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Topic: Chemical oxygen demand

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	RedOrbit - Science - Enhancement of Chemical-Oxygen Demand and Color Removal of Distillery Spent-Wash By Ozonation
		Oxygen gas, containing 1 to 2% ozone, was introduced to the reactor from the bottom through a porous ceramic plate, such that the small bubbles are released into the water column to facilitate mass transfer.
		During ozonation, average COD of the samples declined from 2200 to 1550 mg/L, and the average TOC declined from 770 to 500 mg/L. The third type of ozonation was performed in two batches for preparation of substrate for reactor C. one-consumption data for the first batch is shown in Figure 7.
		During ozonation, average COD of the sample declined from 19 000 to 17 000 mg/L, and the average TOC declined from 6500 to 5500 mg/L. Comparison of Figures 6 and 7 indicates that ozonation in the second case is more efficient, as less gaseous ozone is escaping from the reactor.
	www.redorbit.com /news/science/530253/enhancement_of_chemicaloxygen_demand_and_color_removal_of_distillery_spentwash/?source=r_science (7092 words)

	Chemical oxygen demand - Wikipedia, the free encyclopedia
		In environmental chemistry, the chemical oxygen demand (COD) test is commonly used to indirectly measure the amount of organic compounds in water.
		Because COD measures the oxygen demand of organic compounds in a sample of water, it is important that no outside organic material be accidentally added to the sample to be measured.
		The oxygen demand in the blank sample is subtracted from the COD for the original sample to ensure a true measurement of organic matter.
	en.wikipedia.org /wiki/Chemical_oxygen_demand (999 words)

	Nuts and Bolts of Chemical Oxygen Demand
		Biochemical Oxygen Demand (BOD) is a definitive indicator of required treatment in wastewater, and estimating BOD is an important part of wastewater treatment process control.
		Oxygen demand is an important parameter for determining the amount of organic pollution in water.
		COD testing assesses all chemically oxidizable substances and can be directly related to the true oxygen demand imposed by the effluent if released into the environment.
	www.o3water.com /Articles/TechnicalPapers/Nuts&Bolts_COD.htm (914 words)

	COD (Chemical Oxygen Demand)
		Chemical Oxygen Demand is a vital test for assessing the quality of effluents and waste waters prior to discharge.
		The Chemical Oxygen Demand (COD) test predicts the oxygen requirement of the effluent and is used for monitoring and control of discharges, and for assessing treatment plant performance.
		The impact of an effluent on the receiving water is predicted by its oxygen demand.
	www.aquaticlife.ca /Parameters/COD.asp (118 words)

	GTOS :: TEMS database
		COD is an important, rapidly measured variable for the approximate determination of the organic matter content of water samples.
		In these cases, because of incomplete oxidation under the given test methods, COD values may be a poor measure of the theoretical oxygen demand.
		COD is on the list of variables recommended for measurement by GEMS, but its measurement is not implemented at all stations.
	www.fao.org /gtos/tems/variable_show.jsp?VARIABLE_ID=123 (339 words)

	GlaxoSmithKline: Environment, Health and Safety - Wastewater
		COD is therefore an indirect measure of the foulness of wastewater.
		In 2003, the COD of wastewater was 23.6 million kilograms, a decrease of 0.8 % from 2002 and a decrease of 12.3% from the 2001 baseline.
		Nearly 66.9% of wastewater COD was in the wastewater released direct to sea and to estuary and 3.8% was in the recycled or reused wastewater.
	www.gsk.com /financial/reps03/EHS03/GSKehs-56.htm (620 words)

