DESIGN AND DEVELOP AN EFFICIENT AERATION SYSTEM FOR

TASIK UTeM – AERATION DEVICE

SYAZWAN ARIFF BIN MOHD YUNUS

B041110140

BMCA

Email: syazwanariff22@gmail.com

Draft Final Report

Projek Sarjana Muda II

Supervisor: PROF. MADYA IR. DR TALIB BIN DIN

Faculty of Mechanical Engineering

Universiti Teknikal Malaysia Melaka

MEI 2015

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SUPERVISOR DECLARATION

“I hereby declare that I have read this thesis and in my opinion this report is sufficient in

terms of scope and quality for the award of the degree of

Bachelor of Mechanical Engineering (Automotive)”

Signature : ...................................

Supervisor : ...................................

Date : ...................................

ii

DECLARATION

“I hereby declare that the work in this report is my own except for summaries and

quotations which have been duly acknowledged.”

Signature : ...................................

Author : ...................................

Date : ...................................

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ACKNOWLEDGEMENT

First of all, I am grateful to Allah S.W.T for the grace and kindness given the

time and space as I to complete my project successfully. Also, I would like to give a

round of applause to UTeM (Universiti Teknikal Malaysia Melaka) and FKM

(Fakulti Kejuruteraan Mekanikal) specifically for given us the chance to carry out the

project and ease us in order to get the reference materials about this topic by

providing a lot of facility and convenience like library and cafeteria.

Secondly, a lot sincere and thanks to supervisor, Prof. Madya. Ir. Dr. Abdul

Talib bin Din for his perfect guidance and good explanation from the beginning of

this project until it is completed. Furthermore, I also want to thanks to you for your

commitment and trust to us to get this task done.

Not to mention my parents who give a ton of supports and encouragements

and also pocket money as the money don’t grow on trees this day as to accomplish

this project.

Lastly in a nutshell, I hope that the project that have been done can enhance

our knowledge as a student and hopefully as an engineers in the near future. Besides

that, I hope that this project can provide a lot of information and benefit to the

society and to the world.

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ABSTRACT

The main objective of the project is to design and develop an efficient

aeration system for Tasik UTeM which reduce BOD and COD, and increasing the

dissolve oxygen - aeration device. The key factor that should be taken when carrying

out this project is to choose the most suitable aeration system while having the

efficiency of air distribution based on quality of water, the depth, and the flow of

lake. To achieve this task, a relevant research on existing aeration system such as

fountain aerator, propeller aerator, paddlewheel and diffuser aerator. To provide the

maximum dissolve oxygen to the Tasik UTeM, water quality must be analysed and

the pressure in water is determined so that the blower pump can deliver enough air

through the piping system. At the same time, mechanical factors and other

characteristic should be taken in order to develop and design the aeration such as the

loss of air pressure, air flow, types of pipe and so forth. Besides, the design of this

system not prevent the flows of streams as well as the cost no too expensive.

v

ABSTRAK

Tujuan utama projek ini adalah untuk mereka bentuk dan membangunkan

sistem pengudaraan bagi Tasik UTeM – alat pengudaraan air. Faktor utama ketika

menjalankan projek ini adalah pemilihan pengudaraan yang paling sesuai disamping

mempunyai kadar kecekapan pengagihan udara yang paling maksimum berdasarkan

beberapa factor lain seperti kadar kualiti air, faktor kedalaman, dan aliran tasik. Bagi

proses pemilihan sistem yang sesuai, kajjian dijalankan berkaitan dengan sistem

pengudaraan yang sedia ada seperti pengudaraan jenis pancutan udara (“fountain

aerator”), pengudaraan di permukaan dengan kaedah kayuhan (“paddlewheel”) dan

kaedah udara terlarut melalui sistem paip (“diffuser aerator”). Dalam usaha untuk

membekalkan keperluan oksigen yang maksimum untuk Tasik UTeM, kadar kualiti

air harus diketahui terlebih dahulu dan seterusnya tekanan udara di dalam air supaya

pam udara dapat menyalurkan udara yang mencukupi melalui sistem paip. Pada masa

yang sama, ciri-ciri dan faktor-faktor mekanikal harus diambil kira bagi tujuan

mereka sistem pengudaraan seperti kadar kehilangan tekanan udara, kelancaran

pengaliran udara di dalam paip, jenis paip dan sebagainya. Selain daripada itu, reka

bentuk sistem ini hendaklah tidak menganggu pengaliran arus disamping kos

pembangunan yang tidak terlalu mahal.

