WASH Cluster – Emergency Training
WTS
High water table sanitation
Session 2
Technical options for high water
table sanitation
WTS2
1
WASH Cluster – Emergency Training
WTS
Objectives of session
• Be able to list 4 of the 7 technical options
available to solve the problem of providing
sanitation in high water table locations.
• Be able to discuss the advantages and
disadvantages of each option.
• Be able to identify which option to apply
when in an emergency situation.
WTS2
2
WASH Cluster – Emergency Training
WTS
Group work
• Identify options to solve problems of pit
collapse and ground water pollution?
• Focus on:
– First phase of an emergency.
– Situation when the water table is within 4 metres of
the ground surface (not concerned with flooding or
when water table is above ground level).
• Work in groups and report back with ideas in 10
minutes.
WTS2
3
WASH Cluster – Emergency Training
st
1
•
•
•
•
•
•
•
WTS2
WTS
Phase Emergency Options
For High Water Table Locations
Open defecation fields
Shallow trench or pit latrines
Raised pit latrines
Containers
Ecological sanitation
Pollute groundwater (use conventional pit or
deep trench latrines)
Relocate site
4
WASH Cluster – Emergency Training
WTS
Design considerations
• Technical
• Financial constraints
• Socio-political issues
• Mandate of agency
• Operation and Maintenance
and
• Socio-cultural issues
WTS2
5
WASH Cluster – Emergency Training
WTS
Socio-cultural issues
• Important to listen to internally displaced
persons/users.
• Build on previous practices.
• Consider people who live near/around
the camp (if any).
WTS2
6
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
7
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
8
WASH Cluster – Emergency Training
WTS
Water table (WT) at or above
ground level (GL)
•Consider cause of
flood?
•If necessary
relocate site
•Involves
dismantling existing
camp and
organising transport
to a new location.
WTS2
9
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
10
WASH Cluster – Emergency Training
WTS
Groundwater not used for water
supply?
Remember - It is better to pollute
groundwater than have pollutants on
the ground surface - in ponds, drains
and water courses.
• Can use conventional pit latrines or deep
trench latrines.
• But only if pits can be dug.
WTS2
11
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
12
WASH Cluster – Emergency Training
WTS
Ecological sanitation (Eco-San)
Source: Harvey, 2007
or open system to
soakaway
Double-vault urine-diverting latrine
or compost latrine
WTS2
Image courtesy of WEDCC: Peter Harvey
13
WASH Cluster – Emergency Training
WTS
Example: Elevated compost latrines in
Dominican Republic
• Used in second-phase response to flood-affected
communities.
• The latrines had to be elevated, as the water-table
was less than 1m below ground-level.
• Composting latrines were deemed appropriate as there
were other latrines of this design in the area.
• Other solution involving desludgeable tanks was not
considered sustainable.
• 210 latrines were built, some for individual families
and some shared between three to six families.
• Sanitation and hygiene promotion work before, during
and after the construction was extensive and latrines
were generally used properly and kept clean.
Source: Harvey, 2007
WTS2
14
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
15
WASH Cluster – Emergency Training
WTS
WT is between GL and 2.5m.
Options where the groundwater is used as a
water supply and the water table is
within 2.5 metres of the ground level:
• Open defecation fields;
• Containers;
• Relocate site; and
• Ecosanitation.
WTS2
16
WASH Cluster – Emergency Training
WTS
Containers
This option includes the
use of:
– Bucket latrines;
– Packet latrines e.g.
peepoo bags;
– Cess pits; or
– Chemical toilets.
WTS2
17
WASH Cluster – Emergency Training
WTS
Bucket/container latrines
WTS2
18
WASH Cluster – Emergency Training
WTS
Example: Bucket latrines in Wajir,
north-east Kenya
Situation
• Groundwater table is high.
• Water supply is from shallow wells because
deep aquifer is saline.
• To avoid pollution of groundwater people use
bucket latrines.
• Poor management of transport and disposal.
Outcome
• Resulted in surface contamination and major
pollution problem!
WTS2
19
WASH Cluster – Emergency Training
WTS
Example: Chemical toilets in the
Dominican Republic
Source: Harvey, 2007
WTS2
20
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
21
WASH Cluster – Emergency Training
WTS
Where WT is between 2.5m and
3.5m below GL.
Options when groundwater is used as a
water supply and water table is between
2.5 metres and 3.5 metres below ground
level:
• Shallow pit or trench latrines; or
• Raised pit latrines.
