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Sanitation Technology Options Sanitation Technology Options


									F O R    A    H E A L T H Y                                                            N A T I O N
                                                                                                             February 2002

Technology Options

        Department: Water Affairs and Forestry
             Your partner in creating a better life for all
                                       National Sanitation Task Team
               Department: Water Affairs and Forestry, Health, Education, Provincial and Local Government,
                          Housing, Environmental Affairs and Tourism, Public Works, Treasury
F O R                        A                 H E A L T H Y                                                                   N A T I O N

  The full range of technical options for providing adequate basic sanitation is still not widely understood. In particular, there
  is little appreciation of the long-term financial implications of operating the various sanitation systems. As a result, communities
  and local governments are currently choosing technical options that, in the long term, are unaffordable and unsustainable.

  Complications arise from the wide range of options available and the differing environments in which they must be
  implemented. Experience shows that it is important to allow local solutions to be developed. The options include the
  ventilated improved pit toilet in all its variations, composting toilets and on-site wet systems such as septic tanks, and full
  water borne systems.

  Communities often face choices ranging from single pit ventilated improved latrines to double ventilated improved pit latrines
  to urine diversion/composting latrines. These options promote household management of operation and maintenance. (In
  most cases, the cost of emptying a single pit every five years is estimated at between R35 and a still-affordable R60.)
  Where higher levels of service are chosen, the costs are a lot higher - as much as R500 per household per annum. The
  initial capital cost is also dependent on the choice of technology. One of the lessons learnt from the DWAF programme is
  that it is possible to provide on-site dry systems for an initial, capital outlay of less than R1000. The Archloo, which is
  provided to many cholera-affected areas, is an example of a facility that can be provided at a cost of R600 using local
  materials and local labour - and that can be put into large-scale production. However, such provision must be coupled with
  health and hygiene promotion if health improvements are to be ensured.

  In this document you will read more about the various technical options that meet the requirements for basic sanitation.
  These need to be considered within all the sustainability requirements, e.g. affordability, operation and maintenance. The
  options are divided into two categories: Dry on-plot systems (that do not require water for operation) and wet systems (that
  do require water for operation).The following information is provided for each technical option described:

  •    A technical drawing of the recommended option
  •    A description of the options
  •    An explanation of the principles of operation
  •    Operational and institutional requirements
  •    A summary of costs
  •    Notes on previous user experiences and comments on these

  Technical guidelines are available from the Department of Water Affairs and Forestry for on-site dry sanitation.

  Please note: The capital cost of a given technology varies widely - depending on location, locally available materials,
  construction method, extent of existing infrastructure, etc.

  Options not recommended
  Unimproved pit toilet
  • This system is not recommended (subject to bad smells and insect infestation)
  A top-structure around and /or over a pit, generally unlined where soil conditions allow, with a pedestal or squat-plate.

  Chemical toilet
  • This system is not recommended (expensive and temporary)
  Various modern types. These utilise a water-diluted chemical in a receptacle below the toilet seat to render excreta harmless
  and odourless. These are generally standalone units.

  Bucket toilet
  • This system is not recommended (unhygienic sanitation system, environmentally undesirable)
  A top-structure with the seat positioned above a bucket or other container located in a small compartment beneath.

  Communal toilets
  • This system is not recommended for household use (unhygienic)
  Toilet ”blocks”, which may be based on dry or wet systems as, outlined above.
  Franceys, Pickford & Reed (WEDC) “A guide to the development of on-site sanitation”, WHO 1992. • SMLC, Johannesburg, report to Executive Committee, “Review of sanitation in
  informal settlements” 1999. • Guy Pegram, “A protocol to support peri-urban sanitation provision in the GJMC”, final draft, 2000. • Julia du Pisani, “Providing Sanitation in South Africa”,
  unpublished draft. • The Applicability of Shallow Sewer Systems in South Africa, Guy Pegram and Ian Palmer July 1999.
Dry on-plot systems
Ventilated Improved Pit (VIP) toilet

                                                                                              Fly screen

                                                                                              Vent pipe
               Air (ventilation)

                                                                                              Seat cover

                                                                                               Cover slab

                                                                                                       Pit collar
                                                                                                       (May be extended
                                                                                                       to base of pit in poor
                                                                                                       ground conditions).

