Oxygen sag equation for secondorder bod decay sciencedirect. Aug 16, 2017 this video covers solved examples to find out the deficit in dissolved oxygen at a location and to calculate the critical deficit and time to critical deficit. Oxygen sag curves occur when the oxygen dissolved in the water is depleted. Zones of pollution pollution and selfpurification of stream and changes in the aquatic. Mihelcic encyclopedia of life support systems eolss summary biochemical oxygen demand bod is a measure of the dissolved oxygen consumed by microorganisms during the oxidation of reduced substances in waters and wastes. Picture 2 1 curve of oxygen sag characteristic is based on. A sag curve when an oxygen demand chemical is discharged into a river it affects the concentration of dissolved oxygen in a manner which varies with distance from the point of discharge. Curve b shows the reaeration process observed when oxygen is forced to dissolve in the water due to the oxygen deficit created by the biodegradation taking place. Do sag curve q1, bod1 ss1 q2, bod2 ss2 residents industry saturation do cs travel time, days dissolved oxygen, mgl oxygen depletion initial deficit d 0 oxygen addition reaertaion critical deficit dc t c. The classical streeterphelps models for dissolved oxygen do sag do not account for a significantly settleable portion about 10% in treated. Pdf to text batch convert multiple files software please purchase personal. The do sag curve and the streeterphelps equation one of the earliest mathematical water quality models was developed by for the ohio river by h. Hence the model is referred to as the streeterphelps model.
It is the purpose of this paper to present a systematic analysis of the. The oxygen sag curve is related to all of the following except select one. Provides an excellent balance between theory and applications in the everevolving field of water and wastewater treatment completely updated and expanded, this is the most current and comprehensive textbook available for the areas of water and wastewater treatment, covering the broad spectrum of technologies used in practice todayranging from commonly used standards to the latest state of the. Expert answer 100% 1 rating previous question next question transcribed image text from this question. The p50 is the po2 at which hemoglobin is 50% saturated. Please note the dotted line at the bottom of the graph.
A read is counted each time someone views a publication summary such as the title, abstract, and list of authors, clicks on a figure, or views or downloads the fulltext. Curve b is the expected dry flow do profile after implementation of pollution control measures ahmed and mohammed, 1988. Jan, 2015 the resultant curve so obtained is called the oxygen sag curve or oxygen deficit curve. Oxygen depletion michigan technological university. View notes lecture 47 from cee 260 at university of michigan. Unesco eolss sample chapters environmental and ecological chemistry vol.
Obviously, the place of greatest environmental concern is the do minimum. This differential equation states that the total change in oxygen deficit d is equal to the difference between the two rates of deoxygenation and. Oxygen is not delivered to the tissues efficiently as the oxyhaemoglobin dissociation curve of stored blood is shifted far to the left. Dissolved oxygen sag analysis for a settling fields. Environmental engineering ii unit i linkedin slideshare. Standards for disposal methods dilution mass balance principle self purification of river oxygen sag curve deoxygenation and reaeration streeterphelps model land disposal. The resulting sag curve is able to be modeled to predict the minimum oxygen concentration 5. Model relates the rate of change of the oxygen deficit with distance to the spatial rates of oxygen. Standards for disposal methods dilution mass balance principle self purification of river oxygen sag curve deoxygenation and reaeration streeterphelps model land disposal sewage farming sodium hazards soil dispersion system.
The net result of the oxygen demand and replenishment processes is illustrated by curve c, which is called the dissolved oxygen sag curve. Oxygen demand concepts and dissolved oxygen sag in. Request pdf the development of simple dissolved oxygen sag. The streeterphelps equation determines the relation between the dissolved oxygen concentration and the biological oxygen demand over time and is a solution to the linear first order differential equation. The oxygen sag curve is related to all of the foll. Biochemical oxygen demand encyclopedia of life support. Elevated p50 values indicate a right shift of the curve. Jan 02, 2017 oxygen sag curve, zones of purification, sewage farming, sewage sickness. While the saturated value dos is rarely achieved, a stream can nonetheless be considered healthy as long as its dissolved oxygen do exceeds 5 mgl. Oxygen sag curve, zones of purification, sewage farming, sewage sickness.
Later, as the organic matter becomes used up, the oxygen resources of the river are replenished. The solubility of oxygen in fresh water, at a pressure of 1 atmosphere, decreases with temperature as shown in figure 5. If the streeterphelps equation is differentiated with respect to time, and set equal to zero, the time at which the minimum do occurs is expressed by. Unit v sludge treatment and disposal 9 en8592 wastewater engineering. Usgs scientist is measuring various waterquality conditions in holes creek at huffman park in kettering, ohio. This video covers solved examples to find out the deficit in dissolved oxygen at a location and to calculate the critical deficit and time to critical deficit.
Oxygen demand concepts and dissolved oxygen sag in streams. Ce6605 notes environmental engineering 2 regulation 20. Oxygen sag or the oxygen sag curve refers to the reduction in dissolved oxygen plotted over a distance along a water body from a point at which sewage or other pollutants have been discharged. Theory and practice of water and wastewater treatment, 2nd. The self purification process of water bodies or processes involving biological, chemical and physical. Do sag curve q1, bod1 ss1 q2, bod2 ss2 residents industry saturation do cs travel time, days dissolved oxygen, mgl oxygen depletion initial deficit d 0.
The oxygen dissociation curve plots the % saturation against the partial pressure of oxygen, and its contribution to the total oxygen content. Multiple point source curve a is the present predicted dry flow profile with observed river sampling results. The oxygen sag or oxygen deficit in the stream at any. Self purification of river water prof umesh t kulkarni 2.
Also has students label indicator species found in each zone. Quick assessment for students to make sure they understand the difference between do and bod and the different zones of pollution. En8592 syllabus wastewater engineering regulation 2017. Jan 10, 2018 for the love of physics walter lewin may 16, 2011 duration. Discover how using computerbased mathematical models of the environment can assist in solving engineering problems. Derive a simple mathematical model the incorporates the factors that influence the oxygen resources of a stream. The amount of dissolved oxygen in a stream or lake can tell us a lot about its water quality. Tutorial on heat and oxygen transport an oxygendepleting material i. Qual2e rnodellng can be downloaded in the internet on webslte. Oxygen sag curve land disposal sewage farming deep well injection soil dispersion system sludge characterization thickening sludge digestion biogas recovery sludge conditioning and dewatering disposal advances in sludge treatment and disposal text books. For the love of physics walter lewin may 16, 2011 duration.
Phelps model was developed to predict the dissolved oxygen concentration do in water located down. Steady state and dynamic models employed are basically developed by matlab using two mathematical functions of ode45 and pdepe. Mathematical models of dissolved oxygen concentration in. Dissolved oxygen do is a measure of how much oxygen is dissolved in the water the amount of oxygen available to living aquatic organisms. Dissolved oxygen sag analysis for a settling fields overlapping type. Mihelcic encyclopedia of life support systems eolss summary biochemical oxygen demand bod is a measure of the dissolved oxygen consumed by.
Oxygen sag curve solved examples waste water engineering. The oxygen concentration in the river drops rapidly following the discharge of a waste containing organic matter. When the actual amount of oxygen in the water is less than the saturation value given in the figure, atmospheric oxygen passes into the water at a rate which is proportional to the deficit. Physiology of haemoglobin bja education oxford academic. The amount of do in water is one of the most commonly used indicators of. Dissolved oxygen sag use the previous estimates of the oxygen transfer coefficient, endogenous respiration rate, and fraction of bod exerted note that a different amount of bod was added for the sag curve than for the bod measurement. Biochemical oxygen demand and the dissolved oxygen sag curve in a stream. The oxygen sag curve is related to all of the following except.
