臭氧对生物增强活性炭系统中菌群稳定性影响研究

为提高生物增强活性炭(BEAC)工艺的生物稳定性,进行臭氧工艺对固定的优势菌群稳定性的影响研究。结果表明,臭氧投加量1.5～2.5mg/L,接触时间大于10min时,可有效杀灭进水中的杂菌,且产生的余臭氧量(小于0.25mg/L)不会影响后续工艺中优势菌群的生物活性。通过对比臭氧—BEAC和单独BEAC工艺滤料表面菌群组成随运行时间的变化规律,臭氧—BEAC工艺优势菌在活性炭表面始终占主导地位,菌种组成及生态结构未发生改变,有较好的生物稳定性。单独BEAC工艺运行至6个月时,菌群组成发生较大变化,优势菌数量减少。通过扫描电镜观察,运行6个月的臭氧—BEAC炭上形成菌体重叠的菌团结构,并有较多未被生物覆盖的滤料表面和空缺的地方。单独BEAC工艺活性炭表面粗糙结构较少,被大量污染物与菌团相互包裹的颗粒所覆盖。

Effect of ozone process on stabilization of bacteria on bio-enhanced activated carbon system

To improve the biological stabilization of dominant bacteria immobilized in bio-enhanced activated carbon system(BEAC),the effect of ozone process was investigated in this paper.The results showed that the ozone was effective on killing bacteria existing in influent at the condition of 1.5～2.5 mg/L of the ozone dosage and more than 10 min of the oxidation time.The residual ozone content which was less than 0.25 mg/L did not affect the biological activity of the dominant bacteria.By comparing the ozone-BEAC process and only BEAC process,the composition of the bacteria in two BEAC systems were different due to the invasion of indigenous flora.After 6 months of operation,the dominant bacteria in ozone-BEAC system were stable without the variation of the bacteria composition and ecological structure.However,the indigenous flora was invaded in only BEAC system,dominant bacteria composition was variation and quantity was decreasing.The SEM photos showed that the dominant bacteria on the carbon surface of the ozone-BEAC process flourished to a great amount and the irregular porous structure could adsorb organic substances which supplied the nutrients for the growth of dominant microorganisms.And the carbon surface of the only BEAC process was covered by contaminants and bacteria with less irregular porous.