Workshop on On-site Domestic Wastewater Treatment in Asia
Tokyo, November 2013

On-site Wastewater Treatment
in Vietnam

Assoc. Prof. PhD. Viet-Anh Nguyen•Vice Director, Institute of Environmental Science and Engineering (IESE),
Hanoi University of Civil Engineering.
•Head of Science and Technology Department, Vietnam Association of Water Supplyand Sewerage (VWSA)•Contact: vietanhctn@gmail.com; +84-913209689

Content
1. Urban and rural sanitation in Vietnam
2. Technical and Management aspects of On-site andDecentralized sanitation– On-site sanitation– Decentralized wastewater treatment– Sludge management

3. Discussions
4. Conclusions and Recommendations

Nguyen Viet Anh, Nov. 2013

1. URBAN AND RURAL SANITATION
Urban water supply• 9/2013: 765 cities and towns. 32% total population.
• Total design capacity of urban water supply systems: 6.5 million m3/day.
• Actual operation capacity: 5.7 million m3/day or 89%) (from 48 to 137%
design capacity)• Urban population served with centralized water supply systems: 77% of
32.6 mio. (from 57 to 80%) through 4.7 mio. connections.
• Non-revenue water: 27.8 % (7.2 – 44.9%)• Average water consumption rate: 101 l/cap/day (from 33 to 213 l/cap/day)• Main funding source: ODA.

Nguyen Viet Anh, Nov. 2013

Urban sanitation in Vietnam•
•••
•••

•
•

Combined sewerage system is a major type of wastewater collection
32 cities have executed sewerage and sanitation projects funded by ODA
Access to toilets: > 90%
40 - 70% population have access to sanitation service (sewerage anddrainage network)
Majority of existing sanitation works in urban areas is septic tank: 80%
Only > 10% of urban wastewater is treated
18 WWTPs only treat app. 345,000m3/d of total 3,080,000 m3/d domestic
WW generated
Diversified technologies
Difficulties in operation and maintenance (cost recovery, skills, etc)

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Nguyen Viet Anh, Nov. 2013

Urban Wastewater Management


USD 250 MILLION INVESTED ANNUALLY OVER THE PAST 10YEARS

20 MUNICIPAL WWTPs CURRENTLY IN OPERATION

30 MUNICIPAL WWTPs IN PLANNING/CONSTRUCTION

94% OF URBAN POPULATION HAVE ACCESS TO HOUSEHOLD(HH) SANITATION

90% OF HHs HAVE SEPTIC TANKS

4% OF SEPTAGE DISPOSED SATISFACTORILY

60% OF HHs HAVE ACCESS TO PIPED DRAINAGE/ SEWERAGESYSTEMS

10% OF COLLECTED DRAINAGE/ SEWERAGE TREATED BYCENTRALIZED WWTPS

Nguyen Viet Anh, Nov. 20136

Urban Wastewater Management
92% OF WW CONVEYED BY USE OF COMBINEDSEWERAGE SYSTEMS (CSS)

8% OF WW CONVEYED BY USE OF SEPARATESEWERAGE SYSTEMS (SSS)

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Urban Wastewater Management

13 WWTPs RECEIVE CSS-BASED FLOW



67.5 mg/l – AVERAGE INFLUENT BOD AT WWTPs. (31 –135 mg/l: Range of annual average flows)50 mg/l – NATIONAL CLASS “B” STANDARD FOREFFLUENT BOD

TREATMENT TECHNOLOGIES UTILIZED (among 13surveyed)
ACTIVATED SLUDGE (8)ANAEROBIC PONDS (4)AEROBIC PONDS/STAB. PONDS (1)

N.V.Anh. 10.20138Urban Wastewater Management


4 WWTPs RECEIVE SSS-BASED FLOW

358 mg/l - AVERAGE INFLUENT BOD AT WWTPs (Dalatand Buon Ma Thuot WWTPs data; 336 – 380 mg/l: Rangeof annual average flows)

