It’s not merely the expense. It’s the time. Assume it takes a couple of years to get a 250 million litre/day plant built on about 10.5 acres of land (numbers based off a recent plant built near where I live). That feeds a mid-sized city (say population in the 100000s).
Those membranes and equipment aren’t exactly off-the-shelf, you know. They have to be designed for the location. Then there are clearances, land acquisition,… Final hiccups included, you’re looking at 3 years minimum before it becomes operational.
Even if you were willing to bankrupt the entire California and US Governments to do this, do you really have three years?
Basically, you’d just be pissing lots of money down the drain without a plan.
Even if I wanted to get into a technical discussion with you, which I do not, I have to say that the rather unimaginative limitations with which you are encumbering your argument seems like a mis-step.
In fact, there probably is an interesting, technical discussion concerning the strategies that could be employed as emergency relief in the build up to the shift to a major implementation of a new technology…
Look, I’m not saying the discussions about potential engineering solutions can’t be fun, but you have got to work on the skills you employ to take the conversation into that arena.
Also, self-excusing from potentially very interesting discussions pertaining to imaginative solutions that could be employed aside, I’m going to watch Game of thrones and Silicon Valley. Perhaps my appetite for pontificating about mega-engineering will be whetted in the time away.
In other words, you can’t find anything technically wrong with what I’ve said, so instead you try to find something wrong with my imagination and conversational skills?
Sorry I punctured your fantasy bubble…
Look, I’m not saying that your idea was completely invalid. Just that it’s not going to work well enough under these conditions to make enough of a difference. Of course, California needs to build some desalination, inefficient as that may be, to just feed its population centres. But that’s not going to help agriculture in any measurable way.
No, no, maybe… I think the conversation really does have some merit.
But I’m just about to watch mah stories.
Perhaps you could work on counter-arguments to your suggestions of precipicial limitations and then counter arguments to those so that when I come back you’re already one step ahead of me?
You see, I too have been known to enjoy wrastlin’ in the mud over engineering potentialities.
In an ideal world, we would be willing to endure the political heat and modify the rules on water extraction now, so that we at least keep the aquifers if not the agriculture, rather than letting the agriculture crater those and then die anyway.
Unfortunately, based on observing attempts at keeping fishing within sustainable levels, I’m not optimistic.
The dispersal is precisely the point! Regardless how hard you run the desalination plants, the amount of concentrated brine will never be more than a miniature drop in the olympic-sized swimming pool of the ocean. The plume of brine has only a local impact, and only until it sufficiently mixes with the rest of the ocean. Avoid the local effects and the global ones will take care of neglecting themselves.
So the three to five gallons of waste stream have correspondingly lower concentration.
Which on one side worsens the issue with extraction of dissolved metals and with the waste stream volume, but on the other side reduces the issues with plume mixing when disposing of the stream back into the ocean.
We need more R&D on the membranes. I keep reiterating that.
The Manhattan Project started with a tentative hypothesis and ended with a functional prototype in a matter of few years. Fewer years, including actual building and running of all the plants, than it takes today to even write the environmental impact statement paperwork.
We are crippling ourselves and then wondering why nothing gets done…
Death by a thousand budget cuts!
Sometimes the more expensive choice is the less expensive choice.
How long did it take to develop the membranes for uranium diffusion separation, pretty much from scratch? How long did it take to build the plants?
It can be done, it was done. It was proven it can be done. It was proven it can be done with 40’s technology.
Also, consider that only the scale is the difference between one-of-a-kind and off-the-shelf. The cost per unit production scales nonlinearly; making a thousand membrane units costs less than a thousand times one, and making a million costs less than thousand times of the thousand.
And think about the possibilities of nanotech self-assembly for creating layers with controlled porosity.
Sorry, I didn’t… Got into a wrestlin’ match with a set of Fourier transforms!
Anyway, why I’m into all this at all is, much of my state’s facing an adverse groundwater situation too - nowhere near as bad (we still get rains, just not enough). We’ve been trying all kinds of things, including desalination, and just reduced water usage in agriculture. What we’ve found is that desal is OK for urban supplies, even for some industry with a captive plant, but it’s just not enough to feed agriculture.
