Antiscalant Impacts Water Reclamation Efforts

Tackling water conservation by utilising new technologies

AWC A-110 to control high phosphate and silica scales

Developing AWC A-110 around a complex waste water feed, to control high phosphate and silica scales in the presence of ferric ion carryover.


The Ground Water Replenishing System (GWRS) uses a Reverse Osmosis (RO) system which treats water beyond drinking water standards and then takes the treated wastewater, that would have normally been discharged into the Pacific Ocean and mixes it with the local water supply by replenishing a local groundwater aquifer.

OCWD was experiencing frequent silica precipitation that was not controlled with the antiscalant product they were using.  This prompted OCWD  staff to use ammonium bifluoride (ABF) as a membrane cleaner.  Not only is this chemical dangerous to the operators but if used over a long period of time, it could potentially damage membrane elements and/or related equipment.  This led them to look for an alternative antiscalant.


American Water Chemicals’ AWC A-110 was developed around OCWD’s complex waste water feed, and was designed specifically for control of high phosphate and silica scales in the presence of ferric ion carryover.​


AWC A-110 effectively inhibited scale at a dosage of 3.5 ppm and an operating pH of 6.9.  This increase in operating pH reduced the district’s annual acid consumption by ~$350K per year based on their current production. OCWD then made the decision to install the AWC antiscalant for the full scale 70 MGD GWRS system based on significant operational and financial performance improvement.

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