Intermediate Science Essay Proofreading

I'm in need of a proofreader with an intermediate understanding of science to review my essay meticulously. This task will necessitate a keen understanding of scientific terminologies and concepts.

Key Requirements:
- Exceptional command of the English language
- Experience with essay proofreading, particularly scientific essays
- An intermediate understanding of scientific terms and concepts
- Detail-oriented with a knack for identifying grammatical errors and inconsistencies

The initial task will involve identifying and correcting syntax, structural, and semantic errors in the essay. A successful collaboration could lead to more proofreading jobs in the future. Please provide samples of similar work done in the past, as well as a timeline for completing the task.