Luận văn thạc sĩ material flow analysis of phosphorous and chemical oxygen demand in domestic

THAI NGUYEN UNIVERITY

UNIVERSITY OF AGRICULTURE AND FORESTRY

PHAM MY ANH

TOPIC TITLE:

MATERIAL FLOW ANALYSIS OF PHOSPHOROUS AND CHEMICAL

OXYGEN DEMAND IN DOMESTIC WASTEWATER AND FOOD WASTE IN

SONG CONG TOWN, VIETNAM

BACHELOR THESIS

Study Mode : Full-time

Major : Environmental Science and Management

Faculty : International Training and Development Center

Batch : 2011-2016

Thai Nguyen, 30/06/2015

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Thai Nguyen University of Agriculture and Forestry

Degree Program: Bachelor of Environmental Science and Management

Student name: Pham My Anh

Student ID: DTN 1153170001

Thesis Title:

“MATERIAL FLOW ANALYSIS OF PHOSPHOROUS

AND CHEMICAL OXYGEN DEMAND IN DOMESTIC

WASTEWATER AND FOOD WASTE IN SONG CONG

TOWN, VIETNAM”

Supervisor: Nguyen Huu Tho, PhD.

Abstract:

Vietnam’s fast economic growth has to a large extent been achieved on the

expense of a rapid deterioration of the natural environment, including

eutrophication of local water sources. Proper planning is needed to move towards

a sustainable wastewater management and one recognized tool for such planning

is material flow analysis (MFA).

This thesis uses MFA to define the current flows of phosphorus (P) and organic

matter, measured as COD, in domestic wastewater and food waste in Song Cong

town, Thai Nguyen province, Vietnam. The aim is further to compare two different

improved wastewater management scenarios with a business-as-usual scenario. The

methods used to find data for the MFA are literature review, interviews and a survey

questionnaire. The literature review presents challenges facing the wastewater sector

of Vietnam and treatment techniques for wastewater and septage.

The wastewater sector is affected by technical difficulties such as lack of capacity and

organizational challenges as a result of adjacent and overlapping authorities.

Contradictions and gaps in legislation, poor governance, and problems with financing

are all issues that need to be addressed.

Although the number of wastewater treatment plants in Vietnam is increasing,

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not more than 10% of the wastewater is being treated. Various techniques are

tried out in Vietnam, among others constructed treatment wetlands and activated

sludge techniques, such as Sequencing Batch Reactors and

Anaerobic/Anoxic/Oxic processes. These and other techniques are explained and

compared in the literature review.

From the gathered data three future scenarios for Song Cong’s wastewater and food

waste treatment were created along with one of the current situation. The future

business-as-usual scenario (BAU-2030) shows the development in Song Cong if no

changes are implemented before year 2030, while the centralized scenario (CTP￾2030) redirects flows of wastewater to a conventional chemical/biological treatment

plant. The third scenario, semi-centralized (STP-2030), implements one treatment

plant with enhanced biological phosphate removal (EBPR) followed by a constructed

treatment wetland, and a bigger EBPR plant followed by disinfection. Both of the

improved scenarios also use food waste and sludge to produce biogas and digit ate

that can be used as compost in agriculture.

The results of the MFA indicate that if nothing is done to change the current

management, a 24% increase of pollutants to the Song Cong is imminent in just 15

years. In addition, if one of the improved scenarios is implemented, 92% (CTP- 2030)

or 90% (STP-2030) of the P will be available for reuse in agriculture, reducing the

need for artificial fertilizer. Further biogas is produced, which can substitute

petroleum based gas for domestic purposes or be used to generate electricity.

Keywords

Wastewater, Material flow analysis (MFA),

Phosphorus (P), Chemical oxygen demand (COD).

Number of pages 52 pages

Date of submission 30/09/2015

Supervisor signature

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ACKNOWLEDGEMENT

My bachelor thesis in environmental engineering at Thai Nguyen University of

Agriculture and Forestry, Viet Nam. The thesis is part of a partnership project between

the municipality of Linköping, Sweden, and the Thai Nguyen province, Vietnam. The

overall aim of the partnership is to achieve a democratic and transparent planning

process, involving stakeholders at different levels in the field of wastewater and

organic waste management in Song Cong town. This includes giving stakeholders new

methods and tools for a participatory planning process.

Foremost, I would like to express my sincere gratitude to my supervisor:

Nguyen Huu Tho, PhD of Department of Science Management and International

Relation, Thai Nguyen University of Agriculture and Forestry (TUAF), Viet Nam for

giving permission to accomplish my Bachelor thesis there, and also his constant

motivating supervision during my studies in the research group of Sweden.

I wish to express my thanks to Mr. Duong Manh Cuong of Faculty of

Biotechnology and Food Technology, (TUAF), Viet Nam for support, help, and

encouragement, advise me during visit to Song Cong town.

Besides my supervisors, most of all thank Mr. Olli Sammalisto and

Ms. Zanna Sefane at the University of Gävle, Sweden for helping, giving necessary

advices and guidance, support me during doing the experiment and completing my

thesis.

Last but not least, I would like to say thankful my family and good friends who

encourage and backing me unceasingly.

Thank you so much!

