A presentation about the science of Sludge decomposition.
Presentation about work of developing pit emptying devices, carried out by PID and Engineers Without Borders.
Local government has not yet developed an effective response to the problem of management of pit latrine waste. Practical and economical solutions must be found. This paper describes an appropriate range of options.
FULL VIP LATRINES: Sooner or later all on-site sanitation systems require emptying.
This paper looks at management of faecal waste from on-site sanitation,
technologies for emptying and other questions related to the sustainability of dry sanitation systems.
There is a widespread perception that pit latrines should not be used in areas where the groundwater is used
for domestic water consumption. South Africa=s groundwater protocol does not forbid pit latrines in such
areas, but advises caution and moreover recommends that pit latrines are located at least 75 metres from
water sources.
This paper describes local and international research in this field, and examines the justification of the 75
metre rule. What exactly are the hazards posed by pit latrines, and what are the real risk situations?
The paper describes field research which has been conducted in the Maputaland area of KwaZulu-Natal,
where there are large numbers of both pit latrines and shallow wells. The paper describes the observations
of water quality in a range of well types spread throughout the area, and also describes the water quality in the
groundwater sampled close to pit latrines. The latter were monitored for faecal coliform bacteria and nitrates.
The paper concludes that a fine sandy soil is an effective filter medium and that pit latrines pose a negligible
health risk in such an area, with the safe distance for water abstraction being more like 20 metres. The paper
shows that water quality in wells depends on well design and how the well is used. The paper shows that
properly designed and maintained wells produce water of good quality.
Seven years into the RDP, the backlog in rural sanitation has been reduced by only two percent. One of the
reasons is that practitioners and communities are still mostly locked into the idea that to build a pit latrine you
need a lined pit, a concrete slab and a concrete block superstructure. Such a latrine is far more expensive
than the R600 government subsidy. A further problem with lined pits and concrete superstructures, is that
the pit must be emptied every seven to ten years, or else the latrine must be abandoned.
One response has been to opt for mass produced, small, corrugated iron top structures. However, once the
slab and other costs are factored in, even these are more expensive than the subsidy, and their aesthetic
value is debatable.
This dilemma has led to the development of the Timber Deck VIP latrine, which requires little or no cement,
uses traditional building materials for the superstructure, is spacious and inexpensive. The Timber Deck
latrine is based on the idea that most pits do not need to be lined if the top structure can be moved when the
pit is full. If the top structure is to be moved then all materials of value must be movable. For the walls of the
structure the traditional building materials of the area are used, whether these are wattle and daub, mud
bricks, reeds or stone. The subsidy is used to pay for a 1.5 metre by 1.8 metre CCA treated, sealed and
painted timber deck (which doubles as a pit cover and latrine floor), a vent pipe, a fly screen, roofing, a
moulded VIP pedestal, and some assistance with construction.
This paper describes and illustrates this technology and examines the experience from three pilot projects
where it has been used.
Dry, on-site sanitation systems (mainly improved pit latrines) have been implemented widely across
Southern Africa. Until recently these systems were considered an appropriate lower cost option best
suited to a region of increasingly limited water resources. However, two important factors were not taken
into account: how should these on-site systems be managed on reaching the end of their design life (8 –
10 years) and what will be the impact of remedial measures on water resources. An innovative strategy to
utilise sludge removed from pit latrines as a nutrient source for short rotation forestry (SRF)
programmes is currently being tested in South Africa. An interdisciplinary study that seeks to identify and
overcome some of the technical, cultural and political factors that may limit the usefulness of this
approach is under way. This paper provides background to the study and describes progress made to
date.
This project investigated the potential for modifying the pour flush design, which is used widely in Asia, to
meet the needs of the South African context. The development and application of pour flush systems in Asia
was studied. Three case studies were conducted to investigate the experience of South Africans with low
flush systems in the past and related technologies were surveyed. A prototype was developed and tested
after which the technology was piloted in twenty homes for usage periods of up to eighteen months. The
systems were monitored over the course of the project and performance and user experience were assessed
at the end of the project.
The report includes the results of a survey of over 1 000 people from poor rural or peri-urban communities, approximately half of whom have to date benefited from government sanitation projects. Although the new toilets were found in general to be cleaner and freer of flies and odour, it is a concern that there was no difference found between the two groups in the likelihood of a hand washing facility being found near the toilet.
Over the years a number of aids have been produced to assist planners with the decisionmaking process required to choose an appropriate basic sanitation option for a given area. These include the Site Sanitation Planning and Reporting Aid (SSPRA) produced by Howard et al., 2000, the Norad/DWAF Decision Making Framework for Municipalities produced by Holden et al., 2005, and DWAF’s Groundwater Protocol. There is a need for a software tool that works with the user interactively to progressively eliminate unsuitable sanitation options by asking appropriate questions. There is also a need to combine much of the information required for decision making into one instrument (for example, what is a soil percolation test and how is it carried out?). The Which San? programme has been developed under the aegis of this project to go some way towards realising that goal.