im no expert but this is what i can say:
the R.O. membrane needs 'back pressure' on the waste water outlet to adequately send the water thru the filter and to the clean water outlet. RO filters filter a portion of the incoming water while waste water carries away impurites that would foul the filter. so for any which ro membrane there is a coresponding back pressure that needs to be. when buying membranes and backpressure appliances they corelate to eachotehr by way of 'gallons per day' rating; a 75gpd filter needs a 75gpd pressure fitting. usually this fitting is a capillary straw and plug put into the waste outlet and PEX tubing junction.
might sound complicated but it isnt. the industry uses very standard sizes of membranes, housings, fittings, etc
now no one really uses just a RO filter alone. the chlorine in the water could damage [the most common chemistry of membrane] the membrane. also sediments could foul the filter. these are the two big reasons we see a sediment and carbon block filter before the ro filter.
now lets say you have some super shitty and salty mud to filter and you are standing in an industrial park in flint michigan. a solids precipitating filter like used in aquaponics would come first to take the largest particles out by means of mass, boyancy. then they make vortex solids filters that spin the water and consequently the particles move to the edges of the vessle and clean water is extracted from the center of the vortex.
ok now we can use hollow fiber tech to take out finer particles without having to backflush/purge the hollow fiber tech as much.
.. thats what sawyer filters use, hollow fiber technology. it was used to filter biologics originally, like blood. while this example system^ is filtering flint's mudwater it will need the flow reversed and ultrasonic resonators attached to the outside of the filter housings. oh, every so often a backflush of bleach and coconut oil-soap and washing soda needs to happen to cleanem extra good.
but these hollow fiber tech filters will get the water ready for carbon filtration really. usually water systems opt for a sedimentary filter but the hollow fiber tech surpasses the pore size so a sedimentary filter is useless.they are comressed toilet paper anyway, it aint much.
if you ask me activated carbon is the real star of the RO filter show. it takes chlorine out, lead,,,, after the RO membrane a de-ionizing filter will take 'the rest'(99.999) heavy metals out using activated carbon that has been treated to be more electro negative and epositive(its a twostage, singlepeice carbon filter made with resin).
but yeah after the first carbon filter comes the ro membrane. al these filters are usually linked using 1/4" PEX. they make bigger PEX tubing for larger water filters but ive only use 1/4"pex
the ro filter housing looks a little daunting but what you got is a single inlet on one end and two outlets on the other with one 'off-axis', to the edge.
the outlet in the middle is gonna have waste water, the outlet on the side is gonna have sweetwater(dreams of life in the south)
ok so a deionizing filter would be put next.
and then a carbon filter one more time to 'polish' the water.
people are bombarded by sounds and tastes heavilly and when the atmopshere is silenced we can hear and taste far more subtle sences. i could smell my sons baby cheetos inside my centrifugal extractor fan a day after he touched the inside (it was off!) and it is coupled to a carbon filter. his hands werent even dirty!
ill try and answer questions if anyone has them.
the production of activated carbon is really a keystone to water filtration in a long term shtf senario
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