詹妮弗·k·森田著

2024年7月12日

There’s a “cow” in 萨克拉门托 State’s BAC Yard, but don’t expect it to moo.

囊状态 可持续性’s new food waste digester not only turns kitchen scraps into safe, nutrient-rich fertilizer, it also produces methane gas that can be used to power campus events — and maybe even an electric car.

“Just imagine a giant cow’s stomach,” Waste and 可持续性 Analyst Laura Gonzalez-Ospina said. “It works exactly the same.”

这个消化器是牛津大学减少垃圾进入地区垃圾填埋场的最新方法，这一努力赢得了全国的认可。 今年夏天晚些时候，可持续发展办公室将获得加州资源回收协会（CRRA）颁发的2024年杰出废物预防奖。

囊状态 also earned its third 星级 from the Association for the Advancement of 可持续性 in Higher Education. This year’s score of 73 is the University’s highest-ever on the self-reported rating system, conducted every three years to measure sustainability success.

“There’s been a huge push in the last couple of years to reduce our waste, and the fact that we received the CRRA award and grew in that space within STARS shows that all our efforts have really paid off,” said Ryan Todd, director of Energy and 可持续性. “It means we’ve been putting our efforts in all the right places.”

这个价值20万美元的新消化器是加州海事公司送给他们的礼物，因为该公司无法使用它。 The machine is housed in what looks like a metal shipping container in the Bioconversion and Agricultural Cooperative Yard – the BAC Yard – where 可持续性 has a garden, honey bee hives and composting areas.

Food waste from some campus eateries and the ASI Children’s Center is delivered to the BAC Yard, where staff carefully pick out plastic contaminates, large pits and other items that could clog the machine.

The organic waste is poured into a metal vat and fed into an industrial version of a household garbage disposal, where it is ground up and mixed with the same bacteria found in a cow’s stomach. 细菌分解食物，并在24至72小时内产生一种透明、无味的液体肥料。

“It’s high in carbon and nitrogen and other properties we want,” Gonzalez-Ospina said. “It’s better than any chemical fertilizer being used on campus now, so we hope to use this organic fertilizer to replace some of the not-so-good ones we’re still using.”

任何剩余的肥料都将捐赠给社区，就像可持续发展组织赠送未使用的堆肥一样。

学生和教师也可以使用消化器，教师们已经就在土壤上测试肥料的问题与可持续发展公司取得了联系。

“We want this to be a living lab for students to get experience doing research on things such as food-to-gas ratios, biodigestion itself, and learning how to use our own food waste to create methane and electricity,” Gonzalez-Ospina said.

消化过程也会产生甲烷气体，但它不会被释放到环境中，而是被收集起来，转化为电能储存在便携式电池中。

“We can use it at University events instead of gas generators, so now our events can be powered by campus food waste,” Gonzalez-Ospina said.

可持续性 staff are eager to test the machine’s limits, including whether it can create enough energy to power an electric vehicle.

“There’s been a huge push in the last couple of years to reduce our waste, and the fact that we received the CRRA award and grew in that space within STARS shows that all our efforts have really paid off. It means we’ve been putting our efforts in all the right places.” ——Ryan Todd，能源与可持续发展总监

The new digester is just the latest component of 囊状态’s work to become a zero-waste campus by 2030. Late last year, the University received a 加州资源、回收和回收部拨款179,618美元 to buy its first on-site composter, which turns uneaten food scraps into compost.

可持续性 also created 大黄蜂盈余, an online shop for faculty and staff to browse the University’s warehouse of unused furniture, printers and computer monitors to reuse on campus instead of ordering new supplies, saving 囊状态 money and preventing trash from going into a landfill.

“It shows up at your office like Amazon, but without the boxes,” Todd said.

至于消化器，需要一个专门的团队来维护机器，可持续发展学院与校园食品供应商密切合作，确保有机废物得到妥善分类。 回收者将食物垃圾送到BAC庭院，并协助可持续发展工作人员为消化池提供食物。

在7月一个炎热的日子里，回收员Ysidro Versola从废料桶里捡起一个菠萝头，扔进另一个堆肥堆里。

“It’s too fibrous,” he said. “It won’t digest and it’ll plug up the system. Anything gritty can’t go in there.”

员工们必须愿意弄脏自己。

冈萨雷斯-奥斯皮纳和能源与可持续发展协调员萨里·斯玛特在萨克拉门托县博览会期间花了一个上午的时间在加州博览会清洁摊位，收集了380加仑的牛粪，这些牛粪中含有消化器所需的细菌。

“This is a living machine,” Gonzalez-Ospina said. “There’s multiple millions of colonies of bacteria living in there.”

工作人员还必须不断检查温度，确保温度保持在100华氏度以下，以保持细菌的存活。

“This is amazing,” Gonzalez-Ospina said. “It’s the perfect solution if you have the capacity to do it. We are using food waste and creating an output that we can use without releasing methane gas into the atmosphere.”