Municipal wastewater treatment plants generally utilise biological activated sludge processes to remove organic compounds and nitrogen. The biological nitrogen removal (BNR) occurs in two steps, nitrification (ammonium removal) and denitrification (nitrates removal). This study focused on a medium-sized wastewater treatment plant (WTP) which experienced poor nitrification for years, mainly when the weather temperature drops. Further investigations showed that the wastewater influent had high concentrations of surfactants during the same period, indicating a relationship between the WTP performance and presence of surfactants in the influent. |