	Wastewater treatment in the fishery industry - 2. Wastewater characterization
		The biochemical oxygen demand, also known as BOD, estimates the degree of contamination by measuring the oxygen required for the oxidation of organic matter by the aerobic metabolism of the microbial flora.
		In fisheries wastewaters, this oxygen demand originates mainly from two sources: the carbonaceous compounds which are used as substrate by the aerobic micro-organisms, and the nitrogen-containing compounds which are normally present in fisheries wastewaters, such as proteins, peptides and volatile amines.
		The COD is calculated by titrating the excess of dichromate or by spectrophotometrically measuring the Cr ion at 606 nm.
	www.fao.org /docrep/003/V9922E/V9922E03.htm (3551 words)

	From biological communities to chemical properties of river water (Site not responding. Last check: 2007-10-10)
		Physical and chemical properties give a specific picture of river water quality at a particular point in time, while the biota (living organisms) act as continuous monitors and give a more general picture of water quality over a period of time.
		The problem of inferring the chemical properties from the biota is practically relevant, especially in countries where extensive biological monitoring is conducted.
		Chemical samples contain the measured values of 16 physical an chemical parameters: biological oxygen demand (BOD), chlorine concentration (Cl), CO2 concentration, electrical conductivity, chemical oxygen demand COD (K2Cr2O7 and KMnO4), concentrations of ammonia (NH4), NO2, NO3 and dissolved oxygen (O2), alkalinity (pH), PO4, oxygen saturation, SiO2, water temperature, and total hardness.
	www-ai.ijs.si /~ilpnet2/apps/pcfromb.html (379 words)

	REDUCTION OF CHEMICAL OXYGEN DEMAND FROM TANNERY WASTEWATER BY OXIDATION (Site not responding. Last check: 2007-10-10)
		For all three oxidants complete COD reduction of the wastewater sample could not be achieved despite different experimental conditions (temperatures and oxidation duration).
		COD of this sample was 3413mg/L. The sample was then independently treated with the three oxidants.
		Other reasons for not achieving 100% COD reduction could be the presence of some other metals (in low concentrations) in the sample; added oxidants might have also been consumed in their oxidation.
	ejeafche.uvigo.es /3(1)2004/003312004F.htm (1318 words)

	Chemical Oxygen Demand (Site not responding. Last check: 2007-10-10)
		HI 83099 along with Hanna’s HI 839800 reactor and pre-dosed reagents are all you need to perform simple COD analysis in just a few short hours.
		The COD measurement procedure is based on the well-established Closed Reflux Colorimetric Method over 3 ranges: 0 to 150 mg/L, 0 to 1,500 mg/L and 0 to 15,000 mg/L.
		Hanna’s pre-dosed reagents reduce waste by minimizing the amount of necessary chemicals to properly test COD levels.
	www.hannainst.com /products/prodline/cod.cfm (175 words)

	THERMOREACTOR, VELP, COD, Chemical Oxygen Demand
		Chemical Oxygen Demand means the amount of oxygen from chemical oxidants required for the complete oxidation of substances dissolved or suspended in water.
		By COD determination it is possible to quantitatively evaluate substances which can be oxidized by strong oxidants like potassium dichromate in highly acidic solutions by concentrated sulphuric acid.
		Chemical oxidation is more complete than biological oxidation and therefore COD values for a given sample are generally higher than BOD values.
	www.rhysinternational.co.uk /Medical-Scientific-Equipment/COD/eco25.htm (286 words)

	Chemical Oxygen Demand
		Chemical Oxygen Demand : A measure of the oxygen required to oxidize all compounds, both organic and inorganic, in water.
		Effect of spent cotton stalks on color removal and chemical oxygen...
		...of organic matter in water is measured as biochemical or chemical oxygen demand.
	www.mongabay.com /reference/environment/Chemical_Oxygen_Demand.html (212 words)

	Chemical Oxygen Demand Test Kit (Matriks Chemistry, Turkey)
		Chemical oxygen demand is a means of measuring the pollutional strength of wastewater.
		Cod measurements are preferred when a mixed domestic-industrial waste is entering a plant or where a rapid determination of the output is desired.
		Chemical oxygen demand test kits (reagents) are used in water and wastewater laboratories.
	www.alibaba.com /manufacturer/13017546/Sell_Chemical_Oxygen_Demand_Test_Kit.html (272 words)