                                                                                                   Hand dug
                                                                                                   or mechanically
                                                                                                   dug pit

A top-structure over a pit. The pit is vented by a pipe over which a fly-screen is fixed. The pit may be lined (recommended
                             where emptying is required), or unlined where soil conditions allow.

        Principles                        Operational and                            Costs                      Experience and
       of operation                         institutional                                                         comment
  Waste drops into the pit where       Locate to prevent ingress of        Capital: may range from R600-     Widely used internationally and
  organic material decomposes          storm water to pit, as well as in   R3000, depending on               in rural and peri-urban areas of
  and liquids percolate into the       consideration of local              householder input and choice of   South Africa. Most successful in
  surrounding soil. Continuous         groundwater use and conditions.     materials.                        water-scarce environments.
  airflow through the top-structure    Does not accept domestic                                              Failures generally due to
  and above the vent pipe              wastewater. Cannot be placed        Operating: R60 per year if        inadequate user education
  removes smells and vents gases       inside house. Ensure access for     emptied once in 5 years.          and/or poor design and
  to the atmosphere. A darkened        mechanical pit-emptying and                                           construction. Costly adaptations
  interior is maintained causing       availability of sludge treatment                                      can result where shallow rock
  insects entering the pit to be       and disposal where required.                                          or shallow water tables occur.
  attracted towards the light at the   Ensure repair/replacement of
  top of the vent pipe and trapped     damaged/worn materials.
  by the fly screen. A separate
  hand washing facility is required.
Ventilated Improved Double Pit (VIDP) toilet

    Fly screen

    Vent pipe                                                                                                Swap pedestal
                                                                                                             and vent pipe
     Air (ventilation)                                                                                       from other side
                                                                                                             if pit to be used

                                                                                                              Drop hole and
                                                                                                              vent pipe hole
   Seat cover                                                                                                 sealed when
                                                                                                              pit not in use

    Pedestal                                                                                                     Moveable cover
                                                                                                                 slab (so that pit
                                                                                                                 can be emptied)

                                                                                           Full pit

                                                                           Lined and sealed
                                                                           central wall
A single top-structure over 2 shallow pits, side by side. Only one pit - vented by a pipe protected with a fly screen - is in
     use at any time. Generally lined and the central wall fully sealed to ensure isolation of one pit from the other.

       Principles                        Operational and                             Costs                      Experience and
      of operation                         institutional                                                          comment
 As for the VIP toilet.               As for the VIP toilet, except that   Capital: R2 500-R4 500            Resistance to handling of
 One pit is used until filled to      promotion of manual emptying         depending on householder input.   decomposed waste and timely
 within about half a metre of the     by the householder is usual, and                                       changeover of pits by
 top. The defecation and vent         use of decomposed waste as a         Operating: R35-R135 every 2       householders has often been
 pipe holes are then completely       soil conditioner possible.           years depending on local          overcome through education and
 sealed and the other pit used.       Suitable disposal site necessary.    government involvement,           over time - both internationally
 The contents of the first pit are                                         householder willingness to        and in SA. This VIP alternative
 dug out after a period of at least                                        handle waste, disposal options.   is often applicable where rocky
 two years, once the contents                                                                                or groundwater conditions
 have become less harmful.                                                                                   prohibit deep excavation.
Composting/urine diversion (UD) toilet

                                                                                                  Fly screen

                                                                                                 Vent pipe

                                                                                                  Air (ventilation)

                                                                                                Access cover

      Seat cover

       Urine diversion

                    Urine outlet pipe                         Turning and removal
                    to soakaway or                           of composted material
                     collection pot                                 by hand
A single top-structure over a sealed container, which could be one of two chambers side by side (as for the VIDP), with
     access for the removal of decomposed waste. A vent pipe may be installed to encourage drying of the waste.

