26
HEALTH AND SANITATION
Grey water harvesting: what,
why, and potential impacts
Water shortages are of ever-increasing concern worldwide,
and South Africa faces great challenges in this regard.
By Water Research Commission
Historically, southern Africa is a dry region and periodic
droughts are a recurring crisis in this part of the world.
Population increases with attendant industrial expansion,
the increasing speed of urbanisation, as well as lack
of prospects to expand bulk water storage facilities
mean that the shortage of water for basic human
needs in South Africa can be expected to worsen with
every passing year — and this situation is likely to be
exacerbated by the impacts of climate change.
These realities also have a negative effect on the price of water.
Alternative sources of water are thus a national priority as well
as an economic imperative. There is growing recognition of the
potential significance of wastewater as a valuable resource and
particularly during times of critical drought. This attention tends
to wane during years of normal or above-normal rainfall, as
such usage involves extra work and added costs, and whilst it
presents certain advantages, it also has certain risks.
Several socio-cultural issues related to the management, disposal
and use of wastewater in general (and specifically to grey water
in some instances) have been raised in the literature. There is
reference to the importance of regular awareness-raising and
engagement with beneficiaries of grey water reuse systems, as
well as the importance of targeting appropriate groups of users.
Conversely, it would also be useful to determine what
socio-cultural and religious ‘barriers’ there are likely to be
that would influence uptake of these systems in certain
instances. The published grey water guideline document by
the National Academies of Science in the United States (NAP,
2015) highlights the fact that future research should focus
on understanding the behavioural impacts of grey water use
on overall water management at a household level.
The issue of social dynamics was also raised, albeit in a
different context, in a study of community-level management
of grey water in non-sewered settlements; the behaviour
of residents of informal settlements regarding water and
sanitation services was found to be conditioned to a large
extent by their current circumstances. The overall aim of this
study was to develop guidelines for the management and use
of grey water in South Africa. The document clarifies the legal
Commons
Drought conditions
are increasing
across the globe
and the use of grey
water as a resource
will become one of
the solutions.
Other references allude to the value of determining the most
important ‘influencers’ of social acceptance of home-based
water treatment systems before implementing such systems.
There is also discussion on how the use of grey water to
increase vegetable growth yields in impoverished areas can
have important psychological effects (and therefore encourage
acceptance of such use).
July 2018 Volume 24 I Number 5
www.plumbingafrica.co.za