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TABLE OF CONTENT

CHAPTER CONTENT PAGE

SUPERVISOR DECLARATION i

DECLARATION ii

ACKNOWLEDGEMENTS iii

ABSTRACT iv

ABSTRAK v

TABLE OF CONTENT vi

LIST OF TABLES x

LIST OF FIGURES xi

LIST OF ABBREVIATIONS AND SYMBOLS xiii

LIST OF APPENDICES xiv

1 INTRODUCTION

1.0 Introduction 1

1.1 Background Study 1

1.2 Objectives 2

1.3 Scope 2

1.4 Problem Statement 3

1.5 Idea Concept Design 3

1.6 Research Methodology 4

vii

2 LITERATURE REVIEW

2.0 Background Study 5

2.1 Types of Aeration System 7

2.1.1 Fountain Aerator

2.1.2 Propeller Aerator

2.1.3 Injector Aerator

2.1.4 Paddlewheels

2.1.5 Diffuse Air/Gas Diffuser

2.2 Diffuse Air Aeration 10

2.3 Diffuser 12

2.3.1 Porous Diffuser

2.3.2 Nonporous Diffuser

2.4 Biochemical Oxygen Demand (BOD) and

Chemical Oxygen Demand (COD)

15

2.4.1 Biochemical Oxygen Demand (BOD)

2.4.2 Chemical Oxygen Demand (COD)

2.5 Blower 17

2.6 Air Piping 20

3 METHODOLOGY

3.0 Introduction 24

3.1 Project Planning 24

3.2 Flowchart 25

3.3 Process Flow Explanation 26

3.3.1 Identify problem Statement

3.3.2 Literature Review

3.3.3 Idea Development

3.3.4 Concept Generation

3.3.5 Analysis

3.3.6 Quality Function Development (QFD)

viii

3.3.7 Identify Concept Design

3.3.8 Concept Evaluation

3.3.9 Design Selection

4 DATA AND CAD DRAWING

4.1 Data Calculation 35

4.1.1 Head Losses in Straight Pipe

4.1.2 Power Require for Blower

4.1.3 Design for Fitting/Joint

4.2 Idea Sketching 39

4.3 CAD Drawing 40

4.3.1 Main Pipe Drawing

4.3.2 Sub-line Pipe Drawing

4.3.3 Wye (“Y”) Drawing

4.3.4 Tee Pipe Drawing

4.3.5 Elbow Pipe Drawing

4.3.6 Fine Bubble Diffuser Stone

4.3.7 Coarse Bubble Diffuser Stone

4.3.8 Main Pipe Assembly Drawing 44

5 RESULT AND DISCUSSION

5.1 Introduction 45

5.2 Ansys-Fluent Software 45

5.3 Main Pipe Analysis 47

5.3.1 Contour Analysis Result

5.3.2 Velocity Vector Analysis

5.4 Sub-Line Pipe Analysis 52

5.4.1 Contour Analysis Result

5.4.2 Velocity Vector Analysis

ix

5.5 Wye (“Y”) Pipe Analysis 57

5.5.1 Velocity Magnitude Analysis

5.6 Tee Pipe Analysis 58

5.6.1 Velocity Magnitude Analysis

5.7 Elbow Pipe Analysis 60

5.7.1 Velocity Magnitude Analysis

6 CONCLUSION AND RECCOMENDATION 62

6.1 Conclusion 62

6.2 Recommendation 62

REFERENCES 63

APPENDICES 65

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LIST OF TABLES

NO. TITLE PAGE

Table 2.1 Table Indicate Types Available at Standard 8

Table 2.2 Classification and Description of Diffused Air 11

Table 2.3 Type of Diffuser 12

Table 2.4 Typical Air Velocities in Aeration Header Pipes 21

Table 2.5 Resistance Factors for Fitting in Aeration Piping Systems 23

Table 2.6 Typical Head Losses through Air Filters, Blower Silencers

and Check Valve 23

Table 3.1 House of Quality 32

Table 3.2 Morphological Chart 33

Table 3.3 Possible Combination of Alternative (Aeration Device) 33

