Perfume Creek (above), as it is known for its smell, sometimes containing partially treated sewage, flowing under the Stuart Highway and to Kilgariff. The new suburb (below) during the recent floods.
By ERWIN CHLANDA
The Power Water Corporation (PWC) is not saying what is contained in the partially treated sewage that flowed from the government treatment ponds to the new Kilgariff suburb during the recent rains.
We asked PWC: –
• What bacteria were contained in the creek flow which emanated from the [sewage] ponds, and what was their concentration?
• Is that creek water drinkable?
• Can people safely swim in it?
• Can it be safely used for watering gardens?
• What amount of overflow water was handled by the pipeline to Kilgariff designed to take sewage water to seepage ponds near Kilgariff, to be later recovered for irrigation purposes?
A PWC spokesperson replied: “I forwarded your questions on to Health to address.”
We made the enquiry on January 20 and still do not have a response.
The effluent got to the suburb still under construction after flowing under Ilparpa Road and the Stuart Highway, into St Mary’s Creek, past an Aboriginal training facility, a birthing centre, the racecourse and the Desert Knowledge Precinct.
In an earlier response, Assistant General Manager Water Services evaded some questions, but conceded that “a discharge of treated effluent occurred to the swamp area during the peak of the storm activity.
“This was an extreme event with over 200 mm falling in the catchment.”
We replied disagreeing with Mr Pudney, saying it was not an extreme event: a government spokesman had earlier described the falls a having a probability of occurring once every five years. (An extreme event is one that has a one in a hundred years probability.)
Says Mr Pudney: “The discharge is a very small component of what was caught in the Ilparpa catchment.
“The effluent was treated and diluted further by the extensive rainfall.
“The EPA [Environmental Protection Agency – another NT Government instrumentality] has been notified in accordance with licence conditions.
“Results of sampling indicate that the bacteriological measurements are well within those expected from any system following a rainfall flush on the catchment.”
NEWS: In what systems can those bacteria be expected following a rainfall flush?
PUDNEY: It should be noted that stormwater in flood situations has many natural contaminants and the diluted treated effluent has not resulted in significant elevation of these.
He also said PWC had invested over $15m in recent years to reduce the likelihood and extent of overflows “particularly through progressive expansion of the re-use plant and other operational improvements.
“The cost to carry out works to eliminate all discharge in extreme weather events is cost prohibitive and is not currently being pursued.”
RELATED READING: Alice Springs sewage plant dossier (compiled in October 1998) and google for a large number of other reports on this site about sewerage treatment.