Oil pollution is a serious threat to human life, the environment and eco-system at large, it is important to properly treat our oily wastewater before its discharge or reuse. So, this research study focuses on the synthesis and characterization of plastic-rice husk based membrane for the ultra-filtration of oil wastewater. The raw materials used were Polyethylene terepthalene (PET), Polyethylene glycol (PEG) and Rice husk. Thermally induced phase inversion method was used for the membrane syntheses. The membrane modification was carried out with the aid carbonized rice husk ash (CRHA) of different concentrations using the blending method of modification to produce flat sheet membrane (FSM). The characterization of the membrane samples were done using standard methods. The FSM were characterized using Scanning Electron Microscopy (SEM), Fourier Transform Infrared (FTIR), Thermogravimetric Analyses (TGA), Mechanical Properties and water contact angle (WCA) in order to determine the surface morphology, functional groups present, thermal and mechanical stability in addition to the hydrophilicity of the FSM respectively. Also, the membranes were characterized for their porosity, water content as well as their pure water flux, permeate flux and oil rejection ability using the generic and dead end filtration experiment. The results indicates that addition of CRHA into the membrane solution greatly influenced the thickness, porosity, hydrophilicity as well as the water adsorption capacity, thermal and mechanical stability of the produced FSM samples. The highest thickness, porosity and water adsorption capacity of 0.48cm, 36.22% and 53.17% were obtained for FSM5, FSM4 and FSM2 respectively, while the least values of 8.72Mpa, 4.15%, and 400ᵒC for tensile strength, elongation at break, and thermal strength were obtained for FSM1. FSM4 performed optimally well when compared with other membrane samples, having the highest pure water flux of 1500L/m2h, permeate flux of 813.8L/m2.h and second highest value for percentage oil rejection of 69.42% at a pressure of 3.0bar and filtration time of 30min. Hence, low-cost ultra-filtration membrane with improved permeate flux and oil rejection can be synthesized from waste PET bottles by the addition of PEG and CRHA as pore forming additives.