Trash talk

The Transfer Station mostly just contains huge piles of material, although it does also contain a large machine designed to separate most organics from garbage. That machine is part of the center’s “organics to energy” pilot project, which is helping San Mateo County meet California’s goal of reducing the amount of organic waste (which generates methane gas) in our landfills by 75%.

The second half of our tour covered the truly interesting Materials Recovery Facility. This is where our “single stream” recyclables are separated. The MRF contains a number of giant machines, each designed to perform some part of the sorting process. Connecting them are a number of conveyor belts, with workers positioned alongside to do some amount of hand sorting. Mostly, they are there to pull out non-recyclable items from the waste stream: items such as plastic bags, which gum up the sorting machinery and thus, in our facility, cannot be recycled.

The machines in the MRF are large, and quite noisy. Fortunately, we had been given small radios and headsets, which not only protected our hearing but allowed us to hear what our three guides were telling us. Those guides first showed us how paper and cardboard are separated out by machines employing streams of air and our Earth’s gravity. Next, more high-tech machines with lasers and magnets identify and sort bottles and cans. Some of them separate plastic from glass from metal, while others separate the various types of plastic from one another. Finally, baling machines package up each type of recyclable into large bundles.

The tour included plenty of time for questions. Having heard that China was no longer taking our plastics, we all wanted to know if our plastics actually get recycled. The answer? Yes and no. It seems there is still a market for plastics marked No. 1 or No. 2, so those are definitely recycled and sold. As for plastics numbered 3-7, Rethink Waste continues to sort and bale those, keeping them until a market can be found. Periodically there is demand for these other plastics, and they get shipped off to willing recyclers. Only if there is insufficient demand for a long enough period of time are the bales deposited in our landfill. But continue to recycle all of your numbered plastics (except for black plastic — Rethink Waste doesn’t take that). While they might go into the landfill, there is a real chance they’ll actually get recycled.

As for other materials, glass goes to Gallo Glass in Modesto, and turned into wine bottles. Metals are sent to Sims Metal, in Redwood City. And most of our paper and cardboard continues to go to southeast Asia, although, some does get recycled within the United States.

Prior to the tour, I thought I was clear about what can and cannot be recycled. However, I learned a lot about some edge cases. For instance, Rethink Waste really only wants “grocery store” glass: bottles and jars. No mirrors, window panes or light bulbs. Also, mixed-material packaging — such as juice boxes, which are made of paper, foil and other materials — cannot be recycled; the machinery cannot separate the component parts. Finally, plastic items smaller than 2 inches in width, such as utensils, straws and small plastic bottle caps, shouldn’t be recycled; they turn into microplastics when melted. Unsure? Check out whatbin.com, and learn that, for instance, padded envelopes go into the trash. Correctly following the guidelines is key to keeping costs down while also minimizing the dangerous greenhouse gases generated by our landfills.

All in all, it was a great tour; I highly recommend it. In-person public tours are held only on the first Thursday of the month, at 9:30 a.m. Rethink Waste also presents virtual public tours, also on the first Thursday, at 5 p.m. Do register in advance. Numbers are limited, and walk-ins are not allowed.

Greg Wilson is the creator of Walking Redwood City, a blog inspired by his walks throughout Redwood City and adjacent communities. He can be reached at greg@walkingRedwoodCity.com. Follow Greg on Twitter @walkingRWC.