34
HEALTH AND SANITATION
Management of greywater
in unserviced settlements
Greywater quality is closely linked to the amount
(quantity) of greywater generated, with the volumes
of greywater generated per household varying greatly,
i.e. lowest in low-income households (20ℓ/d to 30ℓ/d)
and highest in households with in-house taps and an
affluent lifestyle (Morel & Diener, 2006).
By Water Research Commission
The mean greywater return in unserviced
settlements in South Africa is 75% of household
water consumption, and the housing density in
these settlements generally means that there is high
overall volumes of greywater generated, even when
the amount of water used per dwelling is relatively
low (Carden et al., 2007). Combined with the high
concentration of pollutants in greywater in informal
settlements, greywater use in these areas is generally
not recommended; rather, efforts should be focused on
its effective management.
In other words, greywater management in these areas should
be directed at disposal or off-site treatment, rather than
considering it as a resource that could be used productively
(refer to Carden et al., 2007 for specific guidance in this
regard). This is because water in these areas is generally
already ‘reused’ many times before it is disposed (e.g. bath
water used to wash laundry; laundry water used to clean
floors, etc.). The greywater emanating from non-sewered
settlements is very often of a quality resembling ‘black’
water (i.e. sewage) and is thus considered hazardous from a
pathogenic and chemical perspective.
Most of the unserviced settlements in South Africa are
in the form of high-density informal settlements. The
management of greywater in these areas is of utmost
importance and concern as it can pose a significant public
health risk to persons residing in these settlements.
As described by Winter et al. (2011, pg. 1-1), when
reporting on WRC project No. K5/1654, ‘Sustainable
options for community-level management of greywater in
settlements without on-site waterborne sanitation’:
January 2019 Volume 25 I Number 1
In non-sewered informal shack settlements in South Africa,
including those with limited waterborne services and drainage,
is that greywater often merges with toilet water and other
effluent flows, thus creating a toxic mix of contaminated water
that poses a danger to human health and the environment.
Although the per capita volume of greywater disposed on the
ground in the vicinity of shack dwellings is low, greywater
run-off often carries solid and liquid waste contaminants that
accumulate in ponds in and around settlements and are then
discharged via stormwater systems into surrounding surface
water systems.
These settlements typically have no or insufficient basic
services for water, sanitation, stormwater management
and solid waste disposal. In such an environment, it is
difficult even to identify greywater as a separate waste
stream that can be diverted (even if the quality was such
that it was suitable for further use), let alone to interest
individuals in trying to put it to beneficial use.
Furthermore, the socio-economic constraints under
which individuals in such settlements typically live
make it near impossible for them to divert financial
resources to establishing or maintaining greywater use
(e.g. irrigation) projects. This burden would then fall
on the local authority which is often operating under
constraints of its own.
The paradox here is that greywater offers great
potential for improvement in household nutritional
status and social functioning in poor rural settlements,
and in urban and peri-urban settlements around the
major metropoles of South Africa (Van Averbeke,
2007). The challenge, then, lies in identifying
conditions and limitations under which greywater
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