fs containment - solidarités international · 2019-10-22 · typically, the pit is at least 3 m...

16/10/2019

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IHE Delft Institute for Water Educationwww.un-ihe.org

Tineke Hooijmans

Shirish Singh

FS Containment

Containment

What is needed for containment?

• User interfase

• Collection and storage/treatment

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User interface

• Operates without flushwater;

• Excreta (both urine and faeces) fall through a drop hole;

• Toilet slab is placed over a pit;

• Hole can be closed with a lid;

Dry Toilet

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Dry Toilet

Pros

• Does not require a constant

source of water;

• Can be built and repaired with

locally available materials;

• Low CAPEX and OPEX;

• Suitable for all types of users

(sitters, squatters, washers,

wipers)

Cons

• Odours are normally

noticeable (even if the vault or

pit used to collect excreta is

equipped with a vent pipe)

• The excreta pile is visible,

except where a deep pit is

used

• Vectors such as flies are hard

to control unless fly traps and

appropriate covers are used

• Operates without water;

• Has a divider so that the user, with little effort, can divert the urine

away from the faeces;

• Urine and faeces are collected separately;

• Drying material (ash, earth) should be added into the faeces hole

after defecating;

Urine-Diverting Dry toilet (UDDT)

Source: UNHCR Emergency Sanitation Overview

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• Does not require a constant

source of water;

• No real problems with flies or

odours if used and maintained

correctly;



• Low CAPEX and OPEX



wipers)

Pros Cons

• Prefabricated models not

available everywhere;

• Requires training and

acceptance to be used

correctly;

• Is prone to misuse and

clogging with faeces;

• The excreta pile is visible;

• Men usually require a separate

Urinal for optimum collection of

urine

Urine-Diverting Dry toilet (UDDT)

• Only for collecting urine;

• Generally for men, although models for women have also been

developed;

• Most urinals use water for flushing, but waterless urinals are

becoming increasingly popular;

• About 2 litres water per flush in current design;

Urinal

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Pros

• Waterless urinals do not

require a constant source of

water


locally available materials

• Low CAPEX and OPEX

Cons

• Problems with odours may

occur if not used and

maintained correctly

• Models for women are not

widely available

Urinal

• Water is poured into the bowl to flush after using

the toilet;

• Approx. 2-3 litres of water should be sufficient;

• Water seal prevent odour and flies coming back

from the pipe;

Pour Flush Toilet

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Pros

• The water seal effectively

prevents odours;

• The excreta of one user are

flushed away before the next

user arrives;



wipers);

• Low capital costs; operating

costs depend on the price of

water;

Cons

• Requires a constant source of

water (can be recycled water

and/or collected rainwater);

• Requires materials and skills

for production that are not

available everywhere;

• Coarse dry cleansing

materials may clog the water

seal;

Pour Flush Toilet

Controlled open defaecation

• May be considered in the acute response phase where random open

defecation is prevalent and no other sanitation in-frastructure has

been set up.

• It includes the provision of designated defecation sites and the

clearing of scattered faeces.

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Controlled open defecation

• Can be built and

repaired with locally

available materials;

• Low (but variable) capital

costs depending on land

availability;

• Rapid implementation;

• Minimises indiscriminate

open defecation

Pros Cons

• Big land area required and costs to

rehabilitate land may be significant;

• Lack of privacy;

• Difficult to manage

Shallow trench latrine

• Simple improvement on open defecation fields.

• Allows users to cover faeces and improves the overall hygiene

and convenience of an open defecation system.

• Trenches need only be 20-30cm wide and 15cm deep, and

shovels may be provided to allow each user to cover their

excreta with soil.


