I was in residential treatment last year and was out this beginning of April. It was very tough. When I first got there I was on there because I had to be there. It was either that or have a compulsory treatment order forced upon me and end up in hospital (naturally I wanted to keep my rights so I volunteered for residential).
It was very structured and supervised. The facility I was at could take in a maximum of 9 people at any one time and there were two staff members supervising the group at all times, and more during meals if needed. The bathrooms were locked and you had to have a nurse flush for you. I found the group therapy there extremely helpful. Hearing the opinions of other patients was also useful and yes, at times it was extremely triggering being around others with an eating disorder but that's something you should expect and something you will also adjust to as time goes on and you move further along in your recovery.
Good luck :)