| Black-odorous river that has a greatly influence on our senses,production,business and our lives becomes one of the most prominent water environmental problem.The physical and chemical methods is commonly used for remediation black-odorous river.These methods need a high cost,and disturbs the balance of water bodyalso,and can cause secondary pollution.Microbial remediation trchnology has attracted general concern for its high efficiency,low cost,easy operation and non-secondary pollution.It is found that the single microbial remediation technology has difficulty achieving the better treatment,but the combined remediation technology has higher efficient treatment and practicability.Therefore,in order to meet the equirements of in-situ remediation in black-odorous river,the in-situ remediation black-odorous river by aeration enhancing functional strains was researched.It is hoped that results will be used for remediation in urban black-odorous river and applied within limits.The research firstly slected the indigenous functional bacteria which was able to degrade the organic matters from the sediment of black-odorous river.Second,the strains were primarily identified.Third,the degradation conditions and mechanism of the strain HC-60 was researched.At last,the indigenous functional bacteria and aeration were combined,the appropriate aeration mode was optimized by the pollutant remediation effects of overlying water and sediment.The main conclusions are as follows:(1)64 strains that could use degrading organic matters as the carbon and energy source were isolated from the sediment of rivers and lakes in Chengdu.According to the degradation rate of the organic matters in sediment,the research isolated 3 strains which had high ability in degrading organic matters.The strains were named as HC-8,HC-25 and HC-60.Their morphological,physiological,biochemical and 16 S rDNA gene sequences were analyzed,the results showed that the colony morphology of HC-8 was white and rounded,and the HC-8 was Gram-positive,oxidase-positive and catalase-positive,methyl red experiment was negative,cellulolytic experiment was negative,it was identified as Acidovorax;the colony morphology of HC-25 was light orange and globose,and the HC-8 was Gram-positive,oxidase-negative and catalase-positive,methyl red experiment was positive,cellulolytic experiment was negative,it was identified as Exiguobacterium;the colony morphology of HC-60 was white and baculiform,and the HC-8 was Gram-negative,oxidase-negative and catalase-positive,methyl red experiment was negative,cellulolytic experiment was negative,it was identified as Acinetobacter;(2)The effect of the indigenous functional bacteria HC-60 degrading organic matter such as dosage of the stain,initial pH,reaction temperature was researched.The research initially determined the optimum temperature that was 25~30℃,the optimum pH that was 6~8,the optimum dosage that was 1~1.5% by single factor experiment.By the Box-Behnken experimental design and response surface method,it was confirmed that the optimum temperature that was 26.4℃,the optimum pH that was 7.7,the optimum dosage that was 1.2%.The function of Oxygen,indigenous flora and indigenous functional bacteria HC-60 in egrading organic matter was researched,the experimental results showed that the organic matter could not be degraded by oxygen directly,it could be degraded by the microorganism.It was more easily for indigenous bacteria to use micromolecule organics.The HC-60 was able to change PAHs into micromolecule organics by co-metabolism.The degradation of organic matter was significantly improved.(3)The research used the method that was aeration enhancing functional strains to remedy black-odorous river,the experimental results showed that the removal rates of CODCr and NH3-N were respectively were climbed to 32.4% and 21.1% by using aerating sediments.After 7 days of experiment,the CODCr was dipped to 20mg/L,the NH3-N was dipped to 10mg/L,the TP was dipped to 0.2mg/L,the water quality of the groove improved,the degradation speed of the organic matters in sediment increased thirty per.The remediation effects of intermitent aeration was close to continuous aeration.The method of aerating sediments and adding HC-60 of indigenous functional bacteria should be adopted base on saving energy and reducing costs. |
