This page contains answers to some frequently asked questions (FAQ's)
regarding domestic sewerage treatment, drinking water treatment and UV
- Do I have to use any special type of detergents and
greatest causes of problems with your treatment plant are cleaning products
and the washing machine.
PLEASE NOTE: The
following information is not intended to promote or discredit the product of
any Company. It is provided to assist in ensuring the satisfactory
on-going operation of your system. To protect the environment and ensure the
longevity and optimal performance of your Nature Flow® HSTP we recommend that
you use environment friendly detergents and cleaners.
Using cleaners and detergents
that contain high levels of ammonia (eg bleach) and/or phosphorus is hazardous
to the biological health of your HSTP. These types of cleaners kill off
the natural bacteria and micro-organisms used to treat the primary effluent.
Reduction of the natural bacteria of your HSTP will result in a much lower
level of primary treatment and may produce unpleasant “septic” odours.
High levels of nitrogen and phosphorus also contribute to the growth of algae
and other less desirable micro-organisms in the environment eg algal growth in
sheets - Do's & Don'ts and
highly recommend visiting this independent website www.lanfaxlabs.com.au
for further information on laundry products. They have a concise,
comprehensive and independent brochure detailing laundry products that is
available for free download.
- Do I have to establish garden beds for disposal of
treated effluent? Do I need to do any
This is subject to your site assessment
for effluent disposal. The need for garden beds, diversion/retention
mounds, soil improvement etc will be ascertained by your site assessor based
on the soil type of your property, property size, ability to comply with setback
distances, hydraulic loading of residence etc.
Special landscapiing is not
generally required as this is usually identified in your site
assessment. However since HSTP's are commonly installed at an early stage of construction it is
sometimes difficult to provide advice with regard to landscaping
It is advisable to ensure that stormwater run-off is diverted away from the
media filter and treatment tank. This is to limit the entry of
excess water which does not require treatment hence increasing the lifetime of
your HSTP. Owners who are concerned with possible stormwater run-off
should talk to their sewerage site evaluator or HSTP installer and advise them
of their concerns - discussion of diversion options can then take place.
As a general rule, if it becomes apparent that stormwater run-off flows in
the direction of the media filter and sewerage tank some landscaping will
be required to divert this flow. This may be in the form of a diversion
mound - a raised mound of grass/mulch covered soil to divert water flow away
from the HSTP or a cut-off drain. Alternatively diversion mounds may be designed in the
form of garden beds .
- Does chlorine kill my plants?
The Nature Flow® Mk II Budget
HSTP with online chlorinator uses chlorine to disinfect effluent prior to
dispersal. The chlorinator used is a dial-up model. This ensures that only the
minimum amount of chlorine needed to effectively disinfect the effluent is
used thus minimising the discharge of chemical into the environment. This also
means that the chlorine residual remaining in the treated effluent is minimal
and as such irrigation of plants and lawns is not adversely affected. Ie
Irrigation with treated effluent from the chlorinator model will not kill your
plants or lawn.
- How often does my system need servicing?
Do I have to get my system serviced?
All Nature Flow® Systems only require annual servicing in standard
domestic applications. Annual services cost approximately $125 plus travel and
any consumeables and
are completed by our service agent.
Servicing is mandatory and a
condition of your approval to install. It is a local authority (council) requirement according to AS1547:2000
- Onsite Domestic Wastewater Management. Penalties apply to anyone infringing
this requirement and spot checks are a regular occurrence.
- What else is involved in maintaining my system?
Apart from the annual service Nature Flow® Systems require minimal
intervention by the homeowner.
The Nature Flow® Mk II Budget HSTP uses specialised chlorine tablets for
disinfection. Generally, a standard household of 4 to 6 people uses 5 chlorine
tablets a quarter. A pack of 5 chlorine tablets costs approximately $10.
