Reef Central Online Community

Home Forum Here you can view your subscribed threads, work with private messages and edit your profile and preferences View New Posts View Today's Posts

Find other members Frequently Asked Questions Search Reefkeeping ...an online magazine for marine aquarists Support our sponsors and mention Reef Central

Go Back   Reef Central Online Community > Sponsor Forums > SpectraPure
Register Blogs FAQ Calendar Mark Forums Read

Notices

Reply
Thread Tools
Old 11/06/2009, 12:46 PM   #1
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
More detailed explanation on Chloramines, RO membranes and Carbon Filters...

More detailed explanation on Chloramines, membranes and carbon filters:

In order to understand the mechanism of chloramine removal, a little background information on the chemistry of chloramines is necessary. Chloramines are formed by the reaction of ammonia and chlorine gas. Chloramines can exist as three chemical species: monochloramine (the predominant species found in tap water), dichloramines and trichloramines. The chloramine species depends upon the pH of the water and the ratios of chlorine to ammonia. At tap water pH levels of 7 to 8.5, the formation of monochloramines is favored. Of the three species, monochloramine is the most stable and difficult to remove, as well as the most damaging to aquatic life.

A “ppm-hour” is defined as the exposure of 1 ppm chlorine/chloramine water for 1 hour. Film-Tec quotes 300,000 ppm-hours (six years at 1 ppm) of chloramine resistance for their TFC polyamide (PA) membrane material, but only 200 to 1000 ppm-hours of free chlorine resistance. This indicates that chloramines will not damage Film-Tec membranes, while free chlorine levels must be held below 0.1 ppm to prevent oxidation damage. The easiest test for chloramine is with a Total Chlorine Test Kit (SpectraPure Part # TK-CL-10). The TK-CL-10 tests for a combination of free chlorine and chloramines. A sample of the wastewater stream from the RO membrane should show no signs of chlorine.

The most important purpose of a sediment filter is to protect the downstream carbon block filters from plugging with sediment. A properly designed sediment filter will have a micron rating smaller or equal to the closest downstream filter element. It will have a gradient density structure such that the outer layers capture the larger particles and the inner layers capture the finer particles. This will maintain a large dirt holding capacity and prevent the finer particles from plugging downstream carbon filters. Using a 5 micron carbon block followed by a 0.5 micron carbon block, maximum chlorine and volatile chemical removal can be achieved without premature filter failure. If a sediment filter is used that passes particles larger than the next downstream filter, that filter will plug, blinding off the active carbon surfaces, reducing its ability to remove chlorine and organic chemicals.

Trade-offs exist in almost any circumstance and carbon filtration is no exception.
The smaller the micron rating, the better the removal capacity due to greater surface area. Carbon block filters made with bituminous carbon are more effective than coconut shell carbon filters for removal of monochloramine. On the other hand, in water supplies with chlorine only, the coconut shell carbon may have higher capacities for the removal of free chlorine and low molecular weight volatile organic compounds such as trihalomethanes (chloroform).

Multi-carbon block pre-filtration is not always necessary, especially in smaller flow rate systems when adequate pre-filtration and sub-micron carbon block filters are used.
Activated carbon will break the chloramine bond and remove the chlorine component leaving free ammonia (NH3+). RO membranes are transparent to dissolved gases that will pass freely through the membrane concentrating in the RO product water.

Generally, reverse osmosis water is slightly acidic, due to the higher ratio of free CO2 to bicarbonate alkalinity. The exception to this rule is the presence of high pH “soda-lime softening” used by some municipalities. Free CO2 dissolved in water forms carbonic acid that lowers the pH to the range of 5 to 6 pH. In low pH RO product water, the ammonia is converted to the ionized ammonium ion NH4+. Downstream de-ionizing resins can then easily remove this charged species. It is cationic and removed by strong acid cation resins (in the hydrogen form) in either mixed bed or separate bed systems. Aquarists can be certain that when salt is properly added to RO or RO/DI water, the expected salinity and pH will be realized.


