Restaurants and households dropping a little too much fat down the drain. http://www.theguardian.com/uk-news/2015/apr/21/huge-10-ton-fatberg-removed-chelsea-sewer-london
there's a fast food themed resteraunt in the town where i live, that goes by the name of "fatburger". each meat patty has just as much texpro as any other fast food burger, but they're each a minimum of quarter pound, and they come two or even three to the bun. yes you can get three patties and all the bacon you want on them too. and there's an over 21 room where you can wash them down with beer. slightly not exactly the same subject i know. every eatery i've worked at had a sperate tank to collect fat in. supposedly hog farmers bought the stuff, and i know now a days, thanks to someone i've never met who shares my last name, you can make diesel fuel out of it too. well london. i mean, its been there since roman times, i'm sure fat is the least of what you might find in its sewers.