| Combined process of hydrolytic acidification (HAT)—sequencing batch reactor (SBR)—biological aerated filter (BAF) was used to upgrade an existing Chinese traditional medicine wastewater station. Technological renovation of the manufacture processes, characteristics of the wastewater and the current treatment status were analyzed and taken into account in this investigation. Considering the factors such as reaction time, temperature, pH value, this investigation studied the effect of aeration time of SBR, temperature of SBR, pH value of the raw wastewater on the performance of the HAT—SBR—BAF system treating Chinese traditional medicine wastewater and suggested the optimum operational parameters of the system.The results of the study are as flows:(1) The starting of HAT—SBR—BAF reactor can be completed in 15 days and the COD removal efficiency was about 91%.(2) BOD5/COD (Five-day Biochemical Oxygen Demand/Chemical Oxygen Demand) value of the Chinese traditional medicine wastewater is improved from 0.16-0.20 to 0.39-0.43 and a good hydrolytic acidification purpose is reached when using anaerobic SBR to simulate hydrolytic acidification tank.(3) The HAT—SBR—BAF process has a strong resistance to the variety of COD loading, pH value, temperature when the Chinese traditional medicine wastewater was treated with the process. Among the factors of aeration time of SBR, temperature of SBR, pH value of the wastewater, aeration time of SBR has the most influence on the HAT—SBR—BAF system treating Chinese traditional medicine wastewater. The treatment efficiency comes to the best when aeration time of SBR is 18 h, but is not much better than it when aeration time of SBR is 14 h. The treatment efficiency comes to the best when pH value of the wastewater is 7.0. The treatment efficiency comes to the best when temperature of SBR is 30℃. Based on overall consideration of various factors, the condition of process is chosen that aeration time of SBR is 14 h, pH value of the wastewater is 7.0, temperature of SBR is 20℃(4) When the aeration time of SBR, temperature of SBR, pH value of the wastewater were 14 h,20℃, and 7.0, respectively, and. when COD, BOD5, SS, chroma in the influent of the system were 1249.4-1444.5 mg/L,201.2-292.8 mg/L, 209-311 mg/L,70-100 times, respectively, COD, BOD5, SS, chroma of the effluent were 123.4-140.8 mg/L,19.4-26.1 mg/L,33-61 mg/L,36-50 times, the average removal efficiency of COD, BOD5, SS, chroma, was 90.3%,90.6%,81.8%,44.0%, respectively. The water quality of the effluent from the process achieved the second grade of the National Integrated Wastewater Discharge Standards (GB8978-1996). At this point, the processing of each unit are as follows. COD, BOD5 in the effuent of HAT tank were 1074.1-1257.3 mg/L,458-523.4, respectively; COD in the effuent of SBR tank was 247.1-319.6 mg/L; the average removal efficiency of COD of HAT tank, SBR tank, BAF tank was 12.6%,76.6%,52.4%, respectively.(5) Optimum operational parameters of HAT—SBR—BAF system treating Chinese traditional medicine wastewater are suggested as follows. The pH value of the wastewater is 7.0; COD volume loading rate of each unit of HAT, SBR, BAF are 9.9,1.1,0.34 kgCOD/m3·d when they are calculated according to the amount of influent contaminant, and 1.2,0.82,0.18 kgCOD/m3·d (BAF volume loading rate for the filter media) when they are calculated according to the amount of removal contaminant, respectively; COD sludge loading rate of each unit of HAT, SBR are 3.3, 0.36 kgCOD/kgMLSS·d when they are calculated according to the amount of influent contaminant, and 0.41,0.27 kgCOD/kgMLSS·d when they are calculated according to the amount of removal contaminant, respectively; Hydraulic retention time (HRT) of each unit of HAT, SBR, BAF are 3.3 h,26.4 h,19.6 h (BAF hydraulic retention time for the empty tower retention time of filter media), respectively, and the value of the system is 19.6 h.(6) Coagulation pretreatment of Chinese traditional medicine wastewater showed that when the dosage of PAM was 2 mg/L, rapid stirring time was 30 s, slow stirring time was 10 min, the precipitation time was 15 min, respectively, the optimum dosage of PAC was 240 mg/L, the optimum pH value was 7-8, the best COD removal efficiency was 27.2%, respectively; the optimum dosage of PFS was 300 mg/L, the optimum pH value was 9, the best COD removal efficiency was 24.9%, respectively.The results show that the combined process of HAT—SBR—BAF is feasible for treatment of the Chinese traditional medicine wastewater. It can be used in practice, but also provides a valuable reference for other Chinese traditional medicine wastewater treatment.
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