SpectraPure is offline   Reply With Quote
Old 04/09/2015, 12:16 PM   #2
mic209
Registered Member
 
Join Date: Apr 2002
Location: Arroyo Grande, CA
Posts: 1,382
Thanks for the links. What do you consider a small GPD system and what is considered a large GPD system?


mic209 is offline   Reply With Quote
Old 04/09/2015, 12:35 PM   #3
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
Depends on the application. A generalization for the aquarium trades is a "Small" GPD can be considered under 500 GPD, and large system over 500GPD. However, filter sizing, life, etc. is dependent of course on the local water conditions, operational factors, and production.
Another important factor to the owner is cost of ownership.
From my perspective, there is no one rule on size, as "it depends".

bruce


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Old 04/09/2015, 02:15 PM   #4
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
Regarding carbon and stages required, this is highly dependent on your local water conditions, your flow rate, your operation conditions and the carbon that you use.

A good thread regarding "when to change" can be found here:

http://www.reefcentral.com/forums/sh....php?t=1735396

If your single stage carbon is not lasting or is passing high amounts of Chlorine then you may wish to add a stage of carbon and/or upgrade the carbon you are using.

Also, good reading on this can be found here:
http://www.reefcentral.com/forums/sh....php?t=1735402

Lastly, previous comments on "rules of thumb" should not be construed as exact advice on generic systems design or operation.

bruce


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Old 04/09/2015, 06:55 PM   #5
Ted_C
Registered Member
 
Ted_C's Avatar
 
Join Date: Jul 2012
Location: Clearwater FL
Posts: 1,970
those links are broken?


Ted_C is offline   Reply With Quote
Old 04/13/2015, 04:19 PM   #6
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
on our main forum here (spectrapure). Sorry, the links do look broken. They are the articles on our forum.
bruce


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Old 04/15/2015, 03:11 AM   #7
CMJones
Registered Member
 
Join Date: Dec 2013
Posts: 110
I'm looking at upgrading my current system with parts from yours. Right now, i have TDS coming out of tap at 450ppm... As is, my current Membrane is only 90% and leaves my RO water coming out at 36-50 (varies) ppm before the DI resin... This leaves me with roughly 200 Gallons per DI refill... Not acceptable at all... I also know my city uses Chloramines as opposed to Chlorine (Dallas Tx area). So... Here's what i'm getting:

Switching my 150GPD / 90% rejection rate membrane with your Spectra Select PlusC 90GPD / Changing the Flow Restrictor with the red (hard water) line as well

My current .5 Micron Sediment and first .5 Carbon filters are visibly dirty (The sediment extremely so), so i planned on swapping these out as well (the 2nd carbon filter still looks perfectly clean and is .5 micron as well).

So, if i replace the sediment filter with a 5 micron (The .5 micron clogged SUPER fast... Like... Less than 200 Gallons fast) and replaced the first carbon filter stage with GAC refillable cartridge. Then have the 2nd carbon stage the .5 micron standard carbon block. Would this be acceptable for this membrane to protect it for it's life? Then of course replacing the DI resin with a standard color changing resin.

From what i've read - this would increase my 200 Gallon production of 0 TDS to 4800 Gallons!!! Is this correct? I also understand that the membrane in question has higher demands on the incoming water than most, so i want to make sure i don't destroy it with our cities horrible water...


CMJones is offline   Reply With Quote
Old 04/15/2015, 03:48 AM   #8
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
CM,

Thank you for your interest in our products. Only certain carbons are effective at breaking the chloramine bond. However the ammonia passes straight through. We need to see what your beginning chloramine levels are. We also need the ph and kh of the tap water. What is the pressure on your system when it is running? I can solve this shortened di life problem that you are having, but I want to go about it the right way. Can you obtain the 2014 total water quality report from your municipal water source? I also have an ammonia removal pre-di filtration set up that will effectively remove the ammonia from the chloramine. This will protect your polishing cartridges. One last thing to remember is that not all DI are equal. Some Di resins are better than others, and some by far.

