title: Physicochemical and thermal characteristics of the sludge produced after thermochemical treatment of petrochemical wastewater.
abstract: The present work describes the physicochemical and thermal characteristics of the sludge generated after thermochemical treatment of wastewater from a petrochemical plant manufacturing purified terephthalic acid (PTA). Although FeCl3 was found to be more effective than CuSO4 in removing COD from wastewater, the settling and filtration characteristics of FeCl3 sludge were poorer. Addition of cationic polyacrylamide (CPAA; 0.050kg/m3) to the FeCl3 wastewater system greatly improved the values of the filter characteristics of specific cake resistance (1.2 x 10(8) m/kg) and resistance of filter medium (9.9 x 10(8) m(-1)) from the earlier values of 1.9 x 10(9) m/kg and 1.7 x 10(8) m(-1), respectively. SEM-EDAX and FTIR studies were undertaken, to understand the sludge structure and composition, respectively. The moisture distribution in the CuSO4 sludge, FeCl3 sludge and FeCl3 + CPAA sludge showed that the amount of bound water content in the CuSO4 and FeCl3 + CPAA sludges is less than that of the FeCl3 sludge and there was a significant reduction in the solid-water bond strength of FeCl3 + CPAA sludge, which was responsible for better settling and filtration characteristics. Due to the hazardous nature of the sludge, land application is not a possible route of disposal. The thermal degradation behaviour of the sludge was studied for its possible use as a co-fuel. The studies showed that degradation behaviour of the sludge was exothermic in nature. Because of the exothermic nature of the sludge, it can be used in making fuel briquettes or it can be disposed of via wet air oxidation.
authors.affiliation: Department of Chemical Engineering, Indian Institute of Technology, Roorkee 247667, India.
authors.forename: Shilpi
authors.initials: S
authors.lastname: Verma
authors.forename: Basheshwar
authors.initials: B
authors.lastname: Prasad
authors.forename: I M
authors.initials: IM
authors.lastname: Mishra
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D057919:Biological Oxygen Demand Analysis; D019327:Copper Sulfate / Q000737:chemistry; D019652:Extraction and Processing Industry; D005296:Ferrous Compounds / Q000737:chemistry; D005374:Filtration; D007220:Industrial Waste; D008855:Microscopy, Electron, Scanning; D010795:Phthalic Acids / Q000737:chemistry; D012722:Sewage / Q000737:chemistry*; D017550:Spectroscopy, Fourier Transform Infrared; D014865:Waste Disposal, Fluid / Q000379:methods*; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D019327:Copper Sulfate; D005296:Ferrous Compounds; D007220:Industrial Waste; D010795:Phthalic Acids; D012722:Sewage; D000099166:Polyacrylamides; C011363:terephthalic acid; C029451:ferrous chloride