Evaluation of water quality in the headwater of nhue river

The main sources of water pollution of the lower Nhue River in Hanoi .... Evaluation of river water quality based on National Technical Regulation on surface water quality: .... Distribu

ACKNOWLEDGEMENTS

Firstly, I would like to gratefully thank my advisor Msc Phi Thi Hai Ninh for her suggestion and instruction She was enthusiastic, encouraging and faithful with me throughout the period of the thesis and has been extremely helpful Besides, I’m thankful

to Dr Nguyen Hai Hoa who helped me to do Arc GISs

Secondly, I am indebted to local people, who are living in the study area, provided good conditions and helpful information for me to do my research

In addition, I would like to thank Hanoi Natural Resources and Environment Department who provided information data about Nhue River When I was conducting thesis research, the Hanoi Monitoring and Analysis Environment Resource Center taught and helped me to carry out experiments in my data analysis process

Thirdly, I am grateful to Vietnam Forestry University, Advanced Education Program, and Developed in collaboration with Colorado State University, USA for providing a professional learning environment and well educated teachers

Finally, I would like to thank my parents and my friends that supported and helped me to complete this thesis

TABLE OF CONTENTS

I INTRODUCTION 1

II OVERALL GOALS AND OBJECTIVES 2

2.1 Overall goals 2

2.2 Specific objectives 3

III METHODS 3

3.1 Method of sampling and sample preservation 3

When collecting water samples, it is importantly noted that: 4

3.2 Laboratory analyses 5

3.3 WQI calculation 5

IV RESULTS AND DISCUSSION 9

4.1 Issue of Nhue River 9

4.2 The main sources of water pollution of the lower Nhue River in Hanoi 11

4.2.1 Domestic wastewater 11

4.2.2 Industrial wastewater 11

4.2.3 Village wastewater 12

4.2.4 Hospital waste 12

4.2.5 Solid waste 12

4.3 Evaluation of Nhue River water quality 13

4.3.1 Evaluation of river water quality based on National Technical Regulation on surface water quality: 14

4.3 2 The evaluation of surface water quality based on WQI 18

4.3.3 Distributing the partition map about Nhue River water quality based on WQI 21

4.4 Solutions for an efficient management and sustainable use of surface water resources: 22

V CONCLUSIONS 22

VI REFERENCES 23

APPENDICES 24

LIST OF TABLES

Table 3.1: Geographical locations of sampling 3

Table 3.2: Laboratory analysis 5

Table 3.3: Specifying qi and BPi values 6

Table 3.4: Specifying BPi and qi values based on %DOsaturaion 7

Table 3.5: Specified BPi and qi values in accordance with pH parameter 8

Table 3.6: Water quality index and status of water quality 9

Table 4.1: The volume of wastewater discharged to lakes and rivers in Hanoi 10

Table 4.2 Analysis parameters of Nhue River 13

Table 4.3: Nhue River water quality and WQI 2014 18

LIST OF FIGURES

Figure 2.1 Map of the lower section of Nhue River 2

Figure 3.1 Map of sampling points within the monitored areas 4

Figure 4.1: pH values at the monitoring points 14

Figure 4.2: DO at the monitoring points 15

Figure 4.3: TSS at the monitoring points 15

Figure 4.4: COD at the monitoring points 16

Figure 4.5: BOD₅ at the monitoring points 17

Figure 4.6: NO₃⁻ at the monitoring points 17

Figure 4.7: Concentration of PO₄³⁻ at the monitoring points 18

Figure 4.8: WQI at the monitoring points 20

Figure 4.9 Map of headwater Nhue River water quality partition 21

I INTRODUCTION

Water resource is an extremely valuable asset, however not endless Although accounting for over 97% of the earth’s surface, water resources that can be used by humans and other living organisms comprise less than 3% Meanwhile, this valuable resource is facing serious issues in relation to human activities Conserving water resources is not only important to the current generation but also to future generation