Thai Nguyen, October 2015

Sincerely,

Pham My Anh

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TABLE OF CONTENTS

ACKNOWLEDGEMENT .......................................................................................... iv

TABLE OF CONTENTS............................................................................................. v

LIST OF FIGURES...................................................................................................... 1

LIST OF TABLES........................................................................................................ 3

LIST OF ABBREVIATIONS...................................................................................... 4

PART I. INTRODUCTION......................................................................................... 5

1.1. Research rationale.............................................................................................. 5

1.2. Research’s objectives......................................................................................... 6

1.3. Research questions............................................................................................. 6

1.4. Limitation of the research ................................................................................. 6

PART II. LITERATURE REVIEW........................................................................... 7

2.1. Challenges in the Vietnamese Wastewater Sector .......................................... 7

2.2. Wastewater Treatment Solutions in Vietnam ................................................. 8

2.3. Conventional Wastewater Treatment Plants .................................................. 9

2.4. Activated Sludge Techniques............................................................................ 9

2.4.1. Enhanced Biological Phosphorus Removal ...........................................................10

2.4.2. Sequencing Batch Reactor ......................................................................................11

2.5. Compilation of P and COD Removal Efficiency in WWTP ........................ 11

2.6. Constructed Treatment Wetlands.................................................................. 13

2.6.1. Free Water Surface (FWS) Wetlands......................................................................14

2.6.2. Floating Treatment Wetlands (FTW)......................................................................14

2.6.3. Subsurface Flows (SSF) ..........................................................................................14

2.6.4. Hybrids....................................................................................................................15

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2.7. Compilation of P and COD Removal Efficiency in Constructed Treatment

Wetlands................................................................................................................... 15

2.8. Further Comparison of the Wastewater Treatment Techniques................ 16

2.9. Sludge and Food Waste Treatment................................................................ 19

PART III. METHODS ............................................................................................... 20

3.1. Survey Questionnaire....................................................................................... 20

3.1.1. Sampling method.....................................................................................................21

3.1.2. Compilation of the Survey Results .........................................................................21

3.2. Scenario Development ..................................................................................... 22

3.3. MFA................................................................................................................... 22

3.3.1. MFA Terminology ...................................................................................................22

3.3.2. Mass Flow and Stock Change Quantification.........................................................23

3.3.3. MFA in STAN..........................................................................................................25

PART IV. RESULTS.................................................................................................. 26

4.1. Survey Results and Scenario Development ................................................... 26

4.1.1. The Survey Results ..................................................................................................26

4.1.2. MFA Processes........................................................................................................26

4.2. Background Data on Song Cong Town.......................................................... 30

4.3. Current Wastewater Management in Song Cong......................................... 31

4.4. Future Wastewater Management in Song Cong ........................................... 32

4.5. Scenario Descriptions ...................................................................................... 34

4.5.1. Baseline Scenario (BLS-2015) ................................................................................34

4.5.2. Business as Usual (BAU-2030)...............................................................................36

4.5.3. Centralized Treatment Plant (CTP-2030)...............................................................36

4.5.4. Semi-centralized Treatment Plant (STP-2030) .......................................................36

4.5.5. Semi-centralized Treatment Plant (STP-2030) .......................................................37

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4.6. Material Flow Analysis of Song Cong ............................................................ 37

4.6.1. Baseline Scenario (BLS-2015) ................................................................................38

4.6.2. Business as Usual (BAU-2030)...............................................................................40

4.6.3. Centralized Treatment Plant (CTP-2030)...............................................................41

4.6.4. Semi-centralized Treatment Plant (STP-2030) .......................................................43

4.7. Compilation of the MFA results..................................................................... 45

PART V. DISCUSSION AND CONCLUSION....................................................... 47

5.1. Discussions. ....................................................................................................... 47

5.1.1. Analysis of the MFA Results...................................................................................47

5.1.2. Scenario discussion.................................................................................................47

5.1.2. Implementation Challenges.....................................................................................49

5.1.3. Sources of Error......................................................................................................50

5.2. Conclusion......................................................................................................... 51

5.2.1. Conclusions. ............................................................................................................51

5.2.2. Future Studies .........................................................................................................51

REFERENCES ........................................................................................................... 53

Appendix A. Parameters for import of P to inhabitants ........................................ 59

Appendix B. Requested data from Song Cong town authorities ........................... 61

Appendix C. Interview questions.............................................................................. 63

Appendix D. Song Cong survey................................................................................. 64

Appendix E. Survey results ................................. Ошибка! Закладка не определена.

Appendix F. Quantification of the confidence interval........................................... 68

Appendix G. Modified parameters in the BAU-2030, CTP- 2030 and STP-2030

scenarios..................................................................................................... 69

Appendix H. Parameters used in the MFA.............................................................. 71

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LIST OF FIGURES

Figure 1. The steps of the different EBPR treatment processes, showing

Anaerobic/Oxic (A/O) at the top, Anaerobic/Anoxic/Oxic (A2O) in

the middle and University of Cape Town (UCT) at the bottom.........11

Figure 2. STAN flowchart showing the processes involved in the treatment of

Song Cong’s wastewater and food waste. ..........................................30

Figure 3. The six urban wards of Song Cong town, with the Cong River running

in the east. ...........................................................................................31

Figure 4. Wastewater canal in Bach Quang ward, Song Cong..........................32

Figure 5. Detail planned map of future Song Cong. Three locations have been

identified by local authorities as suitable for construction of

wastewater treatment plants, location 1, 2 and 3. ...............................33

Figure 6. Solid waste collection in Song Cong town.........................................35

Figure 7. Flowchart of P in the Baseline Scenario (BLS-2015). .......................38

Figure 8. Flowchart of COD in the Baseline Scenario (BLS-2015)..................39

Figure 9. Flowchart of P in the Business as Usual (BAU-2030) scenario.........40

Figure 10. Flowchart of COD in the Business as Usual (BAU-2030) scenario.41

Figure 11. Flowchart of P in the Centralized Treatment Plant (CTP-2030)

scenario. ..............................................................................................42

Figure 12. Flowchart of COD in the Centralized Treatment Plant (CTP-2030)

scenario. ..............................................................................................43

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