TREATMENT TECHNOLOGIES UTILIZED:ACTIVATED SLUDGE (2)TRICKLING FILTERS (1)STABILIZATION POND SYSTEM (1)Nguyen Viet Anh, Nov. 20139Urban Wastewater Management
98% OF FUTURE GENERATED WW FLOW WILL BE CSS-BASED (28 of 31 WASTEWATER SYSTEMS)TREATMENT TECHNOLOGIES SELECTEDo

ACTIVATED SLUDGE (26)o

CEPT/TRICKLING FILTERS (1) – WB-FUNDEDo

STABILIZATION PONDS (1) – ADB-FUNDEDoAERATED PONDS (1)o

PRIMARY SEDIMENTATION (2) – KFW-FUNDED

Nguyen Viet Anh, Nov. 201310

Rural water supply and Sanitation• 2012 (NTP3):– 80% of HHS are with toilets, among them 60% are with hygienic
toilets.
– 85% schools, 85% clinics, 50% rural markets, 80% PC buildings are withWSS facilities.
– 50% live-stock breeding are considered as hygienic including 1 mio.
biogas digesters.
– 35% communes are with solid waste collection and disposal.
– Some trade villages have sanitation planning and waste management
activities.

Nguyen Viet Anh, Nov. 2013

Major sector programs and plans• Over last 20 years: ~ USD 2 bio have been ibvested for WS,including 80% from ODA.
• 1993 … 2011: 135 international projects on urban WSS basedon loans, 67 TA projects and 98 grants have been, and are being
implemented (ADB, 2012).
• In order to provide 100% urban population with clean WS up to2020: USD 2 bio. is needed (2008).
• In order to provide 100% urban population with wastewatercollection and treatment: USD 2 … 8 bio. (WB, 2008; NVA,2011).

Nguyen Viet Anh, Nov. 2013

Government policies• More and more stakeholders have started to recognize importance ofDESA.
• This term is now mentioned more and more as a solution.
• Great efforts are to be acknowledged:– projects and activities of DESA group, IESE,– projects of GTZ and KfW, other donors,– BORDA– private investors and private DESA firms– etc.
• DESA concept and technologies have been brought into teaching curricula
at some Universities.

13Nguyen Viet Anh, Nov. 2013

Government policies (cont.)• Effluent Standard for not connected to the sewers, andsmall flows: TCVN 6772:2000 has been developed, later
replaced by the National Code QCVN 14:2008/BTNMT.
• Some technical guidelines are being compiled.
• Some thousands of DESA systems have been installed for
office buildings, public toilets, hotels, factories, hospitals,
new communities, trade villages, …

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Vietnamese National Code for wastewater effluent quality
QCVN 14:2008/BTNMTNoParameters

Column A(a)Column B(b)

1pH

5-9

5–9

2

BOD5 (20oC), mg/l30

50

3TSS, mg/l

50

100

4NH4-N, mg/l

510

5NO3-, mg/l

3050

6PO43-, mg/l

6107Total Coliforms, MPN/100 ml

3,0005,000(a) - Maximum allowable values for wastewater discharged to water bodies

serving domestic water supply purpose.
(b) - Maximum allowable values for wastewater discharged to water bodies
serving another purposes (irrigation, water transport, etc.).
Nguyen Viet Anh, Nov. 201315

2. Technical and Management Aspectsof Decentralized Sanitation
On-site sanitation options• On-site dry sanitation– UD eco-san toilet
Reuse of urine and compost– VIP• On-site wet sanitation– PF toilet + infiltration pit/trench– PF toilet + Anaerobic treatment: Biogas digester/Septictank/Improved septic tank
– Anaerobic treatment + subsurface filtration (Infiltrationtrenches, sand filter, constructed wetlands)

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Technological options (cont.)• Off-site (decentralized/centralized) sanitation– (Anaerobic treatment) + natural wastewater
treatment: WSP, CW– Conventional treatment processes– Combination: Conventional + natural processes– Package treatment systems: Anaerobic + Aerobicprocesses• Collection alternatives• Conventional combined collection system with CSO• Conventional separate collection system• Septic tank + settled sewerage• Simplified sewerage• Reuse of wastewater and sludge in irrigation, aquaculture
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Hygienic latrine Collecting and isolating of human and livestock wastefrom environment (soil, water, air, insects, …).

