Modeling Remineralization of Desalinated Water by Micronized Calcite Dissolution

Abstract

A widely used process for remineralization of desalinated water consists of dissolution of calcite particles by flow of acidified desalinated water through a bed packed with millimeter-size calcite particles. An alternative process consists of calcite dissolution by slurry flow of micron-size calcite particles with acidified desalinated water. The objective of this investigation is to provide theoretical models enabling design of remineralization by calcite slurry dissolution with carbonic and sulfuric acids. Extensive experimental results are presented displaying the effects of acid concentration, slurry feed concentration, and dissolution contact time. The experimental data are shown to be in agreement within less than 10% with theoretical predictions based on the simplifying assumption that the slurry consists of uniform particles represented by the surface mean diameter of the powder. Agreement between theory and experiment is improved by 1-8% by taking into account the powder size distribution. Apart from the practical value of this work in providing a hitherto lacking design tool for a novel technology. The paper has the merit of being among the very few publications providing experimental confirmation to the theory describing reaction kinetics in a segregated flow system.

A critical review of point-of-use drinking water treatment in the United States

“…Remineralization aims to adjust the alkalinity of RO-filtered water by re-introducing healthy minerals; tap water RO permeate is deficient in healthy minerals, has a slightly dry, burning feeling to the tongue, and is slightly corrosive with pH < 6.0 104 . Product water after remineralization not only makes RO-treated water more palatable, but also non-corrosive 105 , fulfilling the following water quality criteria: pH between 6.5 and 8.5; alkalinity >80 mg/L as CaCO 3 , and calcium carbonate precipitation potential (CCPP) range of 80 < CCPP < 120 mg/L as CaCO 3 106,107 .…”

Hybrid Hollow Fiber Nanofiltration–Calcite Contactor: A Novel Point-of-Entry Treatment for Removal of Dissolved Mn, Fe, NOM and Hardness from Domestic Groundwater Supplies

“…Prolonging the contact time of the feed water with the media is not an economically attractive option as the investment cost of the process would increase. Improved performance of the calcite beds by CO2 injection is mentioned in the literature [12,13]. However, for purpose of the domestic GW treatment, CO2 injection complicates the operation and maintenance of the process and would also add an additional cost.…”

“…Despite the wealth of information on the effectiveness of implementing a calcite contactor to remineralize desalted RO permeates [12,13] and its ability to adsorb divalent metallic cations on its surface [14,15,16], to the best of our knowledge, removal of Mn and Fe from a soft water while simultaneously adjusting its hardness level (without dosing CO2) by means of a calcite contactor is not addressed in the scientific literature. In this perspective, the aim of this research is to design a simple and compact, yet robust hybrid HFNF–calcite contactor process for domestic treatment of GWs (containing a high level of Mn, Fe and NOM).…”

Deacidification through calcium carbonate dosing in combination with ultrafiltration

“…The dissolution kinetics of calcium carbonate are controlled by the particle's surface area (Sjöberg 1976;Gude et al 2011;Hasson et al 2017). A larger available surface area increases the rate of dissolution.…”

“…The dissolution of granular and powdered CaCO 3 has been investigated for many years till now. The literature covers the different parameters as well as approaches to model the dissolution process (Weyl 1959;Morse 1974;Sjöberg 1976;Plummer et al 1978;Dreybrodt 1981;Yamauchi et al 1987;Hasson et al 2017). However, no research has been done on the kinetics in a process combination of dosing powdered CaCO 3 in the UF feed.…”