Josefa Marin went to New York from Mexico in 1987, supporting her daughter back home with the $140 a week she earned at a sweater factory. With that small income, she had to collect recyclables, trading in cans for five cents each.

When the clothing factory closed down in the late 2000s, she became a full-time recycler, picking up cans and bottles to make ends meet.

Marin’s story is not unique. Millions around the world make a living from picking through waste and reselling it — a vital role that keeps waste manageable. In New York City, the administrative department collects only about 28 percent of the cans that could be recycled. Rubbish collectors, however, keep millions of additional recyclables out of landfills every year.

Yet collectors are ruled out by government policies. The United States Supreme Court in 1988 stated that household garbage is public property once it’s on the street. That enables police to search rubbish for evidence, but that protection hasn’t always been extended to recyclers. And in places like New York City, which is testing city-owned locked containers to hide garbage from rats, containers are made clearly inaccessible for collectors.

“There’s value in the waste, and we feel that value should belong to the people, not the city or the corporations”, says Ryan Castalia, director of a nonprofit recycling and community center in Brooklyn.

Recognized or not, waste pickers have long been treated with disrespect. Marin recalls an occasion when someone living next to a building where she was collecting cans threw water at her. “Because I recycle doesn’t mean I am less of a person than anyone else,” she says. It’s a pity to see that the government doesn’t stand by the garbage collector’s side, either.

Fortunately, some governments are starting to realize that protecting the environment and humanity go hand in hand. Brazil classified waste picking as an official occupation in 2001. In 2009, Colombia’s government granted the right to collect valuable garbage. The U.S. is slowly catching on too. After all, to the government, the garbage is garbage, but to the collectors, it’s something they make a living on.

Eating insects is one of those ideas that never quite seem to catch on. The United Nations spread the idea a decade ago, but, in the West at least, insects remain mostly absent from supermarket shelves. Faced with an unsatisfied public, scientists have been exploring other options. One is to feed the insects instead to farm animals, which are not so picky.

Of course, the insects need to eat, too. To date, they have mostly reared (饲养) on leftover chicken feed. But the supply of that is limited, and if insect-reared meat is to take off, new sources will be needed. Niels Eriksen, a biochemist at Aalborg University, suggests feeding them on the waste products of the beer industry.

The world knocks back around 185bn litres of beer every year. Each litre produces between three and ten litres of wastewater full of thrown-away grains. The mix is rich in protein but lacking in carbohydrates (碳水化合物), especially compared with chicken feed.

Most insects grown for feed depend, in the wild, on the carbohydrates found in bad fruit. Whether insects would actually consider beer waste a square meal was, therefore, unclear.

The researchers used the baby insects of the black soldier fly. The young insects were divided into three groups, which were offered beer waste, chicken feed or a mixture of both. The researchers monitored both their weight gain and the amount of CO, they produced. They found the baby insects happily consumed both beer waste and chicken feed, and grew equally well on either food source. Dr Eriksen found few differences in how nutritious the insects would be to farm animals.

The experiment may have implications beyond the beer business, too. Bone meal from farms, and waste from other food industries are all likewise plentiful and protein-rich.

All now look to be reasonable targets for nutrient recycling by insects. Whether consumers will be willing to eat insect-reared beef, though, remains to be seen.