Impacts Of Activated Carbon Porosity Feature On The Removal And Microbiological Characteristics Of BAC

BAC in steady state mainly removes pollutants via microbial activities. During this process, the granular activated carbons serve as the foundation of biodegradation by supporting microbial colonization. A comprehensive comparative study was performed on BAC columns packed with different types of granular activated carbons to determine the effects of the porosity features of granular activated carbons on the colonization of microbes and the removal characteristics of BAC. The chosen granular activated carbons are composed of two newly developed activated carbons based on bamboo as well as three other activated carbons that are commonly used in drinking water treatment.Granular activated carbons all contain pores in 4 pore size ranges – micropores, mesopores, macropores and super macropores. It is beneficial for early bacteria adsorption to decrease the hydrophilicity and increase the volume of super macropores. The accumulation of biomass on granular activated carbon is controlled by the volumes of macropores, especially those whose diameters fall into the range of larger than 100μm. The average bioactivity decreases as the biomass increase. Under the same biomass, activated carbons containing more pores with diameters higher than 100μm are more bioactive. Pores on the activated carbon surface are little selective for microbial community structure, but add to richness and evenness when more pores larger than 100μm are contained.The BAC column containing more biomass and bioactivity removes more DOC from water, and less likely to be affected by high filtration rate and low temperature. BAC mainly removes organic matters of higher biodegradability(BDOC and AOC) and smaller molecular weights(<1k). The BAC with more biomass and bioactivity could remove them more efficiently. BAC could remove both the hydrophobic and hydrophilic organic fractions to similar extents. BAC could reduce florescence of organic matters. By increasing the biomass and bioactivity, a notable reduction in aromatic protein and fulvic acid-like can be expected. The removal of ammonia is a first-order reaction and its rate correlates with biomass and bioactivity on the granular activated carbon.One of the bamboo-based activated carbon(bamboo scrap activated carbon) show good performance in removing organic carbon and ammonia during the bench test because of its large volume of pores larger than 100μm and thus high biomass and bioactivity. This bamboo activated carbon was chosen as the filter for pilot scale test. During the pilot plant test, more biomass is accumulated on this bamboo activated carbon than the compared columner activated carbons already used for 1 and 3 years. The pilot plant columns show good performance in removing pollutants with CODMn and UV254 removed about 30-50%, and turbidity reduced by about 0.1NTU.