1/2 of Sydney, Aust. drinking water has been rendered unusable

[donsu]

http://hisz.rsoe.hu/alertmap/index.php?smp=&lang=eng


More than half of Sydney's drinking water stored in Warragamba Dam has been rendered unusable as authorities now warn a 60km toxic algal bloom could last until March next year. When taken into account, it means the usable supplies of water at Warragamba are effectively 28 per cent of the total supply - the lowest on record. The State Government has tried to deny that the official storage capacity had been reduced due to the first algal outbreak of its kind at the dam in its 40 year history. However, documents obtained by The Daily Telegraph reveal that no filtration plants in Sydney are fitted with technology to treat algal toxins. "Lake Burragorang (Warragamba Dam) supplies raw water to Warragamba, Orchard Hills and Prospect water filtration plants," a Sydney Catchment Authority briefing note from four weeks ago revealed. "These water filtration plants are not designed to remove algal toxins from the drinking water supply because the SCA moves the offtake levels in the dam to areas of best water quality." The algal bloom has rendered an estimated 500 billion litres - or about half of the water in the dam - unusable, meaning the SCA has been reduced to drawing only water from 48m below the surface.

Experts warned, in the same documents, the bloom could double in size every five days in warmer months. The SCA has admitted on its own website that it has contingency plans for a possible and unprecedented closure of the dam should the algal column worsen. This would result in Sydney's main water supply being shut down or restricted. SCA documents show that the usable water from Sydney's main water supply is now about 28 per cent. The documents claim that the plume, first detected in August, extends to 12m below the surface, which is already 14.9m below full. Liberal MP Michael Richardson, the former Opposition environment spokesman and the one who requested the documents from the SCA, said Sydney faced the prospect of going to unprecedented Level 4 water restrictions as a result. "At that point Sydney would have just 35 weeks supply of water," he said. Mr Richardson said the Government had not installed carbon filters in plants because of the cost. They can cost $5 million a year to operate.

A briefing note from Dr Lee Bowling, chair of the scientific committee of the NSW Algal Advisory Group, last month warned SCA the algal bloom may remain until March as warmer months contribute to its growth. Four days ago the SCA confirmed that it "has alternate sources of water that could be used if the quality of the water being supplied from Warragamba Dam were to change".)
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[MadHound]

1. Hmm,

There are several organisms and chemicals that would take care of this algae bloom, perhaps they should use one of those:shrug:

[donsu]

2. where have these chemicals been used to success?

I haven't heard of this chemical use. not in the US, Can. or anyplace else.

[MadHound]

3. Sure, it is used to clean out wastewater treatment ponds of algae

Whenever there is a need to do so. Hell, depending on the algae type, everyday ordinary chlorination can do the trick. Or there are several microbial organisms that eat algae. Hell, algae is even harvested with basically a sieving net. I realize that there are going to be problems of scale, but solutions do exist and something should be tried rather than simply throwing up their hands and saying sorry, have to wait until March.

[donsu]

4. I'm sure if what you say worked, they would be using it.

it must be toxic too, or they would be using it.

[MadHound]

5. Maybe, maybe not.

Some of this stuff is pretty obscure, I'm fortunate enough to have friends deep into biochemical engineering. Perhaps it is simply problems of scale. Who knows:shrug: Hopefully they find some solution though, otherwise it's going to be a rough time over there.