The Board of Supervisors tentatively approved a gravity collection system for the proposed Los Osos sewer Tuesday evening, as they waded through a series of proposals for the long-planned disposal system. “I do not see that a STEP system is … environmentally superior,” said Chairman Bruce Gibson. His four colleagues agreed. The tentative decision came shortly after 6 p.m., after a day of hearings at which supervisors heard a lengthy staff report, sifted through a 900-page document, listened to 17 appeals to Planning Commission approval of the current plan, and deliberated among themselves. “The volume of detail … is truly staggering,” said Gibson. Gibson said supervisors should take the objections one-by-one as they made their decisions. He said decisions remained about the location, emergency access, odor and saltwater intrusion, among others. He indicated he wanted the board to decide on most if not all of the complex issues Tuesday. Gravity versus STEP was one of the major disputes among the dozens of speakers during the public hearing. Under the STEP system a homeowner would install a new tank with a pipe to the street. Another major objection from the audience was the Planning Commission’s decision to site the plant on the Giacomazzi site, agricultural land off Los Osos Valley Road east of town abutting a cemetery. Don Bearden, one of the appellants, said the location disturbs agricultural land and a possible archaeological site. He added that the Giacomazzi site still has not been purchased, and predicted that the Coastal Commission is going to slow the project down with questions and requirements. Bearden, like some other speakers, said the county should move the project back to the Tri W site near the center of town. Other speakers opted for different locations. The 17 appellants ranged from individual Los Osos residents to groups such as the Surfrider Foundation and the Sierra Club, and representatives of Los Osos Valley Memorial Park, the cemetery that abuts the site. In addition to the location and the type of collection system, they objected to the environmental impact report, the possible deleterious effect on low-income homeowners and renters, the cost, aesthetics, inadequate public notice, the effect on Warden Lake, disposal of bio-solids, and other aspects of the project. The stakes are high. The Planning Commission spent five months reaching their conclusions, and the Board of Supervisors is the final county government agency that must sign off, with the state Coastal Commission remaining as a final hurdle. Los Osos has been trying to install a sewage disposal system for decades and disagreements among residents have torn the community apart. “Dealing with sewage is messy,” said Planning Commission Anne Wyatt. Should the board finally agree on a project, construction could begin as early as 2010, said project engineer John Waddell, unless someone sues to stop it or the appeals process drags on. Supervisor Jim Patterson said he hopes the plant will stay in place for the long-term — 70 years. “We want this to be a state-of-the-art facility,” Patterson said.