NT COVID-19 Wastewater Surveillance Program
To protect the health and wellbeing of all Territorians and help stop the spread of COVID-19, a range of surveillance measures are in place to rapidly detect COVID-19 in the community. Wastewater sampling acts as an early warning detection system in the Northern Territory’s defence against COVID-19.
The detection of viral fragments in wastewater can also come from someone who has recovered from COVID-19 and while no longer infectious can shed fragments of the virus.
Should detection of COVID-19 fragments in the sewerage network occur, they will inform public health authorities about the geographical locations that require an increase in clinical testing and any subsequent request to the community to get tested for COVID-19 will be made.Population numbers in each catchment are below 50,000 which is in line with the requirements to capture the accurate detection of COVID-19 cases.
Wastewater sampling catchment sites
Wastewater samples will be routinely collected in the below areas.
Greater Darwin sampling catchment sites:
- Ludmilla Sewage Treatment Plant (STP) inlet
- Stuart Highway Darwin CBD
- Mindil Beach
- Leanyer/Sanderson STPs #1 – inlet from Western Area
- Leanyer/Sanderson STPs #2 – inlet from Northern Suburbs
- Rocklands Drive Tiwi, isolated to RDH campus
- Palmerston Sewage Treatment Plant inlet
- Bridle/Catalina Road intersection
- Stow Road pump station – isolated to Howard Springs Quarantine Facility
Additional samples may also be collected from portable toilet facilities following major events where large numbers of participants are visitors from interstate.
One sample site will be located at the Stow Road pump station in Howard Springs which receives wastewater exclusively from the Howard Springs Quarantine Facility (HSQF).
This sampling site is expected to return a positive result when active cases are residing at Howard Springs Quarantine Facility.
Alice Springs sampling catchment sites
- MH45 Quarantine Facility
- 29A CBD & Gillen
- 24A CBD & Northern
Frequently asked questions
NT Wastewater Surveillance Program compliments results from clinical testing.
Wastewater surveillance is cost effective – one sample is representative of the entire community residing within a sewerage network catchment area.
Wastewater sampling acts as an early warning detection system. It informs geographical locations to increase clinical testing if COVID-19 genetic material (RNA) fragments are located in the sewerage network.
An infected person can shed virus in their faeces even if they do not have any symptoms. Shedding can continue for several weeks after they are no longer infectious
Testing wastewater can help provide an early warning signal of COVID-19 infections in people living in a particular wastewater catchment area.
Wastewater based epidemiology (WBE) is a long established practice, historically used to detect poliovirus and typhoid.
NT Health is undertaking wastewater sampling program with assistance from the Power and Water Corporation (PWC) and Darwin based company Trop Water Pty Ltd.
The program comprises of passive sampling of sewage, at sites prior to treatment, to extract COVID-19 RNA to determine the presence/absence of the virus in particular geographic locations and give an indication of concentrations in sewage.
Samplers are inserted into sewers at pre-determined locations and are left in the flow of wastewater for a 24 hour period. They are then collected and placed into a sealed bag and put on ice for consignment/delivery to the South Australia testing facility.
Fragments of the virus that causes COVID-19 can enter wastewater through an infected person, or recently infected person’s faeces or when washed off a person’s hands or body through toilets, sinks, showers etc.
There are several reasons why fragments of the SARS-CoV-2 can be found in wastewater:
- One or more people who are infectious with COVID-19 are in the catchment area.
- There have been one or more people in the catchment area who have previously had COVID-19 and have recently recovered and are no longer infectious.
- A person with COVID-19 may have been in the area and has since left.
People who have recently recovered from COVID-19 can sometimes continue to shed virus fragments into the sewerage system for several weeks even after they are no longer infectious.
Any positive detection in wastewater samples will be assessed by NT Health.
Further investigations may be undertaken, including immediate resampling if there any doubts about the source of the virus fragments. If there are known positive cases in the catchment area (e.g. at the Howard Springs Quarantine Facility) where a positive sample is identified, this will be taken into consideration during the investigation.
A confirmed positive wastewater test result is particularly important if there are no known recent positive COVID-19 cases in that area.
Public health advice will be issued where action is required by the community. This might include messaging to people in the area to get tested, particularly if they have symptoms of COVID-19 and also might include providing additional testing locations in the area.
It is highly unlikely a person can be infected with the SARS-CoV-2 virus through contact with wastewater.
The virus is easily inactivated (killed) by usual wastewater treatment processes, including chlorine and ultraviolet (UV) disinfection.
Wastewater is treated before it is used in recycled water schemes or discharged back into the environment, with most wastewater subject to UV light or chlorine disinfection.
Wastewater from the Howard Springs Quarantine Facility is exclusively fed into the Stow Road pump station in Howard Springs.
There is no evidence that the COVID-19 virus is transmitted by drinking water. The current evidence is that the COVID-19 virus is most likely transmitted from person-to-person by sneezing and coughing.
Drinking water in Australia is high quality and is well treated. There is no evidence that drinking water will be affected by coronavirus.