Can shale oil residue be used as biomass? I have been thinking a lot lately how to add biomass to desert sand, so it can be used for food production. (Most of the world's deserts, like the Sahara, are man-made, through overuse of fragile environments by prehistoric peoples.)
I understand that such residue is a sludge, difficult to clean up, consisting of the remaining oil and particulates such as sand. But oil will break down over time at the surface. In fact, if an oil tanker becomes stranded and the crew must abandon ship, protocol is usually to scuttle the ship at sea, for the oil does more damage on shorelines than at sea, and it will eventually break down.
My idea is to mix small amounts of soil into the shale oil residue so bacterial action can break it down more quickly then normal. This would probably have to be done in large bins, with other compost materials. The big question is: can the oil itself harm the bacteria in large amounts? Or are only a few types of bacteria suitable for this purpose?
I think the toxic contaminants in the residue would be more harmful than the carbon would be helpful. Particularly if you were growing for food production.
The resulting compost would have to be thoroughly tested, and that after sitting in the bins for several years. But with no artificial inputs other than the residue itself, I suspect even organic farmers might accept it after that.
I am using as my "precedent" the protocol for scuttling ships. If that would result in an eventual breakdown of all toxins, then I believe the same would apply to compost. If necessary, seawater could be added to the compost.
It's a unique idea and you are correct scuttling ships is better than having the oil end up on the shoreline. Scuttling ships certainly does not breakdown all toxins.
What you have to understand is that while the hydrocarbons in oil are utilized by some types of bacteria and can be broken down into safer hydrocarbons, the trace toxic metals that are present can never be removed except maybe through phytoremediation. Thus any plants grown in this treated slurry will more than likely contain elevated levels of toxic heavy metals.
Here in the US we often sink retired vessels through a program called Ship to Reef, in which all petrochemicals and other harmful contaminants are cleaned from the ship and then sunk. So only as a last resort to the scuttle ships with petrochemicals still intact.
What about using successive bins, in the manner of sewage tanks? Also, some places use successive ponds to remove their waste, to the point that the end result is drinkable water.
I'm no chemist, but it seems that heavier elements, being "heavy", would sink toward the bottom of a tank of water, while oil normally floats in the manner of soap.
Something similar was suggested to me for processing salts out of desert sands. (The salt wicks up from beneath and would be a continuing problem for some time.) Basically, the salt would be washed out of the sand and the water would flow into a brine tank with a glass top, from which the water would evaporate and be stored elsewhere. (The salt could then be sold for food seasoning or road salt or the like.) I suspect the difference main difference between water and salt that allows comparatively easy separation through evaporation is that of weight. This is the thought process that led me to the above suggestion in this post.
I'm apparently thinking small-scale by comparison. A resident farmer would slowly convert small amounts of soil at a time in a usable form. (I have visited some organic, hand-worked farms where such improvements are seen as worthy in and of themselves if they help rehabilitate the land or contribute to the farm's incremental growth in a worthwhile fashion.)
In a desert region, he would use distillation, piping the salt water into a glass-covered tank which would allow any water that condenses on the glass from evaporation (or morning dew) to flow into a trough on the side and from there to a separate tank. This is feasible on a small scale and is done in many places, though I know of none where it is done on a commercial scale.
I was thinking mainly of other trace elements like iron. At any rate, the oil itself was created from normal, originally uncompressed biomass like wood.