What is Chlorine?
Chlorine is nothing but a gas which has been compressed to make it a liquid. At room temperature chlorine is a gas.
Why Chlorine is Used in Water?
Chlorination is the most widely used ways to disinfect water from harmful microorganisms like bacteria, viruses and protozoa. Chlorine is very inexpensive and very effective disinfectant and is therefore used by municipalities world over.
The Bureau of Indian Standards (BIS) has set the acceptable limit of free residual chlorine in water as 0.2 mg/L and maximum permissible limit (in absence of alternate source) as 1.0 mg/L.
Adverse Effects of Chlorinated Water?
If you get tap water or municipal corporation water supply at your home then you must have noticed strong smell and poor taste. This is because of chlorine.
Despite Chlorine’s effectiveness, it is considered to have several adverse effects apart from the strong smell and poor taste.
We are not trying to scare you away but you will be surprised to know that Chlorine has been used as a chemical weapon in the World War I. Chlorine when used in high concentration can possibly kill you in minutes.
One of the biggest concerns of using Chlorine is that it can reach with naturally occurring organic and inorganic matter in our water to form harmful disinfection by-products like Trihalmethanes (THMs) and Haloacetic Acids (HAAs) which may pose health risks.
- Chlorinated water smells and tastes awful.
- Chlorine in drinking water not only kills the harmful bacteria but also kills the friendly bacteria found in our intestine that help in the digestion of food. Drinking chlorinated water may result in digestion related issues.
- THMs in water may cause cancer.
- Even if you don’t drink chlorinated water, showering with chlorine water is as harmful as drinking. Our skin can possibly absorb more chlorine as compared to when we drink.
- Not suitable for aquarium and pond fish.
What is Chloramine?
Due to the growing concerns about the adverse effects of chlorination, a growing number of municipal corporations are switching from chlorine to chloramine for disinfecting water.
Chloramine is a combination of free chlorine and ammonia. So adding ammonia to chlorinated water will give you chloraminated water.
Unlike free chlorine which evaporates quickly when exposed to air, chloramines remain in the water. Because of this property chloramines last longer in water during distribution, and are more effective than chlorine.
Chloramines are less harmful as compared to chlorine. Chloramines control the formation of THMs but chloramines have their own adverse effects like:
- Chloramines may cause lead leaching from water supply pipes and result in metal corrosion.
- Chloramines may result in dry, itchy skin and may not be suitable for people with sensitive skin.
- Chloramine also results in foul smell and poor taste.
- Chloramines are a little harder to remove from water.
Chlorine or Chloramines, How to Find?
The easiest way to identify whether the tap water supplied to your home is disinfected with chlorine or chloramines is to simply call your water supply provider and ask what they use to treat the municipal water supply.
Another easier way of identifying whether your water has chlorine or chloramines is testing your tap water for ammonia. You can use an easy to use Ammonia test kit for the same. If the test confirms the presence of ammonia then your water is most definitely disinfected with chloramines.
How to Remove Chlorine from Water You Drink?
Activated Carbon Filter
An activated carbon filter, also known as charcoal filter, uses small pieces of carbon to remove contaminants and impurities using chemical adsorption. Activated carbon used in these filters is usually made of coconut shells, wood or coal.
Activated carbon filter effectively removes bad taste and odor causing organic compounds like chlorine and chloramines from water. Nowadays, most water purifiers come with an activated carbon filter.
If you are not using a water purifier then you can also buy activated carbon filters that you can directly fit on your tap or you can buy a water filter pitcher that uses an activated carbon filter.
Activated carbon filters are very effective in quick and complete removal of both chlorine and chloramines. The only downside is you will need to change them at periodic intervals.
RO (Reverse Osmosis)
Reverse Osmosis uses a very high quality semi-permeable membrane to filter out all the ions and particles from water. RO membrane only allows the water to pass through and blocks all chemical impurities and dissolved solids. RO also filters out all the chlorine and chloramines from water. All RO water purifiers require pre-filtration before the water passes from the RO membrane. And pre activated carbon filter is most commonly used for pre-filtration of water before RO membrane.
RO water purifiers are easy to use but are expensive and waste a lot of water.
You may also read: 10 Best Water Purifiers in India.
Boiling creates heat and aeration (via bubbles), which results in evaporation of volatile chlorine after 20 minutes. However this method is not suitable for dechlorinating large quantity of water.
Boiling does not remove chloramines.
This method is not that practical as it requires a lot of heat energy and is not suitable for large quantity of water.
This is the simplest technique for removing chlorine from water by natural evaporation. Chlorine is nothing but a gas which has been compressed to make it a liquid. At room temperature chlorine is a gas.
So if you leave chlorinated water in a wide container, chlorine will evaporate naturally. However, this may take up to 24 hours for chlorine to evaporate.
This is the simplest method but it takes long time and it does not work if the water is treated with chloramines.
Stripping with Fresh Air
Like Off-Gassing and boiling, this method also works on the principle of evaporation. All you need is one empty vessel and one vessel filled with chlorinated water. Transfer the chlorinated water from one vessel to the other. And repeat it for at least 10 times to removes all the chlorine from water.
The advantage of this method is it is easy and free but it can only be used for small quantity of water.