Regeneration of Ti Coagulants from Water Treatment Sludge Using acid Leaching: Efficiency in Turbidity and Pollutant Removal

• Published in: Water, air, and soil pollution air, and soil pollution, 2024-11, Vol.235 (11), p.695, Article 695
• Main Authors: Bu, Shiyao, Xu, Xia, Guo, Jun, Su, Xiaozan, Zhang, Shenjie, Jiang, Chao, Yang, Yongqiang, Ni, Tengya
• Format: Article
• Language: English
• Subjects: Acidification; Atmospheric Protection/Air Quality Control/Air Pollution; Climate Change/Climate Change Impacts; Coagulants; Domestic wastewater; Earth and Environmental Science; Environment; Hydrogeology; Leaching; Organic matter; Organic phosphorus; Phosphorus; Pollutant removal; Pollutants; Regeneration (biological); Sludge; Sludge utilization; Soil Science & Conservation; Sulfuric acid; Sulphuric acid; Turbidity; Wastewater; Wastewater treatment; Water pollution; Water purification; Water Quality/Water Pollution; Water reuse; Water treatment; Xerogels
• ISSN: 0049-6979; 1573-2932
• DOI: 10.1007/s11270-024-07496-5

The primary obstacle in transitioning Ti coagulants from the experimental to the practical realm is their exorbitant application costs. To address this challenge, this research introduced an innovative recovery process through acidification of water treatment sludge to produce regenerated Ti coagulants, optimizing sludge utilization. The efficiency of the regenerated coagulants was evaluated by simulating turbidity removal from wastewater. The results showed that the three Ti coagulants exhibited effective turbidity removal at elevated H 2 SO 4 concentrations. In a turbidity experiment with baseline turbidity of 15 ± 0.5 NTU, a notable change in turbidity removal was observed at a coagulant concentration of 5 mg Ti/L and H 2 SO 4 concentration of 10 ml/L. As the coagulant dosage increased, the inflection point tended to move to a higher level. Furthermore, the versatility of the acidification process was evaluated using two distinct types of actual water. The pollutants in the actual water showed significant improvement. Among the three kinds of Ti regenerated coagulants used to remove turbidity from lake water, the remaining turbidity was consistently less than 5 NTU. The acidized supernatants of titanium xerogel coagulant (TXC (As) ) exhibited a turbidity value of only 1.99 ± 0.1 NTU. Additionally, the removal of turbidity from domestic wastewater was 80%. Notably, these results showed superior performance in reducing organic matter and phosphorus levels, thereby showcasing their exceptional purification capabilities compared to commercial coagulants. This research presents a viable methodology for the sustainable reuse of Ti water treatment sludge. Graphical Abstract