Experimental Study on Shortcut Nitrification of Sewage from Flushing Toilet with Seawater

Shortcut nitrification was reported to be technically feasible and economically favourable, especially when sewages with high ammonium concentrations or low C/N ratios are treated. Nitritation can be obtained by selectively inhibiting nitrite oxidizers through appropriate regulation of the systempsilas pH, DO, temperature, and sludge retention time, and so on. Nitrification tests were performed in a lab-scale reactor operated to treat wastewater containing seawater. In the plant, temperature was maintained at 28degC and influent pH was regulated at 8.3 by dosing sodium carbonate (Na₂CO₃). The effect of seawater salinity on ammonia nitrogen removals and shortcut nitrification in SBR process for the seawater-flushed toilet wastewater treatment was investigated in this work. The experimental results showed that the shortcut nitrification was achieved when influents contain 30% seawater and nitrite concentrations close to zero in all the experimental runs and complete nitrification to nitrate was achieved when influents do not contain seawater. In comparison with the result treating wastewater without seawater, the nitrogen removal treating wastewater containing seawater decreased 4%. Therefore, the seawater is proposed as a parameter for controlling partial nitrification to nitrite.