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01January

Catalytic Carbon for Chloramine removal

Catalytic Carbon Description

What are Chloramines ?

Most of us are familiar with chlorine, which is the disinfectant of choice in swimming pools  and also our public water supplies. Now, in the case of our drinking water supplies, it is being rapidly replaced by a substance called chloramine, a mix of chlorine and ammonia. The decline in the use of chlorine began with the relatively recent discovery of a group unsavory and often deemed carcinogenic disinfection by-products called trihalomethanes (THMs) that are formed when chlorine combines with organic matter in water.  To put this in practical terms, that pungent odour you get when you go to a public swimming pool, is most likely a cocktail of chloramines and trihalomethanes.  In a swimming pool, the chlorine may combine with ammonia ( from urine and sweat) to form chloramines.  The organics may react with the chlorine to form trihalomethanes- and we just don’t want to know where these organics came from? To meet EPA standards for THMs, which once created are hard to remove, municipal suppliers are turning increasingly to disinfection with chloramines, which produce much lower levels of trihalomethanes.

The problem with conventional activated carbon is that chloramines are very difficult to remove, and require much longer  contact times. It is no surprise that a significant portion of residential applications  experience ammonia or chloramine breakthrough, simply because there is not enough contact time.  Catalytic carbon was invented, and it  has the ability to completely remove chloramines requiring a significantly lower contact time. 

Catalytic carbon for removal of chloramines

Catalytic carbon for removal of chloramines

 

What is Catalytic Carbon ?

Catalytic carbon  has a modified surface performed by a chemical process in which the electronic structure of the carbon is altered in such a manner that the resulting carbon offers enhanced catalytic capability.Catalytic carbon retains conventional carbon’s ability to adsorb contaminants but it also possesses greatly enhanced capacity to catalyse, to promote beneficial chemical reactions. It is by catalytic action that chloramine is reduced. The activated carbon converts chlorine to chloride leaving behind ammonia.  And this is where the catalytic part comes to it’s own, as the ability to retain oxygen enables the ammonia to be oxidised.  Catalytic capacity of carbon is expressed by the peroxide number, which measures the rate of decomposition of hydrogen peroxide by the carbon. The faster a carbon will break down hydrogen peroxide, the greater its catalytic activity. The lower the peroxide number the more effective is the carbon to remove chloramines.

Why remove Chloramines from your water supply?

Chloramines possess a risk for hemodialysis patients and fish, because of their easy entry into the bloodstream through dialysis membranes and the gills of fish. Once in the blood stream, chloramines denature hemoglobin and cause hemolytic anemia. To avoid any accidental use of chloramines treated water, it is must to reduce the chloramines from drinking water as low as 0.5 ppm. While chloramines are not a drinking water health concern to humans generally, their removal improves the taste and odor of drinking water. There has been an increasing public awareness and concern about chloramines and also fluoride being added to our water supplies.   Soft drink manufacturers often want the chloramines removed to  prior to adding other substances to the purified water. Hospitals are also increasingly showing an interest in removing chloramines from their water supplies , to revert to the more conventional way of chlorination. 

Unlike the case of chlorine disinfection, when chloramines are present, there are usually trace amounts of ammonia and hydrochlorite as well in water.  Ammonia can be re moved with natural Zeolite or by Ion Exchange.  Softening can be used effectively for ammonia removal if the primary softener is allowed to load to a hardness endpoint and a polishing softener is used to remove ammonia. In this case, the primary softener must not be operated to hardness breakthrough, as this would cause an ammonia spike and lead to elevated ammonia levels in the final product water.

Also, chloramines are hardly present in ionic form. Due to the low molecular weight, chloramines, in particular monochloramines are difficult to remove from water by reverse osmosis (RO) or water softening. Boiling and distillation cannot be used either. To improve the taste and odour and to remove the inherently toxic chloramines, adsorption by catalytic activated carbon is one of the most promising processes. 

