Modeling and calculations of parameters of the joint treatment of organic contaminations (OC) and nitrogen (N) compounds in bioreactors with using of the fixed biocenosis (biofilm)

Abstract

The mathematical models and the parameter calculations of the simultaneous waste water treatment from the organic contaminants and ammonium nitrogen compounds in the bioreactors-aerotanks with additional fixed biocenosis as a biofilm in their volume are proposed. The questions connected with heterogeneous structure of biofilm from different bacteria and the substantiation of the balance equations system with kinetic reactions for following their realization which are describing of the simultaneous removing organic contaminations (OC) and nitrogen (N) in biofilm taking into account on the oxygen regime O2 are considered. Detailed analysis of aerotank operation with additional fixed biocenosis shown about the possibility of creation of the new conditions for simultaneous removing of the OC and nitrogen by the suspended and fixed biocenosis. At the same time the arrangement of the aerotank-mixture from the three sections where the simultaneous treatment have a place is recommended taking into account on the theoretical substantiation of these sections in one reactor. It is shown that on the different loads the complex heterogeneous structure of the biofilm is formed which consist of from different bacteria. So near the biofilm surface it consists of the heterotrophs during the removing of OC and at during of removing of nitrogen from the autotrophs. At the same time more active heterotrophs may to grow as in anaerobic as in anoxic conditions and the processes that have a place in the biofilm at the simultaneous treatment are connected with the growing of the competition between the heterotrophs and autotrophs in the fight to oxygen. Heterotrophy that are situated are near surface of the biofilm are using of more oxygen than autotrophy that are in the lower part of one. As a result of realization of the created models taking into account on the influence of the different factors on the simultaneous waste water treatment from OC and N processes the recommendations to parameter calculations are proposed. Besides of the boundary conditions of necessary bacteria presence at which the simultaneous removing of the OC and N are occurred and at which conditions some of substrates will limit the waste water treatment processes are determined.