Water Treatment Process

WATER TREATMENT PROCESS Prepared for SHATTIRQ BIN MAZELAN

Mechanical Executive, Syarikat Air Darul Aman SDN. BHD.

By MUHAMMAD ADIB BIN MUHAMMAD AZHAR MUHAMMAD SYAZWAN BIN AZIZAN

Mechanical Trainee, Politeknik Sultan Abdul Halim Muadzam Shah

Abstract This report describes the water treatment process, how the process takes places. In order to clean up or treat water for recycling, it is important to understand what treated water contains, what problem it may cause, and what it takes to clean it up.

Acknowledgements Are known sources of raw water from Malaysia obtained from two main sources. First source is from mainland as much as 97%. The other source is from remaining water underground. Generally raw water from both sources contain chemicals, bacteria, suspended solids and floating material in addition to the unpleasant color and odor. It must be cleaned and treated before it can be used safely.

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TABLE OF CONTENTS

Section

Page

WATER TREATMENT PROCESS INTRODUCTION

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WATER TREATMENT PROCESS MODUS OPERANDI 1 SCREENING

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2 GRIT REMOVAL

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3 AERATION

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4 CHEMICAL COAGULATION & FLOCCULATION

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5 SETTLEMENT / SEDIMENTATION

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6 FILTRATION

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7 CHLORINATION

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8 FLUORIDATION

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9 CONDITIONING

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APPENDIX A – WATER TREATMENT DIAGRAM

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APPENDIX B – DOCUMENTATION & SAMPLES

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REFERENCES

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INTRODUCTION Raw water treated at the water treatment plant to produce drinking water quality complies with National Guidelines on drinking water quality (1983) consistently with quality guidelines from World Health Organization (WHO). To achieve the quality, the raw water must be through a number of stages involving the methods of physical treatment, chemical and bacteriological. In each stage of the water treatment process, the use of one method or combination of methods mentioned is going to happen. The water treatment process is as follow :-

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SCREENING Screening is the first treatment station, both for surface and wastewater. It's purpose to:

Protect the structure downstream against large objects which could create obstructions in some of the facility's units,

Easily separate and remove large matter carried along by the raw water, which might negatively affect the efficiency of later treatment procedures or make their implementation more difficult.

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GRIT REMOVAL Inorganic materials suspended finer called grit. It is then deposited by flowing water slowly through the grit chamber. Thereby reducing the buildup of heavy inert or retained in a reservoir or flocculation entry tank.

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AERATION Aeration is the process by which air is circulated through, mixed with or dissolved in a liquid or substance. It is work by passing the liquid through air by means of fountains, cascades, paddle-wheels or cones. Aeration is where air is mixed with water to allow oxygen gas converts elements dissolved iron and manganese to insoluble material in addition to reducing the amount of dissolved carbon dioxide. Eventually eliminate hydrogen sulfide, methane, and other volatile organic compounds that cause unpleasant taste and odor of water.

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CHEMICAL COAGULATION & FLOCCULATION In the flash mixer, coagulant chemicals are added to the water and the water is mixed quickly and violently. The purpose of this step is to evenly distribute the chemicals through the water. Flash mixing typically lasts a minute or less. If the water is mixed for less than thirty seconds, then the chemicals will not be properly mixed into the water. However, if the water is mixed for more than sixty seconds, then the newly forming floc back into small particles.

After flash mixing, coagulation occurs. During coagulation, the coagulant chemicals neutralize the electrical charges of the fine particles in the water, allowing the particles to come closer together and form large clumps.

The final step is flocculation. During flocculation, a process of gentle mixing brings the fine particles formed by coagulation into contact with each other. Flocculation typically lasts for about thirty to forty-five minutes. The flocculation tank often has a number of compartments with decreasing mixing speeds as the water advances through the tank.

This

compartmentalized chamber allows increasingly large floc to form without being broken apart.

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Floc The end product of a well-regulated coagulation/flocculation process is water in which the majority of the turbidity has been collected into floc, clumps of bacteria and particulate impurities that have come together and formed a cluster. The floc will then settle out in the sedimentation tank, with remaining floc being removed in the filter.

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SETTLEMENT / SEDIMENTATION Sedimentation is a physical water treatment process using gravity to remove suspended solids from water. Solid particles entrained by the turbulence of moving water may be removed naturally by sedimentation in the still water of lakes and oceans. Settling basins are ponds constructed for the purpose of removing entrained solids by sedimentation. Apart from colloidal and suspended materials, bacteria and viruses can also be removed through this process. Research shows virus removal between 90% to 99% can be achieved through the operation of a system of coagulation and sedimentation carefully.

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FILTRATION The purpose of filtration is to remove suspended particles from water by passing the water through a medium such as sand. As the water passes through the filter, floc and impurities get stuck in the sand and the clean water goes through. The filtered water collects in the clearwell, where it is disinfected and then sent to the customers.

Filtration is usually the final step in the solids removal process which began with coagulation and advanced through flocculation and sedimentation. In the filter, up to 99.5% of the suspended solids in the water can be removed, including minerals, floc, and microorganisms.

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CHLORINATION Chlorination is the application of chlorine to water to accomplish some definite purpose. Be concerned with the application of chlorine for the purpose of disinfection, also should be aware that chlorination can also be used for taste and odor control, iron and manganese removal, and to remove some gases such as ammonia and hydrogen sulfide.

Chlorination is currently the most frequently used form of disinfection in the water treatment field. Through this process gas or chlorine compounds are often added to the filtered water to eliminate bacteria and pathogenic organisms which is harmful to health.

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FLUORIDATION Fluoridation is the process of adjusting the concentration of fluoride in public water supplies for the prevention of dental decay. Fluoride in water has been proven to prevent tooth decay among children and to prevent root tip rot. The chemical acts by strengthening the tooth enamel and by making the enamel more resistant to decay. This is a long-term process, with results usually being noticeable only after about 4 to 6 years. Fluoride provided can be measured between 0.5 up to 0.7 mg/l.

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CONDITIONING This process makes the water supply as the water does not corrode. The intention of creating a protective layer on the metal pipe, fittings and plumbing systems in the home is to prevent rust. Other than that, it is to prevent the leaching of lime from the cement, particularly for cement pipe, concrete lining of steel pipes and asbestos. Adjustments can be produced by mixing hydrated lime or soda ash in water.

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APPENDIX A – WATER TREATMENT DIAGRAM

DIAGRAM FROM JABATAN BEKALAN AIR PAMPHLET

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PADANG SANAI WATER TREATMENT PROCESS CHART

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APPENDIX B – DOCUMENTATION

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REFERENCES 1. Screening Process http://www.lenntech.com/library/clarification/clarification/screening.htm#ixzz2Yc588joA

2. Aeration http://en.wikipedia.org/wiki/Aeration 3. Flocculation http://en.wikipedia.org/wiki/Aeration 4. Sedimentation http://en.wikipedia.org/wiki/Aeration 5. Chlorination https://en.wikipedia.org/wiki/Water_chlorination 6. Fluoridation http://en.wikipedia.org/wiki/Water_fluoridation

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