RT Journal Article
T1 Silica removal in industrial effluents with high silica content and low hardness
A1 Latour, Isabel
A1 Miranda Carreño, Rubén
A1 Blanco Suárez, María Ángeles
AB High silica content of paper mill effluents is limiting their regeneration and reuse after membrane treatments such as reverse osmosis (RO). Silica removal during softening processes is a common treatment; however, the effluent from the paper mill studied has a low hardness content which makes necessary the addition of magnesium compounds to increase silica removal. Two soluble magnesium compounds (MgCl2∙6H2O and MgSO4∙7H2O) were tested at five dosages (250-1500 mg/L) and different initial pHs. High removal rates (80-90%) were obtained with both products at the highest pH tested (11.5). With these removal efficiencies, it is possible to work at high RO recoveries (75-85%) without silica scaling. Although pH regulation significantly increased the conductivity of the waters (at pH 11.5 from 2.1 mS/cm to 3.7-4.0 mS/cm), this could be partially solved by using Ca(OH)2 instead of NaOH as pH regulator (final conductivity around 3.0 mS/cm). Maximum chemical oxygen demand (COD) removal obtained with caustic soda was lower than with lime (15% vs. 30%). Additionally, the combined use of a polyaluminum coagulant during the softening process was studied; the coagulant, however, did not significantly improve silica removal, obtaining a maximum increase of only 10%.
PB Springer
SN 0944-1344 
YR 2014
FD 2014
LK https://hdl.handle.net/20.500.14352/33920
UL https://hdl.handle.net/20.500.14352/33920
LA eng
NO Latour, Isabel, et al. «Silica Removal in Industrial Effluents with High Silica Content and Low Hardness». Environmental Science and Pollution Research, vol. 21, n.o 16, agosto de 2014, pp. 9832-42. DOI.org (Crossref), https://doi.org/10.1007/s11356-014-2906-8.
NO European Commission
NO Comunidad de  Madrid
NO Ministerio de Educación (España)
DS Docta Complutense
RD 10 abr 2025