Start with pH control to be slightly acidic (in the summertime, when all the algae is having fun copulating and making the raw water extremely basic, this means dumping lots and lots of sulfuric acid). Add in a nice charged coagulant, PACL in this case (and a nice uncharged polymer could be helpful for greasy bits). Mix vigorously, then less vigorously, and then let sit for a while to let the mud settle out of the water.
After settling, bubble 7% ozone through the water. Then send the water through a prepared filter containing sand, gravel, and charcoal with a healthy biofilm on it (I don't remember the exact order, sorry). Be sure to clean the filters every day. Now dump in a load of hydroxide to make the pH slightly basic (also is less hell on your pipes, especially if there's any lead pipes in the system). Add fluoride for health, and dump in all the chlorine (nowadays as bleach; a chlorine gas pipe leak is no fun for anybody). Add some ammonium to get chloramines to help disinfect the water for longer, and some phosphate for pipe corrosion control.
That's basically the same process that's going to get used for any large (think >100 million gallons/day, enough to supply ~300k suburban households), although ozone treatment is relatively rare. UV and reverse osmosis tend to be too expensive to really scale to the large treatment plants, and slow sand filters (not to be confused with the rapid sand filters that are used in most places) requires craptons of space to push enough water to handle a large municipality.