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| 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：10.11916/j.issn.1005-9113.2015.05.005 |
| Clc Number:X703.1 |
| Fund: |
