FEATURES
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Quality standards due to the significant dangers involved when
working in a confined space.
d. Reduce and/or eliminate the need to perform work inside the
storage tank:
i. Wherever possible, install internal components using
the access port, without entering the tank; or
ii. Have RWH components installed by tank manufacturer,
using personnel trained to work in confined spaces.
e. Install components so that they are accessible for
inspection and maintenance, without entry into tank.
f. Components installed in the tank should be suited to a wet
environment.
A rainwater storage tank should be inspected at least twice a
year for the following:
a. Leaks: Leaks can be identified visually by examining the area
surrounding the tanks, or through poor system performance
or soil moisture (if applicable).
b. Accumulation of debris:
i. Sediment may accumulate on the bottom of the tank
and, depending on the treatment provided, appear at the
point of use. In such cases, the location (height) of the
pump intake (if one is installed) may need adjustment.
Adjust the location of the pump intake so that it is
located 100–150mm above the bottom of the tank.
ii. If sediment is still detected at the point of use,
pre-storage and/or post-storage treatment devices
may need to be installed (or cleaned/maintained) to
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improve rainwater quality (refer to rainwater
quality & treatment).
iii. It may be necessary to remove the accumulated
sediment at the bottom of the tank. Place a
pump capable of handling large debris and/
or solids (for example, a suitable sump pump
or effluent pump) at the bottom of the tank to
pump out the sediment layer. (Note: removal of
sediment and/or tank cleaning is not generally
recommended on an annual basis, as this can
destroy beneficial ‘biofilms’ in the tank. These
biofilms may contribute to improved stored
rainwater quality.)
c. Fault with pump or other control equipment.
d. While inspecting, cleaning, or repairing the tank, follow
all necessary safety precautions provided by the tank
manufacturer.
MINIMISING SEDIMENT TRANSPORT THROUGH RWH
SYSTEMS
Use of roof washers and roof-water filters minimise
the input of particulate matter to the tank. However,
these devices will not completely eliminate input of fine
particulates or the formation of a sediment layer on the
bottom of a tank. Therefore, certain steps need to be
taken to prevent this sediment from being transported
through the distribution system and possibly reaching
the tap. PA
April 2019 Volume 25 I Number 2