Introducing  Choramine Blocker GC 12X30SCI

GC 12x30SCI is a virgin activated carbon which is granular in form.  Made from selected grades of coconut shell, its enhanced microporosity makes it particularly well suited for the removal of most organic compounds, chlorinated by-products such as chloroform and chloramines and other trihalomethanes (THMs). It is also ideally suited for the removal of oxidising agents such as chlorine and ozone from process water. Its superior level of hardness makes it cleaner than most other carbons and gives it longer life expectancy. Certified by the NSF, it is suitable for drinking water and food grade applications.

To purchase this product, see the following link:http://www.pacificwater.com.au/product/catalytic-carbon/

 

01January

Activated Carbon Filters

Activated Carbon Filters for pre-treatment in Reverse Osmosis Water Filters

 

Activated carbon filters are an intrinsic part in any residential or commercial reverse osmosis water filter.   Without activated carbon filters,  RO  membranes will rapidly deteriorate due to the presence of chlorine or chloramines in water supplies treated with secondary disinfection chemicals. 

To prevent oxidation on thin-film RO membranes, the feed water must be dechlorinated. Most membranes will have some chlorine tolerance before there is an observable decrease in salt rejection. Chlorine on the membrane can be discovered by an initial loss of membrane flux followed by an increase in membrane flux and salt passage.

For Dow FilmtecTM RO membranes, degradation can occur after about 500  hours of exposure to 1 mg/L ( ppm) of free chlorine. Unfortunately, chlorine damage is irreversible with any RO membrane, so proper steps must be taken to prevent it.   The activated carbon filter in a reverse osmosis water  system needs to be protected by a sediment filter of 5 micron or less.  Without a sediment filter, there will be an accelerated rate of flux decay  and increased pressure drop impacting on membrane performance,   Activated carbon filters in reverse osmosis water filters are typically installed as two pre-filters and one post filter used for final polishing of the permeate.  The increasing use of chloramines requires longer retention time and hence multiple stages to ensure adequate contact time removes any traces of chloramine. The selection of the activated carbon filters needs to consider the flow rate and water contaminants present in the water.

Benefits of Activated Carbon Filters:

  • Removes any objectionable taste and odour from the water supply.
  • Protects the RO membrane from chlorine damage.
  • Removes organics and to a lesser degree  tannins from the water supply.
  • Removes chlorine and to a lesser degree chloramines from water. 
  • The very high specific surface area means that the activated carbon has a very high capacity to absorb impurities and contaminants in your water.

Types of Activated Carbon Filters:

  1. Granular Activated Carbon( GAC)  Filters:  Typically sourced from coconut or coal, granular is a popular choice in water treatment.
  2. Carbon Block Filters:Solid carbon blocks are one of the most effective and widely used technologies in the Point Of Use (POU) drinking water treatment industry. Carbon block is mainly comprised of activated carbon granules and a binding agent that allows the carbon granules to maintain a static position relative to each other. 

The activated carbon filters can be supplied in different standard cartridge sizes   as listed below:

10″x2.5″ Activated Carbon cartridge

10″x4.5″ Activated Carbon cartridge

20″ X2.5″Activated Carbon cartridge

20″X4.5″ Activated Carbon cartridge (Jumbo cartridge)

In-line Activated Carbon cartridge  10″ x2”  typically used  as polishing filters 

In-line granular activated carbon(GAC) filters can be  fitted to any residential RO system

In-line granular activated carbon(GAC) filters can be fitted to any residential RO system

The frequency of replacement depends on water usage and water quality and the following should be used as a guideline:

Activated  Carbon GAC and Carbon Block Filters  used as pre-filters: 

Residential POU and whole house filtration: Every 6 months 

Commercial Applications:  Every 3 months

Polishing filters : In-line GAC Filters:

Residential POU and whole house filtration: Every 12 months 

Commercial Applications:  Every 6 months

 

Pacific Water Technology stocks the entire range of activated carbon filters  suitable for all RO systems. All our activated carbon filters are independently verified by the NSF.  Our warehouse is located in  Brisbane and we ship to all states of Australia. As an importer and manufacturer our products are competitively priced and  we only supply high performance filtration media.

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