Cambridge’s composting push is laudable but flawed

As residents of one of the 10 communities in the Commonwealth with curbside compost pickup, we read “Something’s rotten in Cambridge, and it’s all good” (Page A1, Aug. 27) with great interest and not a little frustration.

Although the article’s accompanying photo shows a container labeled “compost,” what Cambridge is doing with its waste is not composting but rather anaerobic digestion. The city’s effort to find alternatives to landfilling is laudable, but as the article points out, its solution of the moment produces toxin-laced fertilizers and repurposes food waste into a one-time source of fuel for electricity.

According to the state Department of Environmental Protection, only 20 percent of the solids produced by anaerobic digestion is used for fertilizers, while 60 percent is incinerated and 20 percent ends up being landfilled. It might pass muster to apply these substances to a field once, but repeated applications put soil and human health at risk.


In contrast, the real composting that Salem, Manchester-by-the-Sea, and other towns practice is processed locally (avoiding the steep costs of shipping waste out of area), and it enriches soil continuously for years, with a much-diminished likelihood of toxic contamination. Our contractor, Black Earth Compost, transforms local food waste into high-nutrient compost that reduces contamination by herbicides, pesticides, and insecticides by shunning grass clippings.

We would all be better served if the majority of our food waste was composted by regional service providers, electricity was produced by more efficient means such as solar and wind power, and the state agency stepped up its enforcement efforts so that the Commonwealth could meet its food diversion targets.

Shelley Alpern

Board member

Salem Alliance for the Environment