       Principles                     Operational and                           Costs                     Experience and
      of operation                      institutional                                                       comment
 Waste is deposited in the         Does not accept domestic           Capital (variable depending on   Control of moisture content is
 chamber and dry absorbent         wastewater. Ensure ease of         system and householder input):   vital for proper operation.
 organic material, such as wood    access by householder and          R3 000-R4 000 for commercial     Contents often become too wet,
 ash, straw or vegetable matter    promotion of manual ‘turning’ of   systems.                         making the vault difficult and
 is added after each use to        compost and removal of                                              unhygienic to empty, as well as
 deodorise decomposing faeces      composted/desiccated material.     Operating: R35-R500 per          malodorous. UD systems in SA
 and/or control moisture and       Suitable disposal site/area        annum, depending on local        still being monitored but appear
 facilitate biological breakdown   necessary.                         government involvement and       to be accepted by certain
 (composting). Urine may be                                           householder willingness to       communities and working
 separated/diverted through use                                       handle waste, and disposal       without significant problems.
 of specially adapted pedestals.                                      options.                         Burning of compost prior to
 This may be collected and used                                                                        removal also being tested in SA.
 as a fertiliser. In desiccation                                                                       Proprietary systems have been
 systems, ventilation encourages                                                                       piloted in SA, generally with
 the evaporation of moisture.                                                                          inconclusive results as to their
                                                                                                       likely success on a large scale
                                                                                                       and under varying conditions.
                                                                                                       User educational requirements
                                                                                                       and continuous input significant
                                                                                                       for proper operation in terms of
                                                                                                       the composting process.
Wet systems
Pour-flush toilet

                                                                                          Water tank to be filled
                                                                                          by hand or use a
                                                                                          separate container

                                                                                           Seat cover
                                                                                           Low flush pedestal
                                                                                           Access cover

             Water trap

                                                                                            Lined pit
A toilet with a water-seal arrangement: a pan trap fitted into the floor slab, and optionally discharging through a short stretch
                                                       of pipe or channel.

        Principles                         Operational and                           Costs                       Experience and
       of operation                          institutional                                                         comment
  After defecation, the pan             Appropriate for small volumes      Capital: R2 000-R3 500 which       International acceptance
  requires flushing with a few litres   of water and can accept            can increase where soils are not   demonstrated where water is
  of water. The water retained in       domestic wastewater - generally    well suited to drainage.           used for anal cleansing and users
  the pan provides a seal against       carried by hand to the latrine.                                       squat. Blockages occur through
  smell, flies and mosquitoes.          Ensure access for mechanical       Operating: R150-R300 per           use of inappropriate anal
                                        emptying of contained waste,       annum where subsoil drainage       cleansing material. Offset pour-
                                        and suitable subsoil drainage      is available.                      flush can allow location of toilet
                                        (high reliance on the soil                                            inside house, but generally larger
                                        environment in rendering the                                          flushing volumes are required.
                                        effluent harmless) and/or                                             Experience in SA has seen
                                        availability of sludge treatment                                      failures through lack of user
                                        and disposal.                                                         education and/or poor design and
                                                                                                              construction, use where
                                                                                                              inappropriate and limited
                                                                                                              provision of affordable emptying
Aqua-privy and soakaway

                                                                                  Fly screen

                                                                                   Vent pipe

                                                                                   Water tank may
                                                                                   be hand filled

                                                                                   Air (ventilation)

                                                                                   Seat cover

                                                                                   Low flush pedestal
                                                                                       Access cover

Down pipe maintained
below water level
            Liquid                                                                                 (soakpit or drainage trench)

            Sludge                                                                               Water tight tank

A toilet with a water-seal arrangement: a straight or curved chute running from the seat to below the water level with some
                                      form of waste collection and disposal system.

