experiment 6 aeration test

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CEEB221 INTRODUCTION TO ENVIRONMENTAL ENGINEERING LABORATORY EXPERIMENT 6.0: AERATION TEST NAME ID SECTION : ZIA RAZIFF CHEE BIN FUDIN CHEE CE088743 02DR. CHUA KOK HUA MISS SHIMA : 23 JULY, 2012

: :

LECTURER : LAB INSTRUCTOR:

DATE OF REPORT SUBMISSION

LAB REPORT MARKING Title Page Table of Content Objective Theory Anticipated Result Apparatus Procedure Results Discussions Conclusion Critique References Appendices Attendance TOTAL 1% 4% 5% 10% 10% 5% 5% 20% 15% 10% 5% 2% 3% 5% 100%

TABLE OF CONTENTS 1

No.

Item

Page 2 2 2 3 3- 4 5 5 6 6 6-7

6.1 Introduction 6.2 Objective 6.3 Apparatus 6.4 Procedure 6.5 Results (Data Observations) 6.6 Discussion 6.7 Summary 6.8 Conclusion 6.9 Refferences 6.10 Appendix

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CEEB 221: INTRODUCTIONS TO ENVIRONMENTAL ENGINEERING LABORATORY EXPERIMENT 6.0: AERATION TEST

6.1 Introduction : Oxygen sufficiency is an important factor in water treatment processes, due to the fact that the livelihood of many of the aquatic species is depending on the oxygen present in water, also the microorganisms present in the water use the oxygen to digest the biodegradable substances in the water, in addition, the plants which grow inside the water also use the oxygen for photosynthesis, to grow and also produce more oxygen. There are two terms which are involved with the oxygen usage in the river, lake or etc. one is deoxygenation and other is reoxygenation, deoxygenation refers to usage of oxygen from plants and aquatic species, whereby reoxygenation is the process of introducing oxygen into the water, either by natural mean or human interfere. A simple definition of aeration could be the process whereby water is brought into intimate contact with air by spraying or cascading, or air is brought into intimate contact with water by an air aspirator or by bubbling compressed air through the body of water. Both pressure (closed) aerators and open (gravity) aerators are used. Closed aeration is used chiefly for oxidation; open aeration for degassing. Aeration is the process, by which oxygen is introduced into water for different purposes, from disinfection, to providing oxygen for the microorganism to digest the organic biodegradable substances in water, to remove the odor the water, and prevent it to become septic in the water treatment plants. 6.2 Objective The objective of the experiment is to determine the transfer efficiency of an aerator. Also, the objective of the experiment is to determine the rate of deoxygenation and reoxygenation of a water sample using sodium sulphate and a catalyst of Cobaltous Chloride. 6.3 Apparatus Apparatus 1. Circular tank 2. Aerator 3. DO probe 4. Spatula Chemicals and materials 1. Cobaltous Chloride 2. Sodium Sulphate 3. Distilled water 4. Water sample

6.4 Procedure 3

1. A circular, black tank was used as the container 2. A sample of fresh water was poured inside the tank, the height and diameter of the water was taken, inside the tank. The DOo of the water sample was recorded. 3. Addition of Cobaltous Chloride, the catalyst, and Sodium Sulphate was started at this point, with gentle stirring of the mixture. 4. DO probe was washed and rinsed with distilled water and placed in the tank to take the amount of dissolved oxygen. 5. The readings were recorded as the dissolved oxygen was decreasing, 6. When the minimum amount of dissolved oxygen, 1.89, was reached, the DO probe was once again rinsed with distilled water and placed into the deoxygenated sample, 7. Readings of the amount of DO was taken every 1 minute interval until the original amount of DO was reached. 8. The required analysis was done on the data collected, graphs were plotted and calculations were done, as you can see further in next parts. 6.5 Results (Data Observations)

Time,min 0 3 6 8 10 12 14 16 20 25 30 35 40

DO,mg/l 0.02 0.29 1.21 1.61 2.17 2.47 2.75 3.27 3.64 3.91 4.27 4.44 4.52

-C 8.18 7.91 6.99 6.59 6.03 5.73 5.45 4.93 4.56 4.29 3.93 3.79 3.68

Calculation 4

Cs = 8.2 mg/l ; Temperature = 26C ; Diameter of container = 34cm ; Height = 36.5cm = ln(Cs- ) ln (Cs= ln (6) ln (4.2) 25-10 = 0.3567 15 = 0.0238/min )

Standard =

at 20C ( ) )

= 0.0238 ( = 0.0206/min Oxygenation capacity = 9.1 mg/l Area,A= = = 0.0908

Volume of water = Area Height = 0.0908 0.3650 = 0.0331 = 33.1 OC = Volume of water

= 0.0206 9.1 33.1 = 6.2049 mg/min 10,000 = 6.2049 kg/min

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6.6 Discussion The errors we committed in this experiment was addition of catalyst and the other reagent without any scale or calculation, hence the results were not very accurate. In addition, while measuring the height and the diameter of the cylinder there might have been some parallax errors and hence not having a correct volume. Furthermore, it can be seen from the data that there had been some faulty reading, because when the readings are supposed to decrease, some of the readings are increasing and vice versa.It is known that, the best way of addition of chemicals, is by usage of the diffused system, where we can add the catalyst and Sodium Sulphate from bottom, however in our experiment we just added the chemical with spatula.Also the mixing and stirring of the water sample might not have been entirely uniform, resulting in some of the catalyst and reagent dropping down to the tank and not reacting with the water.Overall, it can be said that the experiment was done correctly, and we were able to get the data required and do the analysis. 6.7 Summary The test procedure involves measuring dissolved oxygen from near zero to saturation against time, and non linear regression is used to determine the mass transfer coefficient. To achieve near zero dissolved oxygen concentration, the water sample is deoxygenated using sodium sulphite. Power consumption of the aeration devices is monitored using power monitoring equipment suitable for systems equipped with variable speed drives. It is common to test aeration systems at several duty points to determine the efficiency across the whole operational range of a particular system. In this experiment, fist a small circular, plastic tank was chosen for this experiment, and fresh water was poured inside it, then Cobaltous Chloride, which is the catalyst, was added into the sample, followed by addition of Sodium, Sulphate, in order to deoxygenize the water. These two chemicals were added to the tank until a point which the DO meter read a value of 1.89, meaning that most of the oxygen in the water sample had escaped. When that point was reached, the aerator was put inside the tank and the bubbles producing bubbles inside the water, and hence reoxygenizing the mixture. At each minute the value that the DO probe read was recorded, also the height of the water and the diameter of the tank was recorded, for further calculation and analysis of the data that we had calculated in this experiment.

6.8 Conclusion 6

As for the conclusion it can be stated that this experiment met satisfaction and the objective of the experiment was met, we were able to deoxygenize the water and reoxygenize it, recognize the reagents and the catalysts, also we can now find the rate of deoxygenization and deoxygenization.

6.9 Refference Lecture note from Dr. Chua Kok Hua ; Introduction to Environment Engineering.

6.10 Appendix

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