Studty of physico-chemical parameters affecting SND process on nitrogenous compounds removal

Treating wastewaters containing nitrogenous compounds is an essential issue due to environmental hazards. New biological technologies such as simultaneous nitrification-denitrification (SND), ANAMMOX and SHARON were developed in the last decades. Such techniques are economical and more effective compared to conventional methods. The aim of this work was to investigate physico-chemical properties of SND process.

In this study, subsequent to constructing a comprehensive survey on papers published in the last two decades, the impacts of effective parameters such as temperature, pH, dissolved oxygen, organic carbon, floc size and sludge retention time (SRT) on SND process were investigated.

SND process reduces carbon source demand. Dissolved oxygen should be adjusted in a particular range to maintain an equilibrium between the nitrification and denitrification.  The process efficiency was higher in the basic pH. The optimum temperature for the growth of SND bacteria were 20-30 ℃. There was no linear correlation between efficiency of process and SRT.

The results of this research approved that new biological processes for nitrogen removal such as SND were promising owing to reducing the need for aeration and carbon source. By controlling the Physico-chemical conditions in process, good efficiencies can be achieved.