INTRODUCTION TO WATER SUPPLY AND WASTEWATER MANAGEMENT IN HUE CITY, - - PowerPoint PPT Presentation

INTRODUCTION TO WATER SUPPLY AND WASTEWATER MANAGEMENT IN HUE CITY, VIETNAM

Pham Khac LIEU*, Nguyen Bac GIANG Department of Environmental Science College of Sciences, Hue University, Vietnam

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

Contents

• 1. Hue city at a glance
• 2. Water sources in Hue
• 3. Water use and supply in Hue
• 4. Wastewater management in Hue
• 5. Threats to water supply and WW

management in Hue

• 6. Remarks

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• 1. Hue City at a glance

Hue City

Phu Vang District Huong Thuy Town Huong Tra Town Huong Tra Town

Hue city

Administrative division in Vietnam

• Province/City* (都道府県)
• City/District/Town (市)
•  Ward/Commune

Thua Thien Hue Province

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• 1. Hue City at a glance

Hue City

• Area: 71.7 km2
• Population: 342,500 (2011)
• Ancient capital of Vietnam

(18th ~ first-half 20th centuries)

• A World Cultural Heritage

(since 1993 by UNESCO)

• Famous destination for

tourists, a “festival city” of Vietnam

The Citadel The King’s Tomb Source: Hue city’s Statistics Office, 2011

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• 1. Hue City at a glance

Land use (2010) Economic activities (2009)

Agriculture 22.5% Forestry 5.4% Specially used 41.2% Residential 29.1% Unused 1.8%

Industry & construction 28.5% Services & tourism 70.2% Agro- forestry 1.3%

(Source: Hue city’s Statistical Yearbook, 2010, 2011)

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

• 1. Hue City at a glance

Climate conditions

• Tropical monsoon, two seasons (dry: Mar ~ Aug, rainy:

Sep ~ Feb)

• Annual average temp.: 24-25°C (highest: 38-40°C)
• Annual rainfall: 2,500 mm

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

Source: www.huecity.gov.vn

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• 1. Hue City at a glance

Flood in Hue city

• Early flood: May- Jun., main flood: Oct.- Dec.
• No. of floods per year: 3-5 (average), 9 (highest)
• Flood amplitude: 3-5 m
• Flooding duration: 3 – 5 days

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Hue Citadel’s Gate before and during flooding

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• Surface water is major

source

• Plentiful water thanks to

high rainfall and extensive network of rivers (Huong river and its branches)

• Unequally distributed

rainfall over the seasons causes flooding in the wet, and some droughts in the dry season.

A dense river network around Hue City

• 2. Water sources in Hue

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Huong river (Perfume river)

Variation in monthly average flow rate of Huong river’s tributaries (Tinh, 2010)

• Average flow: 9,660 m3/min
• Lowest flow: 1,632 m3/min
• 2. Water sources in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

• catchment area: 2,830

km2

• 3 tributaries (2 in upper

and 1 in lower section)

• 4 branches within city’s

boundary

• irregular flow: 70 -75 % of

total flow from Oct.- Dec.

• upstream dams and

downstream barrage

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Sample pH DO, mg/L COD, mg/L BOD5, mg/L SS, mg/L NO3-N, mg/L NH4-N, mg/L PO4-P, mg/L RW1 6.6 7.7 9.7 2.5 14.1 0.3 0.1 0.1 RW2 7.2 7.0 20.5 1.3 23.0 1.0 0.3 0.1 RW3 7.1 6.6 18.0 2.5 18.1 0.8 0.1 0.1 RW4 6.9 5.7 10.5 3.8 12.7 1.8 4.2 0.0 RW5 7.2 5.7 7.6 3.2 10.2 1.2 2.1 0.0 Average 7.0 6.5 13.3 2.6 15.6 1.0 1.3 0.1 National regulation* A1 6-8.5 6.0 10 4 20 2 0.1 0.1 A2 6-8.5 5.0 15 6 30 5 0.2 0.2

Water quality of Huong River

• Generally good for domestic use
• Slightly organic, nutrient and pathogenic pollution

*National Technical Regulation for Surface Water Quality (QCVN 08:2008/BTNMT): A1-applied for surface water able to use for domestic supply without treatment. A2-applied for surface water able to use for domestic supply with appropriate treatment

