Fouling can be defined as adherent deposits of unwanted compounds that are formed by the precipitationof soluble salts from water and crystal growth on the surfaces of processing equipment. The deposition layerbecomes an insulating layer that deteriorates the heat transfer efficiency and shortens the service life. Thedevelopment of functionalized nanomaterial leads to multi-functionality, such as the ability to adsorb scal-ing cations with high thermal conductivity, which is very important for heat transfer applications to managethe fouling problems. The purpose of this study was to evaluate the mitigation of calcium carbonate scal-ing by applying EDTA-treated MWCNT-based water nanofluids on heat exchanger surfaces. A set of foulingexperiments was conducted by using additive EDTA-treated MWCNT-based water nanofluids (benign to theenvironment) to verify the additives’ retardation of the fouling rate of deposition. Fouling solution for de-posit analysis was prepared by using 300 mg/L of artificially-hardened calcium carbonate solution. Also theassessment of the deposition of calcium carbonate on the heat exchanger surface with respect to the inhi-bition of crystal growth was conducted by Scanning Electron Microscope (SEM) and Energy Dispersive X-raySpectrometry (EDS). The results showed that the formation of calcium carbonate crystals can be retardedsignificantly by adding MWCNT-EDTA additives to the solution

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