The topic of waste management has been a hot one within Palo Alto's environmental community since 2011, when the city was preparing to close its landfill in Byxbee Park and residents offered differing visions about the future of local composting and food waste. Proponents of keeping waste management local scored a big victory that November, when voters approved Measure E and "undedicated" a 10-acre portion of the closed landfill that was to be added to Byxbee Park for the anaerobic digester. Opponents, who included several leading conservationists, argued that Byxbee was the wrong place for a waste operation.
Now, three years after that polarizing debate, the trash talking has abated and both sides are offering their tentative blessings to the city's new idea. The latest proposal, which the City Council will consider on April 29, includes rejecting all three of the offers Palo Alto received from the private sector for treating the three waste streams — food scraps, yard trimmings and sewage sludge.
Instead, it would pursue a path that would start with treating sewage at the Regional Water Quality Control Plant on Embarcadero Road, add food scraps about a year later and then finally proceed to yard trimmings.
The approach differs drastically from what officials had in mind just a year ago, when the city was looking to the private sector to build a plant that would treat all three types of organic waste together. Now, Public Works officials are recommending, as the first phase, modifications to the water-control plant that would allow the city to finally retire its antiquated sludge-burning incinerators — a goal shared by both camps of environmentalists.
Concurrently, staff would proceed with a plan to build a wet anaerobic-digestion plant that would ultimately treat the sewage waste and produce energy. Processing food waste would follow about a year later.
Under the new plan, Palo Alto would build a preprocessing facility to remove contaminants from food scraps. Once that is done, food scraps would join sewage sludge in the new anaerobic digester.
The final phase of the city's plan would address yard trimmings, though it's far from clear what that solution will look like. Whereas before officials planned to process the trimmings at the Baylands waste-to-energy plant, now they are preparing to consider other options, including new technologies. The report cites as an example the San Jose/Santa Clara Regional Wastewater Facility, which recently approved a one-year project to gasify wood waste and biosolids. Palo Alto officials plan to follow these emerging technologies to evaluate "whether a local facility on the 3.8-acre relatively flat portion of the Measure E site is a sustainable option," the report states.
For the near term, city staff recommends no change to how it currently handles yard trimmings for composting, which is to send them to Gilroy.
The pivot from the private sector to a city-run operation represents a dramatic strategic shift. In February, council members heard a presentation about proposals the city received from three different companies: Harvest Power, We Generation and Synagro. Synagro offered to export all three types of waste, and the other two companies both offered to build anaerobic-digestion plants. We Generation proposed using thermal hydrolysis, in which cell walls are broken down in organic waste to release more energy.
The new report from Public Works offers several reasons for rejecting the proposals. The strongest one is costs. Staff projects that the proposals by Synagro, Harvest Power and We Generation would cost about $98.9 million, $97.1 million, and $107 million over 20 years, respectively. The city-owned process recommended in the new plan would cost about $76.8 million (continuing with current processes, in which yard waste is exported and food waste goes to San Jose, is estimated to cost about $98 million).
The city's views about the risks of the venture have also evolved. When the city issued its request for proposals in 2013, officials assumed the offers would include various novel technologies. Now, based on the private-sector responses, Public Works staff is confident that wet anaerobic digestion is the way to go (in the past, the city had considered a different process called "dry anaerobic digestion") and that the risk of adopting this well-used technology is relatively low.
"The expectation was that there would be synergy associated with processing the three waste streams together and that would warrant the associated risk," the report states. "However, the technologies proposed (by the companies) were generally considered conventional with a limited amount of risk."
Though the plan has yet to officially launch, it has already achieved one thing: bringing the competing environmentalist camps closer together. In February, members from both sides offered their compliments to staff on the new approach. For one thing, everyone shares the goal of retiring incinerators. Furthermore, the new approach means that the city won't have to build an industrial operation at the Measure E site — at least not any time soon. Walt Hays, who helped lead the campaign to undedicate the parkland, called that one of the chief benefits of the latest proposal.
"One of the exciting things about this is that after all the controversy of Measure E, it looks like we can have most of what we want without having to use the 10 acres, which would be fine for everybody. So a lot of the antagonism that took place during that (campaign) would be eliminated," Hays said.
Conservationist Emily Renzel, who opposed the new Baylands plant, said staff has done "an amazing job synthesizing some very, very complex issues" and that "for once in 14 years, I agree with Walt Hays."
At the February meeting, the council requested more information, including a more detailed timeline and a range of options for the city's ownership of the new facilities. According to the new report, the city projects that the incinerators could be retired and demolished by 2020 and that the new anaerobic digester would be built by 2022.