How to Dechlorinate Water

One of the foundational processes in the Edible Learning Lab is the promotion of good bacteria.  Bacteria are beneficial to healthy soil and plant development in a number of ways.  One of the most important relationships exists between rhizobia, a specific soil bacteria, that fixes nitrogen for plants at the root level.  Plants are unable to use nitrogen that is present in the soil and air. But bacteria converts it to ammonia which plants are able to use to synthesize proteins.  It’s a symbiotic relationship as the plants provide the bacteria with a perfect place to call home.

Chlorine, specifically sodium hypochlorite used by municipal water systems, kills bacteria that might be found in the water.  If tap water is used to water young starts, plants in a raised planter, or as the source for a hydroponics system it would prove to be counterproductive.  The chlorine would kill the beneficial bacteria affecting the viability of the plants.

Soooooooo, clearly there is a need to treat the tap water before it is used is the Lab.  There are a number of ways to do so.

The Expensive Method

Filter systems are the most expensive means to dechlorinate tap water and there are several viable systems to consider.  Reverse Osmosis systems pass water through a membrane to remove ions, molecules and large particles from the source water.  This process depends on screening certain things from the water based on size.  Smaller sized particles are permitted through while larger ones are prohibited.

Reverse Osmosis systems are commonly used to filter household water sources and can often be found under the kitchen sink.  The cost for such systems can run thousands of dollars.

The Time Intensive Methods

Off-gassing and boiling are relatively cheap methods for neutralizing chlorine in tap water but they take time.  Off-gassing refers to the process of exposing water to sunlight which allows some forms of chlorine to evaporate over time, generally 12-24 hours.  Using an aeration pump with diffusion stones will speed up the process.  However, not all water treatment chemicals will off-gas and those that do will require more time at higher concentrations.  Free chlorine will off-gas but chloramine, a chemical that has become more popular with municipal water treatment facilities in recent years, does not.

Boiling water will work but it also takes time.  Boiling batches a few gallons at a time would simply not be practical.  It would take significant time and energy to boil and cool enough water for a small size Lab.

The Cheap Method

Ascorbic acid, known commonly as Vitamin C, neutralizes chlorine and chloramine in tap water in short order.  The process takes just seconds and is a part of our water treatment protocol at the Edible Learning Lab.  A 5 gallon bucket of tap water can be treated with less than a teaspoon of ascorbic acid.

Ascorbic acid is easy to use, is cost effective, doesn’t lower dissolved oxygen in the water as much as other methods, dissipates quickly after application, and leaves nothing behind that adversely affects the quality of the water for plant or human consumption.  This method of dechlorinating water for use with plants, specifically in the hydroponics system, is the best we’ve found and one that has proven viable in the Lab.

Food grade ascorbic acid is inexpensive and can be ordered in the Modern Steader Store.