California recycled water - produce stickers pass through filtration systems ...

Note that the recycled water system to be used as part of the SEQ water grid is more advanced than that of the San Ramon, California wastewater treatment plant.

However:

- the article excerpt below highlights that mistakes can and do happen.

- it took a year to discover and solve the problem.

- it's embarrassing to the Qld government who generally label the whole of California as drinking recycled water (when this is not the case) and hold up California as a great example for SEQ to follow.

Excerpt from San Hose Mercury News:

Tiny produce stickers fouling up water system in San Ramon

4 June 2007

SAN RAMON - There is a sticky situation at the Dublin San Ramon Services District wastewater treatment plant.

Those tiny produce stickers that identify produce as "red delicious" or "avocado" - the ones residents in Dublin, San Ramon and Pleasanton innocently throw down the sink drain - have become a huge headache, gumming up recycled-water irrigation sprinklers at local parks and other areas.

The clogging mystery took a while to figure out.

"It started about a year ago and we didn't know it," said Sue Stephenson, a district spokeswoman.

The Dublin-San Ramon district added a new sand filtration system at its Pleasanton treatment facility that is able to process more water, but can't trap the little stickers, which have the same buoyancy as water.

The pieces float through the filter and to pipes, eventually becoming stuck in various irrigation sprinkler heads.

Once they realized it was the stickers causing the problems, one of the district's mechanics created a screen that caught all the soggy bits. But workers now have to vacuum the screen several times a day.

"It's a hassle," as well as bad for the environment, Stephenson said. Plastics of any kind, no matter how small, should not be in the wastewater stream because they don't decompose, she said.

"They are the kind of our poster child to wage war against plastics in the wastewater stream," Stephenson said.

Not all wastewater treatment plants are having the problem, however.

At San Jose's plant, "I'm not sure if it is a difference in the kind of filtration systems that we have, but we're not seeing it as a problem," said Lindsey Wolf of San Jose's Environmental Services Department. "We have filters, but we're not seeing any of that kind of thing gum up the works."

Lots of debris goes down people's drains and toilets, Wolf said. At the wastewater plant, it is filtered to remove objects like paper, eggshells, sticks and plastic. Then the water is treated multiple times and released into San Francisco Bay with more than 99 percent of the suspended solids removed.

To combat the deluge of stickers in the Dublin-San Ramon area, that agency is holding a contest to see which city can collect the most stickers on little magnets and postcards during the summer. The mayors of the three cities also have a stake in which city wins.

The city that collects the most will have its mayor supervise the other two mayors cleaning the screen in October.

See - Recycled water - stickers getting through the filtration system.