Yes, a presentation for school. I have never heard about this, this is practically new to me. I am sorry to say that I cannot say anything more about this, that is why I need help. Our teacher gives us topics to make presentations, most of those we need for our tests like there was a presentation about DNA and RNA, about polymers and protein, carbohydrates and so on. In short he only gives us these topics and what we do with them is up to us. Believe me, I tried doing research myself but there is so much that I don't know what should I include in the presentation, not to mention that I am Latvian and I tried searching about this in Latvian as well but I came up with nothing. I know what you are talking about when you say grey water, sewage but the title of the presentation is just ''Wastewater treatment modelling'' and that's it. I do not know what is important when it comes to wastewater treatment modelling that is why I need some help. Half of the stuff on the internet I cannot understand because there are so many scientific terms that don't really translate well, I'd have to get a super duper dictionary for that. I am sorry, I might seem desperate and I am. I just want some tips maybe. Thanks.