flocculation

In the lecture notes it says that flocculation of clay particles is caused by electrostatic, van der waals, and hydrogen bonds. What is creating these forces and why don't negatively charged clay particles repel each other? I'm imagining it that water molecules and/or cat-ions adsorbed to a clay particles attract another clay particle. Is this true? Is this the same process for flocculation of humic substances?

Yudel, things are way more complicated in real-life soils than what we have covered in this course. And yes of course, there are numerous ions and water molecules attracted to the charged surfaces of soil particles and all those ions and water molecules act as bridges between interacting solid particles. But that story is left for an upper-level soil science courses.
Hence, in a simplified example covered in this course, re. inter-particle attraction we wanted you to understand that (a) solid particles are charged and (b) they interact with each other through those inter-particle forces.