Natural Greywater Treatment
Nature Clear Grey Water filtration – GWS10
Nature Clear GWS10 provides a simple and low cost effective means of treating grey water. Not only is the equipment low cost, but also, if your site is suitable, the only significant excavation work required to install the system will be the trenching. The ongoing costs will be similar to those of a standard septic system .
In order for the filtration tank to work most effectively food scraps and grease should be removed from the kitchen waste water via a grease trap. A 45 litre grease trap is included with the GWS10. A larger, 300 litre grease trap may be required by some councils, and can be supplied if requested (see below for pricing).
The filtration tank, which is less than 1 cubic meter in size, consists of a pine bark coarse filter on top of different grades of sand and gravel. The pine bark traps large particles not caught in the grease trap plus lint from the washing machine. The sand filter catches still finer materials, polishes the water and reduces the organic content of the water. The pine bark is separated from the sand by filter cloth. The filtered material and bark will compost over time and should be removed every twelve months and replaced with fresh bark, available from your local garden nursery. If your distribution area is down hill from the filtration tank your engineer should be able to design a distribution system without the use of a pump. If this is not the case you will need a pump and pump well.
The treated water must be distributed into trenches as specified by your engineer. Make sure his calculations of size do not include an allowance for toilet water, which would make them unnecessarily large and expensive.
DIMENSIONS: Height 780 mm x Length 1025 mm x Width 820-910 mm
Nature Clear GWS10 has only been approved for use in Queensland and only as a primary treatment system.
In addition to almost all Queensland councils, some councils in NSW and Tasmania have also allowed the installation of Nature Clear.
In other areas, many customers have successfully ‘experimented’ with cleansing their greywater before using it for irrigating the garden.
How it works
Nature Clear provides an odour free method of filtering and cleaning grey water with no moving or electrical parts. The water from all grey water outlets flows into a polymer tank where it is progressively filtered and biologically cleaned. From the tank the treated water flows under gravity into an application area. The application area materials should be supplied and installed by your plumber. It may consist of trenches or 150mm sub surface irrigation, depending on local conditions and regulations.
Because the dwell time of the water in the tank is short, there is no time for bacteria to build up, as there is in anaerobic septic tanks. Consequently the system should always remain odour-free.
Filtering of the water takes place in several layers of naturally occurring materials separated by progressively finer grades of geofabrics. A biofilm is established near the centre of the tank where aerobic bacteria clean the water. The resulting water quality is typically of secondary treatment quality.
There is no disinfection process and consequently most authorities will not allow the water to be disposed of above ground. Whilst it is unfortunate that the water cannot be disposed of above ground, no chlorination process has been used to disinfect the water. Please also note that during periods of drought some councils will permit the use of a diverter to allow discharge of the treated water at the surface.
If the application area cannot be fed by gravity, or the local authority insists on a pressurised irrigation system being installed, a pump well and submersible pump will also be required.
The maintenance of the system is very much reduced if a grease trap is installed on the kitchen waste outlet. Normal maintenance involves replacing the top layer of organic coarse filtration material twice a year and annual cleaning of the top two layers of geofabric. The old materials can be disposed of in your composting toilet or into a suitable area in your garden. The annual cost is less than $10.
Using worms to clean the material for you can reduce the frequency of changing the top layer of material.
The 300 litre grease trap is supplied to remove food scraps and grease from kitchen waste water for medium to larger households. A smaller 45 litre grease trap is available if this volume is not required but some do councils insist on large grease traps to extend the life of the trenches. The 300 L grease trap needs cleaning every 1-2 years whereas the 45 L trap is self-cleaned by retrieving a washable filter every 6 weeks or so.
A 45 litre grease trap is supplied as standard to remove food scraps and grease from kitchen waste water. A 300 litre grease trap is also available for larger households. Some councils also insist on large grease traps to extend the life of the trenches. The 45 L trap is self-cleaned by retrieving a washable filter every 6 weeks or so, the 300 L trap needs cleaning every 1-2 years.
|Greywater systems||Prices March 2017|
|Greywater system complete, with a 45 litre grease trap||$1365|
|Greywater system complete, with a 300 litre grease trap||$1485|
|Greywater tank complete, but without a grease trap or lid||$1140|
|Greywater system lid (extra if required)||$220|
|Grease trap 300 litre alone||$315|
|Grease trap 45 litre alone||$225|
|Prices shown do not include any freight cost from the factory. Goods may be picked up at a Solazone shop, or can be freighted directly to you|