Greywater Reuse in Townsville
Recent amendments to the Plumbing and Drainage Act 2002 will allow residents in sewered areas (from 1 March 2006) to apply for approval to install a Greywater Use Facility for Class 1a dwellings only. This initiative is to help decrease the pressure on public potable water resources, being another tool for a sustainable future and complimenting other Council wastewater recycling programs such as the Magnetic Island Water Recycling program and the Carbon Neutral Water Recycling project.
What is Greywater Reuse
Greywater (that is wastewater) from showers, basins, laundries and clothes washers can be reused by subsurface irrigation (with an approved greywater use facility) or manual 'bucketing' onto household lawns and gardens. The use of greywater from kitchens is not permitted due to the higher potential of problems associated with food waste and grease.
What are the Benefits of using Greywater
- Less chemical and commercial fertiliser use
- Ground water rechard
- Reclamation of otherwise wasted nutrients
- Decreased pressure on public potable water supply
- Less strain on municipal water treatment plants
- Improved water supply security in the present and future
- Less energy use to transport water
It has been estimated potable water savings in the range of 18-29% for an average household can be achieved by reusing greywater on lawns and gardens. In Townsville that works out to be between 107,000 and 176,800 litres, or five typical backyard swimming pools, of water saved per household every year!
| Parameter |
Units |
Mean Greywater |
Raw Sewerage |
| Suspended Solids |
mg/L |
115 |
100-500 |
| Turbidity |
NTU |
100 |
NA |
| BOD5 |
mg/L |
160 |
100-500 |
| Nitrite |
mg/L |
0.3 |
1-10 |
| Ammonia |
mg/L |
5.3 |
10-30 |
| Total Kjeldahl Nitrogen |
mg/L |
12 |
20-80 |
| Total Phosphorous |
mg/L |
8 |
5-30 |
| Sulphate |
mg/L |
35 |
25-100 |
| pH |
|
7.5 |
6.5-8.5 |
| Conductivity |
mS/cm |
600 |
300-800 |
| Hardness (Ca and Mg) |
mg/L |
45 |
200-700 |
| Sodium Faecal Coliform |
mg/L
Org/100ml |
70
10^4 - 10^5 |
70-300
10^7 - 10^10 |
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Is using Greywater safe
Because kitchen greywater and blackwater (that from toilets) are not used and greywater reuse is by manual application to surface or automatic application to subsurface irrigation, health risks are decreased significantly. The table above demonstrates the average differences in water impurities between raw sewerage (blackwater) and greywater.
While health risks with approved greywater reuse are low, potential problems can arise if the system is not properly maintained. These risks are minimised by ensuring that requirements outlined in the Compliance Certificate issued for the facility are followed.
It is also recommended that the Do's and Don'ts of Greywater Recycling (adapted from the Queensland Government) and the information provided in the Queensland Government fact sheets be used.
What is a Greywater Use Facility
Image courtesy of Nylex Water Conservation
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Greywater Use Facilities consist of a greywater diversion device and subsurface irrigation system. Facilities without sufficient elevation may also require surge tanks and/or pressure pumps. Greywater treatment plants (which treat to a higher level than diversion devices) can also be installed, however these are not required. The diversion device consists of a manual switch and coarse filter which a licensed plumber connects to the waste plumbing of the laundry basin, bath etc. The greywater use facility must be installed externally to the house so as to allow easy access and maintenance.
The area irrigated (subsurface) by the effluent is known as the Greywater Application Area. Determining the size of this area will depend on the volume of greywater produced by the household, the constraints of the site and the absorption -evapo-transpiration properties of the soil. The subsurface irrigation system must be installed by a licensed drainer, and irrigation pipes must be a minimum of 100mm below the ground surface.
If you are interested in learning more about the installation of Greywater Use Facilities, subsurface irrigation systems, and greywater treatment plants visit the Department of Local Government and Planning website.
Getting Approval to Install a Greywater Use Facility
A Plumbing and Drainage application for approval to install a Greywater Use Facility in sewered areas must be lodged with the accompanying information:
- Site and Soil Evaluations to the detail and standards as specified in AS1547, 2000: On-site Wastewater Management;
- A detailed plan of the proposed work detailing the diversion device and irrigation system, existing locations of buildings, structures, boundaries, services, ground conditions and proposed vegetation cover; and
- Setbacks to the greywater application area must be equivalent to on-site sewerage disposal land application area setbacks for advanced secondary treated effluent disposal by subsurface irrigation (further information regarding setback distances and provisions for alternative distance will be provided in the Townsville policy and guidelines for greywater reuse in sewered areas)
Your application will be assessed against the Queensland Plumbing and Wastewater (QPW) Code and Council's Greywater Use in Sewered Areas policy which details setback provisions to the greywater application area, greywater register and monitoring operations. Successful applicants may be issued with a Compliance Permit, authorising the installation of the facility. Further compliance assessment of the works is conducted during and at completion of installation, at which time a Compliance Certificate may be issued and the Greywater Use Facility may begin operation.
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Requirements of the Compliance Certificate
- Greywater to automatically overflow to the sewer in case too much greywater is being produced or the system fails to work properly
- A manual 'diversion' switch (so greywater can be diverted to the Greywater Application Area) to be serviceable at all times
- Greywater to be diverted to the sewer during times of heavy rainfall and low evapo-transpiration
- Greywater not be allowed to pond on the surface, produce detectable odours or leave the property
- The coarse filter be correctly fitted and serviceable whenever greywater is being diverted to the Greywater Application Area
- The Greywater Application Area remain undisturbed and maintained, free from obstructions (eg., parked vehicles, structures, swimming pools etc) which could interfere with subsurface irrigation; and
- A licensed Plumber and Drainer inspect the Greywater Use Facility and report to Council at least once every 12 months
Once approved your greywater use facility will be added to the Townsville City Council Greywater Use Facility Register for auditing purposes.
Compliance and Inspection
With the health risks associated with improperly installed and maintained systems, Council may need to inspect your system to ensure it meets performance criteria and is not a concern for public health, amenity or the environment. If the greywater system is not working properly, Council may issue an Enforcement Notice requiring the problem be remedied. Follow up inspections may be conducted to ensure the problem is resolved.
Maintaining a Greywater Recycling System
For Greywater Use Facilities to function appropriately, it is necessary to carry out regular maintenance. This can be as simple as changing or cleaning a filter in the diverter device or pump, and will require residents to be vigilant and responsive. Council recommends care be taken to use products such as laundry detergent and soap which do not have a negative impact on the irrigated land. A number of detergents of detergents can have a high pH and salinity levels, so it's important an appropriate product is used. Click on the link for further information compiled by Lanfax Laboratories.
What Are My Options
There are a range of facilities available for greywater use, however it is important to recognise that in order for an application to gain approval the system must be on the approved list by the Queensland Government. Before you decide on a system, take the time to ensure it meets the legislative requirements for Queensland greywater reuse in sewered areas, as well as the specific requirements outlined by the Townsville City Council.
Further information can be obtained from the Queensland Government Guidelines website. The Townsville City Council will be making available Greywater Reuse Guidelines for the Public, a publication for the wider community, in the future. For information please contact the Hydraulics Certification Unit on 4727 9000 or email enquiries@townsville.qld.gov.au.
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