Abstract

Normally, the food industry produces wastewater containing high organic matter and nitrogen compounds. Along with organic matter removal from these streams, also, nitrogen compounds should be removed. Nitrogen can be removed biologically from wastewater using conventional and novel processes. Although, conventional nitrification/denitrification is an established system for nitrogen removal but the costs of treatment by this system are high because of: high oxygen requirement for nitrification, the addition of external carbon source for denitrification (in the case of wastewaters with low C/N ratio), slow growth rate of microorganisms responsible for both processes, and needing two successive reactor or difficult control of one-reactor system. These disadvantages led to conduction of substantial studies to find better alternatives. Therefore, different novel processes were studied and used for nitrogen removal. Many autotrophic processes including SHARON, ANAMMOX, SHARONANAMMOX, CANON, and OLAND were discovered to be more economical than conventional nitrification/denitrification system. Also, more studies on combination of novel processes with a part of conventional nitrification/denitrification process led to the development of other novel processes such as heterotrophic nitrification-aerobic denitrification, NOx, and DEAMOX processes. Details of both conventional and novel processes were discussed in this chapter. Finally, the possibility of using these processes to remove nitrogen from food industry wastewater is discussed. Because of co-existence of both carbon and nitrogen compounds in food industry wastewater, the use of novel autotrophic processes for mainstream wastewater treatment is impossible. So, carbonaceous contaminants should be removed using anaerobic digestion or high load conventional activated sludge, and then effluent of these processes with high nitrogen contents (low C/N ratio) can be treated using novel autotrophic processes. It should be noted that there are two alternatives including heterotrophic nitrificationaerobic denitrification process and organic-laden DEAMOX process that can be used for mainstream food industry wastewater treatment but the exact characteristics of these processes are unclear and should be accurately studied in laboratory, pilot and full-scale before use.