Table 3.4 Weight Rating Decision Method 34

Table 4.1 Idea Sketching Concept Designs 39

Table 4.2 Comparison Between Idea Concept Designs 40

xi

LIST OF FIGURES

NO TITLE PAGE

Figure 1.1 Map of Tasik UTeM 2

Figure 1.2 Basic Diffused Aeration Concept 3

Figure 1.3 Flow Process for PSM 4

Figure 2.1 Basic Aeration Process 6

Figure 2.2 Fountain Type Aerator 7

Figure 2.3 Propeller Type Aerator 8

Figure 2.4 Injector Type Aerator 9

Figure 2.5 Paddlewheel Type Aerator 9

Figure 2.6 Diffuser Air Type 10

Figure 2.7 Type of porous air diffuser a) aluminium oxide disk, b) ceramic

dome, c) polyethylene disk, d) perforated membrane. 13

Figure 2.8 Commonly Blowers Used for Diffusion-air Aeration; a) Centrifugal;

b) Rotary-lobe Positive Displacement. 17

Figure 2.9 Characteristic Curve for Centrifugal Blower at Various Inlet

Temperatures 20

Figure 3.1 Methodology Chart 25

Figure 3.2 Simulation Process and Comparison 30

Figure 3.3 Example of Block diagram 31

Figure 4.1 Main Pipe Drawing 40

Figure 4.2 Sub-Line Pipe Drawing 41

Figure 4.3 Wye (“Y”) Pipe Drawing 41

Figure 4.4 Tee Pipe Drawing 42

xii

Figure 4.5 Elbow Pipe Drawing 42

Figure 4.6 Fine Bubble Diffuser Stone 43

Figure 4.7 Coarse Bubble Diffuser Stone 43

Figure 4.8 Main Pipe Assembly Drawing 44

Figure 5.1 Pressure contour in main pipe 47

Figure 5.2 Velocity vector in main pipe 47

Figure 5.3 Contour of dynamic pressure at pipe outlet 48

Figure 5.4 Contour of static pressure at pipe outlet 49

Figure 5.5 Contour of velocity magnitude at pipe outlet 49

Figure 5.6 Velocity vectors coloured by dynamic pressure at pipe outlet 50

Figure 5.7 Velocity vectors coloured by static pressure at pipe outlet 51

Figure 5.8 Velocity vectors coloured by velocity magnitude at pipe outlet 51

Figure 5.9 Pressure contour in sub-line pipe. 52

Figure 5.10 Velocity vector in sub-line pipe. 52

Figure 5.11 Contour of dynamic pressure at pipe outlet 53

Figure 5.12 Contour of static pressure at pipe outlet 54

Figure 5.13 Contour velocity of magnitude at pipe outlet. 54

Figure 5.14 Velocity vectors coloured by dynamic pressure at pipe outlet 55

Figure 5.15 Velocity vectors by static pressure at pipe outlet 56

Figure 5.16 Velocity vectors coloured by velocity magnitude at pipe outlet 56

Figure 5.17 Pressure contour in Y-pipe 57

Figure 5.18 Velocity vector in Y-pipe 57

Figure 5.19 Velocity vectors coloured by velocity magnitude 58

Figure 5.20 Pressure contour in T-pipe 59

Figure 5.21 Velocity vector in T-pipe 59

Figure 5.22 Velocity vectors by dynamic pressure 60

Figure 5.23 Pressure elbow pipe 60

Figure 5.24 Velocity vector in elbow pipe 61

Figure 5.25 Velocity vectors coloured by velocity magnitude 61

xiii

LIST OF ABBREVIATIONS AND SYMBOLS

UTeM - Universiti Teknikal Malaysia Melaka

FKM - Fakulti Kejuruteraan Mekanikal

(Faculty of Mechanical Engineering)

