Development of treatment capacity of submerged membrane activated sludge systems and its modelling

IV ABSTRACT PhD Thesis DEVELOPMENT OF TREATMENT CAPACITY OF SUBMERGED MEMBRANE ACTIVATED SLUDGE SYSTEMS AND ITS MODELLING Halil HASAR Fırat University Graduate School of Natural and Applied Sciences Department of Environmental Engineering 2001, Page : 129 In this study, the treatment of domestic wastewater in the -submerged membrane activated sludge system was investigated. The system was hydraulically modelled and the rheological properties of sludge were determined. The total COD concentration of the system effluent varied generally between 5 and 25 mg/1, and the T-COD removal at the organic loads 0.03-0.04 kg T-COD/day was above 98 %. While the inert COD concentration of system influent varied between 3 and 10 mg/1, the value increased to 5-20 mg/1 because of the production and accumulation of inert compounds by micro-organisms in the system. The total phosphorus decreased <1 mg/1 under the aerobic conditions in which the aeration was continuously made and dramatically increased under the aerobic+anoxic conditions in which the aeration was made at differential intervals. The effluent was free of suspended solid (SS) and total coliform bacteria, that is, the removal was 100 % in these parameters. The influent turbidity was removed at levels of 97-99.8 %. Generally, the removal of total Kjeldahl nitrogen (TKN) and ammonium nitrogen varied in the ranges of 87.8-99.1 % and in the ranges of 89.4-99.8 %, respectively. While the effluent nitrate concentrations increased to 26.8 mg/1 under the aerobic conditions, it was determined that the value decreased to 2.4 mg/1 under the aerobic+anoxic conditions.The average ratio of MLVSS/MLSS in the system was found to be 0.76. It was found that the high sludge ages and the accumulation of inert compounds decreased the variability activities at level of 50 %. The flow properties of sludge in system was evaluated according to the models of Newtonian, Bingham and Ostwald de Vaele and the most suitable model was Ostwald de Vaele. As the temperature increased, it was shown that the yield stress and the apparent viscosity decreased. However, it was found that the apparent viscosity increased with an increase in the solid content of sludge. In the mathematical modelling of total resistance in membrane, the non-linear regression model was based on filtration time, transmembrane pressure and filtrate volume and converted to linear. Then, the solution was made according to multi-linear regression model. Key Words: Activated Sludge, Submerged Membrane, Domestic Wastewater, Mathematical Model, Sludge Rheology