Comparative Study On The Water Treatment Effect And Phenol Pollution Emergency Treatment Between O₃-BAC And Aeration-BAC Filter

Biological activated carbon process is an effective advanced drinking water treatmentprocess for micro-polluted source water. As the common biological activated carbon filtertechnology, both ozone-BAC process and aeration-BAC process have been widely studiedand applied at home and abroad. In recent years, the quality of the source water isdeteriorating, and the frequency of the water pollution incident especially for the organicpollution is increasing, seriously threatening the urban water supply safety. This research wasconducted to study the effect of water purification by the ozone-BAC process and theaeration-BAC process for normal pollutants. Simultaneously, the phenol which was dangerousand occurring frequently in water was selected as the object to study the emergency treatmentability of phenol pollution by the two processes. The various factors influencing the removalrate of phenol were also deeply discussed. The study results show:（1）The average removal rates of CODMn、turbidity and NH4+-N are37.5%、54.8%and78.4%respectively by ozone-BAC process, while40.9%、35.7%and91.8%respectively byaeration-BAC process. The aeration before carbon filter increases the dissolved oxygen andoxygen transfer efficiency, as well as promotes the growth of biofilm. As a result,aeration-BAC process has a better removal efficiency of easily biodegradable dissolvedorganics and ammonia nitrogen than ozone-BAC process.（2）The tested water is the water to be filtered, In the water being treated by the twoprocesses of O3-BAC and aeration-BAC, the percentage of organic matters lower than1KDa MW exceeds50%, mainly based on UV254value as token of organic matters. Theaeration-BAC process was prone to remove UV254with MW lower than1KDa, while a greatcomplementary removal of UV254with different MW was attained by ozone-BAC filter,UV254removal rate of which was up to55.3%. Adding ozone can improve removal effect ofUV254which belongs to a kind of macromolecular refractory organics. However, when theactivated carbon contacted with ozone for a long time, the ozone would destroy the surfacestructure of activated carbon, reducing the absorption capacity as a result. （3）In response to the phenol pollution,5times phenol initial concentration can betreated to meet the drinking water sanitary standard(GB5749-2006) by ozone-BAC filter,while2times phenol initial concentration by aeration-BAC filter. Therefore, phenolemergency treatment ability of aeration-BAC filter is limited. In an emergency of phenol athigh initial concentration, aeration-BAC filter needs to combine with other emergencytreatment technology. After adding the phenol, the removal rate of CODMnand turbidity werereduced.（4）Filtering velocity and ozone dosage are the key factors of phenol removal byozone-BAC filter, while the pH of BAC filter influent has a little influence. However, filteringvelocity is the key factor of phenol removal of aeration-BAC filter, the pH and air strippingcan be ignored.（5）After the simulation treatment of phenol pollution, the iodine value, the methyleneblue value and the phenol adsorption of active carbon all decrease in the ozone-BAC filter andaeration-BAC filter. But the decline in the aeration-BAC is less than that in the ozone-BACfilter.