Chemical oxygen demand determination

Wagner and Ruck [190] carried out experiments to test the reliability of two standard procedures (DIN 38409 Parts 41/2 and 42) for the removal of chloride ions prior to chemical oxygen demand determinations on chloride-... 

Oxidation of organic matter for chemical oxygen demand determination... 

M.L. Balconi, M. Borgarello, R. Ferraroli, F. Realini, Chemical oxygen demand determination in well and river waters by flow-injection analysis using a microwave oven during the oxidation step, Anal. Chim. Acta 261 (1992) 295. 

J. Chen, J. Zhang, Y. Xian, X. Ying, M. Liua, L. Jin, Preparation and application of Ti02 photocatalytic sensor for chemical oxygen demand determination in water research . Water Research, 39,1340-1346, (2005). 

A. Canals, A. Cuesta, L. Gras, and M.R. Hernandez. New ultrasound assisted chemical oxygen demand determination. Ultrason. Sonochem., 9 143-149, 2002. 

Discussion. One very important application of potassium dichromate is in a back-titration for the environmental determination16 of the amount of oxygen required to oxidise all the organic material in a sample of impure water, such as sewage effluent. This is known as the chemical oxygen demand (C.O.D.) and is expressed in terms of milligrams of oxygen required per litre of water, mg L l. The analysis of the impure water sample is carried out in parallel with a blank determination on pure, double-distilled water. 

The size of most biological reactors is determined by pollution load, for example, kg BOD (biochemical oxygen demand) or COD (chemical oxygen demand) per kg MLVSS (mixed liquor volatile suspended solids) per day in the case of suspended growth type systems, and kg BOD or COD per m3 of media or reactor volume in the case of fixed-film type systems. 

The chemical method for the determination of the chemical oxygen demand of non-saline waters involves oxidation of the organic matter with an excess of standard acidic potassium dichromate in the presence of silver sulfate catalyst followed by estimation of unused dichromate by titration with ferrous ammonium sulfate. Unfortunately, in this method, the high concentrations of sodium chloride present in sea water react with potassium dichromate producing chlorine ... 

In this study most laboratories employed the chemical oxygen demand procedure for determining organic carbon employing a conversion factor of 0.375 to convert chemical oxygen demand to carbon content. 

The determination of the chemical oxygen demand of sediments has been discussed [22, 54], Markert et al. [174] have described equipment for the collection of sediment and determination of sediment oxygen demand by means of a flow-through diffuser. 

Marty and Aim [177] described an automatic determination of the total oxygen demand of waste water. The method gives rapid results and correlates well with chemical oxygen demand and biochemical oxygen demand. Measurements of corrections are made for nitrogen compounds which are the principal interferents. 

A measure of the total organic material present in slurries can be obtained by determining chemical oxygen demand (COD) or biological oxygen demand (BOD) (3) and the latter measure is used by Water Authorities in relation to the pollution of water courses where oxygen tension in the water is a prime concern. In studies to evaluate aerobic digestion as a means of odour reduction, the dissolved volatile fatty acids are a useful measure of the potential odour nuisance (2). 

A powdered activated carbon fed activated sludge process is designed to treat 15,000 GPD of pharmaceutical wastewater. The SCOD (soluble chemical oxygen demand) of the treated effluent is 590 mg/L. Determine the dose of PAC (powdered activated carbon) required for further reduction of effluent SCOD from 590 mg/L to 200 mg/L. Use the Freundlich equation [48] XjM = (3.7 x 10 ) to determine the dose of powdered activated carbon. 

Potassium hydrogen phthalate has many uses in analytical chemistry. It is a primary standard for standardization of bases in aqueous solutions. Its equivalent weight is 204.2. It also is a primary standard for acids in anhydrous acetic acid. Other applications are as a buffer in pH determinations and as a reference standard for chemical oxygen demand (COD). The theoretical COD of a Img/L potassium hydrogen phthalate is 1.176mg O2. 

Silver sulfate is used as a catalyst to oxidize long chain aliphatic hydrocarbons in the determination of chemical oxygen demand (COD). 

Ozonolysis can be applied for assessing the pollution level of potable and wastewaters, by determining the ozone demand in an apparatus including an ozone generator and UVD for measuring the amount of O3 supplied. A correlation can be established between the ozone demand and the chemical oxygen demand, which is a standard method for pollution evaluation. The advantage of the ozonolysis route is its speed (a few minutes for sample... 

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