Đánh giá nhu cầu oxy sinh hóa và cặn lắng sơ cấp, sục khí và làm sạch trong ở nhà máy xử lý nước thải cảu Viện Phát triển thành phố Yangon_Myanmar

Đánh giá nhu cầu oxy sinh hóa và cặn lắng sơ cấp, sục khí và làm sạch trong ở nhà máy xử lý nước thải cảu Viện Phát triển thành phố Yangon_Myanmar_Evaluation on biochemical oxygen demand and solids of primary sedimentation aeration and final clarifier in wastewater treatment plant of yangon city development committeeBackground InformationYangon is the largest city and is highly urbanized.Since 1888 the wastewater discharged from six downtown townships of Yangon were discharged by conventional disposal system directly into Yangon River.JustificationWWTP is located in Botahtaung Township.It was opened on December, 2006.It treats the wastewater discharged from six downtown townships of Yangon city and disposes the effluent into the Yangon River. The treatment plant has the capacity of 3.25 million gallons per day (MGD). It is now treating about 500,000 gallon of wastewater per day. The two main pipe lines were used for conveying wastewater from these six townships. Wastewater is treated by the processes; preliminary treatment stage, primary treatment stage, biological treatment stage and sludge treatment stage and then the effluent is discharged into the Yangon River.In the WWTP, temperature and pH of wastewater are monitoring routinely.But biochemical oxygen demand (BOD) and solid matters are not measured in this treatment plant. Biochemical oxygen demand and solid matters are important parameters in wastewater treatment. This study aims to assess the biochemical oxygen demand and solids of the effluent in the WWTP. The result of this study is intended to evaluate the effectiveness of the WWTP.Existing Sewerage System in Yangon CitySanitation and sewerage for the Yangon City area is main responsibility of Engineering Department (Water and Sanitation) under Yangon City Development Committee.Existing system, conventional sewerage, consists of: (1) Gravity sewers (2) Thirty nine pneumatic ejector stations (3) Air distribution main (4) Two sewage force mains and outlet

Evaluation on Biochemical Oxygen Demand and Solids of Primary Sedimentation, Aeration and Final Clarifier in

Wastewater Treatment Plant of Yangon City Development Committee

Min Thu Naung MBBS MMedSc (Public Health)

ID-290

INTRODUCTION

• WWTP is located in Botahtaung Township.

• It was opened on December, 2006.

• It treats the wastewater discharged from six downtown townships

of Yangon city and disposes the effluent into the Yangon River The treatment plant has the capacity of 3.25 million gallons per day (MGD) It is now treating about 500,000 gallon of wastewater per day The two main pipe lines were used for conveying wastewater from these six townships Wastewater is treated by the processes; preliminary treatment stage, primary treatment stage, biological treatment stage and sludge treatment stage and then the effluent

is discharged into the Yangon River.

treatment

• This study aims to assess the biochemical oxygen demand and

solids of the effluent in the WWTP

• The result of this study is intended to evaluate the effectiveness of the WWTP.

Existing Sewerage System in Yangon City

Sanitation and sewerage for the Yangon City area is main responsibility of Engineering Department (Water and Sanitation) under Yangon City Development

Committee.

Existing system, conventional sewerage, consists of:

(1) Gravity sewers

(2) Thirty nine pneumatic ejector stations

(3) Air distribution main

(4) Two sewage force mains and outlet

Treatment Processes in Wastewater

Treatment Plant of YCDC

Treatment process is called activated sludge process.

The treatment process can be divided into four stages They are;

(1) Preliminary Treatment Stage

(2) Primary Treatment Stage

(3) Biological Treatment Stage

(4) Sludge Treatment Stage.

Preliminary Treatment Stage

Auto bar screen, pump sump and grit chamber are included.

Primary Treatment Stage

Primary sedimentation tank is used for the solid separation.

Biological Treatment Stage

Aeration tanks are designed followed by the secondary

sedimentation tanks.

Sludge Treatment Stage

Sludge thickener tank and sludge digester tank are included.

OBJECTIVES

General Objective

To evaluate the biochemical oxygen demand and solids of wastewater influent, effluent of

primary sedimentation, effluent of aeration

and effluent of final clarifier in Wastewater

Treatment Plant of Yangon City Development Committee

(5) To compare the qualities of wastewater influent and effluent of

Wastewater Treatment Plant

RESEARCH METHODOLOGY

Sampling Method and Procedure

Sample taking points

point (1) the inlet of raw wastewater

Point (2) was outlet of primary sedimentation tank

Point (3) the outlet of aeration tanks

Point (4) the outlet of final clarifier

Wastewater samples were taken from the sample taking points stated as above with the samplers, which were made up of stainless steel They were inserted into the

wastewater at the sample taking points stated above to collect the wastewater

samples while the treatment plant was operating 3 liters of wastewater was taken from each point 1 liter was for the measurement of pH and temperature, 1 liter for biochemical oxygen demand and 1 liter for total solid, suspended solid and dissolved solid Then the wastewater samples were poured into the bottles which were already cleaned and free from organic matters The bottles were cleaned by use of a detergent

to be free of organic matter and were rinsed with hot water to kill the nitrifying

organisms Then the wastewater samples were transported to the laboratory

Data Analysis

Data analysis was done by the help of computer using software Minitab 14 by comparing with the standard permissible limits

RESULTS

Results in Day Series

Results of pH Level of Wastewater

Results of Temperature (C) of Wastewater

Results of BOD (mg/l) of Wastewater

CONCLUSION

According to test results, average percentage removal efficiency of BOD was 98.81% in overall treatment and the mean value of effluent is 9.4 mg/l Average percentage removal efficiency of suspended solid was 90.83% in overall treatment and the mean

value of effluent is 155.75 mg/l All the pH values were also within the permissible range.

In this study, the influent of the treatment plant was not suitable for disposing into the living

environment without treatment But the effluent of the treatment plant was acceptable to dispose into the Yangon River without harm.

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