	Wastewater Chemical Treatment Processes Compared to Wastewater Evaporation
		Treatment of industrial wastewater using traditional chemical treatment and physical separation (chem/phys treatment) became popular as a method for gross contaminant removal in the 1950's.
		For oily water applications, the procedure often referred to as chemical splitting, involves lowering the pH of the wastewater with acidic chemistry (H2SO4, HCl) to a range of 3-4, which causes the oil to separate from the water.
		chemical handling, chemical inventory, adherence to procedure, sludge generation, ongoing analysis for compliance), flocculation and precipitation can require numerous additional processes and capital equipment, including clarifiers for sludge thickening, sludge pumps, and filter presses.
	www.evaporator.com /comp_chemical_treatment.html (445 words)

	The Cause(s) of Continued Hypolimnetic Anoxia in Long Lake, Washington, Following Advances Wastewater Treatment by the ... (Site not responding. Last check: 2007-10-10)
		Biochemical oxygen demand, chemical oxyen demand, and sediment oxygen demand were determined.
		Sediment oxygen demand was measured under stationary and dynamic conditions with a Gilson Differential Respirometer.
		The phytoplankton standing crop in Long Lake does affect oxygen demand both within the water column and at the sediment-water interface, and is a primary factor in the seasonal decline of dissolved oxygen levels in Long Lake.
	www.ecy.wa.gov /biblio/8231.html (423 words)

	THE CHEMICAL OXYGEN DEMAND TEST (Site not responding. Last check: 2007-10-10)
		This is the final report on the investigations into the chemical oxygen demand (COD) method, which were made during the period October 1977 October 1980.
		The COD of the sample is defined in terms of the "oxygen equivalent" of the oxidizing agent reduced and is expressed in mg/l.
		Mercury(II) sulphate is added to the COD test mixture to suppress the oxidation of chloride ions; however, some chloride is still oxidized, causing an apparent increase in COD.
	www.fwr.org /waterq/dwi0060.htm (354 words)

	Laboratory Results - Canada
		As each vessel contains a known quantity of product to be degraded (chemical oxygen demand (COD)), the correlation between the oxygen uptake (biochemical oxygen demand (BOD)) and the COD indicates the percentage of biodegradation of the product by the microorganisms.
		Finally, a mineral solution called “blank” is tested to mesure the oxygen uptake generated by the organic matter contribution of the microbial inoculum itself.
		The toxicity was realized to determine if the products were toxic to the bacteria at the COD concentration selected for the biodegradation test (5 and 10 mg/l).
	www.biospherecorp.com /labca.htm (705 words)

	WK4100- Standard Test Methods for Chemical Oxygen Demand (Dichromate Oxygen Demand) of Water
		The treated samples are analyzed by ASTM D 1252-00 Standard Test Methods for Chemical Oxygen Demand (Dichromate Oxygen Demand) of Water as described in Test Method B, Micro COD Procedure.
		Due to the silver contained in the cation exchange resin filters, samples need to be neutralized prior to filtration to prevent leaching, which may interfere with the analysis.
		The COD digestion vial can be placed in a small Erlenmeyer flask on an analytical balance.
	www.astm.org /DATABASE.CART/WORKITEMS/WK4100.htm (510 words)

	Biochemical Oxygen Demand and Sewer Ponds - 1997-98
		The chemical characteristic of wastewater is present in fours parts: 1) organic matter; 2) the measurement of organic materials; 3) inorganic matter; and 4) gases.
		The reasons scientists use BOD results are: 1) how to determine the approximate quantity of oxygen present, 2) to determine the size of the waste treatment facilities, 3) to measure the efficiency of some treatment processes, and the last reason 4) to determine compliance with the wastewater discharge permits.
		There have been set limitations for the standards of DO on the aquatic life and fish, the minimum level of DO for a diverse population of fish is 5 mg/l, the standard for freshwater aquatic life is 5.0 mg/l.
	www.cascadehs.csd.k12.id.us /advbio/97-98/biochemical.html (1982 words)

