Technology and Management
situation of decentralized
domestic wastewaterin Vietnam
TRAN Thi Hien Hoa, Dr.,NGUYEN Viet Anh, Assoc. Prof. Dr.,
Institute of Environmental Science and Engineering (IESE),
National University of Civil Engineering (NUCE)

Contents• 1. Introduction• 2. Situation of urban and rural sanitation in
Vietnam• 3. Technical and Management aspects ofdecentralized sanitation– 3.1. On-site sanitation– 3.2. Decentralized wastewater treatment– 3.4. Sludge management• 4. Opportunities and Challenges indecentralized wastewater management• 5. Recommendations and Conclusions

1. INTRODUCTION• October 2013: 766 cities and towns, with 30% of
total population• Nov, 1st 2013: 90 million people.
• Fast urbanization processProcess of urbanization in Vietnam
over last 25 years and forecast to 2020
Year

1986

1990

1995

2000

2005

2009 2010 2011 2020

Number ofurbans

480

500

550

649

689

750

-

760

1000

Urban
population(million)

11.87 13.77 14.94 19.47

22.6

25.4

30.4

29.5
6

46.0

Rate ofurban
populationof the total
population

19.3

26.7

29.6

33.0

34

45.0

20.0

20.75 24.18(Source: Tran Hieu Nhue et.al.,2011)

Urbanization process in Vietnam over last 25
years and forecast to 2020
Number of urban

Urban population (million)

1000

50

900

45

800

40

700

35

600

30

500

25

400

20

300

15

200

10

100

5

0

0
1986 1990

1995 2000

2005
Year

2009 20102011 2020

Urban population(million)/ Rate of urban
pop. of total pop. (%)

Number of urban

Rate of urban pop. of the total pop. (%)

2. Situation of sanitation in Vietnam• Combined sewerage system• 32 cities have executed sewerage and sanitation
projects funded by ODA• Access to toilets: > 90%• 40 - 70% population have access to sanitation service(sewerage and drainage 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)

List of centralized WWTPs in Vietnamese cities

Sanitation status in Vietnam

Sanitation status in Vietnam
Grade of city

Ratio using
septic tank

Large cities (special andgrade 1, 2)
Small city (grade 3-5)50-80%

Ratio using pit
latrines or double
vault latrines
10-20%

20-50%

30-50%

Improvement of sanitation systems for urban,
peri-urban and rural areas in Vietnam is very
challenging and becoming more and more crucial
in this fast-developing country.

Conventional wastewater management

Not affordable
Big investment. Leakage.
Difficult reuseLimited participation...
Decentralized w/w management

More affordable
Less investment and O&M costs
On-site reuseEncouraging participation
Low-cost technologies
Step-wise approach…

12

Government policies– Over the last two decades: about USD 2 bio. forwater and sanitation infrastructure improvement.
– More and more stakeholders have started torecognize importance of DEWATS.
– This term is now mentioned more and more as asolution.
– Great efforts are to be acknowledged:• projects and activities of DESA group, IESE,• projects of GTZ and KfW, other donors,• BORDA, etc.
– DESA concept and technologies have beenbrought into teaching curricula at some
Universities.

13

Government policies (cont.)– Effluent Standard for not connected to the sewers,
and small flows: TCVN 6772:2000 has beendeveloped, later replaced by the National CodeQCVN 14:2008/BTNMT.
– Some technical guidelines are being compiled.
– Some thousands of DEWATS systems have been
installed for office buildings, public toilets, hotels,
factories, hospitals, new communities, tradevillages, …
14

Vietnamese National Code for wastewater
effluent quality QCVN 14:2008/BTNMT
No
1
2
3
4
5
6
7

Parameters
pH
BOD5 (20oC), mg/l
TSS, mg/l
NH4-N, mg/l
NO3-, mg/l
PO43-, mg/l
Total Coliforms,
MPN/100 ml

Column A(a) Column B(b)
5-9
5–9
30
50
50
100
5
10
30
50
6
10
3,000

5,000

(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.).

