Hydrochemical characterization of Pamukkale travertines, Denizli, Turkey, for remediative measures


AÇIKEL Ş. , EKMEKÇİ M.

ENVIRONMENTAL EARTH SCIENCES, cilt.75, 2016 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 75 Konu: 22
  • Basım Tarihi: 2016
  • Doi Numarası: 10.1007/s12665-016-6258-1
  • Dergi Adı: ENVIRONMENTAL EARTH SCIENCES

Özet

The UNESCO World Heritage snow-white travertines in Pamukkale (W Turkey) are discolored as a consequence of algae growth at the surface. The first act to restore the travertines was to abandon the activities and facilities that found to provide nutrients. Discoloration has continued after the pollution sources were abandoned, because the nutrients were sorpted onto the travertine material. The subsurface water was found to be contaminated by desorption of the nutrients. Sorption-desorption characteristics of the travertines had to be quantified in order to achieve an effective remediation and restoration. This study was carried out to determine the sorption-desorption characteristics of the travertines by batch and column experiments. Batch experiments revealed that the sorption isotherms of the Pamukkale travertine fit a linear model for nitrate and Freundlich isotherm model for phosphate. The distribution coefficients (K-d) for nitrate and phosphate were calculated from the isotherms as 24.1 and 181 l/kg, respectively. Incorporating K-d values, the retardation factors were calculated as 142 for nitrate and 1553 for phosphate. Thus, the relative velocity of nitrate and the phosphate was calculated as 7.3 x 10(-2) and 6.7 x 10(-3) m/day, respectively. The data obtained from the column experiment evaluated by fitting a theoretical curve. The results from the column experiment were then interpreted in terms of flushing of nitrate by pore volumes and suggested that the travertines can be cleaned up by flushing at least four pore volumes.