Sludge Watch ==> Toronto - Researchers Make Hydrogen from Sludge and Sludge Pellets

[Maureen Reilly]

Sludgewatch Admin:

This story is about mixing sludge with the expensive pelletized sewage 
sludge pellets that Toronto plans to make.  Because you have to use energy 
to dry the pellets from 75% water to less than 5% water, these dry little 
sludge pellets cost the taxpayer plenty -  $350 - $500 per tonne. And no one 
will buy them as fertilizer for any price...since it seems that they fail to 
meet the requirements of the Canadian Fertilizer Act and the USA is already 
chock-a-block with dried sludge that no one wants.

And the pellets tend to go into spontaneous combustion.

So the idea is to cook the sludge (very very expensive) and mix it with 
those very expensive pellets to make hydrogen to use for energy?

Hello?  Can we get a mass balance and a price check?

And what do we do with the left over sludge..now mixed with a cocktail of 
rotted veggies and gosh knows what else?  More expensive  trucking of the 
remaining sludge 5 hours to to GSI  in Quebec to 'compost' or New York 
State?  Ohio?

Methinks someone is indeed spending too much time in the bathroom with a 
magazine and a locked door.


.......................................


Researchers make hydrogen from waste


Dried sludge pellets from Ashbridges Bay key to formula

Feb 14, 2007 04:30 AM
Tyler Hamilton
Energy Reporter

It turns out that the future of the hydrogen economy may begin with a 
toilet, a magazine and a locked door.

Researchers have found that waste-water treatment facilities such as 
Toronto's Ashbridges Bay plant could produce significant amounts of hydrogen 
by fermenting dried-sludge pellets in a mixture of "primary" sludge – an 
organic cocktail of feces, rotting fruits and vegetables, textiles and 
paper.

The idea of producing hydrogen from municipal waste water isn't new, but 
controlling the amount of hydrogen produced has proven tricky. One problem 
is that sludge contains bacteria that produce hydrogen and bacteria that 
consume it, so the net yield tends to be much lower than its potential.

"In order to maximize production you need to kill all micro-organisms that 
consume hydrogen," said Youssouf Kalogo, a researcher at Hamilton-based 
environmental consulting firm Hydromantis Inc. Doing this, however, means 
boiling the sludge – an energy-intensive process that proves uneconomic.

Kalogo, along with former University of Toronto professor David Bagley, who 
now teaches civil engineering at the University of Wyoming, realized that 
another option was to spike the primary sludge with dried sludge pellets. It 
turns out that the process of making the sludge pellets kills off the bad 
microbes and preserves the good ones.

The two scientists conducted an experiment, the results of which will soon 
be published in the peer-reviewed journal Bioresource Technology, which 
showed that pellets obtained from Ashbridges Bay were an inexpensive, 
practical, and renewable source of microbes for generating hydrogen from 
sludge.

"This is general research that can be applied to any waste-water treatment 
plant, and it's a totally new approach," Kalogo told the Toronto Star. "We 
know that the pellets already exist in plants, so why can't we use the 
pellets directly as a source of micro-organisms?"

The hydrogen that's produced could be used in a fuel cell to produce 
electricity and heat for the treatment facility, with any surplus power 
being sold back into the grid.

"These municipalities have to manage the solids they're producing, and this 
is a very good way of doing it."

The Ashbridges Bay facility once incinerated its sewage, but the city moved 
to a cleaner anaerobic digestion process and a system that dries the sludge 
and turns it into compressed pellets. The pelletizer system was hit by a 
major fire in August 2003 and has since been out of commission. The city 
expects it will be back in full-scale production by the summer.

Lou Di Gironimo, director of waste-water treatment for the city, said the 
sludge digester at Ashbridges Bay produces methane gas that is burned to 
generate heat or flared when there's too much gas.

"Part of the problem with methane is that the gas is really dirty." He said 
hydrogen would be a better gas to produce because it burns clean, has higher 
energy value, and is easier to work with.

"It's not a greenhouse gas concern either, whereas methane is a significant 
concern."

Methane is 20 times more potent than carbon dioxide as a greenhouse gas.

Di Gironimo, who supplied the pellets to Kalogo and Bagley, said he plans to 
review their research and will decide then whether to proceed with a pilot 
project to test their approach.

"The ramifications of this are huge if you look out 10, 20, or 30 years, 
because the energy benefits are significant," he said.

http://www.thestar.com/Business/article/181404