Quantification of kinetic parameters for heterotrophicbacteria via respirometry in a hybrid reactor

Over the last decade new technologies are emerging even more for wastewater treatment.Among the new technologies, a recent possible solution regards Moving Bed Biofilm Reactors(MBBRs) that represent an effective alternative to conventional processes. More specifically suchsystems consist in the introduction of plastic elements inside the aerobic reactor as carriermaterial for the growth of attached biomass. Recently, one of the mostly used alternatives is tocouple the Moving Bed Biofilm Reactor (MBBR) process with the conventional activated sludgeprocess, and the resulting process is usually called HMBBR (Hybrid MBBR). In the MBBR processthe biofilm grows attached on small plastic elements that are kept in constant motion throughoutthe entire volume of the reactor. Indeed, in such a system, a competition between the twobiomasses, suspended and attached, can arise for the availability of the substrates, leading, as aconsequence, to a modification in the biokinetic parameters of the two biomasses, compared tothat of a pure suspended or attached biomass process. This paper presents the first results of astudy aimed at estimating the kinetic heterotrophic constants in a HMBBR pilot plant usingrespirometric techniques. The pilot plant was built at the Acqua dei Corsari (Palermo) wastewatertreatment plant and consisted of two parallel lines realized in a pre-anoxic scheme, in one ofwhich the carrier material was added to the aerobic reactor with a filling ratio of 30%.