Sustainable water treatment: leveraging drinking water treatment sludge for enhanced water quality

This study presents a novel and sustainable approach to enhance drinking water treatment by transforming Drinking Water Treatment Sludge (DWTS), a challenging waste byproduct, into a valuable resource. We investigated the combined coagulation-adsorption process, utilising DWTS as an adsorbent alongside alum coagulant, to address the persistent issue of dissolved natural organic matter (NOM) and turbidity removal. Our findings demonstrate that adding DWTS at a dose of 1.5 g/L effectively achieved simultaneous and significant removal of both NOM and turbidity. This integration remarkably reduced alum consumption by 46.15%, leading to more sustainable chemical usage. Furthermore, the presence of DWTS improved floc properties, evidenced by a substantial decrease in the sludge volume index (SVI) from 166.60 mL/mg to 70.40 mL/mg, and an 8.33% increase in the interface velocity of the formed flocs. This study uniquely highlights the dual benefit of DWTS in both enhancing coagulation efficiency and acting as an effective adsorbent. The combined process also significantly reduced the potential for trihalomethane formation (THMFP) by approximately 77.71%, directly addressing a critical public health concern related to disinfection by-products. This work establishes a robust framework for a circular economy in water treatment, offering a highly efficient and environmentally sound method for mitigating NOM and turbidity while valorising a waste stream.