Impact of temperature on groundwater nitrification in an up-flow biological aerated filter using expanded clay as filter media

Abstract

The temperature influence upon the nitrification rate was studied using a continuous flow pilot installation, which comprises a biological aerated filter with ascendant inflow circulation. Used filter media was expanded clay, 2-5 mm granulometric fraction. The biofilter was fed with raw low - depth groundwater enriched with NH+ 4. Inorganic nitrogen forms (NH4+, NO2-, NO3-) concentrations were measured both within the inflow and outflow of aerated biological filter, at stationary operation regimes in correspondence with various applied NH+ 4 loading. Values of NH4+removal rates were situated within the 515-1337 g NH4+-N/m3*day domain for temperature increase from 11 to 25.2 C degree. The coefficients of reaction rate vs. reaction temperature equation were also determined.