Outcomes and findings
Water sustains life and it is in public interest
that the water supplied by the public utility
conforms to required water quality guidelines.
Specialist teams determine these and the
treatment process is designed according to
the raw water supply. Regular monitoring of
the raw water source, the treatment process
steps themselves, and the final water quality
produced are the only items of evidence that
the utility can produce to assure consumers
that the water treatment process indeed meets
all the required targets that have been set.
When dealing with DPR, the utility should
keep one major risk in mind: one incident that
can be proven to stem from the DPR, where
people in the community have been severely
compromised (death or serious suffering,
mostly caused by acute infection), will lead to a
high probability that the treatment unit may be
closed, or that financial losses will occur owing
to lawsuits. During periods of investigation,
the treatment unit will most probably not be
allowed to operate. With all this said, it is in
the interest of the owner and operator of the
DPR to ensure at all times that good data is
produced from a robust monitoring programme.
The higher cost of monitoring can be compared
to an insurance policy: once any doubt occurs,
it will prove its value to ensure to the public as
well as any panel of judges (either in court or
in the media) that the treatment unit complied
with all set guidelines and regulations.
This policy is a proven one practiced
in Windhoek since the first DPR came into
operation in 1968. With the upgrades and
extensions of capacity of the DPR scheme
in Windhoek, monitoring was intensified.
With numerous water quality issues mainly
caused by natural sources not complying,
the public could be convinced that DPR
tec hnology (monitoring is an integral part
of it) is functioning well and is not causing
any threat. As with an insurance policy, it
provides peace of mind to the operational
staff component, because it proves their
commitment. This is one of the reasons
ensuring that both the citizens of Windhoek,
as well as the owner and operator of the DPR,
are proud of their reclamation scheme.
In the July/August issue of Water,
Sewage & Effluent, we will publish
the second part of the Report to the
Water Research Commission. u
technology
The identification and selection of all the
water quality constituents and other aspects
to be included in the guidelines document
were performed. The status of water reuse
for potable purposes (direct and indirect)
for planning and regulatory purposes was
determined from various sources implementing
or planning the implementation of water reuse.
This was followed by the development
of baseline sources and concentrations of
selected critical constituents (key parameters),
focusing on any improvements that may be
necessary to reduce the risk of raw water
source quality deterioration and quantity
problems, such as the use of reliable online
measurements as early warning systems.
Standardised terminology for water
reuse, including direct potable reuse as well
as indirect potable reuse, was developed in
conjunction with the relevant stakeholders.
The influent monitoring systems were
considered, which include constituents,
parameters, and monitoring systems, while
the focus was on the potential benefits of
various influent monitoring schemes that may
be used for early detection of constituents.
Key factors were considered on how
monitoring systems should be designed in
relation to process design for the various unit
treatment processes in direct and indirect
potable reuse to maintain the treatment
barriers, that is, the prevention of break-
through by pathogens, organic substances,
and other micro-pollutants. A selection of
constituents and parameters that require
monitoring in the final water (those known to
be harmful to humans) was performed. This
included parameter details, health impacts,
analytical methods, and detection limits,
while the ‘minimum’ monitoring programmes
developed in the project were also coordinated
with the Blue Drop programmes (for the water
reclamation plants), and the Green Drop
programmes (for the wastewater treatment
plants feeding the water reclamation plants).
A database was compiled of towns in
South Africa having direct and indirect
potable water reuse potential. Also, a
database was compiled of South African
laboratories that can perform the various
physical, chemical, and microbiological
analyses required for water reclamation
compliance measurements and research
purposes. This was done in cooperation
with DWA’s (currently DWS’s) Regulation
Directorate, which has already developed
databases with information on available
laboratories and accreditation status thereof.
Using all of the information gathered
during the project, and incorporating
existing knowledge elsewhere, a
concise guideline document was
compiled for use by municipalities, water
professionals and other stakeholders.
Methodology
As with an insurance policy,
it provides peace of mind to
the operational staff
component, because it
proves their commitment.
Water Sewage & Effluent May/June 2017
11