Therefore an average expense of $40 per year for chlorine tablets. The
homeowner can replenish the chlorine tablets – a service call-out is not
required. Instructions are available in the owners
manual. No other maintenance is
The Nature Flow® Mk II Ultra Violet HSTP uses UV sterilisation for
disinfection. In a standard domestic application, the UV globe will require
replacement approx. every 3 years at an approximate cost of $161.70* incl GST
excluding packaging and freight, a service kit will also be required at this
time (o'rings & felts) - approx $35* incl GST. We recommend that a
service technician complete any UV lamp changes. To minimise costs this lamp
change may be completed during an annual service. No other maintenance is
The disposal field must be maintained eg keep grass mown and ensure
sprinklers are uncoiled and in good operational condition. Where
subsurface disposal is utilised there may be in-line filters that require
periodical cleaning. Ensure signage is maintained.
- What happens when I go on holidays?
NOT TURN THE TREATMENT PLANT OFF.
The system’s power
consumption is directly linked to use of the treatment plant.
Submersible pumps operate in
relation to inflows into the treatment plant. Pumps may continue to
operate during periods of non-occupation due to ingress of stormwater/rainfall
into the media filter bed. While their operation will obviously be
reduced during periods of non-use they must not be turned off to ensure that
any water ingress into the treatment plant (outside household flows) may be
The control box operates
continuously using minimal power. It must remain turned on at all times.
The control box alerts the homeowner to high levels in the treatment plant
and/or UV lamp degradation.
The treatment plant is robust
and has the capacity to handle periods of non-use without the need for
“reactivation”. Simply commence using the system as usual.
(Ensure that power to the system is on and that disposal hoses (surface
irrigation) are connected and unrolled.)
Servicing periods remain
mandatory and intervals are not reduced due to periods of non-use.
much electricity does this system use?
The Nature Flow® System in a standard domestic application uses approx $51
to $77 of electricity per year*.
Note that calculations have been based on a full 10EP loading of 2500L/Day
based on 250 litres per person per day. However due to recent social and/or
legislative changes regarding water use in the home and specifically the use
of water saving devices the daily loading rate (10EP) is expected to reduce to
an estimated average of 1500L - 1700L per day based on 150 or 170 litres per
person per day.
Thus a standard domestic household of 6 EP could
be expected to generate daily flows of between 900-1020 L/Day which would
result in less than half the electricity consumption calculated below.
Nature Flow UV HSTP $154.02/yr*
Nature Flow Budget HSTP $102.02/yr*
Assumptions: Full 10EP Loading - 2500L/Day
125 Minutes running per Day, based on 2500L/Day @ 20L/minute, 52 Weeks / Year @ 18c per kWh
Controller Amps, based on normal state, NO Alarm state. Therefore visual or audible alarm currents not taken into account.
Operating times rounded up to nearest minute. Pumps are Davey D25A
There are two pumps used in the system.
One for pumping effluent through the media filter to the disinfection
chamber of the tank and the other to pump from the disinfection through the
chlorinator or UV unit to the dispersal method. These pumps do not
operate 24 hours/day. They only operate as required and are activated by a
float switch when a certain level is reached in the tank.
* Based on 6EP 1500-1700L/day. Subject to change depending on current
tarrifs, actual hydraulic loading and pumps used.
- How do these systems protect the environment?
The Nature Flow® Mk II Budget HSTP with online chlorinator uses chlorine
to disinfect effluent prior to dispersal. The chlorinator used is a dial-up
model. This ensures that only the minimum amount of chlorine
needed to effectively disinfect the effluent is used thus minimising the
discharge of chemical into the environment.
The Nature Flow® Mk II Ultra Violet HSTP uses ultra violet sterilisation
to treat wastewater. UV sterilisation is Nature's own method of
disinfection. It does not introduce any chemicals or disinfection
by-products into the environment. It is safe, effective and
efficient. Treated effluent is odourless and disinfected to a very high
- Do these systems treat black and grey water? Do I
need a greasetrap?
Yes. Nature Flow® HSTP’s treat all black and grey water and eliminates
the need for a greasetrap. It is an "all-waste" management system.
It allows the householder to effectively use all their water twice – once in
the house and again for irrigating their lawns and gardens. While a
greasetrap is not required it is strongly recommended that householders
stringently limit the amount of grease/oils entering the system.
Fats and oils should not be disposed of down the kitchen sink.
This continues recommendations that have been in place for sometime regardless
of the type of waste disposal system installed (ie all waste or onsite
Note: Commercial applications may still require a dedicated
greasetrap subject to the nature of the operation.
