|M.Sc Student||Yovel-Pudim Ilanit|
|Subject||Nitrates Removal from Water Using Denitrifying Immobilized|
|Department||Department of Civil and Environmental Engineering||Supervisor||Professor Emeritus Yerachmiel Argaman (Deceased)|
This thesis deals with heterotrophic biological denitrification of underground water by employing a biological reactor in which an immobilized biomass in gel on a membrane. The whole structure (gel + biomass on the membrane) is supposed to prevent passing of bacteria and substrate (carbon source and nutrients) to the side of the treated water. The execution of the thesis was done in three stages: the production of biomass, immobilization of the biomass and the operation of a continuous denitrification system by using the immobilized biomass. The VSS/TSS values in the reactor stabilized around 750/800 mg/l accordingly likewise the sludge age stabilized around 7 days, thus it was possible to use this biomass in a permanent way in order to immobilize and able to continue the sequential experiment.
The results of experiment A were: for a week the process worked as required, that is to say, there was a decrease in the Nitrate concentration in the circulation tank up to the concentration required by the standard, but after a week the Nitrate concentration “soared” and reversed to being high as at the beginning of the experiment. The COD/TOC values and the turbidity in the circulation tank were elevated - a thing which proved passing of organic matter and bacteria from the reactor into the circulation tank. In the experimental reactor anaerobic conditions were created (acidic pH, DO close to zero) which held back the denitrification process. Some modifications had been made in the experiment in order to solve the problems that arose.