Presentation by Brian Clarke from the University of Surrey in the Centre for Environmental Health and Engineering, presented a talk on Water Aid to the Isle of Wight Cafe Scientifique.

1. Not Water Aid……
….but water aid to Rwanda, Aceh,
Darfur & Uganda
Water Treatment in Emergencies and
the Developing World!
Brian Clarke
Deputy Director
Centre for Environmental & Health
Engineering (CEHE)
Faculty of Engineering & Physical Sciences

2. Why is water important?
What has water ever done for you?
• You are over 60% water
• Water is in every cell of your body, except in
hair and nails
• Water dilutes and carries your waste away
• Water is used to regulate your temperature

3. Water Quality
• When it comes to water quality, either raw water or
potable supplies, always think in terms of physical,
chemical and (micro)biological features
• It doesn’t look very nice, ughhhh…
NTU, SS mg/l or particle size µm?
• It doesn’t taste very nice, but…..
organic, inorganic, toxic, hazardous, multiple, site
testing, sanitary survey?
• I feel ill, Cholera Mary’s got me again!
water related disease, faecal-oral transmission route

4. Crisps for breakfast,
couldn’t face the full
English!!

5. How do you measure microbiological
“contamination”?
• Difficult to reliably detect pathogenic
microbes in the considerable quantity flow
of a community water supply
• Pathogens can be present in relatively
small numbers and they may be present
infrequently or at irregular intervals
• Accordingly, searching for pathogens is
not a practicable means of monitoring
microbiological water quality

6. Indicator Organism & Delagua Kit
• A member of the Coli aerogenes group,
Escherichia coli, is used as an indicator
organism (not the enterotoxic variant
currently affecting Northern Germany!)

7. If a water is free of E.coli it is assumed that faecal contamination is
non-existent or Microbial monitoring thatthe
has been eliminated and in pathogens are not
present (actually these are thermotolerant coliform assumed faecal!)
field?
Zero FC/100ml not always an indication of a microbiologically safe
water !!!

8. Returning Refugees collecting
Water
Rwanda

9. Water Related Disease
• Water borne
• Diarrhoea & Dysenteries, Cholera,Typhoid
• Water washed
• Eye infections. Skin infections
• Water based
• Shistosomiasis (Bilharzia)
• Water related insect vector
• Malaria

10. Africa is big but Rwanda is small?

11. Goma and Nyabwishongwezi
Nyabwishongwezi
Goma

12. Refugee Camp 1994

13. Water Supply
• In some camps Oxfam carried out batch
treatment using alum as a coagulant &
hypochlorite disinfection
• MSF had a fleet of trucks carrying up to 2
million litres of water per day to 68 locations
in the campsites, chlorine was added as the
trucks left Lake Kivu and, after travelling for
90 - 120 minutes, was suitable for
consumption (www Susie Low MSF)

14. Batch Physico-chemical System?
Sedimentation,
Coagulant addition
and Floc settlement
Disinfection
~addition of
hypochlorite?
Supply

15. Water Related Disease
• People began to get sick, on July 18th 1994
the first cases of cholera were confirmed in
Goma town
• A laboratory identified the causative
organism as Vibrio cholerae 01, biotype El
Tor, Serotype Twawa, resistant to affordable
drugs such as doxycycline
• More than 3,000 cases of cholera were
reported the first day

17. Refugees Return
• After 3-4 years the refugees were
encouraged to return to Rwanda
• Commencing 1996 CEHE had established a
pilot plant at Nyabwishongwezi to support
DFID funded research
• 20,000 refugees and IDPs settled the
Northern part of the Akagera Game Park
• CEHE advised the UN on the development of
a community water treatment system

19. Slow Sand Filtration
• James Simpson constructed slow sand filters for the
Chelsea Water Company in London in 1829 and,
towards the end of the 19th Century, widespread
application of slow sand filtration occurred in
Europe
• Historically a significant reduction of drinking water
transmitted disease was noted in communities
supplied with slow sand filtered water ( Rachwal et
al, 1996)
• CEHE research confirmed that a multistage system
of gravel prefilters, slow sand filters and terminal
disinfection can provide effective multiple barriers to
penetration by pathogens

