My, such drama!! Actually, they would have been fine if they had 1)simply let the water settle overnight, 2)decant the upper portion, and then boil briefly. I followed this procedure when working in Canyon de Chelly one fine June when the winter runoff was extremely high, rendering the site at which we were excavating (Antelope House) in accessible y motor vehicle. Our only option was to hike down a nearby trail and work and camp at the site, utilizing the water flowing in del Muerto Creek, which was "too thick to drink and too thin to plow." Del Muerto is within the Colorado River drainage so this is actually relevant. We operated in this manner for about three or four weeks before we were able to resume our normal access and utilize normal water. We experienced zero problems drinking del Muerto water, processed as described. There were sheep and people living upstream from us and there were no sewage treatment facilities within miles....

I don't believe the article pinpointed their location within Grand Canyon, but there are quite a few seeps and springs there that furnish quality drinking water, needing minimal or no processing. But you must be mindful and alert. A quality map helps enormously.