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Reaction Rates of Photosynthesis MAN M. VARMA, Director Sanitary Engineering Design and Research Green Engineering Affiliates Somerville, Massachusetts RICHARD S. TALBOT, Sanitary Engineer Hercules Powder Company Parlin, New Jersey INTRODUCTION Stabilization ponds, also called bio-oxidation or sewage lagoons, have provided an excellent method for the treatment of wastewater. The main source of oxygen in a stabilization pond is provided as an end-product of photosynthetic activities of the algae. A much smaller amount, up to about 40 lbs of oxygen per acre per day is provided by absorption at the air-water interface, aided by wind action. Carbon dioxide, inorganic salts, water and energy of the sun are used by algae to produce protoplasm, with oxygen and water released into the surrounding medium. Oxygen is used by heterotrophic micro-organisms as an ultimate hydrogen ion acceptor as they obtain energy through oxidation of organic matter into stable end products. With no photosynthesis occurring at night, stabilization ponds and natural bodies of water tend to become depleted of oxygen during the night by the biochemical oxygen demand of bacteria and other heterotrophic microorganisms, and also by the algae themselves, as they consume oxygen in the absence of sunlight. Septic conditions in the ponds therefore sometimes result. This problem may be alleviated somewhat by the installation of artificial lights to effect photosynthesis and oxygen production through the night hrs. Continuous illumination may be detrimental to oxygen production (1). An alternation of light and dark periods is beneficial for algal metabolism and a balance in the illumination may be required which, in a pond, can be achieved by automatic control. The rate of photosynthesis is affected by (a) intensity of light, (b) pH, (c) temperature, (d) age of the culture. The rate of photosynthesis is proportional to the light intensity up to a certain intensity beyond which the rate of photosynthesis is no longer proportional to the increase in the light intensity. It has been found that the highest photosynthetic rate in direct sunlight is normally about eight ins. below the pond surface for this reason. The determination of the effect of light intensity on the rate of photosynthesis would be an important design or criterion for stabilization ponds. To obtain a high rate of photosynthesis, the pH of stabilization ponds in certain cases may have to be adjusted tor the treatment of wastes. A variation on either side of the optimum pH would change the rate of oxygen production by algae. Stabilization ponds and natural bodies of water can show a diurnal variation in pH that may inhibit or kill the micro-organisms that stabilize organic materials. Biological systems have a temperature range at which the metabolism is maximum. The age of algal cells will similarly influence the rate of metabolism. If algae are to be relied upon to effect treatment of wastes in stabilization ponds, a knowledge of their reaction rate to a changing environment is important. Little or no data is available in the literature to show the effect of changing intensity of light, pH, temperature, and age of the culture on the rate of photosynthesis of Chlamydomonas. Hence, investigations were made to study the - 146 -
Object Description
Purdue Identification Number | ETRIWC196514 |
Title | Reaction rates of photosynthesis |
Author |
Varma, Man Mohan Talbot, Richard S. |
Date of Original | 1965 |
Conference Title | Proceedings of the twentieth Industrial Waste Conference |
Conference Front Matter (copy and paste) | http://earchives.lib.purdue.edu/u?/engext,12162 |
Extent of Original | p. 146-174 |
Series |
Engineering extension series no. 118 Engineering bulletin v. 49, no. 4 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Date Digitized | 2009-05-19 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Resolution | 300 ppi |
Color Depth | 8 bit |
Description
Title | page 146 |
Collection Title | Engineering Technical Reports Collection, Purdue University |
Repository | Purdue University Libraries |
Rights Statement | Digital object copyright Purdue University. All rights reserved. |
Language | eng |
Type (DCMI) | text |
Format | JP2 |
Capture Device | Fujitsu fi-5650C |
Capture Details | ScandAll 21 |
Transcript | Reaction Rates of Photosynthesis MAN M. VARMA, Director Sanitary Engineering Design and Research Green Engineering Affiliates Somerville, Massachusetts RICHARD S. TALBOT, Sanitary Engineer Hercules Powder Company Parlin, New Jersey INTRODUCTION Stabilization ponds, also called bio-oxidation or sewage lagoons, have provided an excellent method for the treatment of wastewater. The main source of oxygen in a stabilization pond is provided as an end-product of photosynthetic activities of the algae. A much smaller amount, up to about 40 lbs of oxygen per acre per day is provided by absorption at the air-water interface, aided by wind action. Carbon dioxide, inorganic salts, water and energy of the sun are used by algae to produce protoplasm, with oxygen and water released into the surrounding medium. Oxygen is used by heterotrophic micro-organisms as an ultimate hydrogen ion acceptor as they obtain energy through oxidation of organic matter into stable end products. With no photosynthesis occurring at night, stabilization ponds and natural bodies of water tend to become depleted of oxygen during the night by the biochemical oxygen demand of bacteria and other heterotrophic microorganisms, and also by the algae themselves, as they consume oxygen in the absence of sunlight. Septic conditions in the ponds therefore sometimes result. This problem may be alleviated somewhat by the installation of artificial lights to effect photosynthesis and oxygen production through the night hrs. Continuous illumination may be detrimental to oxygen production (1). An alternation of light and dark periods is beneficial for algal metabolism and a balance in the illumination may be required which, in a pond, can be achieved by automatic control. The rate of photosynthesis is affected by (a) intensity of light, (b) pH, (c) temperature, (d) age of the culture. The rate of photosynthesis is proportional to the light intensity up to a certain intensity beyond which the rate of photosynthesis is no longer proportional to the increase in the light intensity. It has been found that the highest photosynthetic rate in direct sunlight is normally about eight ins. below the pond surface for this reason. The determination of the effect of light intensity on the rate of photosynthesis would be an important design or criterion for stabilization ponds. To obtain a high rate of photosynthesis, the pH of stabilization ponds in certain cases may have to be adjusted tor the treatment of wastes. A variation on either side of the optimum pH would change the rate of oxygen production by algae. Stabilization ponds and natural bodies of water can show a diurnal variation in pH that may inhibit or kill the micro-organisms that stabilize organic materials. Biological systems have a temperature range at which the metabolism is maximum. The age of algal cells will similarly influence the rate of metabolism. If algae are to be relied upon to effect treatment of wastes in stabilization ponds, a knowledge of their reaction rate to a changing environment is important. Little or no data is available in the literature to show the effect of changing intensity of light, pH, temperature, and age of the culture on the rate of photosynthesis of Chlamydomonas. Hence, investigations were made to study the - 146 - |
Resolution | 300 ppi |
Color Depth | 8 bit |
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