Nhue River is an important river in Nhue - Day basin system located in the right bank of Red river Stretching about 74km, the river starts from Lien Mac dam (Tu Liem, Hanoi), passing through a number of districts in Hanoi and Hanam provin as before joining the Red river system This river is important in terms of water supply to human activities such as drinking water, irrigation, drainage… However, confronts problems such as water depletion and pollution

Nhue River has been strongly affected by socioeconomic development and other living activities Urbanization, rapid population growth, especially the massive wave of migration from rural areas to Hanoi have created stressors on water resources Industrial zones, handicraft villages, factories, minings… have discharged toxic substances to the river, causing water pollution and other environmental damages in the river Therefore, strengthening and improving the management efficiency and water conservation for Nhue River are critical and urgent missions to ensure the achievement of sustainable development goals In order to deal with this issue, the evaluation of the water quality and partition of the river based on water quality are important to manage the river and create water use planning Differences in water quality along the river are also the basis to control discharge points and determine appropriate and sustainable local water use preferences

However, there is a gap between scientific research and management practices of the river The fundamental research on defining the state of rivers and proposing solutions

WATER QUALITY IN THE HEADWATER OF NHUE RIVER’’ has been conducted with the purpose of generating a scientific basis to assess the quality of river water,

partition and consequently, propose solutions for a sustainable management of the river

II GOALS AND OBJECTIVES

2.1 Goals

This project aims to assess the surface water quality of Nhue River and suggest solutions to efficiently manage and sustainably use surface water resources

Figure 2.1 Map of the lower section of Nhue River

(Source: Assoc Prof Dr Nguyen Manh Khai)

2.2 Specific objectives

The project is:

- To evaluate the water quality of Nhue River at monitored areas by collecting water samples at different locations such as: Lien Mac dam (Bac Tu Liem District), Cau Dien ( Nam Tu Liem district

- To create water quality partition maps based on WQI

- To propose suggestions to protect and improve water quality

III METHODS

3.1 Method of sampling and sample preservation

To evaluate water quality within the surveyed area, 16 samples of water were collected in different points from Lien Mac dam to the confluence with Mang Giang River (Table 3.1 and Figure 3.1)

Table 3.1 Geographical locations of sampling

2 NR2 580245 2329157 Culvert on the way to Trai Ga

4 NR4 579284 2323052 Bridge on Thang Long Avenue

5 NR5 581123 2319506 Trang Bridge

6 NR6 584028 2317053 Ta Bridge - Thanh Oai

7 NR7 583542 2315487 Sat Bridge - Ta Thanh Oai

8 NR8 583945 2312354 At the confluence with Hoa Binh river

9 NR9 585078 2310088 Sat Bidge - Khanh Ha

10 NR10 586419 2307886 Chiec Bridge – Hien Giang

11 NR11 588129 2305554 La Bridge - Tan Minh

12 NR12 587088 2301998 Tru Bridge - Lien Chau

13 NR13 588171 2296654 Loi Bridge - Van Trai

14 NR14 590581 2293555 Chuon Bridge – Tan Dan

15 NR15 592829 2288471 Bridge on the road 75

16 NR16 593398 2283869 At the confluence with Mang Giang river

Figure 3.1 Map of sampling points within the monitored areas

(Source: Assoc Prof Dr Nguyen Manh Khai)

When collecting water samples, it is importantly noted that:

- Sampling time: in the mild morning, from 7am - 10am; weather conditions: no rain, lightly windy, and light sunshine

- Sampling equipment: Using plastic bottles of 500 ml volume, rope, tapes, markers and thermal isolation barrel The bottles used to take samples should be carefully and cleanly washed by water or acid alkali, then evenly rinsed with clean water and distilled water; and before getting samples, the bottles must be rinsed with river water

- Taking samples at the depth of 20 - 30cm from the surface, with the distance of 1.5 - 2m from the riverside The bottles must be fully filled up with river water, immediately capped and put into the barrel

- Samples preservation: The samples were stored in a thermal isolated barrel at a temperature of 4-8 °C Afterwards, the samples were transported directly to the laboratory within 3 – 4 hours to test water parameters

