MSR has a new water purification tool/method out, the MSR SE-200 Community Chlorine Maker.
Its basic principle is making chlorine our of salt by electrolysis, and then purifying the water with it.
It is a larger scale application of a withstanding technology application, the MSR MIOX Water Purifier.
It is the scale that changed and the new purfier covers the disinfection chorine solution of small communities.
Check out the tutorial video on the MSR SE-200: