Use of lime clarification and reverse osmosis in water reclamation

The purpose of this paper is to describe the efforts of the Orange County Water District (OCWD) to improve water reuse alternatives. An advanced wastewater treatment (AWT) facility was designed to produce potable quality water for groundwater recharge and for protection against seawater intrusion. The original design provided for treatment of up to 0. 66 m**3/s (15 mdg) of unchlorinated secondary effluent from a municipal wastewater treatment plant. The original treatment processes included lime clarification with sludge recalcination, air stripping, recarbonation, prechlorination, mixed media filtration, granular activated carbon adsorption, final chlorination, and reverse osmosis (RO) demineralization of one-third of the total flow, 0. 22 m**3/s (5 mgd). Efforts have focused on reducing the cost of producing potable quality water.