Hospital leaders broke ground on the Robert R. Rosenheim Foundation Dialysis Center on the fourth floor of Connecticut Children’s Tuesday morning. They expect to finish construction in six months and soon after begin treating young patients from across the state and region in need of dialysis for kidney failure. The Rosenheim Foundation donated $1.5 million to the hospital this year to fund the new center. It will feature three private treatment rooms, a patient training room and waiting areas equipped for parents. The center will provide care for up to 10-15 patients each week, with a staff of four doctors and more nurses trained in pediatric dialysis.