Study On Quick Start-up Of Enhancing Sludge Granulation In Uasb Reactors By Iron

Two hydraulic circulating upflow anaerobic sludge blanket(UASB) reactors are used in this issue,which are the same in structure and in size.In the beginning of start-up of reactors,a concerntration of 300mg/L iron chloride is put in one of reactors(R1) in one-off to research the influence which the ferric ion caurse to sludge granulation.Two reactors had been running for 78 days to reasearch the influence of sludge granlation after the ferric ion was added.1.The removal rate of R1 which added in ferric ion is genearlly higher than R2 which is not added.Most of time the COD_Cr removal rate of R1 is above 80%,sometimes rearched 90%,but the COD_Cr removal rate of R2 is always between 75%and 80%.2.The volume load of R1 which added in ferric ion is faster improved than R2 which is not added.When the volume load of R1 reachs 6.3 kgCOD_Cr/(m³·d),the volume load of R2 just reachs 5.0 kgCOD_Cr/(m³·d).And when the experiment is end, the volume load of R1 reachs 10.0 kgCOD_Cr/(m³·d),while the volume load of R2 just reachs 7.0 kgCOD_Cr/(m³·d).3.R1 is earlier than R2 in sludge granlation.When R1 rearched 5.0 kgCOD_Cr/(m³·d) in the 46th day,while R2 rearched there in the 58th day.At the end of experment of the 78th day,R1 rearchs 10.0 kgCOD_Cr/(m³·d).At the same time,R2 just rearches 7.0 kgCOD_Cr/(m³·d) where R1 rearched before 15days.So R1 is earlier than R2 for at least 15 days in sludge granulation.Meanwhile,the influence of controling pH and aklalinity is also been reasearched1.In anaerobic system,methanogen is sensitive to the changing of pH.So the suitable range of pH for methanogen decide the controlling range of pH in reactor.The most suitable range of pH for methanogen is between 6.5 and 7.8.2.When the aklainity is controlled above 1000mg/L,the reactors run well and never turn acidizing.