Guidelines on the Safe Use of Urine and Faeces in ... - EcoSanRes

Caroline Schönning and Thor Axel Stenström
For waterborne sanitation systems, sewage is an important potential transmission route when
the more or less treated wastewater is discharged into a water recipient or used on agricultural
land. Dry toilets are less likely to affect surface- or groundwater. This may still be the case if
improperly constructed or localized. For dug latrines, like pit latrines, problems with transport
of pathogens from the excreta to groundwater have been recognized in areas with high
groundwater tables, or due to soil conditions favouring microbial transport. Elevating the toilet
and collecting the excreta above ground as suggested in most ecological sanitation systems
can generally avoid this. Shallow pits are an intermediate alternative and limit groundwater
contamination. The construction needs to account for overflow during heavy rains that may
result in run-off to nearby surface waters. Latrines should never be emptied in surface drainage
gutters. From a hygienic point of view, a sealed toilet collection chamber above ground is
preferred.
Figure 4. Material from ordinary pit latrines
or dry latrines should never be excavated and
drained away in drain gutters. Human exposure
to faecal contamination in storm-water drains
is a major risk for transmission of enteric and
parasitic diseases.
In Table 3 possible routes of human exposures and transmission related to dry toilets are
listed along with some counter-measures to avoid exposures. Subsequent exposures from
contaminated surface- or groundwater are not accounted for here. Instead, the measures listed
aim to prevent or minimize the faecal contamination of watercourses and the environment. It
is important to eliminate pathogens as early as possible in the handling chain since risks are
then minimized in subsequent steps.
Direct contact refers to intended or unintended contact with the excreta, e.g. touching the
material and subsequent accidental ingestion from contaminated fingers or utensils. This may
occur before treatment, during treatment including handling, or when the material is used/applied
to soil. Contamination of foodstuffs may occur directly from use but also through unhygienic
practises in the kitchen. Even if the fertilized crop will be cooked before consumption, surfaces
may be contaminated and pathogens transferred to other foods or fluids.
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