Challenge

Maximize recovery on municipal effluent with high concentrations of organics, silica and BaSO₄: Padre Dam Municipal Water District operates an internationally-known water reuse facility 18 miles east of San Diego that purifies municipal effluent for makeup water to the Santee Lakes recreational preserve. The advanced water purification plant strives to recover as much wastewater as possible for reuse and recycle, however recovery was limited by fouling and scaling in a multi-stage traditional RO system.

Solution

As the plant had an existing RO system in place, it was decided to utilize a DesaliTec™ CCRO system as a brine concentrator. An overall recovery rate of 95% was achieved, with 75% recovery in the primary and 80% in the Desalitech unit, with more than 6 weeks of run time between CIPs. 95% recovery represents a record high recovery rate compared to the highest recovery multi-stage water reuse RO plant which runs at 85%. Barium sulfate and silica super-saturate in the SOAR (previously ReFlex) unit’s brine but the CCRO process prevents scale precipitation. Fouling is resisted by high cross flow and salinity cycling.

Results

• Padre Dam achieved record-breaking overall recovery rate of 95% with CCRO.
  
• Barium sulfate and silica super-saturate in the brine but the CCRO process prevents scale precipitation.
  
• Extended CIP frequency; Fouling is resisted by high cross flow and salinity cycling.

Quick Facts

• Industry: Municipal
• Application: Municipal Effluent
• Products Used: DesaliTec™ SOAR CCRO Systems (previously ReFlex™ CCRO Systems).