- Does this system have Department of
Infrastructure & Planning approval for installation throughout Queensland?
Executive Approval 03/2011. Onsite sewerage treatment systems
require approval under the authority of the Department of
Infrastructure & Planning for installation in Qld. Approvals are
granted for 5 years, at the end of which renewal must be applied for to the
relevant department. Approval for Nature Flow Mk II STP is currently
valid until January 2015.
- What is a
"Riser" and when is a Riser necessary?
A Riser is an extension made from concrete used to lower the invert level
of the inlet to a HSTP. A Riser is generally required when the site is flat or where the invert
level is low and the drainer could
have trouble gaining fall to the HSTP. A Riser may also be required if
crushing in an old septic tank and the original is too deep for the inlet to
- What is a
A site assessment for effluent disposal is required for Local Authority
(council) approval. It is a document detailing the layout of the
disposal field (whether it is surface or subsurface, size of area, hydraulic
loading, diversion and/or retention mound etc).
A completed site assessment is required to enable us to provide an
accurate estimate for your project.
Look here for a
list of recommended site assessors in SE Qld.
- What do I need to know about the chlorine
tablets used in my Nature Flow Budget HSTP?
Chlorine tablets are all different and the tablets
used within this system are of a specific composition.
The chlorine tablets used in your system are
slow-dissolve Trichloro-S-Triazinetrione (Tri -Chlor).
If additional tablets are required contact your
manufacturer/service agent to obtain the correct chlorine tablets.
Some basic rules...
Exercise extreme caution when opening or servicing your
Do not inhale any fumes from any chemical feeder or
Protect your eyes, skin and clothing from chemicals at all
When adding the chlorine tablets do not touch the tablets.
Hold the middle of the packet. Carefully split the bottom of the packet
while holding it over the chlorinator container and allow the tablets to
gently fall into the unit.
Avoid chemical contact – do not drop the tablets into the
The chlorinator unit utilises an O'Ring located in the
lid. Take care when unscrewing the lid to ensure this O'Ring is not
damaged. When replacing the lid, grease the O'ring and ensure it it
located correctly in the lid. Avoid cross-threading the lid and
damaging the O'Ring. Do not overtighten - a locking tab is used on the
lid - do not tighten past this tab. If unsure, please do not
hesitate to contact the manufacturer
or your service agent.
Material Safety Data Sheet - Chlorine Tablets.
- What is subsidence?
Subsidence and/or ground movement is an event caused by Nature –
it is unpredictable and extremely difficult to avoid. The degree of
subsidence is dependent on individual site conditions including, but not limited
to, weather (prior to, during and after installation), soil type and location of
installation. It is an event not covered by warranty.
Subsidence around tanks installed in-ground may result in
increased pressure on any pipework connected to the tank. Sometimes this
increased pressure will result in the pipework/fitting becoming "sheared off",
stretched or split (leaking) or broken. Defects arising from subsidence
are not covered by warranty.
Generally subsidence only occurs in the first instance of
changed weather conditions (ie after rain) however it may occur under other
circumstances. Usually after the first instance the ground (and consequently the
tank and other componentry) "finds it level" and you should not experience any
further problems from this phenomenon. In very reactive soils or other unstable
conditions, subsidence may occur again.
Defects caused by subsidence are possible in any installation
involving tankage and pipework being placed in and below ground.
Common minor defects are:
· Shearing, leaking or breakage at the poly dispersal line from
the HSTP tank to irrigation.
· Shearing, leaking or breakage at the PVC pipes between the ASF
and HSTP tank.
· Shearing, leaking or breakage at the stormwater pipe into the
Unless otherwise agreed, all installations are for "loose"
backfill only. Compacted backfill cannot be completed around concrete tanks as
the uneven pressure created when backfilling will result in movement between
mouldings. It is also exorbitantly expensive and will not guarantee that
subsidence will not occur. The use of sand and other bedding materials
will also not guarantee the prevention of subsidence. Often the sand will
simply be pushed out of the trench or cavity by the flow of water leaving a
depression that places strain on the pipework. The best prevention of
defects caused by subsidence is simply to be aware of the possibility and to
maintain vigilance in ensuring depressions are "topped up" and/or breakages etc
are repaired in a timely manner.
*All prices subject to change without notice.