Performance of the Full-scale Loop Hybrid Reactor Treating Coal[KH-*1] Gasification Wastewater under Different Recirculation Modes

Qian Zhao¹, Hongjun Han¹, Fang Fang¹and Wang Bing²

(1.State Key Laboratory of Urban Water Resource and Environment, Harbin Institute of Technology, Harbin 150090, China;2. School of Municipal and Environmental Engineering, Shenyang Jianzhu University, Shenyang 110168, China)



Abstract:

This paper aims to investigate the simultaneous removal efficiencies of both COD and nitrogen in a single reactor treating coal gasification wastewater (CGW). A novel loop hybrid reactor was developed and operated under different recirculation modes in order to achieve simultaneous removal of refractory compounds and total nitrogen (TN) in a full-scale CGW treatment plant. Mid-ditch recirculation was superior to other operational modes in terms of the NH₃-N and TN removal, resulting in a TN removal efficiency of 52.3%. Although the system achieved equal COD removal rates under different recirculation modes, hydrophobic acid (HPO-A) fraction of effluent dissolved organic matter (DOMef) in mid-ditch recirculation mode accounted for 35.7%, compared to the proportions of 59.2%, 45.3% and 39.4% for the other modes. The ultraviolet absorbance to dissolved organic carbon ratio test revealed that effluent under mid-ditch recirculation mode contained more non-aromatic hydrophilic components. Furthermore, appropriate recirculation and anoxic/oxic (A/O) partitions were also demonstrated to remove some refractory metabolites (phenols, alkanes, aniline, etc.), which reduced the chromaticity and improved the biodegradability.

Key words:  coal gasification wastewater  refractory COD  total nitrogen  recirculation mode  DOM fractionation

DOI£º10.11916/j.issn.1005-9113.2015.05.005

Clc Number:X703.1

Fund: