Ammonia removal in a deep reclaimed wastewater reservoir before agricultural reuse

An experimental study has been carried out to determine the ammonia removal in a deep reclaimed wastewater reservoir of 50,000 m(3). The reservoir is part of the Reuse System of Reclaimed Wastewater of South Tenerife (Spain). The study has been conducted under batch mode operation, in three differen t periods (winter, spring-summer and winter-spring), with an average storag e time of 85 days. Vertical profiles of temperature, dissolved oxygen and p H were determined together with NH3-N, NO2-N and NO3-N concentrations at di fferent points and different depths in the reservoir. Maximum removal effic iency was obtained during the winter periods, in absence of stratification and with good mixing conditions throughout the water column. During these p eriods, nitrification took place in some extension, favoring the ammonia re moval. Average NH3-N concentrations in the reservoir were calculated and ap parent first-order rate constants were determined for different stratificat ion conditions. Although ammonia nitrogen could be used as nutrient in the agricultural reuse, its removal from reclaimed wastewater could be useful i n order to diminish the chlorine needs for disinfection.