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  Building a new home or renovating?  

Have you thought about your sewerage system? We can help! 

The Nature Flow® Mk II Home Sewerage Treatment Plant (HSTP) is an environment friendly, efficient and effective system for treating all your grey and black water. Homeowners can effectively use their water twice - once in the home and then again for watering their lawns and gardens through above ground irrigation (subject to local authority requirements). 
The Nature Flow® HSTP is a large system, rated at 10 to 20 persons. It consists of a large concrete treatment tank, in-ground media filter, your choice of disinfection method – either a dial-up chlorinator or patented self-cleaning ultra violet technology and dispersal field (as per your approved design). This system is economical with only one service per year and low running costs. It can withstand long periods of non-use such as holidays etc without requiring costly reactivation. Effluent is treated to a very high standard and is clear and odourless*. 
We have a strong commitment to protecting the environment and take pride in providing quality "eco-friendly" products that are priced within the reach of the average consumer – our Nature Flow® HSTP’s are no exception.
Nature Flow Mk II Sewerage Treatment Systems are approved for installation throughout Queensland under Chief Executive Approval 03/2011 from the Department of Infrastructure & Planning.

The Nature Flow Household Sewerage Treatment System is accredited with the Smart Approved WaterMark, Australia’s water-saving label for products and services around the home and garden.

* Chlorinator model has slight odour of chlorine.


What is a sewerage treatment plant?

An on-site sewerage treatment plant is a purpose built system used for the treatment of sewerage and liquid wastes from a single household or multiple dwellings.

Also know as an Aerated Waste Water Treatment System (AWTS), Household Sewerage Treatment Plant (HSTP), On Site Sewerage Facility (OSSF).

The types of waste that can be effectively treated by the plant include natural household waste eg everything you use in your house that goes into your drains, kitchen, laundry, toilet, shower etc.

When working properly your HSTP will work efficiently and effectively with no odours and little intervention required by the homeowner apart from basic care.


How does a Nature Flow HSTP work?

Standard operation is for effluent to flow through from primary chambers to pump well one where it is pressure fed through the media bed, gravity drained to pump well two and pressure fed through to irrigation/disposal.  Where irrigation/disposal is via surface method, disinfection in the form of a chlorine contactor and/or ultra violet unit must be added prior to disposal.

Primary 1 – Used to collect all black and grey water.  The large size of primary collection increases the retention time and the quality of the treated wastewater.  A large proportion of the solids settle to the bottom of this chamber prior to the effluent flowing to the second primary through a suspended solids filter (Zabel or equivalent).

Primary 2 – This second primary chamber/tank allows the effluent to settle further before it passes through a suspended solids filter to the media filter pump well.

Pump Well 1 – A submersible pump with high level alarm is used to pump wastewater through the media filter and returned via the drainback to pump well 2.

Media Filter – The use of in-ground media filter provides a significant surface area increasing the quality of the wastewater treatment.  Wastewater is pressure fed through PVC rafts (perforated) to ensure that the whole of the media bed is effectively used and to avoid channelling.  The type of media filter varies depending on the installation.  

Pump Well 2 – wastewater is relatively clear.  A submersible pump with high level alarm is used to pump wastewater through the final disinfection method.

Disinfection Options:

Chlorine Contactor (Nature Flow Budget HSTP

The in-line chlorinator provides a budget disinfection method that limits the amount of chlorine that is released into the environment.  It uses a chlorine doser to ensure that the minimum amount of chlorine is released into the water to achieve an effective bacteria kill-rate.  The owner is responsible for checking the level of chlorine tablets in the doser on a quarterly basis and replenishing when required.  

Chlorine tablets cost approximately $10 for a packet of 5 tablets.  One packet should last a household of 4-6 persons approximately 3 months. Due to their chemical nature chlorine tablets cannot be posted to you.  Most service agents carry the correct type of chlorine tablets on board.  (Note that these tablets are of a specific composition - please do not try and replace with any generic chlorine tablets without first checking their suitability with the manufacturer or your service agent.  Do not use liquid chlorine in place of chlorine tablets - this will not provide adequate disinfection.)

Ultra Violet (UV) Disinfection Unit (Nature Flow UV HSTP

The Nature Flow UV Disinfection Unit uses our patented self-cleaning technology to provide final disinfection to effluent prior to disposal.  Use of this disinfection method means the treatment plant is chemical free and does not produce chemical by-products such as chlorine disinfection.  

Maintenance is minimised with only annual servicing required.  The UV unit requires o'rings and cleaning felts to be replaced on an annual basis, the quartz thimble should be replaced every two years and the UV lamp approx every 3 yrs or as required.  

The UV disinfection unit uses minimal electricity as the lamp only operates when the disposal pump is initiated (lamp turns on 2 minutes prior to pump activation to provide necessary warm-up for optimal UV disinfection).

Disposal:  Site dependant – surface or subsurface as per site assessment and/or State/Local Authority requirements.  Refer AS/NZ1547:2000 and Qld Plumbing & Wastewater Code 2010.


Key Benefits

Environment responsible waste management system.  Budget model uses controlled chemical dosing and UV model is chemical free.

Produces treated wastewater to very high standards that allows for water re-use via irrigation subject to local authority requirements.  

Low maintenance - only one service a year not four (most aerated treatment plants require quarterly servicing).

Nature Flow Systems use minimal mechanical parts, do not have blowers operating constantly and the submersible pumps in the system only operate on average 25 minutes per day.  

The Nature Flow System = low energy consumption.

Quiet operation - no noisy aerators or blowers running constantly in the background.

The final effluent is clear and odourless*.  

The system can withstand prolonged periods of non-usage (such as holidays) without costly re-activating.

Media filtration occurs prior to disinfection and disposal - this improves the clarity of the water and the quality of the treated effluent.

Pumps and control box are NOT hardwired.  This is an advantage when pumps require replacement as only one trade is required (plumber) rather than two (plumber and electrician).  


Pricing & Availability

Nature Flow HSTP's are only available in selected areas of Queensland including Brisbane & Greater Region and the Fraser Coast.

Please note that pricing is subject to site assessment for effluent disposal, council approval and site inspection.

Contact us for further information. 



Chief Executive Approval 03/2011

Smart Watermark



Owners Manual NF MKII STP

Operation & Maintenance Manual NF MKII STP


 *Subject to local authority requirements.  Treated effluent from Budget model may have slight chlorine odour.

 All sales are subject to our Standard Conditions and our Privacy Policy.


Send mail to webmaster with questions or comments about this web site.  Copyright © 2015 Nature Flow Systems Pty Ltd atf Nature Flow Systems Trust.  Nature Flow Systems reserves the right to alter product designs and specifications without prior notification.  While every effort is made to ensure the information on this website is up-to-date, no responsibility is taken for incorrect or outdated information.  Last modified: 25-May-2015