	Chemical Oxygen Demand COD Reactors
		For further chemical analysis, the reactors are also provided with one (AL 32) or two (AL 34) further openings, with a diameter of 22 mm.
		The temperature setting of 148 °C (with 100 °C as an alternative) and programming of the reaction time are both carried out by means of a membrane keyboard on the front of the unit.
		This basic principles for COD determinations as a standard laboratory method are set out in regulatory documents such as DIN 38 409 or APHA 508, etc.
	www.metexcorporation.com /Aqualytic/cod_reactor.htm (277 words)

	Biochemical Oxygen Demand (Site not responding. Last check: 2007-10-10)
		Biochemical Oxygen Demand is a common, environmental procedure for determining the extent to which oxygen within a sample can support microbial life.
		To gain a broader appreciation of oxygen demand, additional avenues of interest may be explored including CBOD (carbonaceous oxygen demand), COD (chemical oxygen demand), and TOC (total organic carbon).
		The test for Biochemical Oxygen Demand is especially important in waste water treatment, food manufacturing, and filtration facilities where the concentration of oxygen is crucial to the overall process and end products.
	www.rpi.edu /dept/chem-eng/Biotech-Environ/Environmental/BOD/coda.htm (451 words)

	Biochemical oxygen demand - Wikipedia, the free encyclopedia
		BOD measures the rate of uptake of oxygen by micro-organisms in the sample of water at a fixed temperature (20°C) and over a given period of time(usually 5 days) in the dark.
		The BOD test is carried out by diluting the sample with de-ionised water saturated with oxygen, inoculating it with a fixed aliquot of seed, measuring the dissolved oxygen and sealing the sample (to prevent further oxygen dissolving in).
		The sample is kept at 20 °C in the dark (to prevent photosynthesis and thereby the addition of oxygen) for five days and the dissolved oxygen is measured again.
	en.wikipedia.org /wiki/Biochemical_oxygen_demand (833 words)

	Scharlau Chemie - C.O.D.
		measures the oxygen equivalent consumed by organic matter in a sample during strong chemical oxidation.
		The strong chemical oxidation conditions are provided by the reagents used in the analysis.
		Several methods have been described to calculate C.O.D. but the most broadly used and officially recognized (ISO 6060, NFT 90101, UNE 77004) for water analysis, is the one using potassium dichromate as oxidizing substance.
	www.scharlau.com /english/labor_chemicals/5.htm (256 words)

	PALINTEST - Change in testing chemical oxygen demand
		PALINTEST has extended its range of Tubetest reagents for chemical oxygen demand (COD) with a new product, which provides interference suppression for even very high levels of chloride.
		The test predicts the oxygen requirement of effluent and is used for the monitoring and control of discharges, and for assessing treatment plant performance.
		Until now the Palintest COD range dealt with levels of chloride up to approximately 2000mg/L. Increasingly, samples containing higher levels of chloride are being encountered which require extra suppression capability.
	www.ferret.com.au /articles/E2/0C0111E2.asp (305 words)

	Chemical Oxygen Demand (Site not responding. Last check: 2007-10-10)
		Chemical Oxygen Demand refers to the amount of oxygen required to oxidize the organic compounds in a water sample to carbon dioxide and water.
		This test is used often by wastewater treatment plants to help characterize the plant's influent.The test involves using strong chemical reagents to oxidize the organics.
		For the differnet oxidizing reagents that are available, a stoichiometric equation is used that will relate the amount of oxygen needed to oxidize the organics to the amount of a chemical product formed.
	www.rpi.edu /dept/chem-eng/Biotech-Environ/Biocontrol/cod.html (113 words)

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