15

3. Technical and Management aspects ofdecentralized sanitation

3.1. On-site sanitation• On-site dry sanitation– UD eco-san toilet– VIP

Reuse of urine and compost• On-site wet sanitation– PF toilet + infiltration pit/trench– PF toilet + Anaerobic treatment: Biogas digester/Septic
tank/Improved septic tank
– Anaerobic treatment + subsurface filtration (Infiltration
trenches, sand filter, constructed wetlands)
16

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 + Aerobic
processes• 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,aquaculture17

Hygienic latrine Collecting and isolating of human andlivestock waste from 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

18

VIP latrinesNot flush water
Insects prevention
Low-cost, easy to build
When pit is full: close
the pit for composting
and move toilet toanother site19

percentage [%]Nutrients in Urine andFaeces

100
80
60
40
20
0
N

P

K

S

B Ca Mg Fe
20

Dry ecosan toilet• No flushingwater.
Separating
faece and urine• To add lime orash• Diluting urine for
irrigation• 6 – 12 months
compost fordisinfection
before fertilizer• Low-cost
21

Pour flush toilet

Siphon for odor
control
22

Pour flush toilet + septic tank23

3.2. On-site treatment options
Pollutants loading rate and concentration in domestic
w/w from household or cluster households
Parameter
Loading rate,
Concentration*,g/cap.dmg/lTS115-117680-1.000VS
65-85
380-500SS
35-50
200-290VSS
25-40
150-240BOD5
35-50
200-290
COD
115-125680-730
T-N
6-17
35-100NH4+-N
1-3
6-18
Nguồn số
T-P
3-5
18-29
PO43-P
1-4
6-24

Pollutant concentrations ofEffluent w/w from septic tank

• BOD5 : 120-140 mg/l
• TS: 50-100 mg/l
• NH4+-N:20-50 mg/l
• NO3--N: <1 mg/l
• T-N : 25-80 mg/l
• T-P : 10-20 mg/l
Nguồn số

CoverInfluent
Effluent

Septic tank
Infiltration well

SeptictankST treatment efficiency improvement28

Baffled septic tank with anaerobic filter BASTAF(IESE – SANDEC, 1998 - 2007)

ST <

BAST

<

50 – 60%

70 – 80%STAF
80 – 85%•ST – Septic tank
•BAST – baffled septic tank
•STAF-septic tank with anaerobic filter•BASTAF – baffled septic tank with anaerobic filter.

<

BASTAF (HRT = 48 h)
80 – 90% (COD, CODf, TSS)

29

PRE-FABRICATED WASTEWATER TREATMENT SYSTEMSAFSB® and BASTAFAT®

3.3. Decentralized w/w treatment technologies
Location

Technologies applied

Activated sludge process, MBR
Hospitals, hotels, apartments, Tricking filter, RBC
office buildings in the urban
Submerged aerated filter
centers(a)A2O Jokashou and otherpackaged pre-fabricated plants
Pig farms(a)Biogas digester
Vietnam Friendship Village in Combined sewerage and
Xuan Phuong commune, Tu
drainage with CSOs, BASTAF +Liem district, Hanoi (2008)(b) HF CW
Low-income residential area
Combined sewerage andin Vinh Yen town, Vinh Phucdrainage with CSOs, BASTAF(b)province (2007)•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.
31(b) – by DESA team, IESE.
(c) – by BORDA Vietnam

Location
Technologies applied
Xuan Mai concrete factory
Combined sewerage andresidential quarter, Chuong My
drainage with CSOs, BASTAF
district, Hanoi (2007) (b)Lai Xa village, Kim Chung
Combined sewerage andcommune, Hoai Duc district,drainage with CSOs, BASTAF
Hanoi (2006 – 2007) (b)+ HF CW
Ta Thanh Oai and Huu Hoa
Combined sewerage andcommunes, Thanh Tri district,drainage with CSOs, BASTAF(b)
Hanoi (2005)
Tam Da village, Tien Son district, Combined sewerage and
Bac Ninh province (2002) (b)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.
32(b) – by DESA team, IESE.
(c) – by BORDA Vietnam

Decentralized w/w treatment technologies
Location
Wastewater collection andtreatment system for Cho
Ra town, Bac Kan
province(b)Wastewater collection andtreatment system for Cho
Moi town, Bac Kan
province(b)Wastewater collection andtreatment system for Nuoc
Hai town, Cao Bangprovince(b)Kim Bang district hospital,
Ha Nam province(c)Technologies applied
Separate low-cost sewerage,
BASTAF + HF CW

