Jump to content
Mike

Desalination Plant

Recommended Posts

Here I go again, just like solar 5 years ago.....

I imported a 3000lt per day desalination unit leaves the East Tuesday, installed 3 x 2200lt JoJo's with booster pumps and all, just need to purchase a pool pump / Filter as a pre pre filter and do all the piping. Seeing that i do not stay on the waters edge, i have to "collect sea water" via water trailer at 2000lt at a time and water pump from our local harbour. We will see how i last doing this, might employ someone to do it for me every 2nd day.

3000lt front.png

3000lt unit.png

Share this post


Link to post
Share on other sites

@Mike Looks like a sturdy desalinator. A problem that both you and I have, with our homes not on the seaboard, is what about the waste water. From what I have read so far, only about 25% of the water going through the unit is desalinated. So if you want 1000 liters, you have to put 4000 liters through the desalinator. You need 4 times the fresh water you want and have to deal with the rest which is waste. Letting it run down the street may turn the street into a salt pan. Tricky business but our dam is at 20.8% this morning, 1% less than last week. At 12% it will be below the outlet to our purification plant and water will have to be pumped from lower levels. At least you will be prepared, problems and all.

 

Share this post


Link to post
Share on other sites
20 hours ago, Mike said:

Here I go again, just like solar 5 years ago.....

I imported a 3000lt per day desalination unit leaves the East Tuesday, installed 3 x 2200lt JoJo's with booster pumps and all, just need to purchase a pool pump / Filter as a pre pre filter and do all the piping. Seeing that i do not stay on the waters edge, i have to "collect sea water" via water trailer at 2000lt at a time and water pump from our local harbour. We will see how i last doing this, might employ someone to do it for me every 2nd day.

3000lt front.png

3000lt unit.png

@Mike is there no way you could rent a spot (barter a spot) with sea water access... ie: a harbour resturant/warehouse, etc.  You could then trade some water for the use of the position... run the plant off solar etc as normal?

You then just need to move the clean water home?  

My 2c anyway ;)

Mark

Share this post


Link to post
Share on other sites

As I have learned lately, to move water (actually most fluids), is not easy.

1l = 1kg. Ja ja ja, sounds like "Hellooooo!!! Common sense! We know that." :D

Here is the thing. If you use 10kl per month, that is 10 tons. 10 tons needs a bit of a chassis to carry it, lots of HP to move it. No, you cannot use your SUV. 

So to cart water around, you need to carefully consider the liters. Not only that, a tank that can carry potable water. No use the family goes to hospital and all that.

Then, if you decide to cart the water around:

  • Check your drivers license. Any limitations ito weight you can pull ito trailers?
  • Is the trailer up to specs ito braking?
  • Is you car specced to pull the weight?

Another thing. Carting liquids around in a trailer is a bastard. Allegedly the liquids tend to move, when you pull away, take corners or have to brake fast. :D So driving them is a whole new way of driving.

My point. As easy as it sounds, it is complicated for we use more water than what we can cart around and if we start carting water around, check your drivers license. The weights are enormous.

 

50kl tanker is a solution. 5 months of water at current rate of use.
I can make space for it. And fit a gate.
Have learned to push long trailers back into narrow spaces.
.. just don't have the cash for one. :P

Yes, you can now rent smaller trailers.
And trucks. But at +-2km per liter of diesel, you need to haul a LOT of water to make it viable.

Share this post


Link to post
Share on other sites

If you are near the sea, it may perhaps be best to just drill a borehole on your property and hope you get an influx of seawater. That way you just have to pump it to the surface and desalinate. Also you won't have Environmental Affairs poking their nose into your activities, hopefully. The waste water remains a problem though for which I can't offhand think of a solution.

Share this post


Link to post
Share on other sites
3 hours ago, The Terrible Triplett said:

No use the family goes to hospital and all that

so lets have a look at keeping or getting the water potable. one way is chlorination. me and the missus one day worked out - she has more math sense then i ;), that in order to chlorinate to WHO minimum specs and in order that the chlorine smell and taste is minimal [it has a tendency to clear up after a few days anyhow] we need about 250ml of bleach [1.3% per vol sodium hypo-chloride] per 5000l once per month.

but things aren't always as easy as they seem for chlorine, see here for a lot on water. i attached a chlorine document.

a second method of getting and keeping your water potable is by ionization. its been tested successful in hospitals against legionnaires disease lurking in their water systems and will not only take out bacteria but also the green slimy algae [biofilms] which can harbor bacteria

now, maybe i should have stated from the outset - i am no fundi on either method discussed...

back to ionization. for more on the specs see here  like with all good things the concept has been around for ages, the romans and vikings have made use of it as well as grandmother 'met die tiekkie in die melkbottel - silwerskoon!'

the way we did it is to put a smallish pv on the water tank with two wires going down to a silver and copper piece [both 99% pure] in the water near the outlet under the water. kept apart about 10cm, from there the ions do their job, i cut and paste:

Copper-silver ionization disperses positively charged copper and silver ions into the water system. The ions bond electrostatically with negative sites on bacterial cell walls and denature [pc for kill :-)] proteins. Over the long term, the presence of copper and silver ions destroy biofilms and slimes that can harbor Legionella,