They have a higher concentration than the input; whether that’s good or bad depends on the actual ecosystem into which they’re discharged…
The issue is not the ocean - it’s local ecosystems. Most marine organisms breed in shallow coastal waters. Desalination rejects can quite badly affect these populations. Which has bearing on both fishing and on larger ocean fauna.
There are reports here that the desal plants we have are affecting the fish population, but that’s kind of inconclusive right now - there are other issues like fly ash and high temperature water discharge from powerplants close by, and no specific study has been reported that I know of.
Well, for one thing, they just didn’t have to deal with a few million stakeholders all pulling in different directions - land rights, water rights, agriculture vs industry vs urban supply, various laws,…
And for another, there was a clear and simple goal at the end - same with the moon landing. “Solve the crisis however you can” may not be specific enough for such a thing to work.
Not saying that it can’t… Just looking at potential issues.
Someone once remarked to me that “if it’s a question of your civilization’s survival, what appeared expensive suddenly looks cheap”…
Roughly a year and a half:
Apparently, the Carlsbad plant has taken about three or four years to become operational (it’s scheduled for next year, but they seem to be trying to move it up. That sounds similar to the one I was talking about earlier - started in 2005 and commissioned in 2010 (they had issues with a cyclone setting them back about a year or two).
Yeah, we have a tiny RO unit at home - that’s literally off the shelf. It produces something like ten litres a day. Assume a 250 MLD plant, and say, a unit with ten times that capacity. You’d need about 2.5 million of those membranes in the plant. They’ll wear out in about a couple of years, and so you’d need 2.5 million every two years. It’d be kind of uneconomical…
But those are different from the ones they use in large plants. Those have longer lifespans, and they are also much more heavy-duty - our little unit is meant to handle slightly brackish water, not full-on seawater.
Hmm, I wonder what the economic impact of losing California’s agriculture would be… I don’t mean just financial - what does it mean for the food system in the US and in the rest of the world? Even half-way around the world, we get Californian stuff - sun-dried raisins and the like. Not to mention the wine. I don’t want to lose Californian wines, goddamnit!
Anyway, the impact on the system could be pretty bad either way. I don’t think there’s a real way to go back to things as they were…
That’s why I specified discharging to depth, earlier in the discussion. If we can pull oil a hundred of miles off shore mile deep and then more miles through rock, we can discharge saltier saltwater two miles away in a half mile depth.
Makes one long for a nice, peaceful wartime…
Good start, I’d say. Even the Moon program started more as “show the Russkies who’s the king however you can”.
It was a rhetorical question but the answer is appreciated anyway
Make them reel-to-reel, in a continuous process. Reel-to-reel is a holy grail of mass production of flat goods; makes everything way cheaper.
Yeah, the water rights issue is, insanely, not being addressed even though currently the amount of water promised in water rights exceeds the total amount of water in the state something like five times over. I don’t think property taxes are going to do it. Farmers with water rights can sell on whatever they don’t use, so they can pass on costs while still using as much water as they want until there’s no water left in (former) waterways. Aquifer pumping also seems to be another issue; it’s basically entirely unregulated and amounts to a free-for-all: whoever can pump the water out from underneath their property can do so. What’s going to be required is a total overhaul of how water is used and distributed and with it, an overhaul of California agriculture and the established system of water rights.
What I meant was that it wouldn’t happen on its own. But honestly it’s not going to happen artificially, either. It’s not remotely economically viable without a large amount of free water - which just ain’t going to happen in the Central Valley.
So Californian agriculture is a resource-extraction industry, the main difference from gold miners being that farmers have more political clout, so when the resource is all extracted they will insist that it is everyone else’s problem rather than simply desert their ghost-towns.
Actually aquifer recharging is by far the most economical way of increasing water supplies and we do it in California. There are huge water banks which are just recharged aquifers many funded by Prop 13 in 2001 which was dedicated to it. They are substantially cheaper to build than dams or desalination projects which is why we built so many over the last couple decades.