3.2 Laboratory analyses

In order to evaluate the water quality of Nhue River, the indicators pH, TSS, DO, BOD₅, total phosphorus, and total nitrogen were both analyzed on site and in the laboratory Appropriate analyzing methods are mentioned in table 3.2

based on the WQI (Water Quality Index) The WQI method is employed to evaluate environmental quality of the water surface in accordance with the composite indicators, applied to 9 indicators (pH, DO, TSS, BOD₅, COD, NH₄⁺, PO₄³⁻, Coliforms, turbidity), which is promulgated by the Environmental General Department in Decision No 879/QD- TCMT dated on July 1, 2011 The purposes of the method:

+ Generally assessing water quality in the river

+ Creating fundamental data for mapping partition of water quality

+ Providing information regarding water quality to the community, and increasing community awareness about the environment

On the basis of data collected, the WQI of Nhue River is calculated as following steps:

Step 1: Calculating WQI index:

The WQI index (WQISI) is calculated based on the results of the indicators: BOD₅, COD, N-NH₄, P-PO₄, TSS, total coliform and turbidity, by the following formula:

i i

BP BP

q q WQI

qi+1: WQI value with i+1 on the table corresponding to BPi+1 value

Cp: Parameter values for calculation

Table 3.3 Specifying qi and BPi values

I q i BP i value specified with each parameter

Notes: In case, C p - the value of parameter coincides with value of BP i listed in the table,

we determined the value of WQI as the equal of the value of q i

Step 2: Calculating WQI value with regard to DO parameter (WQI DO ), based on percentage of DO saturation value:

- Calculating %DOsaturation value:

+ Determining DOsaturation value:

3 2

000077774

0 0079910

0 41022 0 652

where T: water environment temperature at the time measured (unit: °C)

+ Calculating %DOsaturation:

%DOsaturation = DOdissolved / DOsaturation *100

DOdissolved: DO value measured (unit: mg/L)

+ Calculate WQIDO value:

 p i  i i

i

i i

BP BP

q q

Cp: %DO saturation value

BPi, BPi+1, qi, qi+1 are values corresponding to i, i+1 in the Table 3.4

Table 3.4 Specifying BPi and qi values based on %DOsaturaion

I 1 2 3 4 5 6 7 8 9 10

BP i ≤20 20 50 75 88 112 125 150 200 ≥200

Notes:

If DO%saturation value ≤ 20, WQI = 1

If 20< value DO%saturation < 88, WQIDO is calculated based on formula 2 and table 3.4

If 88≤ DO%saturation value ≤ 112, WQIDO = 100

If 112< DO%saturation value < 200, WQIDO is calculated based on formula 1 and table 3.4

If DO%saturation value ≥ 200, WQIDO = 1

Step 3: Calculating WQI value with regard to pH parameter:

Table 3.5 Specified BPi and qi values in accordance with pH parameter

Step 4: Calculate WQI

After calculating the WQI based on each water quality parameter, the WQI is calculated by the following formula:

3 / 1 2

1 5

15

a pH

WQI WQI

WQI

WQI

WQI

Where:

WQI a : WQI value was calculated with 5 parameters: DO, BOD 5 , COD, N-NH 4 , P-PO 4 WQI b : WQI value was calculated with 2 parameters: TSS, turbidity

WQIc: WQI value was calculated with total coliform parameter

WQI Ph : WQI value was calculated with pH parameter

Note: After calculation WQI must be rounded to integer

Step 5: After calculating WQI, the index is classified to different levels corresponding

to water quality:

91 – 100 Good conditions for drinking water purpose Blue

76 – 90

Use of supply water for living purpose subject to suitable treatment methods

Green

51 – 75 Use for irrigation purposes and equivalent purposes Yellow

26 – 50 Use for traffic waterway and similar purposes Orange

0 – 25 Polluted water, further treatment methods required Red

IV RESULTS AND DISCUSSION

4.1 Issue of Nhue River

During the dry season Nhue River receives a high volume of wastewater from residential areas which is why the water is seriously polluted The river gathers wastewater and stormwater from a large area of Hanoi city which is about 107.503 ha The discharge leads to fish death and other impacts on the river