Water quality of Huong river and branches in 2011 (survey data)

• 2. Water sources in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

Water quality of Huong River at Van Nien Intake and Da Vien Intake in 2011

(Source: Monitoring data by HueWACO)

5 10 15 20 25 30 35

• Jan. Feb. Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Turbidity (NTU) Van Nien Intake Da Vien Intake 0.00 0.05 0.10 0.15 0.20

• Jan. Feb. Mar Apr May Jun Jul Aug Sep Oct Nov Dec

NH4-N (mg-N/L) Van Nien Intake Da Vien Intake

Nationalstandard value

1000 2000 3000 4000 5000 Jan.Feb. Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total coliforms (MPN/100mL) Van Nien Intake Da Vien Intake

National standard value

• 2. Water sources in Hue

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3.1. Water use

• Public piped water is main use in Hue city

97% 1%2%

Public piped water Drilled wells Dug wells

Distribution of domestic water use by households in Hue city (Center

for Preventive Medicine, 2010)

• Tap water coverage:
• 100% area-based

since 2010 (HueWACO)

• 97% households

(Center for Preventive Medicine, 2010)

• 99% population-based

(HueWACO, 2013)

• 3. Water use and supply in Hue

HueWACO: Thua Thien Hue Water Supply & Construction State-owned Co.Ltd.

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

Public piped water use

• 76% for residential use
• per

capita daily consumption:

• 105 L/day (2008),
• 115 L/day (2009),
• 127 L/day (2010, 2011)

(HUEWACO, 2012).

• 123 L/day in 2011

(survey on 300 households) Public piped water use by sectors in 2011 (HueWACO)

76% 11% 6% 7% Residential Institutional Industrial Commercial

• 3. Water use and supply in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

3.2. Water supply

• HueWACO: only one water supply company
• 23 purification plants with total capacity of

185,000 m3/d for the whole province (2102)

• 3 purification plants located in Hue city with

114,500 m3/d

• Total length of network > 1600 km
• Water source: 100% surface water
• Water leakage <12%.
• 3. Water use and supply in Hue

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Tap water quality

• Meets all requirements by

National Technical Regulation

• n Drinking Water Quality

(QCVN 01:2009/BYT)

• Particularly, turbidity always 10

times lower than limitation value (0.2 NTU vs. 2.0 NTU)

• Declared Water Safety Plan in

2008 (one of three companies in South-East Asia recognized by WHO)

• 3. Water use and supply in Hue

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4.1. Wastewater generation

• Domestic WW major, industrial WW minor

– Domestic WW: 36,600 m3/d – Industrial WW: 2,000 m3/d

(our estimation based on water balance, 2010)

• Domestic wastewater generation

– 108 L/cap/d (our estimation, above mentioned) – Standard design value for for I-class city: 120 L/cap/d (Vietnam Building Code QCVN 01:2008/BXD)

• 4. Wastewater management in Hue

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• 4. Wastewater management in Hue

Huong River 48,466 m3 Public water supply system 44,104 m3 In-plant use 9% = 4,362 m3 Households 40,364 m3 38,812 m3 Water leakage 12% = 5,259 m3 Well water 4% population Grey water 36,328 m3 Seepage 3,229 m3 Septic tank Sewer 10,989 m3 Open channel 10,989m3 Culvert 14,652 m3 301.4 m3 31,496 m3 36,629 m3 Excreta (urine) 347.6 m3 8% 90% 4, 832m3 Water bodies

Water balance for Hue city (daily based) (2010)

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4.2. Domestic wastewater characteristics

Parameter 1997 2005 2006- 2007 2010- 2011 2015 design values National regulation COD, mg/L 170 223 298 181 300 N.A BOD5, mg/L 115 151 213 86 200 30 SS, mg/L 77 113 155 37 250 50 T-N, mg/L 25 15 20.9 29 40 30 (NO3-N) T-P, mg/L 11 9 1.7 3 5 6

Data source Hop et al., 1997 HEPCO, 2007 HEPCO, 2007 Our survey, 2011 HEPCO, 2007 QCVN 14:2008/ BTNMT

Domestic WW in Hue is not so strongly polluted in terms of

• rganic and nutrient contents.
• 4. Wastewater management in Hue

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4.3.Sewerage and drainage network

HEPCO: Hue Urban Environment and Public Works State-owned Co.Ltd.

