Indicator: IW-14 Volume of sewage discharge to surface waters by treatment category (primary, secondary, tertiary)
Data
| 1996-9 | 2001-2 | |||||
|---|---|---|---|---|---|---|
| State / Territory | Effluent, GL/yr | Recycled, GL/yr | % | Effluent, GL/yr | Recycled, GL/yr | % |
| Qld | 328 | 38 | 11.6 | 339 | 38 | 11.2 |
| NSW | 548 | 40.1 | 7.3 | 694 | 61.5 | 8.9 |
| ACT | 31 | 0.25 | 0.8 | 30 | 1.7 | 5.6 |
| Vic | 367 | 16.9 | 4.6 | 448 | 30.1 | 6.7 |
| Tas | 43 | 1 | 2.3 | 65 | 6.2 | 9.5 |
| SA | 91 | 9 | 9.9 | 101 | 15.2 | 15.1 |
| WA | 109 | 5.5 | 6.1 | 126 | 12.7 | 10 |
| NT | 21 | 1 | 4.8 | 21 | 1.1 | 5.2 |
| Aust. | 1 538 | 112.9 | 7.3 | 1 824 | 166.5 | 9.1 |
Source: Radcliffe, J 2003, An overview of water recycling in Australia - Results from the recent ATSE study, CD-Rom, Water Recycling in Australia, 2nd National Conference, 1-3 September 2003, Brisbane, Australian Water Association, Sydney,
Cited in Source: Australian Academy of Technological Sciences and Engineering 2004, Water Recycling in Australia, ATSE, Parkville, Victoria, viewed 4 Oct 2005, http://www.atse.org.au/index.php?sectionid=600, Table 2, p. 7
Effluent discharge to inland waters in Australia is usually from smaller inland communities, with a few exceptions such as Canberra, and other regional cities and larger towns. Most of the effluent recorded in the table above is discharged into the ocean or tidal watercourse.
In Australia (with very few exceptions), discharge to inland waters occurs after a minimum of secondary treatment. Commonly, disinfection is a requirement. There is an increasing need for the removal of nitrogen and phosphorus, particularly for the large discharges, or where the effluent constitutes a significant proportion of total stream flow. Nutrient removal is desirable for discharges to the longer inland rivers, especially where there are other nutrient inputs from agriculture.
Source: National Pollutant Inventory 1999, Emission Estimation Technique Manual for Sewage and Wastewater Treatment, Environment Australia, Canberra, viewed 4 Oct 2005, http://www.npi.gov.au/handbooks/approved_handbooks/pubs/fsewage.pdf.
| Treatment | Volume (ML/yr) |
|---|---|
| Biological nutrient reduction | 710 |
| Partial nutrient reduction | 9 058 |
| Secondary | 11 453 |
| Low cost secondary | 1 796 |
| Not stated | 336 |
| Total | 23 353 |
Source: Environmental Protection Agency - Queensland (unpubl.) 2001, Volume of effluent discharged to non-tidal waterbodies, Qld, 2001, Dr Laurence Knight Environmental Reporting Unit Environmental Protection Agency PO Box 15155, CITY EAST, Qld, 4002 Ph 07 3227 8956, Fax 07 3220 3542 Email laurence.knight@epa.qld.gov.au.
What the data mean
Effluent discharge has increased slightly between the 1996-9 and 2001-02. Capital cites and coastal towns account for most of the effluent.
Issues for which this is an indicator and why
Inland Waters - Habitat scale influences - Water Quality (for surface and groundwater) - Nutrients
Discharge from sewage treatment plants can contribute to nutrient enrichment in rivers and streams. High nutrient levels, combined with the increased periods of low flow due to river regulation and water extraction, have caused blue-green algal blooms to become a persistent problem in some dams, wetlands and lakes.
Other indicators for this issue:
- IW-19 Exceedance of total nitrogen and phosphorus water quality triggers
- CO-46 Comparative water quality of coastal lakes and lagoons (water quality gradient from north to south)
Inland Waters - Habitat scale influences - Water Quality (for surface and groundwater) - Other pollutants
Wastewater from sewage treatment plants can contain pollutants in high enough concentrations to cause ecological harm.
Sewage treatment plant discharges are also a major source of pathogens. Most sewage treatment plants disinfect their discharges to kill pathogens, but the effectiveness and reliability of disinfection varies with flow and age of the sewage treatment plant.
Quantity of sewage discharge to inland waters is a direct measure of these pressures.
Other indicators for this issue:
- IW-15 Volume of sewage discharged to land
- IW-16 Total pesticide use
- IW-21 Exceedance of pH water quality triggers
- IW-22 Exceedance of biological and chemical water quality triggers
- CO-28 Quantity of discharges of different substances from humans activities to coastal and marine waters
Human Settlements - Pressures created by human settlements on the environment - Waste
Sewage treatment plant discharges from cities and towns are a major source of pollutants and nutrients in aquatic environments, which, if in high enough concentrations, can cause ecological harm. Quantity of sewage discharge to inland waters is a direct measure of this pressure of human settlements on inland waters.
Other indicators for this issue:
- HS-53 Total solid waste produced and disposed
- HS-65 Amounts of hazardous waste
- HS-66 Gaseous emissions from waste
- LD-21 Area of land used for landfill
- LD-22 Rate of violations of residue levels in harvested products
- LD-37 Emissions from activities that derive contributions from the land
- IW-12 Catchment nitrogen and phosphorus load
- IW-15 Volume of sewage discharged to land
- CO-23 Aquaculture: volume of discharged sediments and nutrients
- CO-27 Number, frequency, extent and volume of oil spills from all sources
- CO-28 Quantity of discharges of different substances from humans activities to coastal and marine waters
- CO-51 Quantity of sewerage and ballast water dumped by shipping
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