Drive past a farm where City of Muscatine, Iowa, staffers are applying
biosolids and you probably wouldn't know what you were watching.
You'd never see or smell the material. You'd simply see a tractor crawling across the field, apparently doing tillage work — except that it's autumn, the crop is in the bins, and the tractor is attached to a long hose.
City staff members call it an umbilical (or dragline) system: Anaerobically digested material is piped two miles from the city water pollution control plant to a lagoon, and from there it is delivered, again via
