ElectroWetting On Dielectric (EWOD) is a unique method of moving small volume droplets in microfluidic biochips that relies on modifications of surface wetting characteristics using electrical methods. Modeling and simulation of the EWOD phenomena can aid in the design of microfluidic devices using the EWOD effect. This paper presents a validated computational model of droplet motion coupled with biochemical species transport as well as surface and volume reactions. The model is applied to the problem of passive binding of proteins onto the dielectric surface. Ultimately, the results of these computations will be used to construct design rules for digital microfluidics.