        Principles                         Operational and                            Costs                      Experience and
       of operation                          institutional                                                         comment
  After defecation, the pan             Appropriate for small volumes      Capital: R2 000-R3 500 which        International acceptance
  requires flushing with a few litres   of water and can accept            can increase where soils not well   demonstrated where water used
  of water. An aqua-privy requires      domestic wastewater - generally    suited to drainage.                 for anal cleansing and users
  the addition of water to keep the     carried by hand to the latrine.                                        squat. Blockages occur through
  end of the chute submerged.           Ensure access for mechanical       Operating: R150-R300 per            use of inappropriate anal
  Containment of the waste may          emptying of contained waste,       annum where subsoil drainage        cleansing material. Experience
  vary from a sealed container to       and suitable subsoil drainage      is available.                       in SA has seen failures through
  a solids collection system and        (high reliance on the soil                                             lack of user education and/or
  effluent soakaway.                    environment in rendering the                                           poor design and construction,
                                        effluent harmless) and/or                                              use where inappropriate and
                                        availability of sludge treatment                                       limited provision of affordable
                                        and disposal.                                                          emptying service.
Conservancy tank

                                                                                    Fly screen

                                                                                     Vent pipe

                                                                                     Air (ventilation)

                                                                                     Full / low flush toilet
                                                                                     Water trap

                                                                                          Access cover

                                                       Liquid                                                         tank


                  A storage system, i.e. a sealed tank, where low-flow or full-flush toilet systems are used.

       Principles                       Operational and                          Costs                      Experience and
      of operation                        institutional                                                       comment
 Waste is flushed into the tank       Tank sizing dependent on flush   Costs depend on size and          Widely used, particularly in more
 where it is contained in isolation   volumes, domestic wastewater     emptying frequency.               sensitive soil and geo-
 from the surrounding                 levels and frequency of                                            hydrological environments.
 environment before removal by        emptying. Ensure access for      Cost: At R2 000 - R5 000
 tanker for treatment.                mechanical emptying and          depending on top structure and
                                      availability of treatment and    tank volume.
                                      disposal facilities.
                                                                       Operating: R550 per household
                                                                       per annum (based on an
                                                                       estimated emptying cost of R181
                                                                       per tank) assuming the tank is
                                                                       emptied, on average, 3 times
                                                                       per year.
No Water Consumption System (NOWAC)

         Principles of operation           Operation and Institution                  Costs                Experience and Comment
Fill main chamber with water to           Operates:                        Capital:                       Similar systems are accepted
activate the system. No additional        • Without additional water       5000 – 6000 per unit which     internationally in echo
water will be required in future. Waste   • With only the seat as          includes:                      sensitive areas and where
drops into the water in the main            mechanical part                 • The complete system         water is scarce.
chamber where the organic material        • Without any chemicals           • The concrete top
decomposes. This process is natural                                           structure
and executed by organisms. The waste      No maintenance required for       • The transport
moves around in the main chamber for      15 – 20 years. After 15 – 20      • The installation
a period of approximately 100 days.       years the sand layer at the       • The training of each
The brown water moves into the            bottom of main chamber is           household
second chamber. This chamber is           removed with a pump after        Note: Installation costs can
fitted with an anaerobic filter and is    which the system will work for   increase in rocky areas and
situated in the main chamber. It          another 15 – 20 years.           against steep slopes.
destroys approximately 98% of al          Note: Only sand and not the
dangerous pathogens before it flows       water will be pumped out.        Operating:
over into an anaerobic filter where the                                    No costs up to 15 – 20
remains of the pathogens are                                               years.
destroyed by organisms and oxygen.
The volume of the overflow equals the
volume of the waste per person. This
overflow of uncontaminated water
flows into a soak away, which can be
seen as an additional filter.

Added: April 2006
Full bore waterborne sewerage

                                                                                       Wastewater treatment works

                                                                                                    To river




                                                                                             Inlet works

                                                            Full flush
                                                            Water trap
                                                            Rodding eye

     Household wastewater                                                                  Sewer in road reserve
   An in-house full-flush toilet connected to a sewer (pipe) network which drains to a wastewater treatment facility.

