Coal gasification wastewater (CGWW) is a typical toxic and refractory industrial wastewater. Here, a novel phenol and ammonia recovery process (IPE) was employed for CGWWpretreatment, and the coupled system assemble by the IPE process with A(2)/O system (IPE-A(2)/O) were operated to enhance the treatment performance of CGWW. The results showed that the IPE pre-treated effluent had a higher BOD5/COD ratio and lower refractory compounds compared to a typical process (MIBK). Subsequent A(2)/O biological treatment indicated that the A(2)/O-p system (A(2)/O system followed IPE process) obtained a higher average COD removal of 92% compared to 87.7% of the control (A(2)/O-m, A(2)/O system followed MIBK). The GC-MS analysis suggested that the content of alkanes in the IPE-A(2)/O effluent was lower than that of the MIBK-A(2)/O. The high-throughput sequencing revealed Levilinea, Alcaligenes, Acinetobacter, Thauera and Thiobacillus were the core genera in A(2)/O system. The genera Alcaligenes, Acinetobacter, Thauera and Thiobacillus in the degrading consortium were enriched in the A(2)/O-p system, leading to increased removals of organic pollutants and TN. These results suggested that the IPE process was a feasible pretreatment method, and the coupled IPE-A(2)/O system was an alternative technique for treating CGWW. (C) 2019 Published by Elsevier B.V.