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Shallow trench latrine

• Can be built and

repaired with locally



costs depending on land

availability;

• Rapid implementation;

Pros Cons

• Flies and odours are noticeable;

• Limited privacy;

• Short lifespan;

• Big land area required and costs to

rehabilitate the land may be

significant

Generally

Squatting & sitting designs

Urine diversion

Commonly used materials

Wood (in situ)

Plastic (pre-fabricated)

Concrete (pre-fabricated or in situ)

Design: Slab

Excreta Managament in Emergencies by Carmen Paradiso Organization LOGO

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Collection and storage/treatment

http://ecompendium.sswm.info

Deep trench latrine


http://ecompendium.sswm.info/

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Deep trench latrine

Pros

• Inexpensive and quick to

construct;

• No water needed for operation;

• Easily understood

Cons

• Unsuitable for areas with high

water-table, unstable soil, rocky

ground or prone to flooding;

• Often odour and fly problems

and issues with other vectors;

• Needs appropriate faecal

sludge management concept;

• Groundwater contamination

might be an issue

Borehole latrine

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Borehole latrine

Pros

• Inexpensive;

• Quick to construct;

• No water needed for operation;

• Little space required

Cons

• Unsuitable for areas with high

water-table, unstable soil and

rocky ground;

• Often odour and fly problems;

• Groundwater contamination

might be an issue;

• Drilling machine is needed;

• Relatively short lifetime

• Excreta, along with anal cleansing materials

(water or solids) are deposited into a pit;

• Lining the pit prevents it from collapsing and

provides support to the superstructure.

• Average, solids accumulate at a rate of 40 to

60 L per person/year and up to 90 L per

person/year if dry cleansing materials are

used.

• Minimum volume of the pit should be 1,000 L.

Typically, the pit is at least 3 m deep and 1 m

in diameter.

• To prevent groundwater contamination, the

bottom of the pit should be at least 2 m above

groundwater level (rule of thumb).

• A minimum horizontal distance of 30 m

between a pit and a water source is normally

recommended to limit exposure to microbial

contamination.

Single Pit latrine

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Pros




costs depending on materials

and pit depth;

• Small land area required;

Cons

• Flies and odours are normally

noticeable;

• Low reduction in BOD and

pathogens with possible

contamination of

groundwater;

• Costs to empty may be

significant compared to

capital costs;

• Sludge requires secondary

treatment and/or appropriate

discharge;

Single Pit

• The urine storage tank should be appropriately sized to accommodate

the number of users and the time required to sanitize the urine;

• On average, a person generates about 1.2 litre urine;

• Urine should be stored at least 1 month before use;

• Containers should be made of plastic or fibre glass (mobile storage);

Urine Storage Tank/Container

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• Simple and robust technology;



• Low risk of pathogen

transmission;

• Stored urine can be used as a

fertilizer;


• No or low operating costs if

self-emptied;

Pros Cons

• Mild to strong odour when

opening and emptying tank;

• Capital costs can be high

(depending on the size and

material of the tank);

• May require frequent

emptying (depending on tank

size);

Urine Storage Tank/Container

Single Ventilated Improved Pit (VIP)

Source: C Furlong

• It is an improvement over the Single Pit because continuous airflow

through the ventilation pipe vents odours and acts as a trap for flies

as they escape towards the light.

• The vent pipe should have an internal diameter of at least 110 mm

and reach more than 300 mm above the highest point of the toilet

superstructure.

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• Flies and odours are

significantly reduced

(compared to non-ventilated

pits);




costs depending on materials

and pit depth;


Pros Cons

• Low reduction in BOD and

pathogens with possible

contamination of

groundwater;

• Costs to empty may be

significant compared to

capital costs;

• Sludge requires secondary

treatment and/or appropriate

discharge;

Single Ventilated Improved Pit (VIP)

• The double VIP has almost the same design as the Single VIP with

the added advantage of a second pit that allows it to be used

continuously and permits safer and easier emptying;

• When the second pit is almost full (the excreta is 50 cm from the top

of the pit), it is covered, and the content of the first pit is removed.

