Bowing to opposition from south Orange County residents, the Aliso Water Management Agency unexpectedly dropped its bid to reduce treatment of raw sewage before it is dumped in the ocean off Aliso Beach. "It was unanimously concluded . . . that the environmental protection and enhancement of the ocean environment is more important than the apparent economic benefits of reduced treatment," AWMA board Chairman John V. Foley announced. The decision, which came unexpectedly at the agency's regular monthly board meeting, means that raw sewage will still be treated to remove 99% of virus- and bacteria-carrying matter before it is discharged from the outfall, about 7,400 feet off Aliso Beach. Opponents of the plan will now try to get the adjacent South East Regional Reclamation Authority to kill a similar plan.