ABSTRACT
The term trickling filter represents an array of attached growth biochemical operations in which wastewater is applied to fixed media in an air-filled packed tower. Treatment of the wastewater is accomplished by microorganisms growing attached to the media, of which there are several types. Trickling filters are aerobic and are used to oxidize biodegradable organic matter, forming biomass. The produced biomass sloughs from the media and is separated from the treated wastewater in a downstream clarifier. Trickling filters are also used to oxidize ammonia-N to nitrateN. Nitrification can occur either in a trickling filter that is being used for oxidation of organic matter, a process called combined carbon oxidation and nitrification, or in a trickling filter receiving wastewater that has previously been treated to remove organic matter, a process called separate stage nitrification. Both are discussed in this chapter; the theoretical performance of packed towers is discussed in Chapter 16.
