schmutzdecke
n.— «Periodically the top layer of sand (approximately 25 to 100m deep) needs to be removed from the slow sand filters together with the associated biological accumulation (“schmutzdecke”) for cleaning.» —“Tender—Department Of The Environment For Northern Ireland Water Executive—Central Design Unit” Contract Journal January 27, 1994. (source: Double-Tongued Dictionary)
Further reading
In Southern California, June gloom is the familiar marine layer that rolls in with overcast skies. Jeremy from Long Beach wonders if other places have similarly named weather patterns. Indeed, Southern California also has May gray, no sky July, and...
The phrase potatoes and point involves a family tradition from times of scarcity when eaters would point to an imaginary food and ask for it to be passed when there was clearly no such food to be had. Irish sources trace potatoes and point to the...