The characteristics and application of sludge-fly ash ceramic particles (SFCP) as novel filter media

Ceramsite production from sediment in Beian River: characterization and parameter optimization

In order to realize pollution control and resource recovery, sediment from Beian River in Mudanjiang City China was used for ceramsite production. The maximum content of total nitrogen (TN), total phosphorus (TP) and organic matter (OM) in sediments of Beian River were 2975 mg kg^-1, 2947 mg kg^-1 and 29.6%, respectively. So, it should be treated properly for resource utilization. The orthogonal experiment of L ₁₆ (4⁵) was adopted to determine the best conditions for ceramsite production and the result demonstrated that the sewage sludge ratio of 15%, binder ratio of 5%, pre-heating temperature of 450°C, sintering temperature of 1150°C and firing time of 23 min were the optimum conditions. The corresponding product met with the standard of CJ/T 299-2008 and the heavy metal leaching experiment showed it was lower than the threshold of China's industrial standard. Thus, it demonstrated that ceramsite production was a feasible way for utilization of sediment.

Application for oxytetracycline wastewater pretreatment by Fe-C-Ni catalytic cathodic-anodic-electrolysis granular fillers from rare-earth tailings

Fe-C-Ni catalytic cathodic-anodic-electrolysis granular fillers (REGF) coupled with a reactor was studied for oxytetracycline (OTC) wastewater pretreatment. In this study, the REGF were manufactured from the rare-earth tailing (RET), powdered activated carbon (PAC), scrap iron and nickel by balling and calcining. The REGF was characterized by X-Ray Diffraction and Scanning Electron Microscope analysis. The influences of pH value (2-7), OTC concentrations, hydraulic retention time and aeration on the removal efficiency of OTC and total organic carbon (TOC) were studied. This system had good removal efficiency of TOC of 80.0% and OTC of 98.2% under the optimal conditions, which were influent pH of 3, aeration rate of 0 mg L^-1, and HRT of 3 h. After running for 50 d, the REGF did not become hardened and the ability of reaction was more lasting. The system was back-washed by acid solution (pH = 1) in the 25th day. The removal mechanisms were electrophoresis, redox and flocculation. The nickel, which was as the catalyst, was added into REGF to enhance the reduction of pollution with the absorbed atomic hydrogen. This paper provides a way for the recycle of the rare earth tailings and an effective application for wastewater.

Enhanced phosphorus and ciprofloxacin removal in a modified BAF system by configuring Fe-C micro electrolysis: Investigation on pollutants removal and degradation mechanisms

A modified biological aerated filter (BAF) system configured Fe-C micro electrolysis was applied to enhance phosphorus and ciprofloxacin (CIP) removal. A novel sludge ceramic and sintering ferric-carbon ceramic (SFC) were separately packed into a lab-scale BAF and Fe-C micro electrolysis reactor. The BAF and Fe-C micro electrolysis coupled system was operated about 230days. The enhancement of phosphorus and ciprofloxacin removals by Fe-C micro electrolysis, the degradation mechanisms of CIP and the variations of microbial population were investigated. The removal efficiencies of chemical oxygen demand (COD_cr), ammonia (NH₄-N), total phosphorus (TP) and CIP reached about 95%, 95%, 80% and 85% in the combined process, respectively. Configuring Fe-C micro electrolysis significantly enhanced phosphorus and CIP removal, whereas had no promotion on N removal. Four main degradation pathways were proposed according to the LC-MS analysis. More than 12 degradation products were detected through the treatment of Fe-C micro electrolysis and only 3 biodegraded products with low concentration were identified in BAF effluent. The high-throughput sequencing analysis showed that the microbial community changed a lot under CIP pressure. The relative abundance of Sphingomonadaceae, Xanthomonadaceae, Bradyrhizobium, Helicobacter and Pseudomonas increased with CIP influent. This study provides a promising process in CIP wastewater treatment.

A performance evaluation of a new iron oxide-based porous ceramsite (IPC) in biological aerated filters

A novel medium containing iron oxide-based porous ceramsite (IPC) and commercial ceramsite (CC) was used in two laboratory-scale upflow biological aerated filters (BAFs) to treat city wastewater to compare their efficacy in wastewater treatment. The IPC BAF and CC BAF were operated in water at 20-26°C, an air/water (A/W) ratio of: 3:1 and hydraulic retention times (HRTs) of 7, 3.5, 1.75, and 0.5 h and the removal of ammonia nitrogen (NH₃-N), total nitrogen (TN), total organic carbon (TOC), and phosphorus (P) were studied. Our results indicated that IPC BAF was superior to CC BAF in terms of TOC, TN, NH₃-N, and P removal. IPC had higher total porosity and larger total surface area than CC. The interconnected porous structure of IPC was suitable to microbial growth, protozoan, and metazoan organisms were primarily found in the accumulated biofilm layer. Biomass, in the biofilm layer, was detected at three distinct distances (300, 900, and 1500 mm) from the bottom of the inlet filter, again indicating that the IPC was more suitable for biomass growth. The presence of biomass improves the simultaneous removal efficiency of nitrogen and phosphorus in the IPC BAF. Thus, our findings support IPC as a material for use in filter media in wastewater treatment BAFs.

Performance and characterization of a non-sintered zeolite porous filter for the simultaneous removal of nitrogen and phosphorus in a biological aerated filter (BAF)

A novel non-sintered zeolite porous filter (ZPF) and commercially available ceramsite (CAC) are used to investigate the simultaneous removal of nitrogen and phosphorus from city wastewater treated by biological aerated filter (BAF) reactors.