 Killing pathogens in the faeces.
 Clean, convenient for users including elder and children.

+Enabling for reuse of nutrients from faeces andurine for plantation, soil conditioning

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VIP latrinesNot flush water
Insects prevention
Low-cost, easy to build
When pit is full: close thepit for composting andmove toilet to another site

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percentage [%]Nutrients in Urine andFaeces

1008060
40200NPKSB Ca Mg Fe
20

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Dry ecosan toilet• No flushing water.
Separating faece andurine• To add lime or ash• Diluting urine forirrigation• 6 – 12 months
compost fordisinfection before
fertilizer• Low-cost

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Pour flush toilet

Siphon for odorcontrol
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Pour flush toilet + septic tank23
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CoverInfluent
Effluent

Septic tank
Soak pitST treatment efficiency improvement

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Baffled septic tank with anaerobic filter BASTAF(IESE – SANDEC, 1998 - 2007)
ST < BAST < STAF < BASTAF (HRT = 48 h)
50 – 60%

70 – 80%

80 – 85%

80 – 90% (COD, COD , TSS)f

•ST – Septic tank
•BAST – baffled septic tank
•STAF-septic tank with anaerobic filter•BASTAF – baffled septic tank with anaerobic filter.
Nguyen Viet Anh, Nov. 201326

PRE-FABRICATED WASTEWATER TREATMENT SYSTEMSAFSB® and BASTAFAT®

Nguyen Viet Anh, Nov. 2013

Decentralized w/w treatment technologies
Location

Technologies applied

Hospitals, hotels, apartments,
office buildings in the urbancenters(a)Activated sludge process, MBR
Tricking filter, RBC
Submerged aerated filter
A2O Jokashou and other packaged
pre-fabricated plants

Pig farms(a)Biogas digester

Vietnam Friendship Village inXuan Phuong commune, Tu
Liem district, Hanoi (2008)(b)Combined sewerage and drainage
with CSOs, BASTAF + HF CW

Low-income residential area inVinh Yen town, Vinh Phucprovince (2007) (b)Combined sewerage and drainage
with CSOs, BASTAF•A2O – anaerobic – anoxic – oxic treatment process.
•ABR – anaerobic baffled reactor.
•BASTAF – baffled septic tank with anaerobic filter.
•CSO – combined sewerage with overflow chambers.
•HF CW – horizontal flow constructed wetland(a) – implemented by different service providers.
28(b) – by DESA team, IESE.
(c) – by BORDA Vietnam

Decentralized w/w treatment technologiesLocation

Technologies applied

Xuan Mai concrete factory
residential quarter, Chuong My
district, Hanoi (2007) (b)Combined sewerage anddrainage with CSOs, BASTAF

Lai Xa village, Kim Chung
commune, Hoai Duc district, Hanoi(2006 – 2007) (b)Combined sewerage anddrainage with CSOs, BASTAF +HF CWTa Thanh Oai and Huu Hoa
communes, Thanh Tri district,Hanoi (2005) (b)Combined sewerage anddrainage with CSOs, BASTAF

Tam Da village, Tien Son district,
Bac Ninh province (2002) (b)Combined sewerage anddrainage with CSOs, BASTAF•A2O – anaerobic – anoxic – oxic treatment process.
•ABR – anaerobic baffled reactor.
•BASTAF – baffled septic tank with anaerobic filter.
•CSO – combined sewerage with overflow chambers.
•HF CW – horizontal flow constructed wetland(a) – implemented by different service providers.
29(b) – by DESA team, IESE.
(c) – by BORDA Vietnam

