DENITRIFICATION KINETICS OF DRINKING WATER IN MEMBRANE BIOREACTOR

Namen diplomskega dela je bila določitev parametrov Monodove kinetike z uporabo pilotne naprave, modificiranega membranskega reaktorja Zenon ZW 10. Uporabljali smo pitno vodo iz laboratorija, ki smo ji dodajali nitrate, da smo vzdrževali konstantno koncentracijo nitratov na vtoku. Kot vir ogljika smo uporabljali saharozo, ki smo jo prav tako konstantno dodajali vtoku v razmerju C/N = 3/1. Za določitev konstant Monodove kinetike smo morali zagotoviti konstantne pogoje biološke denitrifikacije. Hkrati s konstantnim dodajanjem nitratov in saharoze, je morala biti v biološki enoti koncentracija raztopljenega kisika v vodi pod 0,5 mg/L, da smo zagotovili anoksične pogoje. Prav tako je morala biti konstantna koncentracija aktivnega blata. Skozi 9 ciklov smo spreminjali samo vtok vhodne raztopine iz začetnih 10 mL/min na 170 mL/min. Med eksperimentom smo merili koncentracijo nitratov in nitritov na vtoku, kemijsko potrebo po kisiku na vtoku (KPK), koncentracijo aktivnega blata (MLSS), temperaturo, pH ter koncentracijo substrata na iztoku. S podatki slednjega smo konstruirali diagram hitrosti razredčevanja v odvisnosti od koncentracije substrata, D = f(cs), ter tako določili konstante Monodove kinetike. Dobljena maksimalna specifična hitrost rasti biomase μmax je 0,3461/h, konstanta nasičenja substrata Ks pa 5,833 mg/L.The purpose of this diploma thesis was to determine the parameters of Monod kinetics using the pilot plant, a modified membrane reactor Zenon ZW 10. We used drinking water from the laboratory to which we were adding nitrates to maintain a constant concentration of nitrate at the inflow. As a carbon source, we used sucrose, which we were also adding constantly to the inflow, ratio C/N = 3/1. To determine the Monod kinetic constants, we needed to provide constant conditions for biological denitrification. Concurrently with constant adding of nitrate and sucrose, in the biological unit, the concentration of dissolved oxygen in the water needed to be below 0,5 mg/L, to ensure anoxic conditions. The concentration of activated sludge also needed to be constant. Through 9 cycles only the inflow of the input solution has varied from the initial 10 mL/min to 170 mL/min. During the experiment, we measured the concentration of nitrates and nitrites at the inflow, chemical oxygen demand at the inflow (COD), mixed liquor suspended solids (MLSS), temperature, pH and substrate concentration at the outflow. Using the latter data, we constructed a diagram of dilution rate as a function of substrate concentration, D = f(cs) and thus determine the Monod kinetic constants. The resulting maximum specific growth rate μmax of biomass is 0,3461/ h, and the substrate saturation constant Ks is 5,833 mg/L