Improved ASR-Coastal Reference sites (TRL8)

“At two field sites, ASR-Coastal set-ups have been operating between 2012 and 2017 to store (very) fresh rainwater in a brackish to saline sandy aquifer (10 to 40 m deep). Both sites showed distinct characteristics, but followed the same basic ASR-Coastal strategy: water could be infiltrated and recovered via various independently operated well screens in different segments of the aquifer to increase the recovery of freshwater.
The Nootdorp ASR-Coastal system functioned rather smoothly and was always able to supply sufficient irrigation water to the local horticulturist (~ 7 200 m3/yr after infiltration of ~14 000 m3/yr). The required maintenance was limited and the recovered water quality was very constant after Cycle 1 and met the owners demands. With total costs of 0.59 euro/m3, the ASR-Coastal system provided a significantly cheaper source of high-quality freshwater compared to alternatives. The owner will keep using the system as only source of irrigation water.
The Westland ASR-Coastal system functioned satisfactorily, but clearly suffered from saltwater leakage via a nearby older borehole, which reduced the recovery efficiency from 40% to 22.5%. Per year, 7 500 to 16 000 m3 could be supplied, while 28 000 to 70 000 m3/yr was infiltrated. The system was not able to meet the yearly demand of the local horticulturist. Additionally, yearly cleaning of the infiltration system and ASR wells was required at the start-up of the system after long periods without infiltration. Despite these additional obstructions, the total costs were acceptable (0.84 euro/m3). The owner will keep using the system as additional supply, together with aboveground rainwater storage and brackish water reverse osmosis.
The two sites show that the ASR-Coastal technique is mature and robust (TRL8) and can be further implemented. It also shows that local conditions and mode of operation can lead to differences in performance and operational costs, and should therefore be taken into account.”

(Citaat: Zuurbier, K.G., van Dooren, T., Ros, S.E.M. (Quality assurance: Stuyfzand, P.J.) – Improved ASR-Coastal Reference sites (TRL8) – SubSol – D1.6 (2018))