Decentralized w/w treatment technologies
LocationTechnologies applied

Wastewater collection andtreatment system for Cho Ra
town, Bac Kan province(b)Separate low-cost sewerage, BASTAF+ HF CWWastewater collection andtreatment system for Cho Moi
town, Bac Kan province(b)Separate low-cost sewerage, BASTAF+ HF CW

Wastewater collection andtreatment system for Nuoc Hai
town, Cao Bang province(b)Separate low-cost sewerage, BASTAF+ HF CW

Kim Bang district hospital, Ha
Nam province(c)ABR + HF CW

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Decentralized w/w treatment technologies
Location

Technologies appliedThanh Hoa Children hospital,
Thanh Hoa province(c)ABR + HF CW

Bear care center in Tam Dao
Natural park, Vinh Phucprovince(c)ABR + HF CW

Cluster in Kieu Ky Commune,
Gia Lam district, Hanoi city(c)Combined sewerage and drainage
with CSOs, ABR + HF CW

Cluster in Lim town, Bac Ninhprovince(a)Combined sewerage and drainage
with CSOs, BASTAF + Facultative
pond

Cluster in flood evacuation
cluster, An Giang province(a)Combined sewerage and drainage
with CSOs, BASTAF + Facultative
pond
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Nguyen Viet Anh, Nov. 2013

DWWM in small towns

BASTAF

HF CW

Bac Ninh – living quarter• Type of sewerage and drainage system?
• Coverage? HH connection?
• Wastewater fee collection?
Nguyen Viet Anh, Nov. 2013(Fish) Pond

Bac Kan – small town

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DWWM in peri-urban areas

Lai Xa village, Hoai Duc,Hanoi

Kieu Ky, Hanoi, Gia Lam
Type of sewerage and drainage system?
Coverage? HH connection?
Investment?
Wastewater fee collection?

VFV, Xuan Phuong, Hanoi

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Features of built systems (BASTAF + CW )Parameters

Baffled septic tank

Removal efficiency: COD = 72–
Treatment
90%; BOD = 72–83%; SS = 78–performance94%; TP = 33%; TKN= 47%

Unitconfiguratio
ns1 sedimentation chamber (50% oftotal volume) and 2–3 up-flowchambers;
HRT= 48 hours (0.2 – 0.3 m3 perperson)
Critical up-flow velocity = 0.5–0.7
m/hConstructed wetland

Removal efficiency: COD = 80 –90%; BOD = 75 – 85%; SS = 80 –95%; TN = 40 – 60%
Effluent quality: BOD < 30 mg/L
Series of vertical-flow units,
horizontal-flow units, free-water
surface units ; 2 vertical-flow units
Sizing: 14.5 m2/m3/day or 0.35
PE/m2
HRT = 4 days
Pre-treatment is required

Construction
150–200 USD/m3 of wastewater
costs(land price not included)

OperationandmaintenanceRegular harvesting of wetland
plantsRemoval of oil and grease on theCW surface
Cleansing of CW unit surface 34

Desludging frequency: 2–3 years
Reactor start-up period: 90 days
Critical hydraulic peak-flow factor=4(Morel et al, 2007)

Sludge management••

There is no effective fecal sludge management in place inVietnam.
Previous efforts have been short-lived or only seen as
demonstration efforts.
–A suitable management scheme should be instigated.
–Again, the planning with adequate resources allocation isrequired35

Find more information in:
Business Model Assessmentof Fecal Sludge Management in selected
Vietnamese cities