20. Slow Sand Filter
Supernatant
Schmutzdecke
Biologically active zone
Sand filter
Filter Support
Underdrainage

21. Microbiological Performance
Fabric
Enhanced Depth Bacteriophage Polio Virus
Slow Sand mm % Reduction % Reduction
Filter
SSF A 200 98.77 99.93
SSF B 300 99.88 99.99
SSF C 500 99.97 >99.99

22. Don’t rely on Bio-adsorption!
2-4-D Herbicide Removal

23. Protection of Slow Sand Filters with
Gravel Prefilters
• It is recognised that the operational support
required for water treatment systems will
need to be simple and affordable if they are
to obtain widespread acceptance for small
community applications in the developing
world (Clarke et Al , 1996)
• Employing upflow gravel prefilters as a form
of pretreatment considerably reduces the
risk of the slow sand filter blocking as a
result of the surface straining of particles
present in the raw water

25. Multistage Filtration System
Multiple Barrier Concept
Gravel Prefilters
Upflow 40, 20 & 10 mm
nominal gravel
Depth say 1.0 m Slow Sand Filters
Uniformity coefficient = 2
Sharp sand

29. River Intake Sampling
CEHE Research at
Nyabwishongwezi
2002

30. Abstraction from the
River Umuvumba and
Pumping to the Water
Treatment Works
Four Sedimentation
Tanks
Two Twin-stage Upflow
Gravel Prefilters
Four Fabric Enhanced
Slow Sand Filters
Supply to 15000
Disinfection and Storage people in new
in two Clearwater Tanks communities

31. Nyabwishongwezi Water Treatment Plant
immediately after construction

32. Slow Sand Filters
operating in parallel

33. Nyabwishongwezi Water Treatment Plant
Faecal Coliform
250
200 Raw
Sed. Tank
FC/100 ml
150
Prefilters
100 SSF
50
0
5 7 9 11 13 15 17
Days

34. Samples from a Multistage Filtration WTW
Raw Water, Sedimentation, Upflow Gravel Prefiltration & Slow
Sand Filtration
Nyabwishongwezi, Rwanda

36. Resources
provided by CEHE
for jar tests and
monitoring
disinfectant levels
& completing jar
tests

37. Some things you
cannot predict!

38. Timely technical advice is important?
The Nyiragongo volcano erupted in January
2002 and lava flows ran through Goma

39. Then it rained….

40. ...water + lava = steam!!

41. Oxfam Clarifier Application? ~ CEHE
assisting Oxfam in Tsunami affected
Communities in Aceh, Sumatra

42. Oxfam Field Upflow Clarifier
• Design brief to CEHE
o It had to fit in a standard Oxfam tank
o It had to handle any water quality
o It had to produce up to 10000 litres/hour
o It had to be cheap and integrate with other Oxfam
kits
• Physico-chemical treatment and clarification
• Suction side dosing (thanks to MSF, Brussels)

43. Coagulant Chemistry? (simplified)
• Alum + calcium bicarbonate =
hydroxyl aluminium floc + calcium sulphate + carbon dioxide
Al2(SO4)3 + 3Ca(HCO3)2 = 2Al(OH)3 + 3CaSO4 + 6CO2
destabilisation of colloids
combination with hardness to produce floc
• In Oxfam field work no laboratory balances are available so a weight
of 1100 grams per 1 litre of granular alum is assumed, hence Oxfam
Alum Solution, Al2(SO4)3 n H2O ~ “n” a storage issue?

44. Pump
Suction Side
Coagulant
Dosing
Disinfection
hypochlorite
Clarification
dosing
T11 Field Clarifier
Typical Oxfam
Emergency Water T45 Storage Tank Supply
Treatment System

45. Fabric Fabric fixing
filter frame
Perforated outlet pipe
Schematic
illustration of an
Oxfam Field Floc Blanket
Upflow Clarifier
Dual inlets
for raw
water &
coagulant
from the
spiral pipe
flocculator

46. Tsunami
coastline
interaction

47. Northern Sumatra, Indonesia
Lamno
Meulaboh

48. Lamno and Meulaboh
• CEHE personnel flew to Banda Aceh to
support Oxfam water treatment operations in
Lamno & Meulaboh in May
• Lamno and Meulaboh are towns that suffered
severe damage from the Tsunami
• Lamno is about the size of Ventnor and
Meulaboh a similar size to Newport
• Supervised the construction of an Oxfam
physico-chemical system with the assistance
of Indonesian colleagues