There are 5 rivers and lake receiving wastewater directly discharged from Hanoi (table 4.1) Nhue River is dumped by about 55,000 m3/day of wastewater If that volume of

Table 3.6 Water quality index and status of water quality

sewage is not properly treated before releasing to the river, it can cause serious environmental problems to the city and adjacent areas

Table 4.1 The volume of wastewater discharged to lakes and rivers in Hanoi

(Source: Ha Noi Environment, Science and Technology Department, 2013)

The water quality of Nhue River at Lien Mac dam can be described as follows: when the dam opens, the water quality is as good as Red River water, because alluvial only increases turbidity When the dam closes, the water is polluted by organic matters, turbidity, suspended solids, NH₄⁺, NO₂⁻; the contamination of metals and other indicators

is not significant

The water quality of the section from Cau Dien to Ha Dong Bridge: Since the water receives waste from domestic areas, industrial production and agriculture from suburban areas, Nhue River water is severely polluted The flow is dark in color and blocked by a lot

of garbage and plastic bags This status with the influence of wind causes air pollution over large area

The water quality of the section from To bridge to Thanh Tri: Since the river receives almost all discharge sources from the southern part of Hanoi city, the concentration of water quality parameters of Nhue River is quite significant, especially in

the dry season when the Lien Mac dam is closed During this period Hanoi has closed Thanh Liet dam, so that wastewater from the city is not discharged to the river, consequently water quality in this area is safe enough to supply to Phu Ly- Hanam province During the flood seasons, the river water level rises due to stormwater and waste water is diluted by rainfall; however, water quality of the river is still not up to standard

4.2 The main sources of water pollution of the lower Nhue River in Hanoi

The lower Nhue River is now strongly influenced by economic and social activities According to the investigation, the main causes of Nhue River’s pollution include:

 Domestic sewage from residential areas

 Wastewater from tourism, trade, hotels and restaurants

 Wastewater from industrial zones and small-scale industries such as handcraft villages

 Wastewater from agriculture

Along with the high population density of Hanoi, the population growth has led to

an increasing amount of wastewater Most of the domestic wastewater is not treated and directly discharged into the river This is a major source of water pollution to Nhue River

4.2.2 Industrial wastewater

Nhue River also receives about 63 million m³ of industrial wastewater; whereas Hanoi has the largest amount of wastewater, accounting for 38% of the total wastewater of the whole headwater Wastewater from industrial production facilities contains organic

ingredients, toxic chemicals, heavy metals, oil and grease However, the awareness of the people and business owners about the law for environment protection is limited Additionally, there is a lack of financial resources to invest for wastewater treatment systems, which is why the pollution becomes more and more difficult to control

4.2.3 Village wastewater

Hanoi has 1,350 villages (accounting for nearly 59% of the villages in the Northern area), including 244 traditional villages (accounting for over 50% of the total number of villages along the Nhue River) Nhue River area comprises about 39 villages including silk and weaving villages; food processing villages; pharmaceuticals; waste recycling villages; handicraft villages, embroidery; villages of building materials, stone quarrying, etc The amount of wastewater from handicraft villages is quite large; along the lower Nhue River it amounts to about 43 million m³ /year, which is equivalent to about 94,000 m³/ day; that means the organic pollution is very high

4.2.4 Hospital waste

Medical waste is a serious pollution source Along the lower section of Nhue River there are 164 hospitals and hundreds of medical centers and clinics, whose waste account for 15.17% of the total amount

Currently, the most hospitals in Hanoi do not have liquid waste treatment systems for hazardous medicals They are still trying to solve this through collecting them and storing in tanks, and processing them by microbiological methods (using chloramine B for disinfection, cleaning wastewater before discharging them directly into the general discharge system of the city)

4.2.5 Solid waste

Solid waste is another source for the pollution of surface water of Nhue River Along with the development of economic activities, the process of urbanization and the population growth lead to a constantly increasing amount of solid waste (especially in