The most common inorganic coagulant is Alum. It has been used to clarify turbid water prior to treatment. If you add a bit of Alum to a bucket of turbid water, mix it and then let it stand for a while, the solids will settle out and the clarified water can be decanted. Most water treatment plants use a coagulation/flocculation process prior to filtration and disinfection. For back country water, it's easier to use an Alum Solution in a dropper bottle than to try to use crystals. I suppose that Alum is more commonly used while canoeing where there is ample water, but the water is turbid. The water will still have to be disinfected before it is safe to drink.