Technology brief

Household sanitation

Introduction
Open defecation in fields,
bushes or beaches results indisease-causing pathogens
being spread freely, andshould be prevented. Therearemany designs of toilet,
ranging from a simple pit witha slab and superstructure, to adouble vault composting toilet
producing high quality organic
fertiliser, and any of thesewill effectively contain faecal
pathogens (provided they are
well used and maintained).
Pit toilets have proven to bea popular choice with many
people in various countries
and are highly affordable;
however it is importantthat people are given theopportunity to examine avariety of options and decide
which they would prefer.
Given sensitive guidelines
and a little technical help,
families can build toilets forthemselves at very low cost.
It should be noted that toilets
are only one part of a sanitation
system, particularly in urban
areas. This technology brief isconcerned solely with on-site
sanitation.

1 | Household sanitation

For decentralised systems and collection
and treatment of sludge please refer to thetechnology brief ‘Wastewater Treatment’.
There are three main components in toiletdesign:• Pit• Slab• Superstructure
Many variations of each component exist,
which can be interchanged to design an
optimum solution for a particular area.

Main components
Pit

If the toilet is also to be used for bathing,it might be preferable to have a largerslab, but ideally washing water should bediverted to a separate soakaway.
The slab needs to be strong and easy tokeep clean. Concrete is a good material,and should be used in combination withsteel reinforcement. If none is available,
strength can be achieved by using a
domed shape. Raised “footpads” should becast into the slab and, unless of a domed
design, the slab should be shaped so thatliquid drains towards the central hole.
Larger slabs should not be cast over the pit,
and should be preferably cast in two pieces(for easier transport). Casting a slab in around shape, rather than square, meansthat it can be rolled to its destination.

The pit for a family toilet should be about
1.2m in diameter (this is the smallest
dimension that can be dug conveniently),
with the base of the pit above the watertable. The pit can be built (partially orwholly) above ground level and the depth
should generally be around 1.5m but
can be as deep as 3m. This is influenced
by family size and decisions around how
toilets will be emptied. Specifics will
depend on the particular context: forexample, urban areas or composting toilets
might require shallow pits with frequent
emptying; in unstable ground the pit walls
should be supported with timber, cementrings, stones or trapezoidal blocks.

If the slabs are to be made within thecommunities, they should be supplied withwell-designed steel or timber shuttering
for the casting, and given advice on
concrete mix proportions. Well-trained local
craftsmen must supervise the mixing andplacing of the concrete in the slab.

A twin pit system, with the superstructureand slab being used over the two pits
alternately, allows one pit to be in use
whilst the contents of the other are left
to naturally biodegrade and can have avirtually unlimited life.

Toilet design

Slab

Basic pit toilet

Slabs generally come with either a simple
hole, a pour-flush pan, or a urine diversion
system which separates faeces and urine.
The type of slab used depends on the typeof household toilet treatment system inplace, as detailed below. Most slabs can beeasily adapted to any of the three types.

A basic pit toilet comprises of a pit, slab
and superstructure, built using whatever
local materials are most appropriate. It isrecommended that toilets are upgradedfrom this basic design, as it is susceptible toflies and odours.

2 | Household sanitation

Superstructure
A superstructure can be built of any local
material. It needs to provide adequate
privacy and should be constructed with afloor, walls and a roof. Improved ventilationand other modifications will help to control
flies and odours.

The following technologies can use
interchangeable designs of pit, slab andsuperstructure.

Ventilated improved pit (VIP)
toiletsystem, urine and faeces are seen as aresource ratherthan a waste.

The ventilated improved pit (VIP) toilet
was introduced in Zimbabwe in the 1970s
and has proved successful in overcoming
problems with flies and odours.

Fig 1: Ventilated improved pit (VIP) toilet

The interior of the superstructure must be
well ventilated and darker than daylightoutside. The pit must have a ventilation
pipe which should be at least 100mm indiameter and extend from the pit to about
0.5m above the roof. The top should be
fitted with a fine-mesh stainless steel, GRP
or aluminium fly-screen. Flies attracted
by smell into the pit will be drawn up thepipe by the daylight at the top of it, and getcaught by the screen. Wind passing overthe vent pipe will also cause an up-draught,
removing any smell and helping to drawup flies. The door access should ideallyface into the prevailing wind direction tomaximise the dispersion of odour. However
if the prevailing wind direction means
the access faces the living area of thecommunity, a curved entrance should beconsidered for extra privacy.

