Utilization of hydrothermal technology to process disposable diaper waste into fibers for paving block production

Disposable diaper waste poses a critical environmental challenge, particularly in developing countries like Indonesia, where birth rates remain high. Used diapers decompose very slowly due to their complex composition of plastic, superabsorbent polymers (SAP), and cellulose fibers. This study aims to develop and evaluate the application of hydrothermal technology as an alternative method to convert used diapers into cellulose fibers, which can be utilized as an additive in paving block production. The hydrothermal process was conducted at 150°C and 3–5 bar pressure for 70 minutes using water as the medium. The resulting fiber was then mixed with cement and sand at a ratio of 850 g cement, 2550 g sand, and 600 g fiber. Laboratory tests showed that the produced paving blocks had a compressive strength of 16.8 MPa, water absorption of 6.5%, and a density of 2.2 g/cm³. These results exceed the minimum standard for Class C paving blocks based on SNI 03-0691-1996 (Indonesian National Standard, 1996). These findings indicate that hydrothermal technology not only reduces inorganic waste volume but also produces environmentally friendly construction materials with economic value.