Treatment of Wastewater to Meet the Requirements for Cooling Water Systems in Jordan’s Nuclear Plants

Abstract

Scaling and corrosion associated with the use of natural hard water in cooling towers during recirculation pose great problems from both economical and technical points of view, such as decreased system efficiency and increased frequency of chemical cleaning. Treated municipal wastewater (MWW) is a promising alternative to freshwater as power plant cooling system makeup water, especially in arid regions. In this work, hybrid systems of salt precipitation (SP), nanofiltration (NF) and reverse osmosis (RO) were investigated, as potential pretreatment processes for wastewater reuse as cooling water in the planned Jordan nuclear power plants. The As-Samra wastewater was used to calculate the potential of carbonate and sulfate scale formation. The results were compared to scale potentials from Palo Verde wastewater. Four cases were investigated; SP, NF, SP-RO and NF-RO. The SP pretreatment cases showed the highest monovalent to divalent ratio because of a high removal of Ca and Mg and addition of Na from the chemicals of the SP step. The NF pretreatment cases, showed the lowest calcium sulfate scale potential and this potential decreases with the % pretreatment. The scale amount increases very slightly with concentration times when the SP and NF product is desalinated by RO step.

Behaviour of dissolved inorganic salts in the cooling water of a nuclear power plant open recirculation system and formation of water discharge

“…Once in the ORS, water changes its physicochemical composition under the influence of many factors, and scale formation processes can occur [16], consisting of precipitates of calcium carbonate (CaCO 3 ), sulfate (CaSO 4 ) and magnesium hydroxide [Mg(OH) 2 ] depending on the reaction (1.3)-(1.7) [17,18]. The deposition of CaCO 3 , CaSO 4 and Mg(OH) 2 in ORS (figure 1) causes a decrease in the heat transfer of equipment, which reduces the efficiency of NPP operation and increases the operating costs of descaling [2].…”