Find a sewage treatment plant with similar sewage properties and treatment technology. If all the recruits are majoring in environmental engineering, as long as employees are arranged to work in it for one month, they will integrate theory and practice in their work. For other majors, one month's time is enough to combine some theoretical books and knowledge. Don't go to any so-called professional training institution, it's all empty talk, you can't remember it at all, and it's even more useless.