Arsenic removal from geothermal influenced groundwater with low pressure NF pilot plant for drinking water production in Nicaraguan rural communities

Arsenic removal from geothermal influenced groundwater with low pressure NF pilot plant for drinking water production in Nicaraguan rural communities

Gonzalez Rodriquez, B.J. (TU Delft Sanitary Engineering)
Heijman, Sebastiaan (TU Delft Sanitary Engineering)
Rietveld, L.C. (TU Delft Sanitary Engineering)
van Halem, D. (TU Delft Sanitary Engineering)

2019

This research evaluated the effect of different fluxes (16, 23 & 30 L/m ² h) and temperatures (31,35 & 43 °C) on the rejection of As(V) during nanofiltration (NF) of natural geothermal influenced groundwater in Nicaragua. A NF pilot plant powered by solar panels was built and operated in rural community Telica, exposed to As-rich drinking water sources due to geothermal influences. The results showed that even at high temperatures it is possible to obtain high rejection of As(V) (0.87–0.9) during NF filtration (recovery 10%; flux 16 L/m ² h) of geothermal influenced groundwater, with the additional advantage of requiring low operating pressures (1.2 bar ~ 12mwc). The permeate concentration (~5 μg/L) complied with the WHO guideline for drinking water and the concentrate (~55 μg/L) could be used by local villagers for daily activities (e.g., laundry and bathing). For all investigated fluxes and temperatures the order of rejection of As(V) (as HAsO ₄ ²⁻ ), compared with the other anions, could be interpreted on the basis of its charge, hydrated radius and hydration free energy. At lower temperatures (31 and 35 °C) permeate quality improved slightly (~3 μg/L), but although an increased temperature had a negative effect on the As rejection, As concentrations in the permeate never exceeded 5 μg/L, while the required TMP dropped - depending on the flux - with 0.5 to 1 bar. This decrease in required pressure might be of huge benefit in deserted, rural locations where electricity is scarce, as with an overhead tank of 10–15 m a gravity-fed NF system would be feasible.

Arsenic
Drinking water
Geothermal sources
Nanofiltration
Nicaragua

http://resolver.tudelft.nl/uuid:b76b9694-99ee-4f6c-823e-69c57c3309ec

https://doi.org/10.1016/j.scitotenv.2019.02.222

2019-08-27

0048-9697

Science of the Total Environment, 667, 297-305

Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.

Institutional Repository

journal article

© 2019 B.J. Gonzalez Rodriquez, Sebastiaan Heijman, L.C. Rietveld, D. van Halem