       Principles                       Operational and                          Costs                     Experience and
      of operation                        institutional                                                      comment
 Waste from the toilet, and          Requires a reliable and            Capital: R6 000-R7 000 taking   Widely used and generally the
 possibly domestic wastewater,       uninterrupted household water      bulk and sewerage costs into    aspiration of all South Africans
 is flushed using significant        connection and spatially regular   account.                        although unaffordable to many,
 volumes of water into the sewer     permanent settlements. Specific                                    particularly in terms of access
 system for removal to a             design criteria must be applied    Operating: R400-R800 per        to sufficient volumes of
 treatment facility. There are       throughout the sewerage            annum.                          household water. Appropriate
 several types of such facilities    network. Skilled, organised and                                    anal cleansing material is
 and these treat effluent to high    effective operation and                                            required. The health conse-
 standards prior to discharge into   maintenance capability is                                          quences of failure are
 the aquatic environment.            required for sewers and the full                                   devastating in comparison to on-
                                     functioning of wastewater                                          site, dry sanitation.
                                     treatment facilities.
Septic tank and soakaway or small bore solid-free sewer

                                                                                                                      Wastewater treatment works

                                                                                                                                 To river




                                                                                                                            Inlet works

                                                          Full flush toilet

                                                          Water trap                                                  B
                                                                                      Access cover
                                                                                                                          Small bore sewer to
                                                                                                                          main sewer in road
                             Scum                                                                        To option
                                                                                                         A or B
                             Sludge                                                                                          Soakaway
                                                                                                                     (soakpit or drainage trench)
                                                                 Septic tank
  Septic tank and soakaway: An in-house full flush-toilet connected via pipe and plumbing fixtures to an underground
         watertight settling chamber (the ‘digester’) with a liquids outlet to a subsoil drainage/soakaway system.

Small bore solid-free sewer: An in-house toilet discharging to a septic tank (or on-site digester) with liquids disposal via
                    a small diameter sewer to a central collection sump or existing sewer system.

       Principles                         Operational and                                Costs                       Experience and
      of operation                          institutional                                                              comment
 Septic tank and soakaway              Requires a reliable household          Capital: R7 000-R8 500.             Widely used by formal rural
 Waste from the toilet, and            water connection. Specific                                                 households and farming areas,
 generally domestic wastewater,        design criteria must be applied        Operating: R200-R450 per            where reliable water supply is
 is flushed into the settling          to the settlement tank and             emptying, depending on              available. Provides a high level
 chamber where it is retained for      soakaway system. This option           emptying frequency.                 of service and user convenience.
 at least 24hrs to allow settlement    is applicable only in areas of low                                         Failures due to poor design and
 and biological digestion. Partially   settlement density and where                                               construction, and use of
 treated liquids then pass out of      soils have a high ability to drain                                         inappropriate anal cleansing
 the tank and into the subsoil         effluent away. Ensure access                                               material. Soakaway system is
 drainage/soakaway system.             for emptying of tanks by vacuum                                            particularly prone to failure in
 Digested sludge gradually builds      tanker, as well as availability of                                         the long-term if detailed soil
 up in the tank and requires           sludge treatment and disposal.                                             testing is not carried out.
 eventual removal by tanker.
 Small bore solid-free sewer           Although its water requirements        Within the septic tank and          Not widely used in South Africa,
 As for the septic tank and            may be less than those of a            soakaway range detailed above       except where existing septic tank
 soakaway except that the liquid       septic tank and soakaway, a            if septic tank systems already in   and soakaway systems have
 effluent is conveyed by a system      household connection is needed.        place, otherwise capital cost       been converted for convenience
 of small-diameter pipes to a          Ensure access for emptying of          much higher.                        and/or environmental reasons.
 communal treatment point              septic tank, as well as availability                                       Failures as for septic tanks
 (which may be off-site treatment      of sludge treatment and disposal.                                          above, and due to lack of
 works reached either via existing     Routine maintenance of pipe                                                maintenance of the pipe
 sewerage or by tanker).               network essential.                                                         network.
Shallow sewerage

                                                                                              Wastewater treatment works

                                                                                                              To river




                                                                                                     Inlet works

                                                                      Low flush
                                                                      Water trap
                                                                                                         Sewer from
                                                                                                         next house

                                                                  Inspection box                        Junction box
A toilet, usually in-house, flushed using lower volumes of water than either conventional sewerage or septic tanks, to smaller
 diameter sewers laid at flatter gradients and shallower depths between dwellings on a block. On-site shallow inspection
                                                    chambers are provided.