Separate low-cost sewerage,
BASTAF + HF CW

Separate low-cost sewerage,
BASTAF + HF CW
ABR + HF CW

33Decentralized w/w treatment technologies
Location
Thanh Hoa Children
hospital, Thanh Hoa
province(c)Bear care center in Tam
Dao Natural park, Vinh
Phuc province(c)Cluster in Kieu Ky
Commune, Gia Lam
district, Hanoi city(c)Cluster in Lim town, Bac
Ninh province(a)Cluster in floodevacuation cluster, An
Giang province(a)Technologies applied
ABR + HF CW

ABR + HF CW
Combined sewerage anddrainage with CSOs, ABR + HF
CW
Combined sewerage anddrainage with CSOs, BASTAF +Facultative pond
Combined sewerage anddrainage with CSOs, BASTAF + 34
Facultative pond

DWWM in small towns

BASTAFHF CW(Fish) Pond

35

Bac Ninh – living quarter

Bac Kan – small town

• Type of sewerage and drainage system?
• Coverage? HH connection?
• Wastewater fee collection?

DWWM in peri-urban areas
Lai Xa village, Hoai Duc, Hanoi

Kieu Ky, Hanoi, Gia Lam

VFV, Xuan Phuong, Hanoi

Type of sewerage and drainage system?
 Coverage? HH connection?
 Investment?
 Wastewater fee collection?

36

Features of built systems (BASTAF + CW )Parameters

Baffled septic tank

Removal efficiency: COD = 72–
Treatment
90%; BOD = 72–83%; SS = 78–
performance
94%; TP = 33%; TKN= 47%

Unit
configurations

1 sedimentation chamber (50% of
total 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)

Operation
andmaintenanceRegular harvesting of wetland
plantsRemoval of oil and grease on the
CW surface
Cleansing of CW unit surface

Desludging frequency: 2–3 years
Reactor start-up period: 90 days
Critical hydraulic peak-flow factor=437(Morel et al, 2007)

3.4. Sludge management

Sludgetreatment

SLUDGE TREATMENT & DISPOSAL
Water line
Gas line
Sludge line

Input

Stabilization bychemicals anddisinfection

Dewatering

Raw sludge

Dewatering

Aerobic
composting

DryingFertilizer

Anaerobic
composting

Burning
For agriculture

BiogasDewatering

Landfill4. Opportunities and Challenges
in decentralized wastewater
management
Financing mechanisms for sanitation projects• Work order for O&M: paid by city’s budget. Partof it: collected w/w fees
• Urban w/w fee: 10% surcharge to water bill. Hai
Phong city: 15%. Other cities are preparing toincrease.
• For not connected households: environmentalfee (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)

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 not affordable in the area.
• Others.

42• Technical aspects– There are still very few decentralized technicaloptions 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(large space) is required.
• Alternative options: Packaged system BASTAFAT, Jokashou,
etc.

43

• Technical aspects (cont.)– Collection of wastewater: little national andinternational 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 the community is lacking.
– Environmental industry is still very weak. Lack offirms’ capacity for R&D, marketing strategy, etc.
– Import of hi-tech products with ‘’heavy armed’’marketing campaigns are contributing to weaken
this young industry.

44• Financial aspects– Wastewater fees is still very low in urban areas,
and zero in rural 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 wastewaterdisposal by most of people.
– Wastewater reuse attitudes of the public andpolicy makers hinder the adoption of wastewater
treatment and safe reuse systems.
– The main challenge is to create informed demandfor improved sanitation.
45

5. Conclusions andRecommendations• Sanitation improvement should startfrom household• Ecosan concept• Technical aspects• Wastewater management regulations• Sustainable sanitation model• 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 contexts48

Other issues to be considered• Sludge management (centralized or decentralized.
Resource recovery options).
• A special National policy on DWWM is needed inorder to fill the gap of sanitation coverage besides
Centralized WWM.
• Together with: Codes, Standards, Technical
Guidelines, local w/w management regulations.
Enabling Environmental Industry’s development.
• For sustainability:– Household connection regulation.
– O&M activities– Organization structure, management and financial models.

• DWWM in special environments: flooding, rocky
soil, low density, etc.
49• Sustainable Sanitation Model

50

Thank you very much foryour kind attentions !