| A systematic study was conducted on the biodegradability of heterocycic com- pounds and polycycic aromatic hydrocarbons (PAHs) under laboratory conditions. Experimental results show that: (1) The principal refractory organics in the coke- plant wastewater are pyridine, biphenyl, etc. The degradation rate constandts (K)of these compounds are less than 10x1O-3L/gMLSS.h. (2) Most of the tested com- pounds cannot be served as the only carbon source under aerobic condition, on the contrary, some of them severely inhibit microorganisms. The aerobic biodegradabil- ities of these compounds are improved when phenol is introduced as the cosubstrate. The co-metabolism is the primary metabolism mechanism of these compounds. (3) The mono-hetero-cycic compounds with"hyper π electron structure", have a fair- ly good aerobic biodegradation performance. Comparatively, those with"π electron deficient structure" are reluctant. Condensed with bezene, the aerobic biodegradation performance of heterocyclic compounds is improved. The molecule connectivity in- dex 1Xv and frontier highest occupied molecular orbital energy EHOMO are two important parameters which are markedly correlated with the aerobic biodegradation perfor- mance of heterocycic compounds. The biodegradation rate constant K of heterocycic compound shows a multivariable linearity with 1Xv and EHOMO. (4) Most of the tested compounds, when using glucose as cosubstrate, have a fairly good biodegradation property under anaerobic condition. Among them, the PARs are ready to get acidi- fled, while mono-hetero-cycic compounds show a resistant trend to anaerobic con- version ,heterocycic compounds annelleted with benzene ring may lower the resistance. He Miao(Environmental Engineering) Directed by Gu Xiasheng and Thang Xiaojian...
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