Study on treatment of coking wastewater by biofilm reactors combined with zero-valent iron process

• Published in: Journal of hazardous materials Vol. 162; no. 2; pp. 1423 - 1429
• Main Authors: Lai, Peng, Zhao, Hua-zhang, Zeng, Ming, Ni, Jin-ren
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 15.03.2009; Elsevier
• Subjects: Ammonia nitrogen (NH 3-N); Applied sciences; Biofilm; Biofilms; Bioreactors; Chemical oxygen demand (COD); Coke; Coking wastewater; Exact sciences and technology; General purification processes; Iron - chemistry; Microscopy, Electron, Scanning; Pollution; Wastewaters; Water treatment and pollution; Zero-valent iron (ZVI); Biofilm; Chemical oxygen demand (COD); Ammonia nitrogen (NH 3-N); Zero-valent iron (ZVI); Coking wastewater; Organic matter; Oxidation reduction; Biodegradability; Coagulation; Zerovalent metal; Nitrogen; Waste water; Refractory; Ammonia; Pollutant; Loading; Chemical oxygen demand; Ammonia nitrogen (NH3-N); Flocculation; Water quality; Integrated system; Physicochemical purification; Hydrophilic compound; Waste water purification
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2008.06.034

Experiments were conducted to investigate the behavior of the integrated system with biofilm reactors and zero-valent iron (ZVI) process for coking wastewater treatment. Particular attention was paid to the performance of the integrated system for removal of organic and inorganic nitrogen compounds. Maximal removal efficiencies of chemical oxygen demand (COD), ammonia nitrogen (NH 3-N) and total inorganic nitrogen (TIN) were up to 96.1, 99.2 and 92.3%, respectively. Moreover, it was found that some phenolic compounds were effectively removed. The refractory organic compounds were primarily removed in ZVI process of the integrated system. These compounds, with molecular weights either ranged 10,000–30,000 Da or 0–2000 Da, were mainly the humic acid (HA) and hydrophilic (HyI) compounds. Oxidation–reduction and coagulation were the main removal mechanisms in ZVI process, which could enhance the biodegradability of the system effluent. Furthermore, the integrated system showed a rapid recovery performance against the sudden loading shock and remained high efficiencies for pollutants removal. Overall, the integrated system was proved feasible for coking wastewater treatment in practical applications.