The construction industry increasingly seeks sustainable solutions to reduce environmental impact and energy consumption. This study explores the innovative use of industrial sludge generated from the wastewater treatment of detergent manufacturing as a partial substitute for Portland cement in mortar production. The sludge, characterized by high SiO₂ (46.58%) and CaO (28.66%) content, was incorporated at substitution rates of 0% to 30%. Mortars were prepared and tested according to NF EN 196-1 standards for mechanical strength, and thermophysical properties were assessed using the Hot Disk TPS 1500 system. The results demonstrate that up to 20% sludge replacement maintains acceptable mechanical performance (compressive strength: 12.63 MPa at 28 days vs. 13.91 MPa for the control; flexural strength: 3.93 MPa vs. 4.65 MPa) while significantly enhancing thermal insulation. Thermal conductivity decreased from 1.054 W/m·K (0% sludge) to 0.797 W/m·K (20% sludge), and thermal diffusivity dropped from 0.6096 mm²/s to 0.504 mm²/s. XRD analysis revealed the formation of new phases, such as gismondine, indicating beneficial pozzolanic activity. These findings highlight the dual benefit of valorizing detergent sludge and improving building energy efficiency, offering an eco-efficient alternative to traditional mortars aligned with circular economy and low-carbon construction goals.

Safe drinking water remains an issue all around the world, especially in arid countries that require seawater desalination to obtain safe water. This research seeks to analyze water quality at the major stages of an SWRO plant, i.e., raw seawater intake, RO permeate, reject brine, and distribution network water. For the study, conventional physicochemical methods of water quality analysis, as well as electrochemical impedance spectroscopy, were used. Four water samples were taken at different stages of the treatment process: raw seawater (feed water), RO permeate, reject brine, and distribution network water. Physicochemical parameters, such as pH, electrical conductivity, total dissolved solids (TDS), major ions (Na⁺, Cl⁻, Ca²⁺, and Mg²⁺), and heavy metals (Zn, Cu, Cr, and Hg) concentrations, were evaluated. Electrochemical impedance spectroscopy was used to investigate ionic transport, dielectric relaxation, and interfacial polarization mechanisms within the tested solutions. It has been shown that RO membranes are capable of rejecting major ions up to 95–99%, as can be seen in the low values of conductivity and TDS of RO permeate. EIS analysis also allowed for identifying specific electrochemical characteristics of all four types of water, with brine being characterized by the highest polarization rates and relaxation times.