Bob and Writeacher, I just wanted to inform you that my science project on water has been approved by the EU Commission.

We'll be working on the project starting from September. (I will certainly need your help to work out a list of "scientific words" students will need for their presentations.
I rely on your invaluable help!

Can you check these sentences, Writeacher?

I'm extremely happy our project has been approved by the EU Commission.
I've been busy with end exams for the whole month and now I deserve a holiday.
We won't see our students till the beginning of September.
I congratulate you all on cooperating with me on the project and I wish you good summer holidays!

I'm extremely happy our project has been approved by the EU Commission. = OK

I've been busy with year-end exams for the past month, and now I deserve a holiday.

We won't see our students until the beginning of September.

I congratulate you all on cooperating with me on the project, and I wish you good summer holidays!

And congrats on your project's being accepted!! Super!

The sentences you have provided are grammatically correct. However, I have two minor suggestions for improvement:

1. "I congratulate you all on cooperating with me on the project..." - It would be more appropriate to use the phrase "thank you" instead of "congratulate" in this context. You can say, "I thank you all for cooperating with me on the project..."

2. "I wish you good summer holidays!" - The word "good" can be replaced with a more specific and positive adjective like "enjoyable" or "wonderful". So, you can say, "I wish you all enjoyable summer holidays!"

With these minor revisions, the sentences would be as follows:

"I'm extremely happy our project has been approved by the EU Commission."
"I've been busy with end exams for the whole month and now I deserve a holiday."
"We won't see our students until the beginning of September."
"I thank you all for cooperating with me on the project and I wish you all enjoyable summer holidays!"

Congratulations on getting the approval for your science project, and I wish you the best of luck with your work in September!