Effects of Feeding Methods on Denitrification and Phosphorus Release.

The SBR treatment of domestic wastewater with the fermented food waste (FFW) as an external carbon source and its three feeding methods (i.e., the slug, intermittent, and continuous feeding methods) were evaluated in this study. The use of FFW as an external carbon source was as effective as acetate for nutrient removal. It was observed that the removal efficiency of TN and TP, when the FFW was used as external carbon source, was 89.2 and 73.9%, respectively, at the SCOD/NO3−-N ratio of 10. The feeding method of FFW was an important factor on nutrient removal depending on the SCOD/NO3−-N ratio, especially P-release. It was observed that the denitrification rate was the quickest in order of the slug, intermittent, and continuous feeding in all of the SCOD/NO3−-N ratios investigated. However, the optimal feeding method in the P-release rate was changed according to SCOD/NO3−-N ratio. In the low SCOD/NO3−-N ratio, such as SCOD/NO 3− -N ratios of 7.5 and 10, the continuous feeding was the best of three feeding methods, whereas, in the high SCOD/NO3−-N ratio, such as an SCOD/NO3−-N ratio greater than 15, the feeding method was not a largely important factor. It is supposed that this result is related to the amount of short chain volatile fatty acids (SCVFAs), such as acetate and butyrate, in FFW. Consequently, it is appeared that the amount of SCV-FAs in FFW acts as an important factor in making a decision of the optimal feeding method on simultaneous denitrification and P-release. [ABSTRACT FROM AUTHOR]