The Effect Of Different Cultivation Conditions On The Activity Of Eosinophilic Iron Oxide Biofilms

Due to its special metabolic mode,acidophilic ferric oxide bacteria have achieved remarkable application effects in the fields of bio-metallurgy,valuable metal recovery of waste electrical appliances,heavy metals removal of municipal sludge and contaminated soil nuclides,but at the same time,there are also problems such as bacterial activity,poor bacterial density,influence of organic matter and blockage caused by precipitation.The main content of this paper is divided into two parts :(1)the hanging film of the carrier of the same specification under the 9K culture,and the subsequent batch test of the biofilm in different hanging film stages under the conditions of the number of revolutions,sponge gradient,tail-liquid concentration and other environmental influences;(2)the hanging film of carriers of different specifications in the tail-liquid culture environment,and the subsequent tests of pH,acetic acid,methanol and glucose conditions on the biofilm of carriers of different specifications.The results of membrane hanging test in 9K culture environment are as follows :(1)the longer the membrane hanging time,the biofilm can withstand the oxygen supply mode of higher revolution;(2))the longer the biofilm is hung on the membrane,the metabolites produced in the process of membrane formation will hinder the mass transfer channels inside the carrier,making its oxidation rate slow down;(3)the longer the hanging time of biofilm,the protective effect of biofilm shortens the adaptation period of oxidation cycle under the tailings concentration of 20% and 30%.The results of membrane hanging test in the tailings culture environment are as follows:(1)the experiment under the pH condition shows that,with the decrease of pH,Eh shows a trend of first rising and then falling.During the process of decline,the oxidation column of Z1(the smallest volume of the internal filling carrier)first showed a downward trend,and the lowest acid resistance limit of acidophilic ferric oxidation bacteria was up to pH0.25.(2)experimental results under acetic acid conditions showed that,due to the "cumulative effect" of acetic acid's special inhibition mode,Eh decline appeared in the oxidation column of Z2(medium internal filling carrier volume).At the same time,7mmol/L was the inhibitory concentration of acidophilic ferric oxide bacteria.(3)the test results under methanol condition showed that: the Eh decline of Z2 oxidation column first appeared(the reason was the same as before),and the large amount of precipitation in the tail liquid system caused by methanol addition would adversely affect the stability of Eh value during mass transfer in biofilm and rejuvenation and the operation of oxidation column.(4)the experimental results show that under the condition of glucose in the culture system of open,10 tendency/L glucose concentration under the condition of glucose for energy with heterotrophic microorganisms multiply,eosinophilic clear the formation of iron oxide to competitive advantage,at the same time because of heterotrophic microbial biofilm is not easy to decompose and non-uniformity of the hanging membrane positions,will lead to partial oxidation column in the biofilm activity cannot recover.