MODELLING OF ALGAE BASED WASTEWATER TREATMENT

Abstract

Most of the reactions and processes during wastewater treatment involving microalgae and bacteria systems occur simultaneously. They are complex to understand also due to their dependency on several other factors like temperature, solar radiation, nutrient availability as well as on definite inhibitory conditions. Still, there is not much information available about the reactions (physical, chemical, and biochemical) and processes that occur in wastewater treatment systems involving microalgae. The main aim of the present thesis was to understand the developed kinetic model, which includes vital biokinetic processes to simulate the kinetic parameter estimation of wastewater treatment and to know their contribution in nitrogen removal using algae (A), Algae (A) + sludge (S) and sludge (S) reactor under various light regime i.e. 12:12 h, 16: 8 h and 24:0 h. The kinetic model has proved to be an efficient tool to understand microalgae and bacteria interactions in wastewater treatment and to simulate the kinetic parameters of different algae cultures. In the A + S sludge reactors, the rate of nitrification was found higher in the long photoperiod (16:8) than that of the short photoperiod (12:12) . Low light intensity affected the nitrate uptake (𝑁𝑂3is the main N form at 30 h and thereafter) moreover, the Ammonia volatilization rate slightly increases on increasing the light hours. In both the light regimes, the presence of nitrite was not observed, which shows that ammonia to nitrite conversion was the rate-limiting step.