How to clean a river and keep it that way …

Along the banks of the once-polluted Malden River in Massachusetts, an effort that began more than a decade ago continues thanks to community support and collaboration

MEDFORD, Massachusetts — It was an otherwise normal April day, albeit during these very abnormal times, for workers and residents at the River’s Edge office complex and residential community.

Long ago it was a dumping ground and industrial wasteland. Today a pristine stretch of the Malden River and well-maintained riverbank fronts the development. And a sprawling…