Jeremy


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Old 04/15/2015, 06:58 AM   #9
CMJones
Registered Member
 
Join Date: Dec 2013
Posts: 110
Tap pH is 7.4, dkH 8, pressure is 65 psi, Ammonia 1.0ppm. So, if using the GAC meant for chloramines + .5 Micron Carbon block to remove the chlorine that's leftover from the GAC separation. Would that work? Or would i need a second chloramine level after it? Would the ammonia effect the membrane, and would i have to remove that?

Typical water parameters for chlorines are
Chlorine Residual (Chloramines) - 2.88 Average Level, Max level 3.19
Chlorine Dioxide - Average Level 0.0, Max Level 0.1
Chlorite - Average level .42, Max level .81

Highest level of detected
Chloroform - 24.7
Bromoform - Not Detected
Bromodichloromethane - 17.32
Dibromochloromethane - 8.17
Chloride - 26
Bicarbonate 120

Have been getting the DI resin from Bulk Reef Supply, Purtrex Sediment filter with true graded true polypropylene depth filter
Standard Chlorine removal carbon block .5 micron thus far.


CMJones is offline   Reply With Quote
Old 04/15/2015, 03:59 PM   #10
CMJones
Registered Member
 
Join Date: Dec 2013
Posts: 110
Or here's the most accurate that i could find rather. It doesn't change much year to year. This years report looked pretty much the same

http://www.cityofmesquite.com/DocumentCenter/View/3898


CMJones is offline   Reply With Quote
Old 04/20/2015, 11:10 AM   #11
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
CM,

The Carbon will only remove the chlorine portion. The ammonia passes through regardless. The DI will remove it. When having Co2 or ammonia they take away the life of the DI. It is important that you membrane is rejecting as well as it could be. What are your TDS numbers and pressure?


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Old 05/01/2015, 12:29 AM   #12
CMJones
Registered Member
 
Join Date: Dec 2013
Posts: 110
Previously with the old system - Tap water was roughly 400-420 TDS on any given day
After previous RO - 38-45 TDS
DI resin would get it to 0 for about 50 Gallons (i don't have a full sized DI cartridge. i have 2 of the mini ones that = 1/2 a full DI cartridge together)... So, here's what i've done

So, i had problems getting the tank ready for the rest of drilling... However! i did manage to upgrade the RO unit.

So... Now i have a new and improved... Pretty much for all respects a SpectraPure MaxCap 90GPD... Replaced the 100GPD 90% rejection rate membrane with a 99.8% rejection rate Spectrapure SpectraSelect membrane with preset hard water flow restrictor (red).

Replaced my Sediment filter with a 1 Micron Absolute, first Carbon stage is now a GAC refillable Carbon filter, second stage is a .5 Micron Chloramine Carbon filter, then to the membrane and dual stage DI. Went from 45 TDS before DI to 7... Probably get it down to about 4 or 2 TDS before the DI once it warms up some.

I have no way of measuring the waste vs RO water to double check the flow restrictor. However, since i bought the preset hard water flow restrictor (red) it should already be set and good to go right?


CMJones is offline   Reply With Quote
Old 05/06/2015, 09:09 AM   #13
SpectraPure
RC Sponsor
 
SpectraPure's Avatar
 
Join Date: Jun 2003
Posts: 4,618
Right.

Support at SpectraPure


__________________
Innovators in water technology.
Since 1985!
SpectraPure is offline   Reply With Quote
Reply

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is On

Forum Jump


All times are GMT -6. The time now is 11:42 PM.


TapaTalk Enabled

Powered by vBulletin® Version 3.8.4
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Powered by Searchlight © 2017 Axivo Inc.
Use of this web site is subject to the terms and conditions described in the user agreement.
Reef CentralTM Reef Central, LLC. Copyright ©1999-2014