Thailand Cambodia Jungle Salt Water
Thailand Cambodia Jungle Salt Water
I have a water filter business in Thailand.(I am from the Netherlands)
For a customer who has a small resort in the jungle of Cambodia I have to develop a plan to change sea water into fresh water for showering etc. (not drinking).
I need someone who likes to think this over with me since this is the first time I encounter this kind of situation and I am not sure what to do.
I have done a lot of water filtration projects, but not one under these kind of conditions.
So I see it as a challenge, but I need to be pretty sure that I do the whole thing right in one time.
Not a lot of space for trying and/or mistakes because all materials etc. need to be shipped into the jungle and so there is not an easy way back and forward.
Here is the situation:
It is a small resort on a hill side.
Down the hill (200 meters with a head of 30 meters) there is a river that ends up into the sea a kilometer further or so .
Because of the tides the water level in the river rises and drops.
So we are talking about brakish water but let's go for safe and say it is sea water.
(the salt level I will know later)
I can de-salt the water with reverse osmosis but the water needs to be pre-filtered to protect the reverse osmosis membranes.
I will pre filter with sand or zeolite in a fibertank, followed by activated carbon in a second fibertank, both with a backwash valve on top.
The pre-treated salt water will be stored in a big water tank (P.E.)
from this watertank the water will be lead towards several R.O. Diaphragm pumps and from there to several R.O. Membranes.
Now we have desalted water that will be stored in a second P.E. Tank.
This water will be pumped up hill towards a large storage tank that is already situated there from which the bungalows will be fed with a regular on demand constant pressure pump.
So only the last storage tank is situated up on the hill in the resort.
The whole story before that will be situated as close as possible to the river. (25 meters from the river with a head of 4 meters).
These two locations are 200 meters away from each other and the rise of the hill side (Head) is about 30 meters.
Because of the tides we make a floating platform at which the pump is situated.
The pump must resist salt water so it must be a good stainless steel pump or bronze or brass.
So far I found a submersible pump that can be used with salt water.
This could be a good option because the motor is always being cooled by the surrounding water and there will never be a priming problem.
But the pump needs to be “on demand”.
This can be done by a float switch in the storage tank which is connected with the pump on the platform.
Or a pressure switch in combination with a solenoid valve which is controlled by a float switch.
(not a float valve because the pump will turn on and off very often once the valve is almost closed because of the very slow water inlet and the floatvalves I know are not corosion resistant enough).
But when a pressure switch in combination with a solenoid valve is used, I need to install a pressure tank as well I think.
And that means that the pressure tank and the solenoid valve need to be saltwater resistant as well.
(In normal situations I do not need to combine pumps with pressure switches and pressure tanks because I use "ready to go " pumps that come complete like the Hitachi pumps for home use, so I would like to avoid experimenting with combining these parts by myself.)
So for that reason it is much easier to just use a float switch in the storage tank which is connected to the pump on the platform.
That situation arises an other problem.....
The pre-filters with sand and carbon I want to place in this same line , inbetween the pump and the storage tank.....
If the prefilters clog up because someone forgot to backwash them and the storage tank is asking for more water because the waterlevel drops and the float switch turns on the pump, there will be no water flow and pipes may burst or the pump might be damaged.
So to avoid that kind of situation I could install an inline pressure relief valve of 50 psi or so.
That way at least the water can escape.....
Or go for the pressure switch instead in combination with the pressure tank and solenoid valve.
That way if the filters become clogged up and there is no or not enough flow, the high pressure switch will shut off the pump.
But how to find the right combination that can also be used with salt water might not be easy.......
I have a pump with pressure switch and tank complete (ready to go) in mind but I am not sure jet if it is good enough for this job because of the salt water. : HITACHI WT-PS300GX
The submersible pump I have in mind is the : TSURUMI Submersible Corrosion Resistant Pump
( www.tsurumipump.com )
So far for the first step.
“Problem 2” :
Now the water has been filtered by the reverse osmosis and is stored in the second large PE tank.
From here I need a pump to bring the clean water up hill over a distance of 200 meters with a head of 30 meters to an other storage tank up hill at the resort.
Can this be done in 1 time? Or should it be done in smaller steps with storage tank(s) and pumps along the way?
All has to run on solar power so that is also an issue to keep in mind.......
Hope someone is willing to think a little with me in this matter.
Any ideas, suggestions or advice are greatly appreciated.