# Waste water from RO through HMA filter



## biffster (3 Dec 2013)

is it possible to run the waste water from an RO unit through a HMA unit to use it as part
of the tanks daily water changes


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## sa80mark (3 Dec 2013)

Interesting question,  ive been thinking the same thing, and although I dont know the answer I suspect it can be done but I think the filters wouldnt last very long due to the extra amount of minerals, contaminants etc


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## thomas.bham (3 Dec 2013)

What is the point to use ro filter then? 


Sent from my GT-I9300 using Tapatalk


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## biffster (3 Dec 2013)

the reason being to cut down on waste water from the ro unit an ro unit produces 
four gallons of waste water for every gallon of safe water to use in the tank so cutting down 
or even removing the waste water from the equation altogether


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## Nathaniel Whiteside (4 Dec 2013)

biffster said:


> the reason being to cut down on waste water from the ro unit an ro unit produces
> four gallons of waste water for every gallon of safe water to use in the tank so cutting down
> or even removing the waste water from the equation altogether



Are you using a pump on your RO unit?


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## ian_m (4 Dec 2013)

When my mate produced RO for his marine setup, he piped the waste water (4mm pipe) out into the garden watering tubs of plants and flower beds. Had issues in the winter with outlet pipes freezing, but it felt better than just pouring the waste down the drain.


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## Andy Thurston (4 Dec 2013)

ian_m said:


> When my mate produced RO for his marine setup, he piped the waste water (4mm pipe) out into the garden watering tubs of plants and flower beds. Had issues in the winter with outlet pipes freezing, but it felt better than just pouring the waste down the drain.



If you don't like pouring water down the sink don't use RO or buy a RO plant that produces less waste.

Once you've made the RO water, the waste is inevitable, so it makes no difference where you pour it. You pay for it removing anyway, why feel guilty


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## biffster (8 Dec 2013)

nether i am trying to find out if you can put RO waste through HMA so that there is no waste water no there will be no pump


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## ian_m (8 Dec 2013)

biffster said:


> the reason being to cut down on waste water from the ro unit an ro unit produces
> four gallons of waste water for every gallon of safe water to use in the tank so cutting down
> or even removing the waste water from the equation altogether


Generally a RO unit will produce 1:4 RO to waste if running at 8bar, which is why you use a pump. Average mains water pressure in UK is generally 3.5bar, so if you are using without a booster pump will be in the order of 1:10, even as far as 1:25 reported on these forums.


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## biffster (8 Dec 2013)

normally 1 gallon of product water for four gallons of waste water i know that i want to know if you can put the RO waste water though a HMA filter that is what i am trying to find out i know all the other stuff


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## ian_m (8 Dec 2013)

No you probably cant put a HMA filter or any other filter on the waste output of a RO unit, as any flow restriction will prevent the RO unit from working. RO units generally assume no flow restrictions on waste output.


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## James O (12 Dec 2013)

If your determined you could tank up the waste water then pump it through the HMA and store it again. Then use that in the next water change.

I guess you're thinking of running it through the RO filter again during the filter change?


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## biffster (13 Dec 2013)

the HMA filter does not restrict the waste flow from the RO as HMA will operate under gravity feed 

no i just want to know if you can run RO waste water through HMA and use it to add to the RO water to remineralize it to use in the tank 
so there is no waste water at all


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## ian_m (13 Dec 2013)

biffster said:


> biffster Member Offline Message Count: 278 New the HMA filter does not restrict the waste flow from the RO as HMA will operate under gravity feed


No. There must be a pressure drop in order for force the water through the filter.

See here for example.
http://www.pentekfiltration.com/PentairFiles/Pentek%20Filtration/Literature/CBR2%20Series%20Spec%20Sheet%20310080.pdf


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## biffster (14 Dec 2013)

A HMA filter will run on gravity that is not what my question is my question is "CAN YOU PUT RO WASTE WATER THROUGH A HMA FILTER " i am not bothered about 
anything else this is all i want to know as all the other thing can be over come


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## ian_m (14 Dec 2013)

Yes you probably can run HMA after RO waste, but if mixing RO and filtered afterwards you are really wasting the functionality of the RO unit. Just HMA the water will achieve the same level of purification.

Think about it in your setup the only thing that removes anything from the water is the HMA filter, the ROs achieves nothing as you are not discarding the waste.


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## tim (14 Dec 2013)

Find alternative uses for the waste and feel guilt free, I don't use much ro so I buy from my lfs let them feel guilty about the waste.


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## Nathaniel Whiteside (14 Dec 2013)

The single best way to cut down your wastage is to instal an RO pump.


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## biffster (18 Dec 2013)

right yes RO units strip water of minerals so yes they do do something right what i was getting at was
using the waste from the RO  unit and putting through the HMA units to get safe normal water to remineralize
the RO water i have just taken from the RO unit that would mean that there would be no waste at all as the HMA unit
would trap all the nasty's and leave me with just pure water to mix with the RO water now do you get what i am saying


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## biffster (18 Dec 2013)

Direct Link:
http://i.imgur.com/0PyZyQD.png


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## Nathaniel Whiteside (18 Dec 2013)

Yeah, but your HMA filter would need replacing regularly as the RO waste would be more concentrated in minerals than tap water.

