Treatment of synthetic wastewater in membrane bioreactors

Kroz 32 dana obrađivana je modelna otpadna voda pomoću aktivnog mulja, primjenom MBR-a Zenon s uronjivom membranom tipa hollow fibre, te MBR-a Kubota sa uronjivom membranom tipa plate&frame. Tijekom trajanja procesa proučavane su učinkovitost i stabilnost procesa mijenjanjem protoka, a time i vremena zadržavanja vode u bioreaktorima (16h, 8h i 4h ). Dobiveni rezultati govore u prilog visokoj učinkovitosti uklanjanja organskih tvari (oko 94% uklanjanja organskih tvari izraženih preko KPK i TOC vrijednosti). Tijekom vođenja procesa primjećen je porast nitrificirajuće aktivnosti, 57 % dušika iz ulazne vode prevedeno je u nitrate kod MBR Zenon, dok je 40 % dušika prevedeno u nitrate kod MBR Kubota. Obje membrane su radile relativno stabilno, uz postepeni pad permeabilnosti. Nakon 29 dana vođenja procesa membrana Zenon se začepila, pa je podvrgnuta kemijskom pranju otopinom hipoklorita, nakon čega joj je permeabilnost povećana, što je omogućilo daljnje nesmetano provođenje procesa.The experiment was carried out during 32 days on synthetic wastewater with activated sludge and MBR Zenon with submerged hollow fibre membrane and MBR Kubota with submerged plate & frame membrane. During the experiment, the efficiency and stability of process were investigated by changing the flow and thus the hydraulic retention time (16h, 8h and 4h) in bioreactors. Given results indicate high efficiency of removing organic compounds from wastewater (about 94 % expressed as a KPK and TOC). Nitrification activity were increased throughout the process, 57 % of nitrogen was converted into nitrate in MBR Zenon and 40 % of nitrogen into nitrate in MBR Kubota. The membranes worked relatively stable with graduate decrease of permeability. After 29 days membrane in MBR Zenon was completely fouled so filtration was unable. Therefore the membrane was submitted to chemical cleaning with a hypochlorite solution. Afterwards the permeability was increased and further unobstructed continuation of process