A study tested different methods to clean rural sewage. They used ultrafiltration, reverse osmosis, wetlands, and biofilters. Ultrafiltration removed most pollutants, but not ammonia. Reverse osmosis made the water safe to release. Wetlands and biofilters didn't remove pollutants well. More work is needed on these methods. Ultrafiltration and reverse osmosis together could be a good way to clean rural sewage.