1.782 environmental engineering masters of engineering project · mae la refugee camp water supply...

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1.782 Environmental Engineering Masters of Engineering ProjectFall 2007 - Spring 2008

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MAE LA REFUGEE CAMP WATER SUPPLY

25 April 2008 Mary Harding, Navid Rahimi, and Katherine Vater

MIT - CEE Master of Engineering

MAE LA REFUGEE CAMP WATER SYSTEM

| Background and Overview

| Distribution System Modeling

| Distribution System Mapping

| Water Treatment

MAE LA REFUGEE CAMP

| Karen, Karenni, and Mon refugees from Myanmar (Burma)

| 45,000 people

Vietnam

Cambodia

Bangkok

Yangon

Mandalay

Malaysia

Andam

an Sea

Thailand

Laos

Mae La refugee camp

Myanmar

ChinaYunnanIndia

Songkhla

Mergui Archipelago

Phnom PenhGulf of Thailand

Hainan

Ho Chi Minh City(Saigon)

Quy Nhon

South China Sea

Figure by MIT OpenCourseWare.

1 km

WATER SUPPLY AND GEOGRAPHY

Road

River

Spring 17

Spring 9A Tank

B Tank

M Tank

Christopher Tank

Pump T

C Tank Spring 5

Mae Sot

Thailand Myanmar


SP-9

DRINKING WATER SUPPLY OVERVIEW

Tim pump station

C Tank

Christopher Tank

B Tank

A Tank

Christopher pump station

MOI pump station

MOI Tank

Banana pump

station

SP-10

River

SPRING WATER SYSTEM OVERVIEWFilter

Source

Tap standsStorage





| Water Treatment

WATER DISTRIBUTION MODELING

| Illustration of EPANET

| Model calibration

| Example analysis of system modifications

OVERALL EPANET SYSTEM

SAMPLE RESULTS

PressuresFlows

CALIBRATION OF TAP FLOW

Compu

ted (LPM

)

Observed (LPM)

Correlation: 0.61

CALIBRATION OF PRESSURE

Compu

ted (m

)

Observed (m)

Correlation: 0.59

PRESSURE DISTRIBUTION AND LAYOUT

GEOGRAPHIAL COVERAGE: NEW TAPS

TANK LEVELS AT END OF DISTRIBUTION

17T

Hour of the morning

Leve

l (m

)

TBRings

BT1

S14Rings

CHT1

AT-Old

MOIT

S67Rings

CT

S8Rings

0

0.5

1

1.5

2

2.5

3

3.5

4

98.57.576.56 8






| Water Treatment

WATER DISTRIBUTION MAPPING

| Example visual output

| Geographical errors

| Results: Home distance to nearest tap stand Under-service volume & time

DISTANCE OF HOMES TO NEAREST TAP


SPRING 2 – LOW COVERAGE

0 25 50 100

Meters

Distance to Nearest Tap

0-25m25-50m

50-75m

75-100m

>100m

Tap Stands


ERROR ANALYSIS

| Previous AMI tap stand location data and corresponding elevation error from DEM

| Mostly: 1-2m elevation change per 15m on land | Closer to mountains: 10-15m change per 15m

HOME DISTANCE TO TAP STAND HISTOGRAM

| Assumes everyone gets water from closest tap | Nearly 50% of homes within 30-60m range | Some large outliers with distances >200m (many in SP2

region)

WATER CONSUMPTION AND TRAVEL TIMES | Trip travel times less than ~3 mins. Æ increased

consumption

| If tap within 1.5 min walk or 115 meters

WELL 1998, Guidance manual on water supply and sanitation programmes, WEDC, Loughborough, UK.

60

50

50

40

40

30

30

20

20

10

100

0

Return trip travel time (minutes)

Wat

er c

onsu

mpt

ion

(lpcd

)


WATER CONSUMPTION AND TRAVEL TIMES

| 93% of homes have tap within 115 meters

| Excluding SP2 region, over 95% of homes

WATER VOLUME DISTRIBUTION

| Recommended minimum water consumption: 7.5 liters/capita/day (WHO)

| Assuming 6 people/home Æ 50 liters/home/day

| Use EPANET model results which provides flow estimation for 88 of 129 viable tap stands

WATER VOLUME DISTRIBUTION

| 360 homes (7%) under-serviced | 6 of 88 tap stands

TIME TO COLLECT 50 LITERS

| Compare to available collection time/home | Based on taps/stand and population density | Under-serviced: additional 180 homes | Increase to 10% of homes (from 7% volume)





| Water Treatment

EXISTING WATER TREATMENT

| Disinfection by chlorination y Effective chlorination requires low turbidity levels y Treatment goal: Turbidity ≤ 10 NTU

| Horizontal-flow roughing filter at Spring 10

WATER TREATMENT OBJECTIVES

| Study effectiveness of existing filter y Improve the filter

| Design a general filter for other springs

| Determine necessary maintenance

Turb

idity

[NTU

]

2007 TURBIDITY AT SPRING 10

200

180

160

140

120

100

80

60

40

2010

0

J F M A M J J A S O N D

Month

S-10 Box A S-10 Tank

EXISTING FILTER AT SPRING 10

Internal Wall of Filter

Filter Plan View: Potential Short-circuiting

INFLOW

OUTFLOW

JANUARY 2008 MODIFICATIONS

Baffle Addition to Internal Walls of Filter

Baffles

Filter Plan View: New Flow Path

INFLOW

OUTFLOW

Salin

ity [p

pm]

RELATIVE FLOW TEST RESULTS110

100

90

80

70

60

50

40

30

20

10

0

94 min

29 min Baffles increased residence time by three times.

0 20 40 60 80 100 120 140 160

Time [minutes]

No Baffles Baffles

TURBIDITY SAMPLING

Flow Scenario Co [NTU] Ce [NTU]

Dry season, clean filter 38 6

Dry season, dirty filter 30 14

Wet season simulation, clean filter 240 14

COEFFICIENT OF FILTRATION, Λ

E = Ce = e−λL

Co

Flow Scenario C o [NTU] C e [NTU] Λ [m-1]

Dry season, clean filter 38 6 0.15

Dry season, dirty filter 30 14 0.06

Wet season simulation, clean filter 240 14 0.24

Wet season, dirty filter (extrapolation) -- -- 0.10

Efflu

ent T

urbi

dity

[NTU

]

ACHIEVING CE < 10 NTUBY LENGTHENING FILTER

50

45

40

35

30

25

20

15

10

5

0

0 5 10 12 15 20 24 25 30 35 36 40

Filter Length, L [m]

Dry Season, Clean Filter Dry Season, Dirty Filter Wet Season, Clean Filter Wet Season, Dirty Filter

CONCLUSIONS

| Spring 10 Filter Improvements y Construct second filter y Install outlet weirs

| General Filter Design y Not recommendable

| Filter Maintenance y Monitor turbidity y Clean the filter based on monitoring





| Water Treatment

2007 FLOW VOLUME BY SPRING

8% 2%

1%

14%

4%

3%

17%

26%

7%

13% SP-2 SP-4 SP-5 SP-6/7 SP-8 SP-9 SP-10 SP-11 SP-12/15 SP-14 SP-17

5%

1.782 environmental engineering masters of engineering project · mae la refugee camp water supply...

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