Residents attending a Tuesday community meeting on a proposed plant, near the West Side Treatment Facility, that would turn city sewage sludge into energy were mostly supportive of the project. The city has issued a request for proposals for an anaerobic digester, a facility that would take sewage sludge and let bacteria break it down in a closed vessel. The resulting energy could be used to fuel liquefied natural gas trucks to carry sludge to New Haven, instead of the diesel-powered vehicles that do so now. The water that remains after the sludge is digested will be trucked to New Haven, and will not add to the facility's capacity, said RichardErickson, a senior vice president at Birdsall Services Group, which prepared the RFP. Jose Pereira, who works at the treatment plant as a maintenance supervisor, asked if the anaerobic digester was safe.