Experimental Assessment of Treated Wastewater for Sustainable Mud Brick Production: Integrating Architectural Sustainability and Engineering Performance

Abstract

As the demand for sustainable construction materials has grown and freshwater scarcity has become a major concern, the use of treated domestic wastewater (T.D.W.) in construction has emerged as a potential solution for conserving freshwater, reducing environmental pollution, and promoting circular economy principles. This study experimentally investigated the feasibility of using treated domestic wastewater as an alternative to freshwater in the production of hand-moulded sun-dried mud bricks. Bricks measuring 228.6 × 114.3 × 76.2 mm were prepared using three mud-to-treated-wastewater mixing ratios (70:30, 75:25, and 65:35) and cured naturally under sun exposure. Water absorption was evaluated after 24 hours, while compressive performance was assessed after 7, 14, and 21 days in accordance with ASTM C67/C67M. The results showed a water absorption of 20%, which falls within the maximum allowable limit of 25% for clay bricks used under normal conditions. The average failure loads were 25.8 kN after 7 days, 23.4 kN after 14 days, and 25.3 kN after 21 days, corresponding to average compressive strengths of 0.99 MPa, 0.90 MPa, and 0.97 MPa, respectively. The findings indicate that the use of treated domestic wastewater did not negatively affect the physical and mechanical properties of the bricks.