Chlorine, Chloramine, Monochloramine and Chlorine Dioxide – Carbon Filtration

Water - Chlorine vs Chlorine DioxideWater disinfectants can be harmful, even deadly, to dialysis patients if the chemicals are not removed before hemodialysis. In addition, water disinfectants can disrupt laboratory operations if the chemicals are not removed. While data exists related to chlorine and chloramine on hemodialysis filtration equipment (carbon and reverse osmosis filtration) and laboratory filtration equipment (carbon and demineralizer filtration), there is very little data available. There is also very little information related to monochloramine, chlorine dioxide and its byproducts.

The Environment Protection Agency (EPA) has established Maximum Contaminant Level (MCL) of disinfectant chemicals:

When chlorine becomes added to water, it can combine with the organic matter. This will formulate byproducts, Trihalomethanes (THM) and Haloacetic Acids (HAA5). They can be toxic when it comes in contact with the skin, is inhaled or consumed. THM’s and HAA5’s (in chlorine, chloramine, and monochloramine) are respiratory irritants.

Mixing chlorine and ammonia produces a chemical called monochloramine. Monochloramine does not disperse from the water as chlorine does. When you let chlorinated water sit for a short period of time (30-60 minutes) it will disperse from the standing water. However, it will leave behind byproducts. Monochloramine does not disperse as quickly.

Chlorine dioxide is used as an alternative to chlorine, chloramine and monochloramine for microbe removal. When treating water, it decomposes quickly into chlorite and chlorate. Chlorite is regulated by the EPA; however, chlorate is not.

Chlorine, chloramine, monochloramine, chlorine dioxide, and chlorite cannot be removed by conventional water treatment systems. Carbon filtration media is needed to remove the chemicals previously mentioned.

Research studies have been done on chlorine and chloramine chemicals since typically they are in drinking water introduced by water treatment facilities. Very little information exists related to monochloramine, chlorine dioxide and chlorite. The majority of the research studies report that small amounts of chlorine, chloramine monochloramine, chlorine dioxide and chlorite in the water will not pose a significant health risk.

While chlorine, chloramine, monochloramine, chlorine dioxide and chlorite do not pose a significate risk (per the EPA), they do pose a health risk to people on dialysis and will impact laboratory functions. These chemicals need to be filtered out from drinking water before hemodialysis and laboratory functions are performed.


Large amounts of water are used for hemodialysis to clean waste products out of a patient’s blood. Dialysis centers and portable dialysis units must remove all chemical disinfectants, such as chlorine, chloramine, monochloramine, chlorine dioxide, and chlorite before the water can be used for dialysis.

People having liver or kidney problems and those with inherited urea cycle issues are at increased risk for ammonia toxicity that can be found in water.

Kidney hemodialysis patients cannot utilize chlorinate, chloramine, monochloramine, chlorine dioxide, or chlorite treated water in their dialysis machines since it will cause hemolytic anemia.

These chemicals must be totally removed from the water in hemodialysis treatment utilizing carbon filtration and reverse osmosis.

In addition to hemodialysis, large amounts of water are used in laboratories (such as slide staining, etc.). Laboratories must remove all chemical disinfectants, such as chlorine, chloramine, monochloramine, chlorine dioxide, and chlorite before the water can be used for laboratory functions.


Carbon filtration is utilized to remove chlorine, chloramines, monochloramine, chlorine dioxide, chlorite, and other chemicals. Related to hemodialysis, carbon filtration capacity is commonly sized for the Empty Bed Contact Time (EBCT) required to remove chemicals from the supply water. AAMI standards for EBCT are 10 minutes for chlorine and chloramines removal. Currently there are no standards for monochloramine, chlorine dioxide, and chlorite. Carbon beds are installed in a worker-polisher configuration with test ports installed at the output of both carbon beds. AAMI recommends a test for free and total chlorine is conducted prior to every patient shift, but not chloramine, monochloramine, chlorine dioxide, and chlorite.

Portable Reverse Osmosis (RO) units have a separate dual block carbon system (condensed carbon rather than granular activated carbon) for chlorine removal. The block carbon is used to supply dechlorinated water to a portable RO unit obtaining the 10 minute EBCT requirement. In addition, there must be one dual block carbon system per portable RO and each portable RO must supply one hemodialysis machine. These requirements are supported by the following excerpts from ANSI/AAMI RD52 and the International Standards Organization (ISO), which AAMI currently supports.

Published information related to the use of chlorine is readily found related to the chemical effect on hemodialysis and laboratories. However, little information can be found related to the use of chloramine, monochloramine, chlorine dioxide, and chlorite (the byproduct of chlorine dioxide).