The most common way to recharge acquirers is to use recharge ponds to prevent rain prevent run off when it does rain. There is a huge amount of runoff that happens when it rains that is simply lost to evaporation or which runs into the sea, so this method is not only economical, but effectively free.
Then there are injection wells which force water into the the ground. They require less land, but more energy.
Typically we charge the aquifers during the high spring surface water flows from rivers and streams when the snow begins to melt since supply of water far outstrips demand. This water is effectively free. It would otherwise flow into the ocean.
We also use waste water from agricultural runoff (which there is a lot of), stormwater systems and treated wastewater (also known as sewage). Treated wastewater for instance is being injected into aquifers in Santa Clara County and Orange County. Apparently, as long as you put your treated urine through the ground first, no one complains.
A rather large $7.5 billion water bond was passed last year with a full $2.7 billion going to water storage and it looks like a good chunk of it will go to aquifer recharging since it is so much cheaper than building new reservoirs.
Massive investment with massive commitment can advance the state of the art massively in a time frame that can seem like pure fantasy to the naysayers.
Perhaps in some fields, in others really not so much, especially when they’re mature industries. As I said before there has already been a lot of R&D into desalination ( @shaddack unlike the Manhattan project).
Seriously you seem to be arguing in binary: there are two options, invest heavily in desalination research which will rapidly overcome all the current technological hurdles and allow the Californian agriculture industry to continue as is; or allow the agriculture industry to destroy California by business as usual. Nobody here is arguing the water table should be allowed to be depleted, so stop the strawman arguments.
Why not: some (realistic) desal investment; massive investment in greywater recycling; expansion of “3rd pipe” systems (two pipes are hot potable water & cold potable water, 3rd pipe is non-potable water for appropriate uses i.e. toilet flushing, irrigation, etc); and most importantly a serious reconsideration of the agricultural practices of Californian farmers.
Are Californian farmers growing the sort of crops that should be grown in drought stricken lands? Has the “free water” from water-rights allowed a completely unsustainble industry to develop (all evidence indicates yes!). Are there other technologies/techniques that could drastically cut the amount of water needed? Are there alternative crops Californian farmers could be growing that are less water hungry? Are there better places to grow the sort of products California Ag is currently exporting?
Avoid the local effects and the global ones will take care of neglecting themselves.
Still trying to work out how you plan on avoiding the local impacts. Deep water or not the brine will still be concentrated at the entry point, and wherever the dominant currents carry water from there. It will disperse, but slowly, and it will leave a somewhat sterile patch of ocean in its place until the plant is turned off. I guess you could build a series pipes and alternate dispersal every few weeks/months, but that would be even more expense. Did I already mention the chemicals tainting the water?
Pick a locality (in the 3d space) where there’s not much undersea life that could be bothered. Sure, there’ll be a deadly plume there. But there’s not that much life in quite a lot of the ocean; most of it is concentrated in the shallow waters. Avoid those and you’re golden.
Also, instead of a single outlet pipe, a long diffusion zone could be considered. Actually, this is something where the US could be better at the research; most of the others developing this tech are hardly the most probable candidates for environmental mitigation research…
It was interesting, so…
Maybe… But again, I’m not sure of the setup time for it.
Yeah, until that happens, everything else is deck chairs and Titanic territory… From what I read, those water rights laws are a freakin’ nightmare…
All agriculture… Especially mechanized, large-scale agriculture. Water, soil, fertilizer,… It hasn’t been Old MacDonald for at least 50 years now…
Fascinating! we have a few similar things too - better yet, they’re even traditional. Some of those structures are a couple of thousand years ago (and in pretty much continuous use)…
This! Pretty much exactly what I’m getting at!
I don’t think anything will make any difference until you get agriculture to at least shift to less water-intensive crops. I’m not sure of the current crop-mix, so it’s tough to say what exactly that would entail. But from what I’ve read, it’s not going to be easy in any case…
