Method for Increasing Reverse Osmosis Recovery for High Silica Waters

A multi-phase process for treating water containing silica in a reverse osmosis (RO) system including a silica adsorption unit and an RO unit that produces a permeate and a concentrate, the process comprising:

• in a first production phase:
• mixing the concentrate from the RO unit with the water to be treated to form an RO feed and directing the RO feed through the RO unit to produce the permeate;
• continuing to direct the RO feed through the RO unit until a silica concentration in the concentrate reaches a setpoint, at which time the process is switched from the first production phase to a second production phase;
• in the second production phase:
• reducing the concentration of the silica in the concentrate by mixing the concentrate from the RO unit with the water to be treated to form the RO feed and directing at least a portion of the RO feed through the silica adsorption unit containing a media that adsorbs silica from the RO feed as the RO feed passes through the silica adsorption unit;
• after passing the RO feed through the silica adsorption unit, directing the RO feed, depleted in silica, through the RO unit and continuing to produce the permeate;
• continuing the second production phase of the process until a production threshold setpoint is reached, at which time the process is switched from the second production phase to a third concentrate purge phase;
• and
• in the third concentrate purge phase:
• purging the concentrate from the RO system.

A multi-phase process for treating water supersaturated, saturated or nearly saturated with silica in an RO system including a silica adsorption unit and an RO unit that produces a permeate and a concentrate, the process comprising:

• in a first production phase:
• mixing the concentrate from the RO unit with said water supersaturated, saturated or nearly saturated with silica to form an RO feed;
• reducing the concentration of silica in the RO feed prior to reaching the RO unit by directing at least a portion of the RO feed through the silica adsorption unit located upstream from the RO unit that contains a media that adsorbs silica from the RO feed as the RO feed passes through the silica adsorption unit;
• continuing the first production phase until a first setpoint is reached;
• once the first setpoint is reached, switching the process from said first production phase to a second production phase;
• in the second production phase:
• bypassing the silica adsorption unit with a substantial portion of the RO feed and directing the substantial portion of the RO feed through the RO unit to produce the permeate and the concentrate;
• continuing to direct the substantial portion of the RO feed through the RO unit and causing the concentrate produced by the RO unit to become supersaturated with silica;
• upon reaching a second setpoint, switching the process from the second production phase to a concentrate purge phase;
• in the concentrate purge phase:
• purging the supersaturated concentrate from the RO system.

A multi-phase process for treating water containing silica in an RO system including a silica adsorption unit and an RO unit that produces a permeate and a concentrate, the process comprising:

• in a first production phase:
• mixing the concentrate from the RO unit with said water containing the silica to form an RO feed;
• reducing the concentration of silica in the RO feed prior to reaching the RO unit by directing at least a portion of the RO feed through the silica adsorption unit located upstream from the RO unit that contains a media that adsorbs silica from the RO feed as the RO feed passes through the silica adsorption unit;
• continuing the first production phase until a first setpoint is reached;
• once the first setpoint is reached, switching the process from said first production phase to a second production phase;
• in the second production phase:
• bypassing the silica adsorption unit with a substantial portion of the RO feed and directing the substantial portion of the RO feed through the RO unit to produce the permeate and the concentrate;
• continuing to direct the substantial portion of the RO feed through the RO unit and causing the concentrate produced by the RO unit to become supersaturated with silica;
• upon reaching a second setpoint, switching the process from the second production phase to a concentrate purge phase;
• in the concentrate purge phase:
• purging the supersaturated concentrate from the RO system.