God bless

 

 

 

chlorineresidual.pdf

Share this post


Link to post
Share on other sites

@The Terrible Triplett our harbour is primarily just a breakwater with launching slipways. If you extract seawater from the seaside of the breakwater there will be no pollution. All the pollution that you Capetonians dump into the sea is totally diluted by the fast north flowing Benguela current by the time it reaches our shores about 80 Km north of you folks. Tests for a Blue Flag beach did not indicate anything harmful outside acceptable limits for the purpose. Sewage was never and is not now dumped into the sea but about half of the 1500 or so houses still have french drains. These were outlawed for new builds in 2004 so newer houses have conservancy tanks that are pumped and trucked to the Darling sewerage plant.

It occurred to me that waste water from desalination could perhaps be used for flushing toilets if you have a separate feed pipe to toilets, something I installed when I built our house in 2006. This may mostly solve the issue of dealing with waste water from desalination for @Mike. Won't work too well with french drains as it is sure to kill bacteria but should not be a problem with conservancy tanks provided your pipes are synthetic and not copper. I doubt that copper pipes are going to like the brine over time.

Share this post


Link to post
Share on other sites
22 minutes ago, ebrsa said:

... waste water from desalination could perhaps be used for flushing toilets ...

If done in CoCT, would that not affect the waste water treatment plants also?

Don't they also rely to a certain level on bacteria to breakdown the affluent?

Share this post


Link to post
Share on other sites
2 hours ago, The Terrible Triplett said:

If done in CoCT, would that not affect the waste water treatment plants also?

Small amounts of salt might not be a problem. But I can imagine that large amounts of salt dumped into sewage will cause a problem downstream.

Share this post


Link to post
Share on other sites
56 minutes ago, plonkster said:

Small amounts of salt might not be a problem

although we don't have to use salt to clear ice from our roads, extra salt in the eco-system is not a good thing
see
here
here
here
God bless
g

Share this post


Link to post
Share on other sites

Any significant amount of salt water dumped into the sewerage system of a town or city is bound to have negative results. But how many residents can reasonably be expected to buy desalination plants and do that. Of our approximately 700 permanent households, it is only Mike who invested in a desalinator as far as I know.

Our water security in Yzerfontein can be assured if a desalinator is installed by the municipality as we have two sizable reservoirs on a hill behind the village. Such desalinated water could also be piped to Darling if the feeder pipeline from the Voelvlei dam can withstand the pressure which I expect will have to be higher than the presure when water gravitates from the dam to our reservoirs. Things are surely going to get worse before they get better and one can only hope that rainfall this year is not the same as last year. That will be a catastrophy of epic magnitude.

Share this post


Link to post
Share on other sites

I think the burp we now feel with the drought, is but a warning for what is to come.

Recalled when the Jhb members went all out with water plants because the Vaaldam was nearly dry ... then their rain started, months of it, and this year it continues. 

So therein me wondering, if the Tvl gets so much rain, then the Cape will be left with nothing. :)

No seriously, patterns have changed. Maybe we are in for a burp, maybe we are in for the whole shebang. The Bible (the oldest most argued about book in the existence of man), in Revelations, do make a mention or two about problems to come. 

4 hours ago, ebrsa said:

Our water security in Yzerfontein can be assured if a desalinator is installed by the municipality ...

All towns next to oceans should have such installed, dams there for the security of the farmers efforts, not households, powered by wind and solar as their main power sources with surplus power sold back to Eskom ... dang, stop dreaming, your coffee is cold. :D

Share this post


Link to post
Share on other sites
16 hours ago, plonkster said:

Small amounts of salt might not be a problem. But I can imagine that large amounts of salt dumped into sewage will cause a problem downstream.

Was talking to some people who thought getting seawater to flush toilets was a good idea.

Share this post


Link to post
Share on other sites

On the whole topic. I did some research a whole ago on the cost of recovering water from sewage as opposed to desalination, and there was an interesting result: In some areas desalination is used to extract water from a brackish source, and in terms of cost, extracting from a brackish source is cheaper than from sewage, and (as you might expect) extracting from sewage is again cheaper than desalination from the sea itself.

From that result, I can conclude that since it costs more to extract water from the sea than from sewage, that if you dump sea water into the sewage... it's going to cost more in some or other manner downstream. Probably not in a good way.

Share this post


Link to post
Share on other sites

--- RANT  ----

"DA Cape metro chairman Grant Twigg said this week the drought levy would create "an undue burden on ratepayers"."

Undue burden ... what would one call no water in the taps? 
You are paying less for water, so you are winning on that level. What would losing your job constitute versus "Undue burden"?

Cannot understand how the majority, to lazy to THINK, is being lead around by a few load mouthed self serving hypocrites, wanting more votes from the poor. The biggest problem is the suburbs, the people with pools and jacuzzi's and gardens and long showers and / or daily baths with washing machines using a lot of water!

Loss of R1.7 billion in revenue is a disaster in the making. If you use less water (you have to), the revenue is reduced which in turn results in less money to spend on repairs, maintenance with NO chance of any new desalination plants / other ventures, can only result in we ALL are going to suffer.  

