Floc structure and strength play important roles in a range of industrial processes such as particle separation and water treatment. Our proposal will provide key information to test basic ideas of heteroflocculation with particles of different size of particles with different shapes. The determination of how each species is arranged in flocs by using contrast matching to observe the structure overall and arrangement of individual components will allow sensitive tests of models that relate particle volume fraction, dynamics and 'sticking probability'. The results of experiments on latex particles and clay that exploit the novel natural flocculent protein from Moringa seeds will also be directly relevant to the development of new water purification technologies. Experiments are designed specifically to allow initial studies that test simple physical models and to avoid complication of orthokinetic flocculation that arise in strong shear.