Below is detailed information published by The Johns Hopkins Hospital in 2004 related to carbon filtration for water to remove chlorine, chlorine dioxide (ClO2), and chlorite for hemodialysis and laboratories:

Dialysis and Laboratory Filtration Equipment

No data was available for chlorine dioxide (ClO2) and its disinfectant byproducts on hemodialysis filtration equipment (carbon and reverse osmosis filtration) and laboratory filtration equipment (carbon and demineralizer filtration).1 

Extensive testing was conducted to ensure performance of hemodialysis and laboratory equipment prior to continuous operation of the ClO2 generator system. ClO2 was introduced at various levels into the hemodialysis and laboratory filtration equipment. Chlorine, ClO2, chlorate, and chlorite levels were measured at each stage of filtration. A water meter was utilized to record total water usage in gallons through the filtration systems. Carbon filters were utilized to remove oxidants and disinfectant by products.1

Water for the hemodialysis units is filtered through two external carbon tanks piped in series.  The tanks are 10″ x 35″ with 0.75 cu. ft. of 12×40 mesh Granular Activated Carbon (Norit, acid/washed, low fines granular activated carbon, Norit Americas Inc, Atlanta, GA) #20 flint, underbedding (approx. 4 inches) with 14 inches freeboard. The tanks are designed at a flow rate of 3.5 gpm (continuous)/ 5 gpm max., with an operating flow rate of 1 gpm. The water then passes through a portable reverse osmosis unit (Mediport P.B., Better Water, Inc. Smyrna, TN).  Water through this unit is pre-filtered through a carbon cartridge. The cartridge is a 0.125 cu. ft. of 20×50 mesh granular activated carbon, acid washed, minimum iodine #1000. The water is then post filtered by a 10 inch spun wound 5.0 micron sediment filter before passing through the reverse osmosis membrane.1

For this application, no historical data was available regarding carbon tank capacities. As a safety precaution, the carbon tanks for portable dialysis equipment were sized to achieve 10 minutes EBCT (empty bed contact time) as required for monochloramines.[i] At the end of testing each day, each carbon tank was backwashed separately to prevent channeling. The tank was backwashed to drain for five-minutes to stir up the carbon. Then the tanks went through a five-minute rinse cycle to slowly reset the carbon, completing the backwashing of the tanks.1 

Water for the lab filtration equipment passes through one carbon filter (Neu-Ion OA6 carbon tank, Neu-Ion Inc., Baltimore, MD) and two demineralizer filtration tanks for laboratory water pretreatment. The carbon bed is sized for two-minute EBCT. The lab filtration system was not modified in any way before, during or after the study. No extra precautions or measures (such as backwashing) were taken prior to, during or after the study.1 

Dialysis and Laboratory Filtration Equipment

The ClO2 generator system was designed to provide a maximum ClO2 level of 0.8 mg/l. Before the building was fully occupied, elevated levels as high as 2.0 mg/l of ClO2 was introduced into the potable water system during water restrictions and non-occupied hours, to test the efficacy of the filtration equipment. When the test ended, the hemodialysis carbon filtration tanks were exposed to 12,310 gallons of elevated levels of ClO2 treated water, which is equivalent to 67.8 hemodialysis treatments. The carbon filters removed all ClO2, chlorite, and chlorine from the product water to the hemodialysis filtration equipment during the evaluation. 1

The laboratory carbon filtration tank, at the end of the testing, was exposed to 2,334 gallons of elevated levels of ClO2 treated water. As with the testing of the hemodialysis unit, the filtration equipment was subjected to levels as high as 2.0 mg/l of ClO2. The two-minute EBCT carbon filter effectively removed all residuals of ClO2, chlorite and chlorine during the evaluation.1 

Laboratory and Hemodialysis Filtration Equipment

To our knowledge, the study of ClO2 and its impact on laboratory and hemodialysis filtration equipment was the first of its kind. The study addressed concerns associated with the ability of carbon filters to effectively remove all oxidant residuals.1


1 Gregory Bova, The Johns Hopkins Hospital, Baltimore, MD; Paul Sharpe, Water Chemical Service, Inc., Aberdeen, MD; Tim Keane, Legionella Risk Management, Chalfont, PA – “Evaluation of Chlorine Dioxide in Potable Water Systems for Legionella Control in an Acute Care Hospital”; “65th Annual International Water Conference(r), Pittsburgh, PA (USA), October 17-21, 2004″

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