Utredning av processavloppsvatten från Thermo Fisher Scientific : Föroreningsinnehåll samt utvärdering av driftförhållanden för bäst reningseffekt

Sammanfattning: Thermo Fisher Scientific (TFS), ImmunoDiagnostic (ID), Uppsala, produces instruments for allergy and autoimmunity tests. As TFS ID applied for allowance to increase the production level, it was given on the condition that the wastewater would be biologically pre-treated on the site, and a Moving Bed Biofilm Reactor (MBBR) was therefore built. Another condition was that the effluent wastewater should be of the same quality as normal household wastewater. This thesis investigated the contents of acetone, total organic carbon (TOC), biochemical oxygen demand (BOD 7), nitrogen (Ntot), phosphorus (Ptot) and some toxic substances in the process wastewater from TFS ID Uppsala. Furthermore, the reduction capacity of the MBBR was investigated at two different operating modes; step loading and serial operation. The reduction capacity was determined for the different operating modes by test sampling and by modelling. The model used was based on the active sludge process (ASM1) and Monod kinetics. Based on the calculated reduction capacity and studied litterature, polishing steps that would further reduce the contents of pollutants which did not meet the criteria of effluent wastewater were suggested. Finally, the future reduction capacity of the MBBR was investigated, based on the assumption that the production level would increase in time. The results showed that the contents of P tot and BOD7 in the effluent water exceeded that of normal household wastewater. It was hence suggested that a chemical precipitaionstep and a disc filer should be installed as complements to the MBBR. These polishing steps could potentially reduce phosphourous and separate larger BOD 7-particles by about 90 %. No significant difference was seen in the reduction capacity of the different opertating modes based on test sampling. However, the modeling results showed a lower effluent level of BOD 7 as the tanks were operated in complete series. No toxic substances were found in the wastewater, but effluent wastewater was still slightly toxic for green algae. Further investigation is needed to detect what is causing the toxicity, and to suggest measures that could decrease the pollution from TFS ID Uppsala. The future reduction capacity was recognized to be significantly lower than today, as N tot was the only substance that met the criteria of normal household wastewater when the production level increased. To improve the efficiency of the MBBR, it was suggested to increase the volume of the equalization tank and the amount of carriers in the reactors. Key words: MBBR, step loadning, serial operation, process wastewater, reduction capacity, BOD 7, phosphorus, nitrogen, acetone