In 5-quart Dutch oven or stockpot, heat split peas, onions, celery and water to boiling.
Reduce heat to low; cover and simmer 1 hour to 1 hour 10 minutes or until peas are tender.
Puree pea mixture with immersion blender.
(Or pour about 3 cups mixture into blender.
Cover; blend until smooth.
Pour into heatproof pitcher or bowl.
Repeat with remaining mixture; return to Dutch oven.
)
Stir in bell peppers, pasta, parsley, oregano, salt and pepper.
Cook over medium heat about 15 minutes, stirring frequently so pasta does not stick to pan, or until pasta is tender.
Top individual servings with cheese and olives.