• 4. Wastewater management in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

– Combined system – Components:

• 81 km of ditches, 127 km
• f sewers, 9035 manholes
• 16 km canals and rivers,
• 40 ponds

– Service coverage: ~ 30% – Gravity-principal

• peration

(HEPCO, 2013)

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In Hue Citadel: ponds and canal play important role as drainage function

Ponds Sewers& Manholes Huong River

• 4. Wastewater management in Hue

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Inundation due to poor drainage system

• Several times a year
• Estimation: rain at probability of 50%, 72 mm in 3 h 

70% of streets under 0.1 – 0.5 m (Provincial Dept. of Transportation)

Inundated after heavy rain (Oct., 2007) Inundated after heavy rain (Oct., 2009)

• 4. Wastewater management in Hue

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4.4. Domestic wastewater treatment

• At present

– No central WW treatment plant in Hue – pretreated with septic tank or simple settling tank or directly discharged into rivers, ponds,…

• On going project “Water Environment

Improvement in Hue city” (24 bill.JPY, 87% loaned

from Japan) – 1st phase (2008-2016)

• targets to south side of Huong River (new urban areas)
• construction of a MWWTP with capacity of 30,000 m3/d

– 2nd phase (after 2016):

• upgrade treatment plant in south side 40,000 m3/d
• collection and treatment system in the north side

(HEPCO, 2007; Thua Thien Hue PPC, 2009).

• 4. Wastewater management in Hue

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Planned location of WWTPs in Hue

• 4. Wastewater management in Hue

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4.5. Household sanitation (as of 2011)

• Accessibility to toilet: 97.8%
• Hygienic toilet: 95%

Treatment facilities 2006 2009 2011 Septic tank 80.4 86.7 87.1 Cesspool (seepage pit) 5.3 4.5 3.6 Double vault latrine 2.5 2.6 3.8 Ventilated pit latrine 0.7 0.8 1.2 Others 4.1 0.6 2.1 Sum (having access to toilet) 92.9 95.2 97.8

Data source: Provincial Center for Preventive Medicine, 2011

• 4. Wastewater management in Hue

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On-site treatment facilities (% of total households)

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• 5. Threats to water supply and wastewater

management in Hue Factors Possible impacts Expansion of the city

• Lower service

coverage Climate change

• More inundation
• Saline intrusion

Operation of upstream works

• Reducing peak flood
• Worse quality of

water source

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Example: Inundation under climate change (MONRE, 2012)

• Sea level rise of 1 m: about 0.4% of area of Hue city inundated
• However, annual rainfall will increase 3 – 5% (2050) and 4 – 8%

(2100), max.daily rainfall will increase 20% (scenario B2)

• 5. Threats to water supply and wastewater

management in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

Inundation map of Hue city at maximum water depth for the year 2100 under B2 scenario Source: Tran Thuc, VNU Journal of Science, 26(2010) Hue 26

Example: Upstream dams and reservoirs - possible impacts:

– Changes in flooding regime/duration – prevents from peak floods – Changes in water quality, e.g. higher Mn (II), DOC concentrations

Ta Trach Reservoir (under construction)

• Dam height = 56 m
• Dam length = 1,112m
• Storage capacity = 646 Mm3

Binh Dien Dam (operated)

• Dam height = 83.6 m
• Dam length = 362.8m
• Storage capacity = 424 Mm3

Huong Dien Reservoir (operated)

• Dam height = 82.5 m
• Dam length = 180 m
• Storage capacity = 820 Mm3

HUE

• 5. Threats to water supply and wastewater

management in Hue

GEOSS-AP/AWCI Session, Tokyo, May 27th 2014

• 6. Remarks
• Current status of water supply and WW

management in Hue city: – Good water supply practice: plentiful source, reliable supply system, high quality. – Inadequate drainage and sewerage system: low coverage, no sewage treatment, etc.⇒ health risk during inundation and flooding. – Upstream works and climate change may bring about negative impacts on water environment

• An inter-linkage study on water-related health risk

linked to flood and inundation is very important.

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GEOSS-AP/A WCI Session, T

• kyo, May 27th 2014