WTS2
22
WASH Cluster – Emergency Training
WTS
Raised pit latrines
Source: Harvey, 2007
Source: Franceys, Pickford and Reed, 1992.
WTS2
23
WASH Cluster – Emergency Training
Is WT at or
above GL?
Yes
WTS
Relocate site or consider
appropriate flood sanitation
measures
– see other modules.
Site is flooded and it is
impossible to dig a pit or
construct a hygienic
latrine of any kind.
No
Is groundwater
used for water
supply?
No
Can a deep pit
latrine be dug
in the wet soil?
Yes
OK to pollute groundwater so
use conventional pit latrines or
deep trench latrines.
No
Yes
Are people
accustomed to
using Eco-San?
Yes
Consider using same
Ecological Sanitation
system that users are
familiar with.
No
Is depth to WT
over 2.5 m.?
No
Select from:
•Open defecation fields;
•Containers;
•Relocate site
Yes
Is depth to WT
over 3.5 m.?
Yes
No
Select from:
•raised pit latrine; or
•shallow pit or
trench latrine.
How to
select
the right
option?
Use conventional pit latrines or
deep trench latrines.
WTS2
24
WASH Cluster – Emergency Training
WTS
Where WT is over 3.5 metres below GL
Options when groundwater is used as a water
supply and water table is over 3.5 metres below
ground level:
• Can use conventional pit latrines or deep
trench latrines.
• Ensure bottom of pit is 1.5 metres above water
table.
• When the water table is deeper than 3.5
metres it does not generally conflict with
sanitation provision.
WTS2
25
WASH Cluster – Emergency Training
WTS
Group work
In groups of at least 2 people take one of the
specifically high water table sanitation
options and discuss;
• Advantages and disadvantages
• Include how well it solves the problems?
• And also privacy, safety, access for the
vulnerable, cultural appropriateness.
• Be ready to present back to the group in 10
minutes
WTS2
26
WASH Cluster – Emergency Training
WTS
Raised pit latrines
• Advantages
– Allows use of pit type technology.
– More hygienic and will last longer than open field or
shallow latrine options.
– Can be built with local materials.
• Disadvantages
– Not suitable if water table within 2.5 metres of GL.
– Moderately resource intensive - takes time to
construct and requires reasonable level of skilled
labour.
– Moderately costly.
– Poor access for disabled.
WTS2
27
WASH Cluster – Emergency Training
WTS
Containers
• Advantages
– Bucket latrine option relatively easy to implement.
– Options do not require digging of pits or trenches.
– Can be used regardless of water table level.
• Disadvantages
– Bucket latrines require handling of fresh excreta.
– Peepoo bags require users to change defecation
behaviour.
– Chemical toilet option is very expensive.
– Need to transport and dispose of excreta (probably
by burial off-site where water table depth is lower).
WTS2
28
WASH Cluster – Emergency Training
WTS
Pollute groundwater
• Advantages
–
–
–
–
Can use conventional pit and trench latrines.
Simple technology – familiar to users.
Excreta does not need to be handled.
Relatively low cost (note - cost increases
with pit depth).
• Disadvantage
– Ground water must not be used for water
supply.
WTS2
29
WASH Cluster – Emergency Training
WTS
Eco-San composting toilets
• Advantages
– Does not pollute groundwater.
– Provides useful compost.
• Disadvantages
– Resource intensive – takes considerable time, skill
and materials to construct.
– Very costly option.
– Only recommended if users are accustomed to using
method.
– Poor access for disabled.
WTS2
30
WASH Cluster – Emergency Training
WTS
Relocate site
• Advantages
– Enables selection of site where adequate
and safe water and sanitation services can be
provided.
– Does not pollute groundwater.
• Disadvantages
– Stressful for displaced persons.
– Logistically complex to organise.
– Very costly option.
WTS2
31
WASH Cluster – Emergency Training
WTS
Hygiene promotion
• Important to promote good hygiene
practise alongside all sanitation
interventions.
– Handwashing;
– Personal hygiene;
– Menstrual hygiene management.
WTS2
32
WASH Cluster – Emergency Training
WTS
Monitoring and evaluation
• Critical to carry out monitoring and evaluation
of latrine usage.
• Monitor:
– Usage and cleanliness
– Acceptability of facilities to users
– Health impact
• Evaluate and report back findings then design
and implement changes.
• Feed learning into Phase 2 design.
WTS2
33