Biochemical oxygen demand BOD

The biochemical oxygen demand (BODp) is the mass of dissolved molecular oxygen which is needed by microorganisms for the oxidation (and also conversion) of organic substances in a sample (20 C) of water under defined conditions and within a defined period of time (index n in days or hours). 

The biochemical oxygen demand, which is quoted in mg/1 water and is often designated as the oxygen consumption within the period of investigation, serves as a unit for evaluating the influence of organic contamination on the level of oxygen in a particular water. It has to be remembered that the 

However, only the oxygen consumption of the first stage of breaking down is desired for the BOD, and here nitrification is regarded as a disturbing effect. It will be clear from the above that the BOD in a defined, narrow 

The magnitude of the BOD is influenced by many factors nature and concentration of the organic substances in the water to be broken down, nature, 

An incubation time of 3 days (BOD5) has proved to be useful. Since the time bacterial processes require to start up varies, a shortening of this period could lead to incorrect values or ones having a low level of reproducibility. On the other hand, the reproducibility is also impaired if the period for the BOD analysis is too long, as the bacterial flora which bring about the 

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The amount of oxygen used in the degradation process is called the biochemical oxygen demand (BOD). A standard test has been devised to measure BOD in which the oxygen utilized by microorganisms in contact with the wastewater over a 5-day period at 20°C is measured. 

Several methods have been developed to estimate the oxygen demand in waste water treatment systems. Commonly used laboratory methods are biochemical oxygen demand (BOD), chemical oxygen demand (COD), total oxygen demand (TOD), total organic carbon (TOC), and theoretical oxygen demand (ThOD). 

Biochemical Oxygen Demand. The biochemical oxygen demand (BOD) test is an empirical determination of the oxygen requirement of a sample. It is most often appHed to wastewaters, industrial effluents, and poHuted waters. The decrease in the dissolved oxygen concentration resulting primarily from biological action is measured after storage for 5 d at 20°C. 

Petrochemical units generate waste waters from process operations such as vapor condensation, from cooling tower blowdown, and from stormwater runoff. Process waste waters are generated at a rate of about 15 cubic meters per hour (m /hr), based on 500,000 tpy ethylene production, and may contain biochemical oxygen demand (BOD) levels of 100 mg/1, as well as chemical oxygen demand (COD) of 1,500 to 6,000 mg/1, suspended solids of 100 to 400 mg/1, and oil and grease of 30 to 600 mg/1. Phenol levels of up to 200 mg/1 and benzene levels of up to 100 mg/1 may also be present. 

Nutrients can be classified into three groups based on levels required in waste treatment systems. These are given in Table 9. The major nutrients can be identified from the generalized biomass formula (Ceo Hg2 O23 Ni2 P). The actual quantity needed depends on the biochemical oxygen demand (BOD) of the waste. The higher the BOD the greater the quantity of cells produced. The minor and trace nutrients are needed in small quantities and are given in terms of concentration because these are the levels needed in solution to force the small amount required inside the cell across the cell-wall membrane. 

The objective disinfection biochemical oxygen demand (BOD) or chemical... 

Biochemical oxygen demand (BOD)- Amount of dissolved oxygen consumed in five days by biological processes breaking down organic matter. 

Biochemical oxygen demand (BOD) The molecular oxygen used in meeting the metabolic needs of aerobic organisms in aqueous medium containing an oxidizable organic molecule. 

The organics contaminants, whose concentration is usually expressed in terms of biochemical oxygen demand (BOD), are utilized as food for the bacteria. Besides oxygen, nutrients (nitrogen and phosphorus) are also needed by the bacteria for its metabolism. The concentrations of oxygen, bacteria, organic contaminants, and nutrients, as well as other factors, have an affect on the biological treatment rate. 

The pulp and paper industry is the largest industrial process water user in the U.S.5 In 2000, a typical pulp and paper mill used between 15,140 and 45,420 L (4000 to 12,000 gal) of water per ton of pulp produced. 1 2 3 4 General water pollution concerns for pulp and paper mills are effluent solids, biochemical oxygen demand (BOD), and color. Toxicity concerns historically occurred from the potential presence of chlorinated organic compounds such as dioxins, furans, and others (collectively referred to as adsorbable organic halides, or AOX) in wastewaters after the chlorination/ extraction sequence. With the substitution of chlorine dioxide for chlorine, discharges of the chlorinated compounds have decreased dramatically. 

This treatment process employs the use of physical operations such as screening and sedimentation to partially remove suspended solids and organic matter from the wastewater. This process provides the secondary treatment with wastewater that is partially free of solids, in order to facilitate further treatment. The effluent from the primary treatment contains primarily organic matter and is characterized by a relatively high biochemical oxygen demand (BOD).2... 

A strain of yeast and a strain of bacterium were co-immobilized to fabricate a biochemical oxygen demand (BOD) sensor based on sol-gel derived composite materials97. This novel type of biosensor was developed for water monitoring and was used to determine the BOD values of OECD synthetic wastewater, domestic wastewater, and lake waters. The microorganisms Trichosporon cutaneum and Bacillus subtilis were coimmobilized in the sol-gel composite material, which was composed of silica and the grafting copolymer of poly (vinyl alcohol) and 4-vinylpyridine (PVA-g-P(4-VP)). 

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