Shalom Fox

Department of Environmental Hydrology and Microbiology



Dr. Gabriel Rubanenko Prize for Excellence in Water Research, 2007-8


Shalom is 29 years old and was married to Osnat a year ago, they recently celebrated the birth of their first child, Shahar. Shalom has one more year to complete his Master's degree.

 

Shalom Fox grew up in Alon Shvut, a small community village south of Jerusalem, in the countryside of the Judea Mountains. He studied in the local Elementary school and for high school and traveled to Jerusalem every day. After graduating from high school He was recruited to the army for three years, and served in a reconnaissance unit acting as a sergeant major in an operational team. During his service they were stationed, among other places, in Lebanon and in the Gaza strip.

 

After his military service he took some time to see the world and travelled to London, South America and India. Soon after returning to Israel he started studying for his Bachelor's degree in soil and water sciences in the Faculty of Agriculture at the Hebrew University, Rechovot. Shalom completed his studies with excellence and started a research entitled "Denitrification in re-circulated aquaculture ponds" in the Department of Environmental Hydrology and Microbiology under the supervision of Dr. A. Gross and M. Mozes, as part of his Master's degree in A. Katz School for Desert Studies.



Description of research:

Development and optimization of a field-scale denitrification unit as part of a sustainable marine land base RAS

Supervisors; Amit Gross and Noam Mozes

 

Abstract:

In recent years aquaculture has become the fastest growing section in agriculture and its market is estimated at over 60 billion dollars a year worldwide.  The growing demand for fish has forced the fish farming industry to move from extensive (less than 10 kg of fish per cubic meter of water) to intensive fish farming (up to 120 kg of fish per cubic meter of water). This shift has urged the development of new technologies in order to deal with the new challenges of intensive fish farming.

 

Today, one of the leading technologies in the world of aquaculture systems is the Recirculating Aquaculture System (RAS). In these systems, water from the fish rearing tank is circulated through a series of treatment facilities such as solid filter and a bio filter for converting toxic ammonia to non toxic nitrate, and the treated water is circulated back to the rearing tank. These systems allow efficient use of water and land to maximize fish production. Yet, there are several inherent problems with the commercial systems, including the nitrate pollution and the high concentration of organic solids in the effluent.

 

PB110115


The goals of this research are to remove nitrate solids from the effluent as well as minimize the use of fresh sea water.  This is obtained by the introduction of a novel active sludge denitrification unit for nitrate and solid removal into a land base marine RAS that produces Gilthead Sea bream (Sparus aurata). The research is conducted mutually at ZIWR and at the National Center of Marine aquaculture (NCM) in Eilat and is part of an international effort to remove marine aquaculture from the sea. Denitrification is the reduction of nitrate to nitrogen gas. This process requires a carbon source -electron donor, electron acceptor-nitrate and anoxic conditions (no oxygen). In the denitrification unit the process is carried out by Heterotrophic bacteria that use the fish excrements as an intrinsic carbon source for fuel for the denitrification process.


Preliminary results have shown that the nitrate removal is successful and we have 100% removal efficiency with a substantial decrease of the amount of salty sludge produced by the system.  As a result of the unit’s operation, the use of fresh seawater was reduced dramatically.


Further research:

  • Optimize the system performance. Test the hypothesis that improvement of the water quality in the aquaculture system (by the use of the reactor) will allow minimizing the water exchange rate and consequently the volume of sea water used and produced effluents 
  • Calibrate a model based on the research results for implantation in a 100 ton pilot plant in Eilat.