Study On Experimental Treatment Of Caffeine Pharmaceutial Wastewater

By analysising the characteristics of caffeine pharmaceutial wastewater, whichcontains high COD, high ammonia, and poor wastewater biodegradability,“Fe-Cmicro-electrolysis-UASB-MBR” processes were used to treat it. The main results wereshown as following:1）Fe-C micro-electrolysis pretreatment for caffeine pharmaceutical wastewater hasachieved good results. The optimal operational conditions were determined as the initialpH value of4.0, the volume ratio of Fe, C of2:2and reaction time of105min. In theoptimal operational conditions, the results were the concentration of COD decreased from16500mg/L to9549mg/L, the removal rate reached to40.5%. The concentration ofammonia decreased from650mg/L to396mg/L, the removal rate reached to36.9%. ThepH value increased from4to5.4. The pretreatment enhanced the biodegradability of thecaffeine pharmaceutical wastewater.2）The UASB reacter was used to treat caffeine pharmaceutical wastewater, andobtained good results. The best conditions for UASB treatment of caffeine pharmaceuticalwastewater were: the HRT was24, the volume loading rate was8kgCOD/(m~3·d). Underthe best conditions above, the concentration of COD decreased from8000mg/L to1100mg/L and the removal rate of COD was85%. The concentration of effluent ammonia was250~300mg/L. The biogas production was4L everyday. In the volume loading rate of9.5kgCOD/(m~3·d), the reactor took place acidification. The reason may be: on the onehand, the reactor operated overload. The VFA accumulation exceed more than600mg/L,and the ractor occurred acidification. On the other hand, the concentration of ammoniasurpassed300mg/L and inhibited the methanogenic bacteria.3）The optimal operational conditions of MBR was: the HRT was12, the volumeloading rate was2.2kgCOD/(m~3·d), the MLSS concentration was7000mg/L. Under thebest conditions above, the membrane was washed every five days. The concentration ofCOD decreased from1100mg/L to80mg/L, the removal rate reached to93%. Theconcentration of ammonia decreased from270mg/L to18mg/L, the removal rate reachedto93%. The effluent quality met the required standards.