NEW YORK—Ghislaine Maxwell, the British socialite fighting U.S. federal sex trafficking charges, remains subjected to raw sewage, water deprivation, “hyper-surveillance” by overbearing guards, and other unacceptable treatment in jail, according to her lawyer. Maxwell, 59, is preparing for a possible November trial on charges she procured four underage girls for the late financier Jeffrey Epstein to sexually abuse. Maxwell has pleaded not guilty and faces up to 80 years in prison if convicted. In a Tuesday night filing, lawyer Bobbi Sternheim said Maxwell was forced to change cells at the Metropolitan Detention Center in Brooklyn after raw sewage last week permeated her cell. Sternheim also said guards are still able to read Maxwell’s confidential legal papers and monitor her meetings with lawyers, and that neither Maxwell nor her lawyers were allowed water during a four-hour meeting on Sunday. Despite complaints about Maxwell’s treatment, “little if anything has been done,” Sternheim …