BOD - Biochemical Oxygen Demand

COD - Chemical Oxygen Demand

Pa - Pascal’s

DO - Dissolve Oxygen

CAD - Computer Aided Design

CFD - Computational Fluid Dynamic

MATLAB - Matrix laboratory

W - Watt

V - Volt

N - Newton

J - Joule

cm - centimetre

m - metre

mm - milimetre

in - inch

kg - kilogram

mg - miligram

L - Litre

xiv

mL - Mililitre

HP - Horse Power

min - minute

ºF - Degree Fahrenheit

ºC - Degree Celsius

K - Kelvin

Ø - Diameter

ft - feet

ppm - Parts per million

Hg - Mercury

FAS - Ferrous ammonium

QFD - Quality Function Development

HoQ - House of Quality

SOTR - Standard Oxygen Transfer Rate

R - Rating

WR - Weighted Rating

IW - Importance Weight

xiv

LIST OF APPENDICES

NO. TITLE PAGE

1 Map of Tasik UTeM 66

2 Gantt Chart PSM I 67

3 Gantt Chart PSM II 68

4 Drafting Main Pipe Drawing 69

5 Drafting Sub-Line Pipe Drawing 70

6 Drafting Wye (“Y”) Drawing 71

7 Drafting Tee Drawing 72

8 Drafting Elbow Drawing 73

9 Drafting Fine Bubble Diffuser Stone 74

10 Drafting Coarse Bubble Diffuser Stone 75

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CHAPTER 1

INTRODUCTION

1.0 INTRODUCTION

There are six titles will be provided in this chapter. First of all is the background

study followed by the objective, scope and problem statement provided early of the

semester. Then, it will be continued with idea concept design which indicate the

basic concept of water aeration and research methodology.

1.1 BACKGROUND STUDY

Water is most precious resource in daily life and lake is one the resource to

obtain besides river and mountain. Lake is categorized as an area that surrounded by

land apart from any river. It is also vary in shape, depth and exists at different

elevations. Some measure only a few square meter and small to fit the backyard

referred as ponds. Lakes can be contrasted with rivers or streams, which are usually

flowing. However most lakes are fed and drained by rivers and streams. The water in

lakes comes from rain, stream and groundwater. Usually most lakes contain

freshwater.

Now, in the modern day, lakes are constructed for industrial and agricultural

purpose. Besides, it is used for generate power like hydro-electric power generation

2

or domestic water supply. At the same time, lake is also use for recreational

activities. In this project, the scope, objective and problem statement according to

Tasik UTeM. Figure 1.1 shows the map of Tasik UTeM A and B. The area of Lake

A and B is 26148.1m2 and 48076.8m2 respectively.

Figure 1.1: Map of Tasik UTeM

1.2 OBJECTIVE

To design and develop an efficient aeration system for Tasik UTeM which

reduce BOD and COD, and increasing the dissolve oxygen - aeration device

1.3 SCOPE

Literature review on water quality at Tasik UTeM water focus on the

parameter of dissolve oxygen (DO).

3

1.4 PROBLEM STATEMENT

Throughout this project, there are several aspects and factor that need to be

considered. First of all is to design a suitable aeration system included the blower,

automatic switch which suitable on decreasing biological oxygen demand (BOD) and

chemical oxygen demand (COD) and increasing the dissolve oxygen. However,

some precaution need to be done on the model so that it is durable and not having

any pressure loss in order to provide the oxygenation need for Tasik UTeM

Next, the level of BOD and COD in Tasik UTeM need to be determined so

the correct amount of oxygen can be provided by the aeration system. Besides, a

precise pressure level in the water also has to be determined so that the blower can

provide enough air through underwater piping. Lastly, the installation process of the

aeration system must correctly install.

1.5 Concept Designs

Diffused air type will be used for this project where by a tube will be place in

the middle at the bottom of the lake. Apart from that, there are branching structures

of the main channel to the overall sides for aeration. A blower house will be located

and equipped with two mechanical blowers which operate intermittently to provide

air for aeration process. The blower operated automatically controlled by switch

depends on BOD and COD of the water. The figure below shows the basic concept

diffuse air that will be install at Tasik UTeM.

Figure 1.2: Basic diffused aeration concept.

