can reverse osmosis be used on sea water?

[watchman8]

The resulting sludge can be further processed as fertilizers but don't know what Singapore does with it, maybe sanitized and repackage out to the people of Singapore via the Braddell Brothel

Used for building hdb flats. It was a NUS civil engineering project in the 90s. Also used in land reclamation.

 

[watchman8]

IF RO is possible on seawater, why use Desalination?
Desalination Defintion refers to any of several processes that remove some amount of salt and other minerals from saline water. it does not say...boiling the water to get the vapour and consenser the pure vapour back to get water(leaving the salt behind)

maybe Desalination is the general term for process..RO is the technology...i may be wrong

i alway had the thinking RO on saltwater is easlier rather than RO on sewage which contain so many other chemical plus solid waste.
i would rather drink from purify saltwater than purfiied sewgae watrer

I think is because raw sewage has to be treatment anyway. Can't just dump all the shit into sea water.

 

[moolightaffairs]

is it possibe to filter out fine salt using reverse osmosis?
if yes, why it is just restrain to filter out human waste and urine and recycle water.

yes, it is use in US warships including submarines and this is not something new. imagine those warships build in the 70s or even 60s already using this technology for the fresh water needed for the crew on board. i think this technology first came by due to the space expeditions in US.

 

[ykhuser]

Used for building hdb flats. It was a NUS civil engineering project in the 90s. Also used in land reclamation.

not used in hdb lah.heard is mix with ash and compact into brick,used for those carpark brick flooring with red color.(not the clay square brick), those modern color brick used for flooring

 

[ykhuser]

i think this is the closest answer i could think of.
sewage had to been treated anyway before being pump into the sea.
instead of dumping them into the sea, and used massive energy again to draw back seawater to filter out salt,might as well have 2 system into 1..

I think is because raw sewage has to be treatment anyway. Can't just dump all the shit into sea water.

 

[Kuailan]

is it possibe to filter out fine salt using reverse osmosis?
if yes, why it is just restrain to filter out human waste and urine and recycle water.

Peasantpore have 17 reservoirs beside these Peasantpore also have at least 2 or more
desalination plants purchased by our Woody when he visited Florida during his Premiership .

 

[PlayStation]

size of the pores in the RO membrane is the key: water molecule is about 175 pm at its largest, sodium ion about 180 pm. me could be wrong :o:o:o

So what does that means?

 

[ykhuser]

aiya easy la..
i think he mean...for example size of hiv virus is 1cm in diameter.condom under mircoscope the pore is 0.9cm.
so the hiv virus cannot escape from the condom loh...the reverse also true..the hiv virus from female pineapple juice also cannot seep into the condom

So what does that means?

 

[Bigfuck]

not used in hdb lah.heard is mix with ash and compact into brick,used for those carpark brick flooring with red color.(not the clay square brick), those modern color brick used for flooring

Meant for interlocking pavement tiles. Old tech that is used in Cheena too. The quality of the product is no good for serious concrete and bricks.

 

[Bigfuck]

I think is because raw sewage has to be treatment anyway. Can't just dump all the shit into sea water.

COD and BOD issues. Never treat, all Singapore canal and river life dies or is infested with algae. So must treat. Dump into sea is as long as sea currents carry them away. Problem is the aquatic life before going into the see. Also, raw sewage is packed with antibiotics and shitloads of chemicals too.

 

[Bigfuck]

i think this is the closest answer i could think of.
sewage had to been treated anyway before being pump into the sea.
instead of dumping them into the sea, and used massive energy again to draw back seawater to filter out salt,might as well have 2 system into 1..

Problem is not enough storage space. Deep Tunnel Sewerage System was developed to make sure Singapore does not get flooded. Water you use is only 10 percent at best. 90 percent flushed is only 1-3% contaminated. It is very easy to clean this water. Problem is can you store 90% of the water you flush away when using?

 

[goodtool]

julibee, appears that u r frm the water industry, LOL
but why u earlier say not for seawater?
RO use as 3 barrier for water reclaimation but also use for desalt of sea water
for water reclaimation (sewage or blackish water) typically operate less than 20bar pressure. For desal, the operating pressure is more than 40bar hence more energy used and of course cost more

 

[steffychun]

is it possibe to filter out fine salt using reverse osmosis?
if yes, why it is just restrain to filter out human waste and urine and recycle water.

Supposedly our big Navy shits do that

 

[zhihau]

julibee, appears that u r frm the water industry, LOL

more bite size information for the good folks out here:

osmosis is a natural process where water molecules constantly move in a state of flux from any region of higher water potential to a region of lower water potential across a selectively permeable membrane.

for reverse osmosis to occur, enough pressure must be used to artificially increase the water potential so that water actually moves from the dirty water region across the selectively permeable membrane to the clean water region.

 

[Fook Seng]

more bite size information for the good folks out here:

osmosis is a natural process where water molecules constantly move in a state of flux from any region of higher water potential to a region of lower water potential across a selectively permeable membrane.

for reverse osmosis to occur, enough pressure must be used to artificially increase the water potential so that water actually moves from the dirty water region across the selectively permeable membrane to the clean water region.

In practice, how do they increase the pressure? Can gravity do the job?

 

[zhihau]

In practice, how do they increase the pressure? Can gravity do the job?

need to visit the NEWater plant off Changi Coast Road to find out... :o:o:o

 

[Bigfuck]

need to visit the NEWater plant off Changi Coast Road to find out... :o:o:o

Bro, use brain. Earth pressure is 1 atm. Since when you hear pilot fly 8Gs got air pressure go up by 8 atm? The pilot become hum zim bang. You need external force to hit that kind of pressure. 40 bar almost 40 atm.

 

[Fook Seng]

Bro, use brain. Earth pressure is 1 atm. Since when you hear pilot fly 8Gs got air pressure go up by 8 atm? The pilot become hum zim bang. You need external force to hit that kind of pressure. 40 bar almost 40 atm.

Obviously not just pure atmospheric pressure. Need a very long column of liquid? How about using a very heavy weight together with a pressure multiply? Of course once the weight has gone down, it needs to be lifted up again using energy. Using a pump, you need to supply energy continuously.