Microalgae Can Promote Nitrification in Poultry-Processing Wastewater in the Presence and Absence of Antimicrobial Agents

Wastewater from poultry-processing plants can be challenging to treat, partially because of the antimicrobial processing aides such as peracetic acid (PAA) and cetylpyridinium chloride (CPC) which suppress nitrifying bacteria. The objective of this research was to test the effects of adding microalgae, PAA, and CPC on nitrification in poultry-processing wastewater. Batch experiments were designed to test two different green algae along with PAA or CPC in a set of full-factorial experiments. The presence of C. sorokiniana increased nitrate production up to 2.7 fold compared to cultures without algae, but this effect was only statistically significant in one of the experiments. The measurement of nitrate was confounded by the fact that this alga consumes both nitrite and nitrate. Carrying out the experiment with A. protothecoides (which does not consume nitrite or nitrate) resulted in 4-9-fold higher peak nitrate concentrations compared to cultures without algae (p < 0.005). These improvements were more than enough to overcome the negative suppressive effects of PAA and CPC. The results suggest that incorporation of algae into engineered treatment systems for poultry-processing wastewater could improve the function of nitrifying bacteria, enabling potential water reuse in hydroponic plant irrigation.

Automated summary

The presence of microalgae in poultry-processing wastewater can enhance nitrification and mitigate the suppressive effects of antimicrobial processing aides, PAA and CPC.