Membrane technology boosts freshwater recovery upon aquifer storage

Aquifer storage and recovery (ASR) of freshwater surpluses in brackish or saline aquifer suffers from freshwater losses upon mixing. In combination with desalination using reverse osmosis, freshwater recovery can be boosted up to 100% of the injected freshwater. At the DESSIN Westland demo site, the high-end ASR and RO technologies are integrated for the first time in order to obtain an optimal, robust, and sustainable ecosystem service.

Bruine de Bruin (SME within DESSIN) compiled the fit-for-purpose RO-treatment facility, which was added to the existing ASR system. The facility is feed by rainwater mixed with saline groundwater abstracted by the (deeper) ASR wells, which are called Freshkeeper wells. As a result, more freshwater is produced via RO, but at the same time, the shallower ASR-wells are able to abstract more freshwater, since upcoming saltwater is intercepted. DESSIN milestone MS20 therefore has been achieved.

KWR and Bruine de Bruine will now analyse and optimize the performance of the RO-membranes upon desalination of the mixed, brackish rainwater-groundwater. It is expected that desalination of this water type may induce membrane clogging. The results of the DESSIN RO-system are compared to the current RO-treatment facility at the site, which is abstracting mixed water from the fringe of the ASR bubble.

Cross section of the ASR system that is combined with RO treatment of brackish mixing water from the base of the target aquifer.