Synthesis, characterization and application of dewatered municipal sludge-based creamsite and its phosphorus adsorption characteristics

Authors：Qin, Jiafu; Zhu, Zijian; Chen, Zhenguo; Wang, Xiaojun^*; Zhang, Yangzhong; Chen, Haochuan

Source：JOURNAL OF CLEANER PRODUCTION, 2023, 391: 136216.

DOI：10.1016/j.jclepro.2023.136216

• Phosphorus recovery
• Dewatered sludge
• Ceramsite
• Column studies

Direct utilization of sludge-based biochar for phosphorus recovery exists numerous deficiencies (secondary pollution, poor stability, etc.). This study further explored dewatered sludge/bentonite ceramsite application for large-scale use of sludge-based biochar with low potential environmental risk. The best parameters for optimized ceramsite (SBC 900) were concluded as follows: mass ratio (dewatered sludge: bentonite: kaolin: starch) was 5:5:2:2 with 5% Na2SiO3, preheating temperature = 400 degrees C, sintering temperature = 900 degrees C. Batch experiments show that the optimized ceramsite could significantly remove phosphorus (Qe: 4.29 mg g-1) in a wide pH range (4-10). Column studies with quantitative analysis demonstrated that SBC 900 as fillings could effectively control phosphorus effluent during advanced treatment process. Breakthrough curves of SBC 900 from column experi-ments were described well by Thomas model (QT: 0.3691 mg g-1) and Yan model (QY: 0.1417 mg g-1). Compared to other factors, human acid (HA) is the key factor restricting advanced treatment of secondary effluent. Saturated ceramsite could be simply separated for subsequent utilization (fertilizer or building mate-rials) to shift solid wastes toward marketable resources. This study provided another safer sludge resource uti-lization and effluent advanced treatment view which could be a beneficial and sustainable solution for sludge reclamation.