Chick-Pea, Chard, and Lima Bean Soup

Cut stems and center ribs away from chard leaves. Slice stems and center ribs thin. Chop leaves coarse and reserve. In a 6-quart heavy saucepan cook chard stems and ribs, onion, celery in oil over moderately low heat, stirring occasionally, until onion is softened. Add chick-peas, lima beans, water, and broth and simmer, partially covered, 10 minutes. Stir in orzo and simmer, uncovered, stirring occasionally, until orzo is tender, about 10 minutes. Stir in reserved chard leaves and simmer until leaves are tender, about 5 minutes. Stir in salt to taste. Serve soup with harissa to taste.