4

1.6 Research Methodology

Figure 1.3: Flow process for PSM

START

Title Confirmation

Identified the Aeration System

Identified Objective & Scope of the project

Collect Relevant Information & Data

Analyze & Identified the Problems

Experimental on Water quality

Design and Simulation by

CAD/CFD

-

PSM 1

PSM 2

YES

NO

Design Detailing

Testing & Validation

5

CHAPTER 2

LITERATURE REVIEW

2.0 BACKGROUND STUDY

Aeration is the process which area of the contact between water and air is

increased, by natural or mechanical devices for oxygenation process. This process is the

most efficient techniques frequently apply in the improvement of the physical and

chemical properties and characteristics of water. The function of aeration improves the

taste and odor of the water, such as lake and river by supplying the enough oxygen,

rescuing the free carbon dioxide and eliminating much of the hydrogen sulfide and other

odorous presents. Besides that, removal of iron and manganese from such oxygen

deficient waters also usually requires aeration as an initial step. This initial step allows for

the lower oxides of these minerals that are dissolved in the water and combined with

carbon dioxide to be converted to higher insoluble oxides and in turn removed by

subsequent sedimentation, contact or filtration. The benefit from aeration are:

Improve overall water quality.

Increase the population of fish.

Cause circulation currents that might create favorable conditions for more

desirable algae to out compete blue green algae.

Reduce the mortality of aquatic life due to low oxygen levels.

Speed up the rate of organic decomposition.

6

The efficiency of the aeration process depends on almost entirely on the amount

of surface contact between the air and water. This contact is controlled primarily by the

size of the water droplet or air bubbles. The goal of an aerator is to increase the surface

area of water coming in contact with air so that more air can react with the water. As air

or water is broken up into smaller drops/bubbles or into thin sheets, the same volume of

either substance has a larger surface area. Figure 2.1 below shows the basic process of

aeration

Figure 2.1: Basic Aeration Process

Aeration removes or modifies the constituents of water using two methods which

are scrubbing action and oxidation. Scrubbing action is caused by turbulence which results

when the water and air mix together. The scrubbing action physically removes gases from

solution in the water, allowing them to escape into the surrounding air. Based on the figure

above, carbon dioxide and hydrogen sulfide are shown being removed by scrubbing

action. Scrubbing action will remove tastes and odors from water if the problem is caused

by relatively volatile gases and organic compounds.

7

Oxidation is the other process through which aeration purifies water. Oxidation is

the addition of oxygen, the removal of hydrogen, or the removal of electrons from an

element or compound. When air is mixed with water, some impurities in the water, such

as iron and manganese, become oxidized. Once oxidized, these chemicals fall out of

solution and become suspended in the water. The suspended material can then be removed

later in the treatment process through filtration.

2.1 TYPES OF AERATION SYSTEM

There are several types of aeration system used for wastewater treatment. The

system used depends on the function to be performed, type and geometry of the reactor,

and cost to install and operate the system.

2.1.1 Fountains Aerator

For this kind of aerator, it works very well in small pond and relatively shallow. Fountains

improve a pond's aesthetic appeal and recirculate the water near the pond's surface.

Fountains are generally ineffective because it does not recirculate the water near the

bottom of the pond.

Figure 2.2: Fountain type aerator

In most cases, water near the pond's surface usually has enough oxygen to support the

plants and animals found near the water surface. A fountain should be in the middle of the

8

pond, and the waves creates by the fountain should dissipate before reach the edge. This

system is not efficient because energy is used to create the display.

2.1.2 Propeller Aerator

This propeller aerator was specially developed for intensive production of fish in tanks

and ponds. This unit employs a float, motor, and prop to splash at the water surface with

fairly decent oxygen transfer rate. The maintenance free, heavy duty, motor (230 or 380

Volt) with low power consumption (0.18-1.00 kW) has a mounted propeller which allows

a high water circulation of up to 50-180 m3/h (splash height 60-90 cm and splash diameter

160-250 cm). The small float size, compact and lightweight system make it fast and easy

to install. This aeration system is not efficient at moving water at deeper level.

Figure 2.3: Propeller Type Aerator

The following types are available as standard:

Table 2.1: Table indicates types available at standard

Power consumption kw/HP 0.18/0.2 0.37/0.5 0.75/1.0

Water circulation m3/h 50 100 180

Water splash Ø cm 160 180 250

Splash height cm 60 75 90

weight kg 26 28 30