        Principles                       Operational and                               Costs                     Experience and
       of operation                        institutional                                                           comment
  Waste from the toilet and           Requires reliable household             Capital: R 2500 to R 3000 -     Have not been used widely in
  possibly domestic wastewater,       availability of water and high levels   savings of up to 50% over       South Africa although used, with
  but at much lower volumes than      of connection into the sewerage         conventional sewerage capital   reported success, under a wide
  for conventional sewerage, is       system are necessary. Can,              costs.                          range of conditions in a number
  flushed into the on-site sewerage   however, be laid out in less formal                                     of South American countries,
  system and progressively            and spatially irregular settlements.    Operational: R300 - R450        Ghana, Pakistan and Greece.
  washed down to either a             Less stringent design criteria - but    assuming that all maintenance   Pilot projects have been
  dedicated treatment facility or     organised and effective operation       is provided by the service      completed in Durban and Free
  into street sewers and then on      and maintenance capability is           provider. Drops to R312 where   State, with ongoing monitoring
  to a major treatment works.         required. This can be delegated         residents are responsible for   to determine overall success and
                                      to residents for on-site sewers.        operation and maintenance of    sustanability. These indicate
                                      Significant user education and          block (not bulk) sewers.        savings of up to 50% over
                                      acceptance of shared                                                    conventional sewerage capital
                                      management of the system is
                                      critical.                                                               costs.
 Who can be contacted?
National Sanitation Task Team              DWAF Regional Offices
Department of Water Affairs and Forestry   WESTERN CAPE
Ms T Mpotulo                               Lionel Visagie
(012) 336 8811                             (021) 950 7152              
Private Bag X313                           Private Bag X16
Pretoria, 0001                             Sanlamhof
Department of Health
Zama Zincume                               MPUMALANGA
(012) 312 0503/(012) 323 0796              Richard Mbambo
                                           (013) 752 4183
Private Bag X828
Pretoria, 0001
                                           Private Bag X11259
Department of Education                    Nelspruit, 1200
Charles Sheppard
(012) 321 5470/(012) 321 5478              KWAZULU-NATAL                   Viv Naidoo
Private Bag X895                           (031) 336 2763
Pretoria, 0001                   
                                           P O Box 1018
Department of Housing                      Durban, 4000
Johan Wallis
(012) 421 1440/(012) 341 2560              FREE STATE                  Gabriël Hough
Private Bag X655                           (015) 430 3134
                                           P O Box 528
Department of Provincial and               Bloemfontein, 9300
Local Government
Zama Nofomela                              NORTHERN CAPE
(012) 334 0750/(012) 334 0769              Antonino Ross
                                           (053) 831 4125/(053) 831 5682
Private Bag X804
Pretoria ,0001
                                           P O Box 416
Department of Environmental                Kimberley, 8300
Affairs and Tourism
Lucas Mahlangu                             EASTERN CAPE
(012) 310 3536/(012) 320 1167              Mfusi Mpendu                 (043) 643 3011
Private Bag X447                 
Pretoria, 0001                             Private Bag X7485
                                           King Williams Town, 5600
Department of Treasury
Simon Maphaha                              GAUTENG
(012) 326 6311/(012) 315 5151              Johan Enslin               (012) 392 1300
Private Bag X115                 
Pretoria, 0001                             Private Bag X8007
                                           Hennopsmeer, 0046
Department of Public Works
Lorraine Malebo                            NORTH WEST
(012) 337 2764                             Logogang Bogopa
                                           (018) 384 3270/(018) 392 2998
Private Bag X65
Pretoria, 0001
                                           Private Bag X5, Mmabatho, 2735
                                           NORTHERN PROVINCE
Mr Thabo Mokoene (CEO)                     Masia Mgwambani
(012) 338 6700/29                          (015) 290 1238/(015) 295 3250            
PO Box 2094                                Private Bag X9506
Pretoria, 0001                             Pietersburg, 0700

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