19th WEAP Annual Meeting & International Workshop

WEPA action program in Lao PDR
Sengkeo Tasaketh & Phengxay Deevanhxay
30 January – 1 February 2024, Kanagawa, Japan

Contents
Objectives of WEPA action program in Lao PDRMethodology
Findings from the field survey
Outline Draft of technical guidline
ConclusionObjectives of WEPA action program in Lao PDR:
The main objective of the action program is to provide scientific basis for
improvement of wastewater management system and strengthen the capacity of
relevant stakeholders for water environment improvement.
The specific objectives are:
1. To identify legal, institutional, financial, technical issues for improving
domestic wastewater management systems in Lao PDR
2. To study the domestic wastewater quality in public canals and performanceof some decentralized wastewater treatment facilities in 3 cities (Vientiane
capital and Luang Prabang) and , Khammouan province.
3. To develop “training material for maintenance and operation of septic tankand decentralized waste water treatment facilities"
4. To strengthen the capacity of relevant stakeholders for maintenance andoperation of septic tank and decentralized waste water treatment facilities.

Methodology
1. Literature review• Review the existing document and data
2. Conducted field survey• Interviewed decentralized wastewater treatment
facilities’ operators• Collected previous data and drawing of facilities• Conducted water quality measurement andSampling• Analyzed in the Laboratory• Period (2022 – 2023)
3. Survey team
• Officers from Department of Natural Resources
and Environment Inspection, MONRE• Lecturers and students from Department ofChemistry, Faculty of Natural Sciences, NUOL

4

Field survey in dry season and rainy season
1. Field survey in dry season
PlacesPublicCanal

BORDA
DEWATS

Johkasou
1(2)Vientiane Capital

1 (2)

3 (7)

Luang Prabang

1 (3)

1 (2)

Khammouan

Septic Tank

Sampling Date
24-25 Nov 2022

1(2)

1 (4)

30 Dec 2022
17 Jan 2023

2. Field survey in rainy season
PlacesPublicCanal

BORDA
DEWATS

Vientiane Capital

1 (2)

3 (7)

Luang Prabang

1 (3)

1 (2)

Khammouan

JohkasouSeptic Tank

1(2)

1 (1)

7 July 2023

1 (2)8-9 August 2023

1 (4)

Note:
• Number in parenthesis () is number of samples• Mainly take samples at inlet and outlet of facilities

Sampling Date

28 July 2023

Survey on wastewater quality and sampling planCity

Vientiane capital

Luang phrabang

Type of facility

Sampling point

Kualuang temple DEWATS

Inlet

OutletThongkhankham DEWATS

Inlet

OutletJohkaso at Airport terminal

Inlet

OutletSeptic tank
Canal
Septic tankNight market DEWATS
JohkasouInside
Upstream
Inlet
Inlet
Inlet
Upstream,
Middle stream

Canal

Theun Hin Boun Power Company
DEWATS Anaerobic +Camp,Constructed Wetland+ aeration
Inlet
Khounkhamdistrict,and UV
Khammouan Province

Downstream
OutletOutletOutletDownstream

Outlet7

Survey in Vientiane capital - Dry season(24-25 Nov 2022)

8

Survey in Vientiane Capital Rainy season(7 July 2023)

Survey in Luang Prabang - Dry season

9(30 Dec 2022)

10

Survey in Luang Prabang Rainy season

8-9 August 2023

11

Survey in Facility of Theun Hin Boun Power Company (Khammouan) Dry season(17 Jan 2023)

12

Survey in Facility of Theun Hin Boun Power Company (Khammouan) Rainy season

28 July 2023

13

Example of layout of decentralized wastewater treatment system

Plan viewSource: BORDA Lao

Case of community decentralized wastewater treatment system
Parameter

Inflow/
outflow

Unit

Number ofusers
COD-crDesignedcondition(2010)*

Sampling
in 2011**

Chanthavila Thisy et al (2017) time
(Nov,202 (July
2)
2023)

146
Inflow

mg/L

970

485

280

276

Outflow

mg/L

80

359

116

148

>60

149

35

57

BOD5 *,** Source:Inflow
mg/L
540
82
226
Summary Final Report-The Study on Improvement of Water Environment inVientiane City,
Lao People’s
Democratic Republic
Outflow
mg/L
28

36

162

• Effluent BOD5 is almost the same with the value in 2011. It show that the treatment facility still
operates well, maybe because desludging was conducted in August 2022.
• However, the value is slightly over effluent BOD5’s national environmental standard for community
village ( BOD5 30 mg/L)

