Abstract:

The wastewater discharged from a highly-intensive chemical industrial park area has the characteristics of strong concentration, high colourity, frequent variability and difficulty of biodegradation. A novel anaerobic reactor—jet biogas inter-loop anaerobic fluidized bed (JBILAFB) was self-designed and fabricated for the pre-treatment of complex chemical organic wastewater. The designed capacity of the reactor was 24 m³·d-1. Zero-valent iron was used as biological catalyst in the reactor. During the wastewater pre-treatment, the mechanism of the catalytic deoxidation process was discussed and the technological parameter of the JBILAFB was obtained. The results showed that the active circulation of biogas and wastewater in the JBILAFB with the jet mode could maintain good contact and mass transfer of biological catalyst, active carbon, anaerobic sludge and wastewater. Anaerobic biological pre-treatment effect was enhanced with hydrogen generation, flocculating deposition and nourishment supply during the catalytic deoxidation process of zero-valent iron granules. When the volume loading rate (VLR) and influent colourity were 0. 874—2. 996 kg COD·m^-3·d^-1and 250—2000 times respectively, the colourity and COD average removal rate of the JBILAFB could reach about 26. 2% and 70. 8% with the recycle ratio in the JBILAFB, environmental temperature and hydraulic retain time (HRT) being 2, 23—34℃ and 12—24 h respectively. Moreover, the effluent pH was maintained at 6—8 and the average BOD/COD of wastewater increased from 0. 26±0. 04 to 0. 43±0. 03. Organic pollutant was partially removed and biodegradation of wastewater was improved obviously during the catalysis deoxidation process. The JBILAFB reactor and process offered a highly efficient technology for the pre-treatment of complex chemical organic wastewater.