A review: organic matter and ammonia removal by biological activated carbon filtration for water and wastewater treatment

摘要

Biological activated carbon filters provide solutions to remove organic matter from drinking water and municipal wastewater, mainly biodegradable organic compounds not easily removed in conventional treatments based on physical-chemical processes. These biodegradable organic compounds may be responsible for bacterial regrowth in water distribution systems and also for increasing the formation of by-products during disinfection processes due to their capacity to react with disinfectants such as chlorine. Simultaneously to organic matter removal, biological activated carbon filtration can potentially remove the nutrient nitrogen commonly present in contaminated water resources and municipal wastewater, especially under the form of ammonia which is very harmful when discharged into the environment and toxic to living organisms. Thus, the potential of biological activated carbon filters in removing organic matter and ammonia for the treatment of drinking water and wastewater was reviewed. Operating parameters, such as contact time, backwashing regime and filtration rate, adopted for the filter operation and the biofilm growth in the activated carbon media were also discussed, as they may influence the treatment performance. Various scientific studies point out the remarkable ability of activated carbons to adsorb organic matter when compared to their performance for organic matter biodegradation. However, strategies to enhance the biological activity, and consequently biodegradation efficiency should be considered. These strategies, for instance, can include operational changes in contact times or in backwashing regimes. Investigations related to organic matter removal in biological activated carbon filters are more explored when compared to ammonia removal; however, high efficiencies of ammonia removal have been reported.