14

400
350
300
250
200
150
100
50
0

COD-Cr -Dry Season
Influent

Eflluent (F-1)

Eflluent (F-2)
COD-Cr (mg/L)

COD-Cr (mg/L)

Result of water quality analysis – COD-Cr and BOD5
400
350
300
250
200
150
100
50
0

Eflluent (F-1)

Influent

Eflluent (F-1)

Eflluent (F-2)

BOD5-Rainny Season
Eflluent (F-2)

160
140
120
100
80
60
40
20
0

BOD5 (mg/L)

BOD5 (mg/L)

BOD5-Dry Season
Influent

COD-Cr-Rainny Season

Treatment Facilities

Treatment Facilities

160
140
120
100
80
60
40
20
0

15

Influent
Eflluent (F-1)
Eflluent (F-2)

Treatment Facilities
Treatment Facilities
Dot lines: National effluent standards for water quality control from toilets and resettlement villages (BOD5 30mg/L, COD-Cr 125 mg/L)

16

Result of water quality analysis – T-N and T-P
T-N-Dry Season
Influent

Eflluent (F-1)

100.0

Eflluent (F-2)

80.0

T-N (mg/L)

T-N (mg/L)

100.0

T-N-Rainy Season

60.0
40.0

40.0

0.0

0.0

TKN (35mg/L)

Treatment Facilities

T-P-Dry Season
Eflluent (F-1)

T-P (mg/L)

T-P (mg/L)

Treatment Facilities

Treatment Facilities

Eflluent (F-2)

60.0

20.0

Influent

Eflluent (F-1)

80.0

20.0

20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0

Influent

20.0
18.0
16.0
14.0
12.0
10.0
8.0
6.0
4.0
2.0
0.0

T-P-Rainy Season
Influent

Eflluent (F-1)

Eflluent (F-2)

Treatment Facilities

Dot lines: National effluent standards for water quality control from toilets and resettlement villages (TKN 35

Case of decentralized wastewater treatment system at THPC camp

Source: THPC

18

Case of community decentralized wastewater treatment system
Plain view

S
AF

ABR

Cross section view

Aeration pond
UV
Planted gravel filter

Source: THPC & BORDA Lao

19

Process performance (Influent & effluent water quality)
Parameters

DesignIn

Actual (2012-2022)
Eff

Influent(Average)

Performance(%)

THP-004

THP-005

<50

242

189

215

17

87

20

46

40

43

9

75

T-N

26.2

17.3

14.0

13.2

32

T-P

1.7

2.3

2.1

1.1

45

12*106

16*106

14*1060.05*106

99

TSS
BOD

540

Coliform

AVG

Effluent(Average)
THP-008

80

80

67

60

56

60

14

29

42

40

23

18

35

20

29

32

40

6

13

12

10

9

6

4

20
5

0

Removal percentage (%)

100

79

100

47

Average BOD(mg/L)

AVERAGE OF BOD5

0
2012

2013

2015

2016

2017
Inlet

2018
Outlet

2019
%

2020

2021

2022

Source: THPC

20

Result of water quality analysis• Influent: COD-Cr 36-332, mg/L, BOD5 11-150 mg/L
• Effluent BOD5 of 4 Anaerobic DEWATS• Dry season : (3) DEWATS 12-35 mg/L, (1) DEWATS 120 mg/L
• Rainy season: 8-57 mg/L
• Effluent BOD5 of DEWATS with Anaerobic-Plant gravel- Aeration anddisinfection with UV: 4-6 mg/L (Influent 11- 48 mg/L)• Effluent BOD5 of Septic tank: 45-58 mg/L
• Effluent BOD5 of Joukasou: 21- 23 mg/L

• BOD5 in national environmental standard for community village and toilet
effluent is 20-30 mg/L. BOD5 of 2 DEWATS (35 -120 mg/L), and a
Septic tank (45-58 mg/L) did not pass the effluent standard.

Facilities maintenance related findings

21

Soil got into frame, made it difficult
to open the manhole cover

Metal frame of manhole cover got
erosion, made it difficult to open the
manhole for maintenance
Holders got erosion
and broken

Facilities maintenance related findings

22

Lot of scum layer at
the sedimentationchambers, notregularly remove

Garbage, plastic in thesedimentation chamber, notregularly maintenance23

Septic Tank

Wat Siphouthabath

Consultation Meeting on the Water Environment Partnership in Asia (WEPA)
Action Programme in Lao PDR 3 February 2023 Vientiane Capital, Lao PDRConsultation Workshop on Training Material Under the WEPA Action Program