National Government, who has ignored the problem and still doing so, BECAUSE they have no money because with the Gupta's, KMPG and a number of others, with help of the Banks, robbed SA blind. So ja, it makes sense to duck and dive for it you say there is no money, the next investigations starts.

Rant was because of this: https://www.businesslive.co.za/bd/national/2018-01-17-why-cape-towns-levy-looks-dead-in-the-water/

--- RANT END ----

Share this post


Link to post
Share on other sites
8 minutes ago, The Terrible Triplett said:

--- RANT  ----

This is rock and hard place territory.

  • Technically national government should be paying for this. This is OUTA's argument and I agree with them.
  • DWS is bankrupt though, so if anything is forthcoming it will take a long time.
  • In the mean time the city is in a pinch, less income from water, more expensive on the same.
  • If this was a housing complex (for example), such unplanned expenditure (eg. upgrading the security system because of frequent break-ins, been there, paid that) would be passed on to the tenant/owner as a temporary (often once-off) special levy.
  • Is it fair? No. Always having to pay up because others are stealing sucks.
  • But what's the alternative?

I will therefore suck it up and pay the levy. I am not happy about it, but it seems to me that shouting about it is akin to shouting to the cashier because the product was mislabeled. Not his fault. Not in a position to fix it. Call the manager.

I've been calling the manager for years now. Have another opportunity in 2019. Sadly... it seems some people are now blaming the ruling party (of the province) for mistakes (ostensibly) made by the city (as if they are one and the same thing) and are threatening not to vote for them next time (not sure who else, if anyone). So irony of ironies... the guys who actually did something about the problem might well take a political hit for this, while the guys who caused it might benefit from it.

Pfffft.

Share this post


Link to post
Share on other sites
9 minutes ago, plonkster said:

This is rock and hard place territory.

We agree, but in my mind it is not rock or hard place, is is smack bam against the wall with the rock pounding us.

Weather is changing on a world wide scale. It is affecting us in Western Cape with less rain. Maybe the rains come back but from studies done over decades, CPT was earmarked as a problem area. It has arrived.

But we can solve it. Desalination like the Israelies have done with great success.

We all should pay the levy, get the problem dealt with once and for all, locally managed to eliminate ANC theft. Yes, afterwards the price per liter will go up. Like cheap Eskom, it is over.

You can curb the additional expense by using less water, which brings one full circle to more efficient use of water = less water required = costs the same.

Like we did with Eskom and electricity. Once we understood the costs of batteries, we reduced our loads at great expense. Like with water, we will get efficient washing machines, shower heads, toilets water from waste water.

 

The De Lille issue is a storm in a teacup, like you say "the guys who actually did something about the problem might well take a political hit for this, while the guys who caused it might benefit from it."

Makes me sick to my stomach that the majority of Cpt does not stand up and say STOP, enough, sort it and sort it now.

Share this post


Link to post
Share on other sites
1 hour ago, The Terrible Triplett said:

The De Lille issue is a storm in a teacup

Gabriel will likely appreciate this more than others, but I tend to look at that issue from a "you will know them from their fruit" angle. What do we know about this lady? Has she been trustworthy and dependable in the past? Well, let's see... remember the original weapons scandal? Remember who blew the whistle? Yes, this lady. Does it mean she can never do wrong from this point forward? Of course not. Does it mean she deserves a bit more benefit of the doubt when things do surface? Absolutely.

Let's not do that same experiment with some other politicians now, shall we...

Share this post


Link to post
Share on other sites

Can you drink that water? I was in CT last week for a couple days, and the one guy said you can't drink desalinated water. In Gauteng, we don't have this problem, yet. But it would be good to know what needs to be done, in future, to scale out on this model. 

 

Cape Town will be the first modern city, which have to learn to (possibly?) cope with water loss and making alternative arrangements for clean drinking water. It is quite clear that the government doesn't know how to solve this problem. Engineers and entrepreneurs would have to. And It's quite clear, from this forum alone, that we (South African's) have the knowledge and will power to solve this riddle. 

Share this post


Link to post
Share on other sites
29 minutes ago, SilverNodashi said:

one guy said you can't drink desalinated water

the guy must've been on something

its already been done locally

then there is this team International Desalination Association

who give these numbers:

18,426
The total number of desalination plants worldwide (as of June 30, 2015)

More than 86.8 million cubic meters per day
The global capacity of commissioned desalination plants (as of June 30, 2015)

22.9 billion US gallons
The equivalent of 86.8 million cubic meters per day (as of June 30, 2015)

150
The number of countries where desalination is practiced

More than 300 million
The number of people around the world who rely on desalinated water for some or all their daily needs

 

 

Share this post


Link to post
Share on other sites

Dubai desalinates about 2.15 billion liters per day, most with vacuum desalination and the rest with RO. The heat for the desalination plant is waste heat from a electricity generating plant and an aluminium smelter. That is more than 3 times Cape Town's current usage. So why is it so difficult for what passes for government in RSA to get to grips when all the information is readily available. Besides with all our sunshine in summer, that heat source will minimize energy running costs to near zero.

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


×