Pellet Softening Process for the Removal of the Groundwater Hardness; Modelling and Experimentation

Abstract

A lab scale pellet reactor (PR) was designed and fabricated to carry out extensive investigations on theremoval efficiency of the hardness of groundwater. The groundwater of 2200 – 2600 mg/L hardness wascollected from Abdulla Ibnalhassan wells area located at the west desert of Al-Shinafiyah district (70 km tothe southwest of Al-Dewaniyah city, Iraq). Both hydrodynamic parameters of the pellet reactor (porosityand fluidized bed height) and the parameters of calcium carbonate crystallization process (calcium carbonateequilibrium, pellet size, and density) were modeled and compared with the experimental results of the labscale pellet reactor. The comparison showed that fair agreement between modeled and measured results wasobserved. The removal efficiency of both calcium and magnesium ions were 62.5-99% and 83-99%respectively. The removal efficiency was found to be strongly dependent on pH and the ratio of NaOHsolution flow rate to the groundwater flow rate in the pellet reactor.