Assoc. Prof. Dr. Nguyen Viet Anh
Institute of Environmental Science and Engineering (IESE),
Hanoi University of Civil Engineering3. Discussions
Financing mechanisms for sanitation projects• Work order for O&M: paid by city’s budget. Part of it:collected w/w fees
• Urban w/w fee: 10% surcharge to water bill. Hai Phong city:
15%. Other cities are preparing to increase.
• For not connected households: environmental fee (10%).
(Decree No. 67/2003 to be revised)• Industrial w/w charges: Decree No. 67/2003, followed by
Decree No. 04/2007 (kg of COD, BOD, SS, heavy metals
discharged)

Nguyen Viet Anh, Nov. 2013

Major challenges in sanitation projects• Lack of knowledge of decentralised options• Quality of design and construction, associated with– consultants’ competency,– administrative appraisal procedures,• Low rate of household connection,• Capacity building component during project
implementation is poor,• Financial sustainability,• Problems in O&M, M&E• Shortage of qualified work force and skills for O&M.
• Out-sourcing services are often not available or notaffordable in the area.
• Others.
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• Technical aspects– There are still very few decentralized technical options
developed and applied.
– Systematic review has not been conducted:• DEWATS system performance, public acceptance, etc.
• Balancing of investment, and O&M costs, including
required space, manpower, energy and chemicals.
– After AD (mostly under-ground), polishing step (largespace) is required.
• Alternative options: Packaged system BASTAFAT,
Jokashou, etc.
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• Technical aspects (cont.)– Collection of wastewater: little national and international
experience in combined drains + septic tanks.
– Design guidelines are still lacking.
– Most of urban sanitation projects: neglect tertiary network.
– Most of rural sanitation projects: focus on on-site sanitation
facilities.
– Environmental sanitation and infrastructure planning of thecommunity is lacking.
– Environmental industry is still very weak. Lack of firms’
capacity for R&D, marketing strategy, etc.
– Import of hi-tech products with ‘’heavy armed’’ marketing
campaigns are contributing to weaken this young industry.
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• Financial aspects– Wastewater fees is still very low in urban areas, and zero inrural areas (Decree 88…)
– Private sector is till not interested in this business.
• No recovery for O&M and system upgrading• Lack of financial sustainability after construction works.
• Social aspects– Traditional acceptance of untreated wastewater disposal bymost of people.
– Wastewater reuse attitudes of the public and policy makers
hinder the adoption of wastewater treatment and safe reusesystems.
– The main challenge is to create informed demand for41
improved sanitation.
Nguyen Viet Anh, Nov. 2013

4. Conclusions and Recommendations
••
•
•
•

Sanitation improvement should start from household
Ecosan concept
Technical aspects
Wastewater management regulations
Sustainable sanitation model

Nguyen Viet Anh, Nov. 2013

Nguyen Viet Anh, Nov. 2013

• Technical aspects– Combination of different options– Cost-benefit analysis of different sanitation options
should be developed.
– We need information of unit costs of different sanitation
options, in different local contexts

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Other issues to be considered• Sludge management (centralized or decentralized. Resource
recovery options).
• A special National policy on DWWM is needed in order to fill thegap of sanitation coverage besides Centralized WWM.
• Together with: Codes, Standards, Technical Guidelines, local w/w
management regulations. Enabling Environmental Industry’sdevelopment.
• For sustainability:– Household connection regulation.
– O&M activities– Organization structure, management and financial models.
• DWWM in special environments: flooding, rocky soil, low density,etc.

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Source of funding for urban wastewater mgmt
in Vietnam

Nguyen Viet Anh, Nov. 201346

Recommended financing mechanisms
for wastewater investment and O&M

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CONCLUSIONS & RECOMMENDATIONS (Cont.)• Sustainable Sanitation Model

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Xin trân trọng cảm ơnThank you

Assoc. Prof. Dr. Nguyen Viet Anh
Institute of Environmental Science and Engineering (IESE), Hanoi University of Civil Engineering.
Add. 55 Giai Phong Rd. Hanoi, Vietnam. Tel. 04-3628 45 09, Fax 04-3869 3714, MP. 091320.9689,
Email. vietanhctn@gmail.com; www.epe.edu.vn
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