Supernatant Sludge Treatment on the Ljubljana Wastewater Treatment Plant

Supernatant, generated from mechanical compaction previously anaerobically stabilized sludge at the wastewater treatment plant, is heavily loaded with ammonium nitrogen. Usually is leaded to an inflow of wastewater treatment plant and represents approximately 30 % of the additional nitrogen load in the biological treatment stage. To avoid this problem and due to increasingly stringent regulations, which has in recent years heavily limited emissions of nitrogen in the effluent from wastewater treatment plants and also because of economic benefits of operating such systems, in Europe and worldwide are practicing separate treatment of supernatant. For this purpose, various biological processes and technologies are being experimentally tested. Economically favourable treatment of supernatant is partial nitritation of ammonium nitrogen to nitrite with Anammox process that follows. The latter process is well defined by theory, but with less experience in practice. Within M. Sc. Thesis, we have done experimental treatment of Sharon process or nitritation on a pilot treatment plant. The thesis in details defines all the technological parameters that significantly affect the process (alkalinity and pH, temperature, oxygen concentration, hydraulic retention time and sludge age, presence of toxic substances and substrate inhibition). The process was constantly monitored and evaluated with physical and chemical parameters.\ud \u