Question on Bromine and chlorine tablets- not pool related

[Bill1974]

I have been reading the posts on using bromine on this site to find out more about it use and how it compares to chlorine.

BTW I use the BBB method for my pool and it been working great.

A project I am working on (not pool related) has issues with filters clogging because of biofilm forming on the outer surface of the filter and impeding the flow through the filter. I was thinking of putting a slow release chlorine tablet in the filter to try and kill the biofilm, but chlorine is really that good for other equipment in the system where the filter is installed. So it dawned on me that there are other pool sanitizers, and bromine came to mind but I know nothing about it.

How long do slow release bromine tablets last compared to typical slow release chlorine tablets? The flow through the filters is really low (5 - 10 gallons a day) or stagnate much of the time.

Does bromine attack any metals? plastics? is there any chemicals that bromine should not come in contact with?

 

[JoyfulNoise]

Bromine tablets (BCDMH, BDMH, etc) are acidic. You need to put them is special bromine tab floater or else they will dissolve too rapidly and crash the pH and TA of the water that they are in. If this application is an open-loop water system (constant fresh water input), then you could be ok using them as long as everything in the equipment stream is compatible with bromine. Bromine is still a strong oxidizer (not as good as chlorine) so if there are components that are not compatible with chlorine, switching to bromine will not change that.

What about using surfactants or cleaners to remove the biofilms? A strong dose of Polyquat-60 will kill algae or bacteria and act as a clarifying agent or a powerful surfactant/clarifier like ABDAC or polyDADMAC could be used to remove biofilms. The spa cleaning product Ahh-Some works this way - it uses a powerful surfactant to break up biofilms thus liberating them from the surface of the plumbing and allowing chlorine to penetrate and destroy them.

 

[JVTrain]

Chlorine and bromine aren't necessarily that aggressive on metals and plastics but both chlorine (trichlor) and bromine (BCDMH) tablets are acidic in water. With limited flow, you might have local areas of high chlorine/bromine concentrations and low pH conditions. This can be hard on plastics and rubbers, similar to putting these products in a toilet tank reservoir. Mixing dry tablets with any other concentrated chemical could have violent reactions. But when submersed in water, any reaction with other chemicals is likely to be slower, less dangerous.

 

[Bill1974]

Thanks for the feedback and information. It was what I was looking for. My application has to do with effluent, so it's really to just to stop the growth on the particulate filters. Basically trying to build a better mouse trap. The products in today's market stop working prematurely or are overly complicated and expensive. The market is dictated because of EPA and local regulation that require these devices.

I have done some more research and found out that Bromine is not a viable option. There a fair amount of bronze and brass in these systems and bromine does not play well with brass and bronze, chlorine is a lot easier on brass and bronze.

Are there any really slow release chlorine tablets? What controls the rate at which a chlorine tablet breaks down? I am sure flow is a large factor and in my applications there is little flow (10 gallons a day at best). It would be ideal to have to replace these filters on 6 month or longer intervals. Much depends on what is actually in the effluent.

 

[JoyfulNoise]

Hard to really advise on this as your application is not really germane to pools and honestly, unless you share a lot more information and technical details about the setup and application of your filtration process, there's not much anyone here can do. Your question might be better suited on some kind of industry-specific forum.

As for chlorine tablets, the answer is no. At those flow rates, the tablets will dissolve too fast and your tank is going to build up a large excess of free chlorine as well as low pH. I don't think chlorine is suited for your application. A wide spectrum biocidal/anti-microbial agent like a linear quat algaecide (ABDAC) will probably work better as it will act as both a sanitizer (although too slow for EPA pool standards) and a clarifier/surfactant. Though you will have to figure out some kind of automated dosing system. There are test kits made by Taylor that can determine quaternary ammonium compound (QAC) concentrations so one could, in principle, run a series of experiments to see if the process works.

 

[Bill1974]

I agree this is not the place to come up with an answer, it was more of poke to see find possible new avenues explore.

I have read many posts here (mainly explaining the BBB method and automating the dosing of chlorine) and found that there are a number of very helpful people like yourself here that share their knowledge and it is appreciated.

Carrying a half gallon bleach across the yard daily got old quickly, wheeling out a few cases every few weeks is nice. Plus being able to tweak the chlorine dosage by changing a timer is nice. I use a couple of z-wave relays/contactors to control my pool pump and stenner, now I just tweak the run time of the stenner after testing the water. Since the chlorine is dosed more consistently that when I added it manually I have found that I don't need to test as much too.