
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Synthesis of Nd-doped ZSM-5 and its application to treating slightly polluted water
In this study, ZSM-5 zeolite was synthesized using diatomaceous mud as the raw material, and then doped with different amounts of Nd2O3. The orthogonal experiments were performed to investigate the influence of Nd:Si molar ratio, zeolite dosage, contact time, solution pH and temperature on the removal of humic acid (HA). The removal of HA was comprehensively evaluated by chemical oxygen ...
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Experimental design to optimise colour removal of diazo dye Congo Red using Zero–Valent Iron
Two types of zero–valent iron named Iron Powder (IP) and Iron Wool (IW) were used for colour removal of Congo Red (CR) dye from aqueous solution. Strong acidic condition (pH 2–3) favoured 99% colour removal with 2454–2485 mg/g of dye removal capacity by IP and IW. Decolourization of CR followed first order kinetics. At acidic pH, COD (Chemical Oxygen Demand) removal was 14–15% probably by ...
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Effect of ionizing radiation on antioxidant compounds present in cork wastewater
A preliminary study of the gamma radiation effects on the antioxidant compounds present in cork cooking water was carried out. Radiation studies were performed using radiation between 20 and 50 kGy at 0.4 and 2.4 kGy h−1. The radiation effects on organic matter content were evaluated by chemical oxygen demand. The antioxidant activity was measured by ferric reducing power assay. The ...
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Influence of thermal and alkali pretreatment to solubilisation and biomethane production of garden waste
The objectives of this study were to determine the effect of pretreatment to the garden wastes under thermal and alkali conditions and to evaluate biochemical methane potential. In thermal pretreatment different temperatures and application times were examined and solubilisation improved by heating. Soluble chemical oxygen demand (sCOD) concentration upgraded by increasing temperature with ...
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Impact of the climate conditions on the purification power of Beni Messous natural lagoon
In this study, we will establish the correlations between the climate variables and the outputs of the pollution elimination in the natural lagoon of Beni Messous, using multiple regression method. We have chosen the ascending method 'FORWARD' for the selection of these variables in each regression. After the analysis, it has been noticed that the elimination output of the biochemical oxygen ...
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Environmental impacts with waste disposal practices in a suburban municipality in Sri Lanka
Solid waste disposal is a major threat to environments of developing countries since most of the solid waste generated end up directly in open dumps. This paper presents a case study conducted in a municipality in Sri Lanka. Officials, More than 300 householders of different income groups and landfill operators were interviewed to examine current practices and environmental problems. Groundwater ...
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Electrochemical degradation of methyl parathion
This paper describes the degradation of commercially available methyl parathion by electro oxidation using Ti/RuO2 as anode, stainless steel as cathode and sodium chloride as a supporting electrolyte. Experiments were carried out at constant flow rate and various current densities such as 10, 12 and 15 A/dm² and various concentrations of sodium chloride. At regular time intervals, reduction of ...
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