This was honestly the first I've heard about concerns regarding phosphate and potassium supplies. After some quick googling, possible projections are 2030 for peak phosphate, 2057 for peak potassium:
* https://en.wikipedia.org/wiki/Peak_phosphorus (TIL a large majority of the world's phosphorus reserves are in Morocco)
* Peak Potash study: https://www.sciencedirect.com/science/article/abs/pii/S03014...
https://en.wikipedia.org/wiki/Milorganite
>Milorganite is a brand of biosolids fertilizer produced by treating sewage sludge by the Milwaukee Metropolitan Sewerage District. The term is a portmanteau of the term Milwaukee Organic Nitrogen. The sewer system of the District collects municipal wastewater from the Milwaukee metropolitan area. After settling, wastewater is treated with microbes to break down organic matter at the Jones Island sewage treatment plant (also called "Water Reclamation Facility") in Milwaukee, Wisconsin.
>The byproduct sewage sludge is produced. This is heat-dried with hot air in the range of 900–1,200 °F (482–649 °C), which heats the sewage sludge to at least 176 °F (80 °C) to kill pathogens. The material is then pelletized and marketed throughout the United States under the name Milorganite. The result is recycling of the nitrogen and phosphorus from the waste-stream as fertilizer.
>The Milwaukee Metropolitan Sewerage District's Jones Island Plant had the largest wastewater treatment capacity of any in the world when constructed in 1925. It was the first plant in the United States to succeed in using the activated sludge treatment process to produce fertilizer.
Potassium is excreted by humans mainly in urine, which is easy to recover. But NPK fertilizer is just one piece of the puzzle. AFAIK, plants require 17 essential micro- and macro-nutrients to grow [0]. I'm just a lay gardener, not a chemist nor research scientist, so I'm not sure how to approach recovering calcium, magnesium, sulfur, or metals like zinc and molybdenum for nutrient solution manufacture. That's the nice thing about composting for soil-based gardening; so long as the right microbes are there to make it bioavailable, all the elements you need are in the used-up biomatter. If it was eaten and not exhaled, sweated out, nor incorporated into the body, it'll be there in the waste stream.
[0] https://www.researchgate.net/figure/There-are-17-essential-p...
Electric power to run the LEDs, if obtained from renewables, is protected from cost shocks, but such power might be more profitably sold at such times than used to drive LEDs and sell the produce.
Bold statement, I'd be impressed if it holds up by mid-century.
SpaceX cans are woefully inadequate even to maintain a Mars outpost.
The usual term is "outpost", or for a larger operation, "base".
There are no undersea outposts, even. Construction crews sometimes encamp for a few weeks for big hazard pay. There are two (count 'em!) low-orbital outposts that get literally all supplies except energy from the ground.
The word colony in the sense of space exploration and other extreme habitats means permanent occupation and exploitation of the resources there.
>4. Sabatier reactor
>Inside this machine, a blast of roughly 750°F heat breaks the bonds inside CO₂, forcing it into its constituent elements. The carbon and oxygen combine with hydrogen from the station’s oxygen generating system to make H₂O and methane (CH₄), the latter of which vents into space.
Even if this pessimistic prediction comes true, the same nutrient-recycling solution could support human life in resource-poor regions on Earth, such as Antarctica or Detroit!
The bigger question is how the liar benefits from the lie. Pumping stock value is the usual guess: (Tesla stock is only now starting to correct, and that largely because of the Twitter debacle.) The fusion-energy startup business runs this way.
https://en.wikipedia.org/wiki/Rhizosphere
To farm plants without soil, they must be supplied with a water-based nutrient solution. The solution contains a precise mixture of all chemical substances a particular plant needs to grow. Yield efficiencies can be realized by carefully tailoring this mixture to each plant. The problem is where to source the ingredients once extracting them from mineral deposits turns uneconomical.
Compost- and manure-amended soil theoretically has everything plants need, but that's not very useful for soil-free farming. The precise ratio of nutrients in a given patch of soil is also outside of the farmer's control. Perhaps the individual nutrients can be leached, distilled, or otherwise chemically separated from compost and biological waste products to enable their reuse in finely-mixed solutions? I don't know. Maybe someone with more knowledge can answer.
They don't disappear from the planet when consumed.
This doesn’t need to stop at the hydroponics system. There are plenty of opportunities to create better nutrient loops in our food production system.
We have been working on this for nearly five years. We currently participate in a project which has two dozen companies participating in closing this nutrient loops and create better and more efficient food production.
One question about this video— at 1:46 the speaker says, "fish provide all the nutrients [for] our vegetables, which means we don't have to add anything artificial." Is this accurate? My impression was that aquaponics mitigates but does not completely eliminate the need for industrial fertilizers/nutrient solution additives, in addition to replacing what's removed when fish or vegetables are eaten:
https://www.youtube.com/watch?v=oGmJETrqzN4&t=1m46s
Another question— with aquaponics, how do you incorporate food waste into the circularity? Do you feed it to the fish, extract nutrients via an external physical/chemical process, or just dump it in the water reservoir and let it decompose?
We see that a very large portion can be done with circular biological systems. We have been working to incorporate food waste via insects. We take allowed food waste and feed insect larvae. There are several teams in Sweden working on this together, with some government support.
I haven't seen the "fermented plant juice" before, but the principle is the same, let bacteria work on it.
How will hydroponic farmers adapt? Where will they economically obtain the necessary nutrient solution additives? Are there practical techniques to extract these nutrients from traditional sources, like urine or manure? The aspiring Mars colonist or hydroponic homesteader will need to figure this out, or return to traditional "regenerative" farming practices which compost biological waste and return all used-up nutrients and their constituent elements to the soil.
And for someone like a Moon or Mars colonist, even regenerative farming isn't simple. Composting relies on bacteria to convert waste products like nitrogen-containing urea, whose nitrogen isn't bioavailable to plants, back into useful and bioavailable forms like ammonium. Keeping cultures of bacteria alive and healthy indefinitely will be essential to a colony's continued survival. Are there practical chemical processes to replace the function of these microbes, e.g. to convert urea to ammonia without urease enzymes? I don't know. Maybe someone with more knowledge can comment on this.
I hope this problem can be solved. Hydroponics has many benefits, from dramatically lowered water consumption vs. soil-based agriculture, to higher yields driven by precisely-managed nutrient ratios. Spacefaring farmers will appreciate the weight saved by leaving all that excess water and soil on Earth. It'd be a shame to abandon this technology simply because we couldn't pivot away from fossil fertilizers.