AWWA WQTC71337

The primary objective of this pilot testing study was to evaluate the ability of the treatment technologies to reliably remove sediment from the Santa Ana River (SAR) and thereby sustain percolation rates within the Orange County Water District's (OCWD) recharge basins for longer periods of time. This primary objective would assist OCWD in optimizing the performance of the existing recharge facilities as one of the approaches to reaching their long-term goal of 700 cfs winter/spring recharge capacity and 400 cfs summer/fall recharge capacity. Testing focused on the benefits of removing sediment from the recharge water since sediment accumulation is believed to be the primary factor that reduces percolation. Other objectives associated with the pilot testing included collection of data for each sediment removal process to develop specific design criteria to meet the production goals of the selected treatment technologies. As part of the feasibility study, a pre-selection process was conducted to evaluate viable technologies and narrow the field selected for pilot testing. The treatment alternatives tested during this pilot study were categorized as follows: chemical/physical removal - conventional flocculation-sedimentation (Floc-sed); ballasted sedimentation or high rate clarification (HRC); dissolved air flotation (DAF); and, mechanical removal - cloth filter river bed filtration, and filtration through native sediments using a perforated pipe collection system. Includes tables, figures.