Whey, the by-product of dairy manufacturing, is most cheaply disposed of by feeding to pigs. The excess the pigs can't eat is supposed to be safely disposed of, but this is often deemed too costly, and it ends up in the river. A bribe to the right official will be cheaper anyway.
So I started to buy the stuff, for pennies per decalitre. Dairies didn't have to bribe officials anymore, and the river is spared. My refrigerated truck then brought this enormous amount of whey to my nanofiltration pump (setup with the help of a local chemical engineer), where we split it into Whey Protein Isolate, which is the powder bodybuilders drink. I then became a local supplier for the (at the time) only South American company that produced and marketed protein powders in Brazil, sold my share of the business, and came home a slightly wealthier man.
Every stage of this was a nightmare. The uses of whey have been well documented in the literature since the 1920's, and the equipment is cheap. In engineering terms, it's a completely solved problem. But the bureaucracy....