Felix Kirzhner

Publications of Felix Kirzhner

• Efficiency of phenol biodegradation by planktonic Pseudomonas pseudoalcaligenes (a constructed wetland isolate) vs. root and gravel biofilm.

  Authors: Eyal Kurzbaum, Felix Kirzhner, Shlomo Sela, Yoram Zimmels, Robert Armon

  Water research. 09/2010; 44(17):5021-31.

  In the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. While most of the studies showedIn the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. While most of the studies showed excellent removal of various pollutants, the exact contribution, in kinetic terms, of its particular components (such as: root, gravel and water) combined with bacteria is almost nonexistent. In the present study, a phenol degrader bacterium identified as Pseudomonas pseudoalcaligenes was isolated from a constructed wetland, and used in an experimental set-up containing: plants and gravel. Phenol removal rate by planktonic and biofilm bacteria (on sterile Zea mays roots and gravel surfaces) was studied. Specific phenol removal rates revealed significant advantage of planktonic cells (1.04 × 10(-9) mg phenol/CFU/h) compared to root and gravel biofilms: 4.59 × 10(-11)-2.04 × 10(-10) and 8.04 × 10(-11)-4.39 × 10(-10) (mg phenol/CFU/h), respectively. In batch cultures, phenol biodegradation kinetic parameters were determined by biomass growth rates and phenol removal as a function of time. Based on Haldane equation, kinetic constants such as μ(max) = 1.15/h, K(s) = 35.4 mg/L and K(i) = 198.6 mg/L fit well phenol removal by P. pseudoalcaligenes. Although P. pseudoalcaligenes planktonic cells showed the highest phenol removal rate, in constructed wetland systems and especially in those with sub-surface flow, it is expected that surface associated microorganisms (biofilms) will provide a much higher contribution in phenol and other organics removal, due to greater bacterial biomass. Factors affecting the performance of planktonic vs. biofilm bacteria in sub-surface flow constructed wetlands are further discussed.

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• Underground disposal of hazardous waste in Israel – Design principles and conceptual approach

  Authors: Yoram Zimmels, Felix Kirzhner, Karl-Heinz Lux, Torsten Zeller

  Tunnelling and Underground Space Technology.

  The careless or unprofessional handling of hazardous wastes in many places around the world led to severe damage of nature, concurrent with considerable long-term health risks to human beings. ThisThe careless or unprofessional handling of hazardous wastes in many places around the world led to severe damage of nature, concurrent with considerable long-term health risks to human beings. This motivated several countries to develop new secure and sustainable waste management strategies in order to enhance the future quality of nature and life. The process of world globalization and the coalescence of its markets increased the importance of formulation and implementation of accepted environmental standards. The rising environmental and ecological awareness in Israel puts the contemporary and common waste handling practices under close scrutiny. An intensive exchange of experiences with other countries is called for, so that the responsible authorities can formulate improved and sustainable waste management strategies, which are specifically tailored to the particular environmental, demographic, economic and political conditions of Israel.The German environmental protection and waste legislation demands an underground disposal of highly contaminated wastes, in order to guarantee that harmful substances are excluded durably from the biosphere. In view of its size and the political situation in Israel, this way of waste disposal seems to be an appropriate waste management strategy aimed at minimising the environmental risks, and the harmful effect of hostile actions against deposits of hazardous wastes. The German waste management policies and practices, which are based on many years of experience, are reviewed first as a guideline for safe long-term underground disposal of hazardous wastes in Israel. Using these guidelines, potentially suitable locations in Israel are selected with special reference to their geohydrological, geological and geomechanical conditions, and then they were evaluated using environmental criteria derived from German standards of waste disposal. The results of this preliminary environmental evaluation, and some relevant geomechanical designs, are presented and discussed. Finally, economic aspects, and further steps, which are needed to safeguard future implementation of the underground disposal system, are considered.