Double Ventilated Improved Pit (VIP)

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• Longer life than Single VIP

(indefinite if maintained properly);

• Excavation of humus is easier

than faecal sludge;

• Significant reduction in

pathogens;

• Potential for use of stored faecal

material as soil conditioner;

• Flies and odours are significantly

reduced (compared to non-

ventilated pits);



Pros Cons

• Manual removal of humus is

required;

• Possible contamination of

groundwater;

• Higher capital costs than

Single VIP; but reduced

operating costs if self-

emptied;

Double Ventilated Improved Pit (VIP)

• Compared to the Double VIP, which is just designed to collect, store

and partially treat excreta, the Fossa Alterna is designed to make an

earth-like product that can be used as a nutrient-rich soil conditioner;

• Cover material (soil, ash, and/or leaves) should be added to the pit

after defecation (not urination);

• The full pit degrades while the second pit is filling (ideally, one year);

Fossa Alterna

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Pros

• Because double pits are used alternately, their life is virtually unlimited;

• Excavation of humus is easier than faecal sludge;

• Significant reduction in pathogens;

• Generates nutrient-rich humus with good potential for use as soil

conditioner;

• Flies and odours are significantly reduced (compared to non-ventilated

pits);

• Can be built and repaired with locally available materials;

• Low (but variable) capital costs depending on materials; no or low

operating costs if self-emptied;

Cons

• Requires constant source of cover material;

• Manual removal of humus is required;

• Garbage may ruin end-use opportunities of the product;

Fossa Alterna

• This technology consists of two alternating pits connected to a Pour

Flush Toilet;

• As this is a water-based (wet) technology, the full pits require a

longer retention time (two years is recommended) to degrade the

material before it can be excavated safely)

Twin Pits for Pour Flush

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Pros

• Because double pits are used alternately,

their life is virtually unlimited;

• Excavation of humus is easier than FS;


• Potential for use of stored faecal material as

soil conditioner;

• Flies and odours are significantly reduced

(compared to pits without a water seal);

• Can be built and repaired with locally


• Low (but variable) capital costs depending on

materials; no or low operating costs if self-

emptied;


Cons

• Manual removal of

humus is required;

• Clogging is frequent

when bulky cleansing

materials are used;

• Higher risk of

groundwater

contamination due to

more leachate than with

waterless systems;

Twin Pits for Pour Flush

• Alternative to pit-based latrines in areas with rocky ground, high

water tables or flood affected areas.

• Depending on site conditions they can either be built as

autonomous facilities entirely above ground with a holding tank

below the user interface or by raised partially above ground,

reducing the risk of groundwater contamination.

Raised Latrine

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Pros

• Applicable in areas with

challenging ground

conditions and frequent

flooding


costs Small land area

required

Cons

• Inclusive design is more

difficult than for technologies

that are not raised

• Emptying costs may be

significant compared to capital

costs

• Collected sludge requires

further treatment

• For above ground facilities

emptying service needs to be

in place from the design stage

Raised Latrine

• Dehydration vaults are used to collect, store and dry (dehydrate) faeces;

• Small amount of ash, lime, dry soil or dust is added to cover faeces after

every use to encourage drying, prevent flies and minimize odours;

• WHO recommends a minimum storage of 6 months if ash/lime are used

as cover material (alkaline treatment) otherwise at least 1 year for warm

climates (>20 °C average) and for 1.5 to 2 years for colder climates;

Dehydration Vaults

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Pros

• Because double vaults are used alternately, their life is virtually

unlimited;


• Potential for use of dried faeces as soil conditioner;

• No real problems with flies or odours if used and maintained correctly;

• Can be built and repaired with locally available materials;

• Suitable for rocky and/or flood prone areas or where the groundwater

table is high;

• Low (but variable) capital costs depending on materials; no or low

operating costs if self-emptied;

Cons

• Requires training and acceptance to be used correctly;

• Requires constant source of cover material;

• Manual removal of dried faeces is required;

Dehydration Vaults

Container-Based Toilet

• Faeces and urine are collected in sealable, removable containers

(also sometimes called cartridges), where they are sealed and stored

until they are transported to a Transfer Station or treatment facility.

