Just out of curiosity why would you want to dechlorinate water in your irrigation system?

The UV from the sun will destroy the chlorine within minutes, breaking it down into chloride (depending on what else is present in the water most likely sodium or magnesium chloride) and oxygen...I guess to answer your question, some sort of inline UV lamp would work, but I'm troubled why you would need it? The levels of chlorine in your irrigation system should be really low, low enough that the second it hits the sun 90% of it will be gone before it ever hits the ground, especially on a warm day.

You can put the water in a cistern, and the chlorine will come out naturally after a few days. I think I heard 5 days was the timeframe, depending on volume, but I could be wrong about that.

gravity or pump flow to the system

Okay, I'm not familiar with that study... but theoretically, chemically speaking you can get rid of chlorine with an activated carbon filter, or possibly a copper or zinc filter. The challenge would be finding a filtering system with enough activated carbon to keep up with the high flow demand of the sprinkler system. The water has to have enough time to interact with the activated carbon in order to be effective. If the flow of the water is too fast through the filter it won't be effective. I think your best bet would be to source a whole house water filter system and retrofit it for the sprinkler system, those systems should be designed to keep up with enough flow for an irrigation system since they are designed to be big enough to treat a whole house. These types of systems will remove 99% of the chlorine, but I think you could expect to shell out $500 or more.

Chemically, you could treat it with ascorbic acid, but you'd have to design a pumping system that injects the ascorbic acid into the line. This could be done with the pumps that they use for chlorinating an aerobic septic system, same concept but instead of treating effluent, you'd be treating the influent.

But this all sounds like a lot of trouble unless you have a serious chlorine problem. Maybe the easiest thing to do would be to treat the soil every so ofter with some powder ascorbic acid (vitamin C), or better yet just use an ordinary lawn fertilizer to replace whatever it is that the chlorine is taking away from the lawn.

Or, spend the extra $20/month on your water bill and water during the day and let the sun do it for you...

Best bet is granulated activated carbon in my opinion. You can put it in a filterbag housing with a loose-mesh bag and change it out as needed. Unless your yard is huge with giant zones/flow this should work ok. You can get the bagged carbon at a local culligan branch or something similar.

If you go that route, id veer toward the plastic housings with a twist off lid. The metal ones can be a pain.

People have used tap water for garden/landscape watering for years. Someone finally figured out another way to separate people from their money. A reasonably healthy soil will not be affected by the small amount of chlorine in tap water. Chlorine may kill a small amount of soil bacteria, but if your soil is in such bad shape that that makes a difference, you can spread some compost to fix that.

There's a reason why rain gets much better results than city water. Could be lack of chlorine, ozonated rain drops..who knows but there's something much better about rain.

Good Morning,

What ever came of your dechlorinating process?

I found your question thinking about it myself.

Thanks,
Matt

http://rb.gy/7eth9
Whole house water filter?