Date: 22 November 2023 Luang Prabang Province, Lao PDRConsultation Workshop Under the WEPA action Program in Lao PDR
18 January 2024 Vientiane Capital, Lao PDROutline Draft of Technical Guideline forOperation and Maintenance of Decentralized Wastewater Systems
in Lao PDRPart I Introduction of current situation for
operation and maintenance wastewaterPart III Maintenance of wastewater treatment
treatment systemsystem
1. Objectives
1. Responsibilities of operators
2. Definitions
2. Tools and equipment
3. Scope and who are the users
3. Frequency of operation and monitoring
Part II Operation of wastewater treatment
4. Basis of inspection operation of wastewater
systemtreatment system
Role and responsibility of each sectors
5. Repair and replacement the equipments
1. Natural resources and the environment sector 6. Emergency response
2. Public work and and Transport sector
Part IV Management of Sludge disposal
3. Vientiane city office management and another 1. Service providers and transporters
cites/district
2. Sludge disposal and treatment/reuse
4. Business entrepreneur
3. Permit for Desludging service company
5. System users
4. Safety of Operator
6. Service provider company desludging and5. Data recording
others
6. Financial management to be sustainable28

Findings from the field survey
1. Organic pollutant in public canals was quite high (BOD5 4-39 mg/L, COD-Cr 8-101 mg/ L,
which were higher than surface water category 4 national environmental standard (<12mg/L).
2. Some DEWATS facilities operated well and passed the effluent standard. However, BOD5 of
2 DEWATS (35 -120 mg/L), and a Septic tank (45-58mg/L) did not pass the effluent standard.
3. Manual on maintenance of DEWATS were available . However, regular monitoring andmaintenance were lacking in some facilities, especially thick layer of scum and lot of garbage
were observed in sedimentation chambers of some DEWATS facilities.
4. Some operators were lack of understanding on the technical operation of DEWATS.
5. Frame and holders of manhole cover got erosion, which made it difficult to open thechambers. User friendly design may be needed.
6. Lack of technical guideline or Standard Operation Procedure for Septic tank and fecal sludge
management.
7. Most of facilities did not have specific budget and budget plan for operation and maintenanceof the facilities.

Conclusion
By the end of the implementation period, the WEPA action
program will have achieved the following target outputs:
1) Training Curriculum for Proper Operation and Maintenanceof Domestic Decentralized Wastewater Treatment Facilities
in Lao PDR
2) Draft of Technical Guideline for Operation and Maintenanceof decentralized wastewater treatment system
3) Strengthened the capacity of relevant officers for O & M of
septic tank and decentralized waste water treatment systems andenhanced knowledge and skills of operators and relevant entities

30

References
1.
2.
3.
4.

National report on state of environment for 5 years period 2016-2020, MONRE (2021).
National Environmental Quality Standards. Pollution Control Department, MONRE (2017).
National policy on water supply, sanitation and hygiene (2019).
Vision to 2035, and 9 year strategy on development of water supply and sanitation sector (2022-2030) ,MPWT (March, 2022)
5. BORDA Laos DEWATS Service Packages.
https://borda-sea.org/wp-content/uploads/2019/02/20160721_LBOR_DEWATS-Brochure.pdf
6. Erick BaetingsO’LearyDeclan, Rapid assessment of household sanitation services Vientiane, Lao PDR.
WSP (2010).
7. Johkasou Technology JECES (2022).
8. The project for urban development master plan study in Vientiane capital. JICA. (2011).
9. Project completion report-the project for urban water environment improvement in Vientiane Capital in
the Lao People’s Democratic Republic. (JICA, 2017).
10. .
11. State of pollution Khammouane province year2020 .
12. Minaphone ChanthavilayWang, Wang Ying and Fengting Li.Hongtao. (2019). International Journal ofAdvance Research, 5(4), 335-344.
13. Water and Sanitation Program. (2016). Latrine Sales Agent Trainee Handbook (Lao PDR).
14. Agreement of Vientiane Capital’s governor on management and de-sludging service from household in
Vientiane Capital (No. 0522/VT, dated 31 May 2018)

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Acknowledgement
•
•
•
•
•
•
•
•
•
•

Ministry of the Environment, Government of Japan (Support fund for thisWEPA action program)
Institute for Global Environmental Strategies (IGES)
Department of Water supply, MPWT
Luang Prabang Urban Service Office
Vientiane City Office for Management and Service
DONREs of Vientiane Capital and Luang Prabang Province
National Academic for Politics and Public Administration
Theun Hin Boun Power Company
BORDA Lao
Lao-Japan Airport Terminal Service (L-JATS)ຂອບໃຈ
Thank youThank you