The presence of sewage reduces the oxygen content of the water and increases the. Standards for disposal methods dilution self purification of surface water bodies oxygen sag curve land disposal sludge characterization thickening sludge digestion. Rate constants for a secondorder bod equation may be evaluated by graphical or numerical methods. The derivation of the do sag equation is the objective of this article. The variation of the concentration of dissolved oxygen is shown in the following graph, commonly referred to as a sag curve. Point source pollution external organic matter u z o. Sag curves occur downstream of sewage works and the like so the answer is b. The phenomenon of oxygen sag is usually related to the release of organic pollutants or nutrient elements, which promote the growth of oxygen consuming. Introduction it is a natural process of rivers, lakes or canals to recover the rate of dissolved oxygen values of the highest concentration of oxygen which is one of the best indicators of water quality. This is caused by the addition of anything which increases the biological oxygen demand such as biological waste and sewage.
Pdf study of dissolved oxygen do profile in nalanda lake, sri. In rivers, oxygen depletion takes a special form called the dissolved oxygen sag curve. In the storage solution, sagm saline, adenine, glucose, and mannitol, 2,3dpg levels are very low after 14 days. Oxygen sag curve benoit cushmanroisin by far the most important characteristic determining the quality of a river or stream is its dissolved oxygen, do measured in mgl. The resultant curve so obtained is called the oxygen sag curve or oxygen deficit curve. Samples of water are taken at areas upstream and downstream from the sewage outlet. The p50 reflects the affinity of hemoglobin for oxygen. Elevated p50 values indicate that hemoglobin will surrender oxygen to the tissues more easily. This is an s shaped curve due to the alterations in hemoglobins affinity for oxygen in response to other physiologic factors. Biochemical oxygen demand and the dissolved oxygen sag curve. Download link is provided and students can download the anna university ce6605 environmental engineering ii ee ii syllabus question bank lecture notes syllabus part a 2 marks with answers part b 16 marks question bank with answer, all the materials are listed below for the students to make use of it and score good maximum marks with our study materials. The self purification process of water bodies or processes involving biological, chemical and physical processes. This is called the oxygen sag curve or the streeterphelps oxygen sag curve. From the curve, the oxygen deficit d and oxygenation balance 100d% in a stream after a certain lapse of time can be found out.
The phenomenon of oxygen sag is usually related to the release of organic pollutants or nutrient elements, which promote the growth of oxygenconsuming. Biochemical oxygen demand and the dissolved oxygen sag. Four quick analysis questions follow the labelingdrawing. The general mathematical properties of point of pollution initial or reference point. Environmental engineering 2 notes free pdf download. Oxygen sag oxygen sag model one of the earliest mathematical water quality models was developed by for the o hio river b y h. Oxygen sag curves the curve obtained when the concentration of dissolved oxygen in a river into which sewage or some other pollutant has been discharged is. Wastewater engineering syllabus en8592 pdf free download. Lecture 4 ce 433 excerpts from lecture notes of professor m. Ee pdf notes unit 5 civil branch downloads smartworld. Dissolved oxygen sag curve readings for this class. To study and evaluate the important constants related to the oxygen sag curve of a river or streeter phelps equation. So, whenever possible, download links to functioning matlab codes were.
On the do sag curve a minimum concentration occurs at some point, along a stream. Ce6605 notes environmental engineering 2 regulation 20 anna university free download. Derivation streeterphelps equation professor john r. The classical streeterphelps models for dissolved oxygen do sag do not account for a significantly settleable portion about 10% in treated to about 60% in the untreated wastewater discharged of the total biochemical oxygen demand bod inputs into rivers through wastewater outfalls, and therefore, they can not be used to predict the do sag to any accuracy and rationality. This paper was aimed to provide more detail explanation focusing on the development of simple dissolved oxygen do sag curve in a lowland nontidal river under steady flow condition. The minimum lies where ddodx 0, which is found to be at. Dissolved oxygen, the acquisition of raw wastewater effluent sample for bod. The do sag equation incorporates exponential integral functions. Pdf ce6605 environmental engineering ii eeii books. Scribd is the worlds largest social reading and publishing site.
These two concurrent processes of oxygen consumption and oxygen replenishment produce an oxygen sag curve, i. Oxygen sag curve fillintheblank worksheet by effler. Fundamentals of wastewater treatment and engineering. Pdf on apr 1, 2016, madhubhashini makehelwala and others published.