Reverse Osmosis Coagulants – RoQuest

Organic polymers and inorganic/organic polymer blends used to minimise colloidal fouling on RO systems.

Reverse Osmosis Coagulants – RoQuest

Avista Technologies formulates a variety of liquid coagulant/flocculant chemicals which are compatible with reverse osmosis membranes under the RoQuest name.  RoQuest® 3000 is a blend of organic polymers while the RoQuest® 4000, 5000, and 6000 are a blend of organic coagulants and ferric sulfate.

Product datasheets are available at

RoQuest formulations change the behaviour of particles and colloids which normally exhibit negative charges in naturally occurring feed waters. Because like charges repel each other and unlike charges attract each other, the addition of the positively charged RoQuest polymer allows the negatively charged particles to clump together. This creates larger particles which are more readily retained in the multimedia filter (MMF), resulting in improved MMF filtration.


Studies have proven that MMF performance without coagulant addition will remove approximately 35% – 50% of the feed water particulates.  A nominal dosage of a RoQuest coagulant may allow the MMF to remove up to 98% of the particulates, resulting in improved effluent turbidity and reduced SDI values. The resulting improvement in filtrate quality positively effects the downstream filtration equipment including reduced cleaning frequencies and longer system run times of membrane systems.

Avista Technologies will assist in the selection and testing of the best product for you reverse osmosis application using a range of techniques including jar testing and pilot filtration trials at your site.

NOTE – Avista Advisor 3 has just been released and now allows users to calculate ALL formulated chemical requirements for RO systems.  You can now calculate antiscalant, biocide, coagulant and cleaner requirements and summarise plant chemical consumption.

Please contact Avista Technologies to receive your copy of the software.  (


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