| The pharmaceutical wastewater has the problems of high concentration of organic matters, high toxicity and less-biodegradable. According to the characteristics of pharmaceutical wastewater, taking chemical raw medicine wastewater from a certain pharmaceutical chemical limited company in Chongqing to be the subject investigated, the Ferric-carbon Micro-Electrolysis was put forward to undertake the pretreatment process, which was aimed to empolder the technique of pharmaceutical wastewater treatment with high efficiency and low energy consume. The factors effected treatment efficiency of the sequence batch equipment of Ferric-carbon Micro-Electrolysis and the aerated Ferric-carbon Micro-Electrolysis filter were investigated systematically, and the optimum running condition were obtained. Through orthogonal experiment, the comprehensive influence produced by pH value, Fe/C volume ratio, reaction time, aeration rate and the load were discussed. Meanwhile, aiming at the practical problem which were existent in the motion of the Ferric-carbon Micro-Electrolysis, this paper put forward the retentive treatment performance technology, the effluent pH control technology and the multi-stage technology of Ferric-carbon Micro-Electrolysis, and obtained the key process parameters. Also investigated the nitrate removal efficiency by Ferric-carbon Micro-Electrolysis, through the research on combined process of hydrolytic acidification–ASBBR–SBBR, the discharge to reach standard of pharmaceutical wastewater was realized. The main conclusions are as follows:1)The experimental results of the sequence batch equipment of Ferric-carbon Micro-Electrolysis indicates that: under the condition of pH=3, Fe/C volume ratio=1:1, particle size of Fe and C is 16 items, the load is 175.5kgCOD/(m3·d), gas-water ratio is 10:1, reaction time is 2h, when the influent COD and chroma are 19000mg/L and 600 times respectively, the effluent COD was decreased to 8490 mg/L, with 55.29% removal rate, and the effluent chroma was 20 times, with 96.67% removal rate. Orthogonal experiment results shows that the degree of influence on treating performance were in sequence of pH value>reaction time>Fe/C volume ratio, the load and the aeration rate had no significant influence. The Orthogonal experiment regression equation of the integrated effect of pH value, Fe/C volume ratio and reaction time is:η=99.21-14.07pH+25.59T-36.99Fe/C-2.39(pH)·(T)+5.43(pH)·(Fe/C)(%) 2)The experimental results of the Ferric-carbon Micro-Electrolysis filter indicates that: under the condition of pH=3, Fe/C volume ratio=1:1, the load is 192kgCOD/(m3·d), gas-water ratio is 10:1, reaction time is 2h, there is a good removal effect about COD and chroma, with 62.84% and 96.67% removal rate, respectively. Orthogonal experiment results shows that the degree of influence on treating performance were in sequence of pH value>reaction time>Fe/C volume ratio> gas-water ratio, the load had no significant influence. The Orthogonal experiment regression equation of the integrated effect of pH value, Fe/C volume ratio, reaction time and aeration rate is:η=0.55+5.12pH+16.31T+3.26Fe/C+0.51β- 0.53(pH)·(T)-3.64(pH)·(Fe/C)-0.05(pH)·(β)(%)The sequence batch equipment of Ferric-carbon Micro-Electrolysis and the aerated Ferric-carbon Micro-Electrolysis filter can improve biodegradability of the wastewater remarkably, the effluent B/C value increased from 0.19 to 0.50 above, resulting in the benefit to the follow-up biological treatment.3)The results show that: running state of Ferric-carbon Micro-Electrolysis can be divided into active section, stable section and attenuation section, through activation and backwashing using 3% dilute hydrochloric acid, the system performance can be recovered from attenuation section to stable section. Maintenance operation cycle is general 10d, the system can maintain the performance by cleaning and regeneration. When regulating the effluent pH to 8, the COD removal rate of system reach 55.70%, increased 25.95% compared to the system which have no pH regulating technology. Toward the refractory wastewater, multi-stage Micro-Electrolysis system is an efficient path of improving treatment efficiency, two stage system achieve 61.80% COD removal rate compared to single stage system.4)The experiment results of nitrate removal by Ferric-carbon Micro-Electrolysis shows that: under the condition of particle size of Fe and C is 35 items, pH value is 3, Fe/C volume ratio is 3:1, gas-water ratio is 5:1, reaction time is 1.5h, the removal rate of nitrate reach 50.82%, the NO3--N is decreased form 793mg/L to 390mg/L.5 ) When the influent COD, NO3--N and chroma are 20000~22500mg/L, 750~853mg/L and 800~900 times respectively, the combined process reduce the effluent COD, NO3--N and chroma to 143~200mg/L, 12~17mg/L and 5~20times, respectively, total removal rate are 99.16%, 98.13, 98.82% respectively, reach the secondary standard of the types of chemical raw medicine in comprehensive discharge standard of sewage.
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