One type of these system is the Sintex Digester.

But, of course, they don't look like rocks and sludge now.

Large quantities of mercury were detected in fish, shellfish and sludge from the bay.

Oil sludge constitutes the most important type of solid waste in terms of quantity (Linden et al., 1990).

Such franchises may cover local sanitation network extension, sludge removal and disposal, sewage collection and treatment and other service delivery.

It can wash the sludge off high mountain peaks and hills, down into the lowlands. So stop and think for a minute.

Then we would have an anaerobic digester, which could deal with all the biodegradable waste from the local area, turn that into heat for the greenhouse and electricity to feed back into the grid.

If we look around us, much of what surrounds us started life as various rocks and sludge buried in the ground in various places in the world.

These include biodigester septic tanks for treatment of domestic sewage anaerobic pond systems for treating agricultural processing wastes and anaerobic sludge reactors for the treatment of food processing waste water.

But these haze particles, it was surmised, before we got there with Cassini, over billions and billions of years, gently drifted down to the surface and coated the surface in a thick organic sludge.

While high density urban settlements generally require sewerage networks and waste water treatment facilities, in low density settlements on site sanitation, such as septic tanks with sludge removal, may be an option with significantly lower costs.

Sewage is produced by all human communities and is often left to compost naturally or is treated using processes that separate solid materials by settlement and then convert soluble contaminants into biological sludge and into gases such as carbon dioxide or methane.

And the tourist brochures pointed me in the direction of this bridge I love bridges, metaphorically and symbolically and structurally and it was a bit of a disappointment, because of the sludge from the river was encrusted on it it really wasn't in use.

These are the Athabasca tar sands, and there's an enormous amount first of mining, the largest trucks in the world are working here, and then you've got to pull out this black sludge, which is basically oil that doesn't flow. It's tied to the sand. And then you've got to use a lot of steam to separate it, which only works at today's oil prices.