49. Lamno Town Centre

52. The Tsunami damage was severe

53. In Lamno CEHE supervised the construction of
an Oxfam clarifier

54. The Tsunami and earthquakes had totally
destroyed the adjoining water treatment works

55. Bladder Tank on Relief Organisation
Lorry

56. Whoops! It’s the rainy season, any
ideas?

57. JCB were very generous and their
machines were extremely useful…

59. Pressure Filters
• Pressure filters consist of a small pressure
vessel with a system for distributing the
influent water over the surface area of the
filter media and a drainage system for
collecting filtered water at outlet
• Filters are operated until the headloss across
the units reaches a predetermined maximum,
typically read on a pressure gauge, or the
effluent turbidity reaches a predetermined
maximum

60. Raw water
Dirty
inlet
washwater
effluent
Filtered
Washwater effluent

61. LMS Pressure Filters

62. Rainfall can present problems!

64. Tsunami Power!

68. Genocide in Western Sudan

69. Issues associated with an Emergency
Response
• Available water resources for IDPs and refugees?
• Raw water quality?
• Supply problems
• What about the “non technical” aspects of the crisis
response?
– Community locations
– Population figures
– Diplomacy
– Security
– International politics

70. Population Figure - Bredjing Camp – Central Axis
Registered refugee
Villages
Spontaneous
Lira = 800 inhabitants
Mabougin = 625 inhabitants
Bredjing = 1054 inhabitants

71. Population Figure - Bredjing Camp – Central Axis
Village
Registered refugee
Agency facilities
1000 m
Spontaneous

73. Uganda is bigger than Rwanda but is still
small by African standards?

74. Novel disinfection system in Uganda

75. Some Hazards are Unexpected?

77. Groundwater OK, jerrycans contaminated

79. Contamination of jerry cans before and after cleaning
(N.B. the numbers on the diagram represent the specific count).

83. Electrolysis & Disinfection
• All mammals need salt and,
accordingly, it is universally available
• Electrolysis of salt and water produces
sodium hypochlorite
• Disinfection by hypochlorite drip is a
practical option in the developing world
• Disinfection α Cx t ?

84. Electrolysis Research

85. Salt type Weight Time of Total Total Chlorine
Rotation Chlorine
grams seconds mg/l mg/l per gram salt
Processed 1,38 45 2000 1450
1,38 60 2000 1450
Rock 1,04 45 5000 4807
1,11 60 4000 3607
Sea 0,5 45 4000 8000
0,5 60 8000 16000

87. Sachet Water Treatment Systems
• Sachet water treatment products are
currently generating interest with UNICEF
and the main relief agencies
• PUR and Watermaker are the main products
currently under consideration by leading
Relief Agencies

88. Interesting Menu?
• The specific composition of the PUR sachet
was described by Reller et al. (2003) as
containing ferric sulphate, bentonite, sodium
carbonate, chitosan, polyacrylamide,
potassium permanganate and calcium
hypochlorite

89. Sky Juice
Membrane
Filtration Unit

90. Ceramic Candle Filters
• Ceramic candle filters can remove
particulates and micro-organisms from raw
surface water at the point of use to provide
only drinking water (2litres/day/candle?)
• Ceramics typically provide micro-filtration
• Surface blocking requires regular hand
cleaning

91. Ceramic Candle Filters
Reverse osmosis <0.0001 µm
Nano-filtration <0.001 µm
Ultra-filtration 0.005-0.01 µm
Before Use Micro-filtration 0.2-5.0 µm
After 1 Run
After Cleaning

92. Ceramic Candle SEM Surface Features
CEHE, 2004
Stefani Hong Phuk
Katadyn

93. Bacteriophage ~ similar size to pathogens?
• The bacteriophages ØX174 and PRD-1 were used in
2006 – 2007 to test the abilities of a selection of
ceramic candle filters and sachet treatment products
to reduce viral numbers from suspension
• The phage ØX174 can be used to “represent”
Norovirus, whereas the larger PRD-1 can be used to
“represent” both Rotavirus and Adenovirus
• Substantial (complete) removal of bacteria but poor
removal of viruses ( < 1 log PRD-1 )

94. The ability to make a
good value
judgement is the
mark of a true
Engineer!

97. Always give clear
instructions!

98. Eat grass, if you want to
live long enough to
enjoy your retirement!

99. Thank you ~ Any Questions
Some water problems can
appear to be very difficult,
don’t worry, there is always a
solution!
Guildford 2000