microalgae cell adhesion is global and plays a critical role in different scientific and engineering problems especially in wastewater treatment. this study focused on both experimental and theoretical studies on microalgal cell adhesion and interactions on membrane surfaces. microalgal cells (chlorella vulgaris (c.v.)) were cultivated and characterized for cell adhesion study on various hydrophobic membrane surfaces (pdms, pu and ptfe). microalgal cell adhesion kinetics were studied using a quartz crystal microbalance d (qcm-d). furthermore, a quantitative scale to predict cell adhesion was suggested by identifying the major interaction between microalgae and membrane surface. this thesis reports the total interaction energy between algae cells and membrane surfaces in the different group of membranes based on the extended derjaguin, landau, verwey, overbeek (xdlvo) method using the physiochemical particle and surface properties. the simulation and calculation were on membrane and two different shapes of microalgae (circle and ellipse). the results of cell adhesion kinetic studies using qcm-d showed that the properties of membranes had a significant impact on cell adhesion. a more hydrophobic membrane led to a fast and large quantity biofilm formation. the modelling results indicated that membrane asperity height and particle asperity number were more and less effective factors in the range of total interaction energy and adhesion. also, the results show that membrane material is another significant factor in interaction energy because proximity was observed between the results of two sensors. the interaction energy trends were consistent with the experimental results in that a stronger attractive interaction energy favored a fast and large quantity of microalgal biofilm formation on more hydrophobic membrane surface.