Fly screen

Alternative pit
squat hole
temporarily seal
Alternative pit
vent pipe hole

Vent pipe

Removable
cover slab

Sludge safe formanual removal
after one year

Pit in use

Fig 2: Pour flush toilet

Pour flush toilet
In villages where people use water for anal
cleansing, pour flush toilets can be more
appropriate. The squatting slab is siteda metre or two away from the pit, which
it drains to via a communication pipe. To
prevent smells rising from the pit, a U-bendwater seal can be incorporated or a closefitting squat-hole cover fitted.
For a double pit design, a drain junction will
be needed to block the pipe to the pit not
currently in use.

Ecological sanitation
Ecological sanitation is the principle ofreturning the nutrients contained inhuman waste to the land. These toilets
are often referred to as ‘eco-san’ toilets
and are designed to biodegrade humanwaste into a humus-like soil which is safe
to handle, rich in nutrients and can be used
to increase agricultural production. In this3 | Household sanitation

Groundlevel

Cover slab

WatersealpanConnecting
drainComposting toilets
A basic composting toilet has the same
design as a basic pit toilet. A handful of a
mixture of soil and ash is added to the pit
after each use to keep the pit dry, which
limits odours. Other organic material
can also be added, such as leaves, grassclippings and vegetable waste, to aidcomposting. After being left to decompose
for 12 months, the resulting compost
can be dug out and applied to the land
as a fertilizer.

A variation on the basic composting
toilet is called the Arborloo where thesuperstructure and slab are removed to anew pit once the old pit is two thirds full.
The old pit is then filled up with soil and atree is planted inside.
The Fossa Alterna is a design with two pits
which are used alternately. One pit is useduntil it is full and then the second pit is usedwhile the first pit rests. Just before reusethe resting pit is emptied and the dug out
compost can be used as fertiliser.

The composting toilet is not appropriate forgreywater disposal. For this reason waterused for anal cleansing should be diverted
where possible, although small amounts
can be tolerated.
1.

2.

Sometime later...
Once a pit is full a tree isplanted a new hole is dug

Fig 3: Arborloo

2m

Top layerof soil

1m

Fig 4: Fossa Alterna
1.

2.

Latrine slab

4 | Household sanitation

3.

Urine-separating toilets
This toilet separates urine and faeces
by a urine diverting slab or pan. Faeces
drops into a vault, where they are stored
until all pathogens are destroyed and it
is safe for application to land and crops.
The decomposition process is aided by
the application of soil, ash or lime after
each use. It is essential that no water isallowed to enter the vault. Urine is collected
separately and can be diluted and applied
to crops. Whilst urine is theoreticallysterile, it is advisable that it is left for ashort time before use, in case of possible
contamination.

Fig 5:
Urine-separating toilets

UrineFaeces

Urine collection

Dried
Faeces

These toilets are often built above ground,making them appropriate for rocky areas or
locations with a high water table.
Vaults can take the form of buckets ortanks. If the vault is large, then the dry
matter should be periodically spread about
with a pole to prevent build up in the centre
and to facilitate drying.

Advantages and disadvantagesof Ecological Sanitation:
Advantages

Disadvantages• Creates fertiliser which can be used inagriculture•S ome communities unwilling to accept thereuse of faeces• Does not require water•R equires ash, sand or lime

• Double pits used alternately have avirtually unlimited life•C annot be used for disposal of greywateror anal cleansing water• No problems with flies or odours if usedcorrectly•R equires education and acceptance to beused correctly•R equires commitment to maintenance

5 | Household sanitation

General toilet construction

Choosing a toilet type

Full-scale demonstration toilets, preferably
showing the range of designs for toilet
slabs, should be built in each village before
the start of a sanitation project. It is vitalthat the families should be able to decide
which toilets are right for them, and notwith what is thought good for them. Eachfamily should be given detailed advice
on the siting of pit toilets (preferably
downwind, away from trees and not too
close to places where food is stored orprepared).

As well as household preferences there areoften external reasons which influence thechoice of sanitation technology. Examplesof these are given below. A compendiumof different technologies should be used toinform any decision, such as the Sandec/EAWAG tool.

The following points are also important toconsider and should be explained to thecommunity when designing their toilet:• Pit toilets should be located for convenient
access by sludge removal vehicles whererequired.
• Twin pits are preferable where possible.
• Pit toilets should not be built near trees toprevent tree roots damaging the pit• Pit toilets should be sited downhill and agood distance from the nearest well or
borehole used for water supply (there arevarying opinions on exactly how far is safe;
however, 30m is generally considered tobe adequate).
• A buffer zone of 1.5m between the baseof the pit and the water table should
be ensured to minimise contamination;
however, this is subject to the type ofaquifer/soils and hydrogeological advice
should be sought.
• Pits in unstable soils should be fully lined.
Unlined pits should be circular and should
not exceed 1.5m in diameter.
• Measures should be taken to prevent
rainwater, soil and rubbish from entering
the pit.

6 | Household sanitation•G round conditions and groundwater level:
For example, in areas of high groundwaterecosan should be considered with a raised
toilet structure. This allows for a shallower
pit and less pollution from pit contents.
•D ensity of settlement: Depending on thedensity of a settlement, toilets may not
be able to be dug fresh each time one isfilled. The method by which a toilet will be
emptied should determine its design.
•M arket for compost and/or fertiliser: If
there is no end user for the compost froma composting toilet then this may not be
an ideal solution, as the waste product will
still need to be disposed of. The extra workrequired to manage a composting toilet
needs to be offset by a useful end product.

Case study

Water Easy
ToiletFabian Odugu,
Water Easy Toilet
Supplier, Enugu,Nigeria.
WaterAid/Peter Feldman
In 2011, WaterAid ran a study of oursanitation approach in Nigeria, which
revealed that disgust – a common motive– was not motivating toilet construction
in Nigeria, and that pride was a muchstronger motivator.
To explore this further, we designed theSustainable Sanitation Project to look at
how sanitation marketing can be usedin Enugu and Ekiti states to address thecountry’s sanitation crisis. We worked witha creative agency to develop innovative,

8 | Household sanitation

pride-based promotional materials tohelp encourage people to buy sanitation
products and adopt crucial sanitation andhygiene behaviours.
By testing what motivated people, we
designed a new type of toilet slab, theWater Easy Toilet integrating a “SaTopan”, a low-flush pedestal to replace thecommon (and more expensive) U-bend.
The promotional materials helped tomake people react and in turn buy
better toilets.A note on hygiene

A note on equity and inclusion

It is very important to place handwashingfacilities near to toilets. An example of basic
handwashing facilities is the Tippy-Tap – aplastic bottle suspended on a Y-shaped stickor string with soap attached, which canbe tipped over to pour out water without
touching or contaminating the bottle.

When thinking about toilet
design,consideration should be made foraccess and ease of use. A toilet should
be sensitive to both genders and local
culture. Specific attention should be given
to menstrual hygiene issues. Users withspecial needs should be provided with anopportunity to design their own adaptations
for toilets. See the ‘equality and nondiscrimination’ section of the WaterAidwebsite.

Fig 6:
Tippy-Tap

9 | Household sanitation

Useful resources
Sanitation portal of Akvopedia
http://www.akvo.org/wiki/index.php/
Portal:Sanitation
EcoSanRes
Closing the loop on sanitation
http://www.ecosanres.org/
EAWAG / SANDEC, Compendium of
Sanitation Systems and Technologies,
http://ecompendium.sswm.info/

10 | Household sanitation

Part of a series of WaterAidtechnology briefs available atwww.wateraid.org/uk/technology

WaterAid is an international not-for-profit,
determined to make clean water, decent
toilets and good hygiene normal foreveryone, everywhere within a generation.
2018
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