Los Angeles: County Sanitation Districts, 1949. Hardcover. 159p., superior presswork on excellent paperstock in titled pressboard covers with a cloth spine: a presentation designed to impress. Features twenty fullpage b&w photos of various sludge treatment plants (speading grounds, trickling-filter types) in Whittier, Azusa, Covina, Tri-Cities and other locales, plus huge folded charts and maps and an aerial photo of Rio Hondo Coastal Basin spreading grounds. The hard covers are a bit bumped at one corner, a carbon copy of a relevant letter laid in is quite edgeworn, in general item is in very good condition.