• The portable Container-Based Toilet allows for private in-home use

and easy and convenient collection and transport.

• Very large containers also can be in-stalled below multiple latrines to

simplify emptying

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Container-Based Toilet

Pros

• No need for permanent structures, thereby accommodating the

needs of mobile, or transient residents

• Reduces risk of gender-based violence

• Can be used within the household, thereby ensuring easy access

both day and night and can also improve management of children’s

faeces

• Suitable where constraints such as risk of flooding, high water table,

rocky ground or collapsing soil exist

Cons

• Medium to high initial cost

• Depends on the quality of a regular collection service

• Need for secure disposal or treatment site

• Requires well-trained user and service personnel for use,

maintenance, servicing and monitoring

Chemical Toilet

• The Chemical Toilet, commonly referred to as a ‘porta-loo’, can be

used as an immediate solution in the acute response phase of an

emergency.

• Chemical toilets are generally contained in a single prefabricated

plastic portable unit, or cubicle, that collects human excreta in a

sealed holding tank which contains chemicals that disin-fects excreta

and/or decreases odours.

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Chemical Toilet

Pros

• Can be mobilised rapidly

• Good in terms of acceptance, dignity and containment of excreta

• Can be moved easily if needed

• Can be used in areas where digging is impossible, or in urban areas

Cons

• Expensive (particularly O & M)

• Requires daily servicing

• Impossible if there is no secured place to dump the sludge nearby

• Relatively uncommon outside Europe, North America and some parts

of Latin America

• The Worm-Based Toilet is an emerging technology that has been used

successfully in rural, peri-urban and camp settings. It consists of a pour

flush pan connected to a vermifilter (filter containing worms).

• The effluent infiltrates into the soil and the vermicompost (worm waste) is

emptied approximately every 5 years. ;

Worm-based toilet

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Pros

• No odour

• Design is adaptable to

locally available

materials

• Low emptying

frequency (> 5 years

of use)

• Easier and more

pleasant to empty

Cons

• Requires water for flushing (min 200

ml) and composting worms (100 g

per person)

• Unclear if menstrual hygiene

products can be digested by the

worms

• Bleach or other chemicals cannot be

used to clean the toilet

• Lack of evidence on O & M

Worm-based toilet

• Settling and anaerobic processes reduce solids and organics, but the

treatment is only moderate (50% of solids, 30 to 40% of BOD and a

1-log removal of E. coli);

Septic Tank

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Pros

• Simple and robust technology;

• No electrical energy is

required;

• Low operating costs;

• Long service life;

• Small land area required (can

be built underground);

Cons

• Low reduction in pathogens,

solids and organics;

• Regular desludging must be

ensured;

• Effluent and sludge require

further treatment and/or

appropriate discharge;

Septic Tank

Key considerations:

Space availability – required size

Soil conditions (including when wet)

Pit shape

Distance to water table (including during rainy season)

Available materials

Design: Pit Liners

Excreta Management in Emergencies by Carmen Paradiso Organization LOGO

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Key considerations:

• Safe (protect from the elements)

• Private (provide dignity)

• Secure (protect from harm)

• Acceptable to all users

Design: Superstructure


The design should consider their users, including:

• Children• Women• Elderly• Less mobile• Wheelchair users• Visually impaired

Consider providing individual facilities to people with special needs.

Design: Accessible Structures


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• Anal cleansing practices

• Beliefs, preferences and taboos

• Number of facilities needed

• Siting of latrines

• Availability and competency of labour

• Availability of construction materials

Key Considerations – Cultural and Technical Aspects

Excreta Management in Emergencies by Carmen Paradiso

• Menstrual hygiene management

• Hand-washing stations

• Lighting

• People with special needs

Additional Considerations

Organization LOGOExcreta Management in Emergencies by Carmen Paradiso

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IHE Delft Institute for Water Educationwww.un-ihe.org

Thank You!

Any Queries?

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fs containment - solidarités international · 2019-10-22 · typically, the pit is at least 3 m...

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