Use a pump and cut your waste down to minimal, forget 'no waste' as itll cost you more in the long run.


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## biffster (18 Dec 2013)

how there is no water at all going down the drain


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## Nathaniel Whiteside (18 Dec 2013)

biffster said:


> how there is no water at all going down the drain



Running through your HMA would cause it to need replacing more regularly than if using a HMA on a normal tap, due to the accumulation of Solids in the waste from the RO.


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## ian_m (18 Dec 2013)

As I said before if you are mixing the RO water with HMA'ed RO waste water there is no point in having the RO unit.

1. The RO pre-filter will remove sediment, chlorine, chloramine & organics (same as HMA filter will). Chlorine and organics will degrade the RO membrane.
2. The output of the RO will effectively be pure water.
3. The RO waste will contain the carbonates, nitrates, chlorides & metals (mainly magnesium and calcium).
4. Feeding this via a HMA filter will remove the heavy metals, leaving the carbonates, nitrates, chlorides, magnesium and calcium. The HMA would also remove chlorine and organics, but these have been removed by the RO pre-filter.
5. You mix RO and HMA water. You now have water with same levels of carbonates, nitrates, chlorides, magnesium and calcium as you source water, just no chlorine, organics (filtered by RO filter) and no heavy metals (filtered by the HMA filter).

You could therefore achieve exactly the same using just the HMA filter.

In fact even cheaper just use UK tap water and any good brand dechlorinator. As well as taking out chlorine/chloramine most will remove heavy metals as well, not that heavy metals in UK tap water is ever an issue.


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## geoffbark (20 Dec 2013)

ian_m said:


> As I said before if you are mixing the RO water with HMA'ed RO waste water there is no point in having the RO unit.
> 
> 1. The RO pre-filter will remove sediment, chlorine, chloramine & organics (same as HMA filter will). Chlorine and organics will degrade the RO membrane.
> 2. The output of the RO will effectively be pure water.
> ...


 


+1 agree

Apart from point 5. Cutting tap water ( RO waste water in this case ) with RO water is a good way to get desiried KH GH NO3 levels etc without adding costly buffers etc. 




biffster said:


> is it possible to run the waste water from an RO unit through a HMA unit to use it as part
> of the tanks daily water changes


 
Yes

But why would you want to?

If it is to conserve water then you can run the waste water through a second RO membrane, increasing your RO production.

If it is so that you can cut RO with Tap (- Clorine etc) then go for it. You may want two storage tanks though one for Ro and other for HMA treated waste water.

And as others have said with the rest of the waste, water the garden


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## biffster (28 Dec 2013)

geoffbark said:


> +1 agree
> 
> Apart from point 5. Cutting tap water ( RO waste water in this case ) with RO water is a good way to get desiried KH GH NO3 levels etc without adding costly buffers etc.
> 
> ...


 


it is so that there is no waste water at all using a second membrane still as waste water with using the ro waste water
through a HMA unit there is no waste water at all and the water from the hma will ne used to reminerlize the RO water


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## geoffbark (28 Dec 2013)

I think that is a good idea. Especially for people who are on a water meter. 
And you also save on re mineralising salts


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## biffster (14 Jan 2014)

geoffbark said:


> I think that is a good idea. Especially for people who are on a water meter.
> And you also save on re mineralising salts


well thank you i was given the idea from someone else to be honest


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## biffster (14 Jan 2014)

Nathaniel Whiteside said:


> Running through your HMA would cause it to need replacing more regularly than if using a HMA on a normal tap, due to the accumulation of Solids in the waste from the RO.


but it would work and yes the hma water would be used to reminerlize the RO water that is what i am wanting
it to do why is people think that if you use RO water you have to use it to remove carbonates the waste on the RO
passed through HMA should do the job fine then


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## ceg4048 (19 Jan 2014)

The objective is illogical due to Non sequiter.

RO waste water contains highly concentrated levels of toxins and pathogens.

The Heavy Metal filter resins do not remove these toxins, so the only way to prevent reintroduction of them into the tank is to have additional specific filtration modules, such as a carbon stage. HMA only removes exactly what it's name implies; Heavy Metals. It may easily be therefore that your water is not high in Heavy Metals concentration, but yet could be high in many of the toxins that HMA filters ignore.

So, on your schematic where is is annotated "HMA Clean Water", in fact, the water is anything but clean.

I suppose if you monitor and control the amount of the HMA output that finds it's way back into the tank, as we often do when using RO waste to remineralize the RO Clean water, then that would be OK, but it will be an illusion of the highest order for you to assume that the water is clean exiting the HMA filter. That water should still be considered RO waste. You also have to consider what effects those waste products in higher concentrations will do to your HMA resins.

Cheers,


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