i have collected some information on my topic but still i want the exact manner of the topic.

Hi,
you can tell about the need for waste disposal, the harmful environmental effects, effects on humans, types of waste generated, the processes generating the waste, the chemical nature of the waste-the exact nature, solubility and other physical properties, the different existing waste disposal techniques, future technologies, case study etc and the information that you feel is relevant. You can also ask your seminar guide teacher for guidance.